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PML Complete FAQ - Public Missiles Ltd

1. Glassing Kit is 4 parts white to 1 part clear e When you see lightly sand fillets in our instructions it means don t sand with too much pressure High pressure will generate heat and gum up the epoxy while sanding e Most brands of epoxy adhesive bond well with no adverse affect to Quantum Tubing The bonding area must be sanded prior to applying epoxy Follow the suggestions in Do s and Don ts in the Airframe FAQ Quantum Tubing section e Scuff all areas where epoxy will be with 120 grit sandpaper This includes motor mounts fins INSIDE the airframe etc Use 220 or 320 on surfaces that will be painted 02 24 07 2 74 PMLCompleteFAQ doc Fiberglass Nosecones If using epoxy in a fiberglass cone to retain nose weight do just a little at a time allowing the epoxy to cool between batches This will prevent the resin used in manufacture of the cone from breaking down due to the heat of the setting epoxy When you put a lot of quick set epoxy into the tip of the cone the heat generated during curing can exceed 200 degrees F The resin the cone is made of begins to deteriorate at 170 degrees Better yet use a slow setting 24 hour epoxy or our Two Part Expanding Foam sold on the Adhesives page of the webstore PML Two Part Expanding Foam This foam is great for fin encapsulation securing noseweight etc It s especially handy for those tight situations where you just can t get into the airframe to get nice interna
2. Thicker fins 0 063 should go to 0 093 0 093 should go to 0 125 Fin to airframe joints should be glassed 02 24 07 10 74 PMLCompleteFAQ doc 30 minute epoxy should be used throughout the build Also we say so in all the instructions but make sure you lightly sand any area to be bonded This is important to get a good bite on the materials for the epoxy and is especially important in high stress applications Something else to remember about strengthening your kits you probably should upgrade one chute size to compensate for the weight of the glassing as well A larger chute should also be considered due to the extra weight of many of the longer motor casings that will generate flight conditions where reinforcement may be required Nimbus Glassing Kit When you purchase the Nimbus Fiberglassing Kit the glass wrap kit supercedes replaces the glass patches for the fins in the base Nimbus kit Follow the fiberglassing kit instructions rather than applying the glass fin patches as discussed in the Nimbus instructions The cloth in the Nimbus Fiberglassing Kit is 10 oz and the mixing ratio of the two part epoxy is 4 parts white to 1 part clear 02 24 07 11 74 PMLCompleteFAQ doc PML CENTERING RINGS and BULKPLATES FAQ Centering rings Thickest and strongest in the industry Precision made guaranteed good fit Birch plywood 3 16 thick up to and including 3 9 diameter larger are 1 2 thick
3. appear cold but they likely are not Remember these are plated feed thru holes 02 24 07 25 74 PMLCompleteFAQ doc 02 24 07 so the surface pad condition in no way visually indicates the integrity of the joint Q I recently bought a Co Pilot and powered it up for the first time today and seem to have a problem It does not detect continuity on either the drogue or main outputs when in input test mode it sees all five switches but not the main or drogue but when in the output test mode it works properly and fires both outputs when first turned on with a e match in both outputs the unit does not beep indicating no continuity Am I doing something wrong or do I have a problem with my copilot A Your battery voltage is too low The continuity circuit bias voltage is unable to operate the circuit on a weak 9V battery approximately 8V give or take Your Co Pilot is working exactly as designed it s trying to tell you something by not going into certain operational modes properly You need to read and follow the instructions about testing the battery even if it s a brand new battery right out of the box You MUST test your battery every single time you re going to use the Co Pilot Very cheap insurance considering a 2 50 battery can make the difference between getting your multiple hundreds of dollars of rocket and hardware back Q Reading through the manual I was trying to find some sort of rule of thumb for using the Mach Delay
4. but there s more to it than just igniting the sustainer stage and immediately ejecting the booster recovery system The booster itself will coast fairly well on it s own after separation so you need to figure that out too A good way to approximate what delay time you should use for the booster is to calculate the coast time to apogee for the entire rocket as though there were no upper stage motor Basically use the entire two stage rocket in your sim but install only a booster motor and no sustainer motor run your simulation and look for when the rocket reaches apogee That time is a pretty good estimate of what delay to select for the booster motor because 02 24 07 73 74 PMLCompleteFAQ doc the booster itself will coast about that long after separation Let s do a hypothetical example let s say you re going to use an 1284W as your booster motor Load your simulation with an 284 in the booster and no motor in the sustainer stage Run the sim and see when it says the rocket will reach apogee Let s say it s about 10 seconds So you ll want to use about a 10 second delay in your booster motor for your real two stage flight since the booster will tend to coast about that long If you use anything too terribly much shorter than that you run the risk of stripping the chute off the booster section It doesn t seem to make sense that the booster would coast that long without a nice aerodynamic nosecone on it but it will Two stage rockets ar
5. 0 375 and 0 5 e For fiberglassed tubes only 0 093 slot widths are available with a maximum of 8 slot length e For fiberglassed tubes with slot widths from 0 125 0 5 the maximum slot length is 26 Custom Tube Cutting e Tube cutting 0 050 for 3 9 and smaller e Tube cutting 0 125 for 6 0 and 7 5 e Tube cutting 0 25 for 11 4 Kit Strengthening Any of our kits that are 2 56 or greater that will reach equal or greater than 0 85 Mach need to be strengthened Here are the calculations so you know the raw numbers Mach STP Standard Temperature amp Pressure 1116 ft s fps 760 9 mph 1116 fps x 0 85 948 6 fps 760 9 mph x 0 85 646 7 mph Therefore PML kits 2 56 and larger should be reinforced for gt 950 fps or gt 650 mph flight We feel that kits 2 1 and smaller can be flown without body tube fiberglassing though all other items listed below should be done as well as building the rocket with plenty of epoxy and good sanding of areas to be bonded As mentioned in the chart itself the Motor Recommendations Chart is highlighted for kit motor combinations that require strengthening We recommend the following changes for any yellow highlight kit and motor combination Fully glassed airframe which requires phenolic as a starting point not QT You must special order your kit with phenolic as all kits 3 9 and under except Nimbus come standard with QT e
6. 74 PMLCompleteFAQ doc applications as well such as scratch built deployment systems The Co Pilot is based upon Missile Works RRC altimeter The Co Pilot provides two stage barometrically controlled pressure sensing deployment of rocket recovery systems and equipment Note Regarding CPR3000 and Altimeter Manufacturers Some customers have asked why we chose to select the PML Co Pilot and Transolve P6 as the standard altimeters that fit CPR3000 and the Transolve P4 or P5 Adept ALTS 25 and BlackSky ALTACC altimeters with our optional additional cost adapters First we believe very strongly in supporting our customers PML has sold hundreds of CPR2000 kits that use the Transolve P4 or P5 or Adept ALTS 25 altimeter and many of those altimeters to go with the kits as well We want our current customers to have complete compatibility immediately It makes sense for us and for them to use an altimeter they re already familiar with and is interchangeable between their current CPR2000 rockets and any CPR3000 systems they may choose to buy Second the better question might be How come the altimeter manufacturers don t make theirs fit CPR We re the only company that offers a standardized ready out of the box dual deployment system and we have over a thousand of these systems in the hands of rocketeers so it would make sense for the altimeter manufacturer to make their product fit the rocketry system that s most likely to use their
7. Our 2 rings are made of 9 ply birch Any hole pattern can be produced See Custom Centering Rings in this FAQ ID OD tolerances for all centering rings and bulk plates is 0 010 Custom Centering Rings Need ring thickness OD number amp ID of holes amp hole pattern layout 1 8 spacing minimum No custom centering rings in 3 9 or smaller diameters will be made of 2 ply If you feel you must have a thicker CR in 3 9 or smaller order 2 3 16 rings and epoxy them together Custom centering rings are only made to fit PML tubing sizes Custom Cluster Centering Rings PML now offers a line of standard Cluster Centering Rings CLCR for 3 0 and 3 9 diameter Rockets Cluster Centering Rings for 6 0 7 5 and 11 4 are also available on a special order basis Since there are literally hundreds of cluster combinations possible in these sizes we cannot stock or even list all of the combinations Turn around time on the special order rings is usually 2 days Use the Custom Centering Ring Form on the Custom Work or Centering Rings pages of our website when ordering the large cluster rings On the 6 0 and 7 5 rings the cluster holes are bored on a 4 diameter circle around the center hole On the 11 4 ring the cluster holes are bored on a 7 75 diameter circle around the center hole Bulkplates A Bulkplate is simply a centering ring with no hole s in it Same specifications and requirements as
8. Piston systems require less black powder BP than non piston systems This is very important as most recovery system damage we see to our kits can be traced back to too much BP and a too strong ejection charge The following shows how much BP to use with our piston systems for a piston travel of under 30 inches e 1 5 2 0 diameter 0 3 0 5g BP e 2 5 3 0 dia 0 6 0 8g BP e 4 0 dia 0 8 1 2g BP 02 24 07 62 74 PMLCompleteFAQ doc e 6 0 dia 1 4 1 7g BP e 7 5 dia 1 7 2 0g BP The measuring cup provided in our LES Kit measures out gram If you don t have the measuring cup from the LES kit the cup provided in the kit measures out about 4 teaspoon of 4f FFFFg black powder We also offer the cup separately CPR 1GM on our CPR Systems page The following will give you an idea of how much ejection charge BP is commonly supplied with various size motors e G 0 7g e H 1 4g e I 2 0g e J K 2 1g The values below are intended as a guide for determining the proper amount of ejection powder used with various diameter CPR MAX rockets using a piston ejection system and a 24 fore or aft recovery airframe 6 0 dia 1 0 to 1 3 grams 7 5 dia 1 2 to 1 5 grams Using too much BP for the ejection charge causes damage like that described by this customer in an email to us I discovered damage to the piston tube on the piston ejection assembly About a 1 inch square portion on the end opposite the b
9. Timing We nearly always ship within 24 48 hours after receipt of your order Custom work is usually shipped within 48 72 hours of your order Fiberglass nosecone and tube wrapping orders usually ship within a week Parts damaged in shipping will be replaced quickly Return Policy If you don t like it send it back Remember mistakes may happen but we will do whatever it takes to make the situation right with you We are absolutely committed to your satisfaction Always have been always will e There are no returns on custom items unless we made a mistake Custom items are by definition unique specialized parts and they cannot necessarily be resold to another customer e The PML website always has the latest Warranty information on the Warranty Policy page and Shipping information on the first page after clicking the Webstore button Check there for questions on these items or for the latest information PML Email Newsletter Public Missiles Ltd has an email distribution list for distributing information about new kits new products and new information direct to the rocketry community People on this list will be the first to know about new products sales and other information of interest There s no cost to you and the list will only be used by PML to notify you of developments at PML Your email address or other information will not be distributed by PML to other companies or organizations How do you sign u
10. What s a Good Starter Kit for Higher Power As far as getting started into high power take a look at our 29mm motor AMRAAM 2 Callisto Io or Tiny Pterodactyl which fly on F and G motors F and G being the next step to the lower edge of high power Or try the 38mm X Calibur or Small Endeavour or the 38mm Callisto or Io with our ADPTR 38 29 optional motor adapter That way you can fly it on 29mm F and G motors then move to 38mm H and I when you re ready You might also like the Bullpuppy The military styling is cool and it too can be flown on some 29mm motors with a ADPTR 38 29 installed but is built with a 38mm mount so you can fly H and I on it when you re ready Or you can fly our Bullpuppy 2 1 on 29 s 02 24 07 34 74 PMLCompleteFAQ doc Callisto Io Phobos Ariel they re all popular kits and would be good starters The best bet is to take a look at the Motor Recommendations Chart click on Specs Page on our website at the kits that will fly on Gs and maybe some F s and small H motors and then look at which one of those you might like The KitSpecs Chart also on the Specs Page of the website lists all the detailed information about all PML kits What PML Kit Should I Get for my Level 1 Flight I know it keeps coming up in this section of the FAQ but the best is to take a look at the Motor Recommendations Chart on the Specs Page section of our website See the kits there that will perform to a level that d be
11. above Custom Bulk Plates Need OD amp thickness Specify holes no holes in center for eyebolt no charge for eyebolt hole Maximum hole size in 6 0 bulkplate is 4 5 Maximum hole size in 7 5 or larger bulkplate is 6 diameter Bulkplates are only made to fit PML tubing sizes 02 24 07 12 74 PMLCompleteFAQ doc PML CLOSE PROXIMITY RECOVERY CPR FAQ CPR Close Proximity Recovery PML exclusive system which deploys a small drogue chute at apogee to allow the rocket to descend quickly but stable with the main chute s deploying at a user selectable altitude AGL above ground level IMPORTANT NOTE TO HELP PREVENT BLOWBY DAMAGE Through testing we ve determined that customer complaints of black powder blowby is attributable in nearly every case to improper incomplete prep of the charge cylinders In all CPR prep instructions there is a step usually Step C that states Push a small wad of tissue into the hole using a pointed object This will seal the hole and keep the black powder from leaking out In our tests we ve determined that not performing this step completely is the 1 cause of BP blowby The wad of tissue referenced must be packed tight and must fill the hole completely Please take additional care in the future to check and recheck yourself on this important step If our prep instructions are followed carefully and completely there is very little chance of any significant blowby CP
12. are not significant enough for us to rework all the files for 5 0 or higher Also the files we have provided for 4 0 still work with 5 0 or higher though the reverse isn t true 5 0 or higher use a different file format that will not open with 4 0 Real life flying conditions will cause variations greater than the difference between the two versions For example motor thrust variation of up to 15 is allowed by both the NAR and Tripoli motor testing organizations for a motor of a certain classification and the difference between the 4 0 and 5 0 or higher simulations isn t nearly 15 The difference between simulations could very easily be washed away by real world conditions It s simply not worth the time involved to do it because the real world is going to be different from the simulation anyway Version 4 0 or 5 0 or 6 0 or whatever point oh the data will just be a guide for you to go by not absolute data that you should expect to match with your flight 02 24 07 67 74 PMLCompleteFAQ doc Quantum Tubing and RockSim Many people ask about why Quantum Tubing is not in the PML RockSim database here s the answer The manufacturer says the QT density is 1 05 g cc However when you add QT to the materials database using that figure and construct tubes from it basically just pull up one of our phenolic tubes change to custom then change the material you ll find that the weights in RockSim don t match our measured wei
13. as can sometimes occur to cardboard or phenolic tube You will find this new material easy to work with and very forgiving even during those less than perfect flights All components that fit PML phenolic tubing fit QT also e The Quantum Tube QT has been tested and found compatible with the following paints lacquer enamel epoxy and urethane as well as many different primers As with any paint apply several light coats allowing each to flash before re coating e Most brands of epoxy adhesive bond well with no adverse affect to the tubing The bonding area must be sanded prior to applying epoxy Follow the suggestions in Do s and Don ts below e The Quantum Tubes are molded in medium gray and have a glass smooth finish with NO SPIRAL GROOVE You no longer have to fill and sand the airframes to achieve the perfect finish e All QT part numbers will be prefaced with the letters QT such as QT 2 15 e The Quantum Tubes are resistant to the heat of ejection charges As with any tube repeated ejections will leave a black gritty residue inside the tube To remove the residue simply wipe the tube interior with a wet cloth wrapped around a dowel or broom stick and allow to dry e QT can be cut easily by hand with a hacksaw and cuts nicely with a power miter box or bandsaw as well e QT does not fiberglass well for body tube strengthening We DO NOT recommend QT for 0 85 Mach kit strengthening as mentioned elsewhere in t
14. d plan on using yet can achieve an altitude that you like when flown on an L1 motor Then when you ve narrowed down which ones will fit the flying specs you ll need to meet you can decide which one has the looks or other features you like Some kits that quickly come to mind are AMRAAM 4 Tethys Endeavour and Miranda However there are many PML kits that can fill the bill for L1 and L2 depending on your situation Contacting PML and Information Resources e All telephone contacts except fax 24hrs 7days are 9am 5pm EST Monday through Friday Telephone 810 327 1710 or fax at 810 327 1712 For orders only no technical or order status questions please 1 888 PUBLICM e Online at our web site www publicmissiles com All pricing information quoted in FAQs is subject to change Always see the website for the latest prices Our entire retail price list is available on the entry page to the Webstore section of the site and the prices for individual items are listed next to the item in the webstore 02 24 07 35 74 PMLCompleteFAQ doc e Our catalog is FREE and can be ordered at the above phone numbers or on the Hardware page of our website However the website is always the freshest source of information as the paper catalog can t be updated after it s printed whereas the website is updated regularly e See the Contacting PML page of the website for how to direct your question to PML via email Services Returns
15. due to the chute trying to dump air See the Recovery page of the webstore for approximate spill hole sizes they vary slightly from chute to chute within a size e Ifa rocket experiences rotation or swinging under a PML spill hole chute this is because the shroud lines are not completely equal lengths to the tie off point e Our 18 chute has a relatively large spill hole as it is intended for drogue applications This chute is not a good choice as a replacement for a plastic 18 chute from other manufacturers due to the large spill hole Sizing e Chutes come in the following sizes 18 24 30 36 48 54 60 72 84 96 and 120 We also offer a drogue X form chute and a 4 x144 streamer you can cut to length e Our diameter ratings for our chutes are measured as follows From shroud line attach point along panel seam across spill hole down opposing panel seam to shroud line attach point e Parachute Sizing Upgrades PML chutes are sized for Midwestern and Eastern flying as opposed to the open areas and hard landing surfaces of many Western sites We size our chutes for minimal drift for smaller landing sites while still allowing a safe descent rate into the grassy areas prevalent in the Midwest and East However if you re flying in Western areas where drift is not as much a concern and where landing areas are harder such as desert playa or if you re flying from high elevation launch sites with lower density air we can ups
16. flakeoff e Double shock cord chute eyelets which make them much stronger You may need to clear out flashing from manufacturing in the nosecone eyelets to pull the shock cord through use an X Acto knife If you must open up the eyelet to allow the shock cord to pass through easier do it toward the body of the nosecone not toward the edges of the eyelet that will weaken the eyelet An easy way to pull through a shock cord strap is to put one corner through the eyelet and pull the strap through using pliers e Ridges on shoulder that can be easily sanded to achieve perfect fit shoulder also provides better sealing like piston rings in an engine e Polyethylene is notorious for being difficult for adhesives to adhere to First of all wash the OD in very hot soapy water and the ID for plastic boattails and rinse This will help remove any mold release compound from manufacturing Secondly sand all surfaces to be bonded with 120 grit sandpaper sand exceptionally vigorously inside 02 24 07 57 74 PMLCompleteFAQ doc boattails made of our plastic nosecones since appearance doesn t matter here getting a good bite on the epoxy does Our Two Part Expanding Foam sold on the Adhesives page of the webstore is perfect for this application Urethane automotive topcoats over paint can increase resistance to paint chipping e Fill imperfections in plastic nose cones with Squadron Green or White putty automotive spot putty etc e Neither
17. good for the flying field you have available basically look at the predicted altitude on say H128 29mm or H123 and H242T 38mm motors both popular Level One cert motors then take a look at the webstore for what the kits look like and find one that strikes your fancy Some quick ones that come to mind are the Io Callisto Phobos Quasar Explorer Black Brant VB Ariel Miranda D Region Tomahawk Tethys Small Endeavour and X Calibur It really depends on the type of performance you want out of the rocket both for your L1 cert flight under 2000 altitude and simple are our recommendations there and for fun flying after you ve achieved your L1 Some people who fly in the Midwest have smaller fields where altitudes and trees surrounding the field are a limiting factor and like to need to keep the altitudes down whereas people out West often have miles of uncluttered desert to fly on So it all depends I Want to Get a PML Kit That Be Good for Level 1 AND Level 2 Really there are a number of PML kits that would work well for L1 and L2 but a lot of the decision depends on 1 What you like as far as looks and features and 2 The altitude waiver of the club you ll fly with at their field Take a look at the Motor Recommendations Chart on our Specs Page It will tell you how each kit will perform on various motors Obviously you ll want to pick one that ll stay under the waiver for your field when you fly it on the L2 motor you
18. it to fit CPR systems The Co Pilot provides two stage barometrically controlled pressure sensing deployment of rocket recovery systems and equipment PML also carries the AccuFire Timer made exclusively for PML by G Wiz Partners The AccuFire is an adjustable 0 25 sec post motor burnout timer Like the G Wiz LC LC Deluxe and MC AccuFire uses a progressive launch detect algorithm The timer must see either 2g for 0 5 seconds or 4g for 0 25 seconds or 8g for 0 125 seconds to determine that launch has occurred and begin monitoring for motor burnout Accelerometer based detection of motor burnout occurs upon detection of deceleration negative g s after launch detection the timing to the firing event begins at motor burnout The AccuFire uses a standard 9VDC battery as a power source and provides an output current to the pyro channel of up to 1 25A Also the AccuFire is NOT affected by hybrid motor harmonics it s completely safe to use with hybrids IMPORTANT CUSTOMER ALERT For the AccuFire to function as a 2nd stage ignition device you MUST use 1 BlackSky HiRMI Standard electric match preferably dipped in pyrogen or 2 DaveyFire N28F preferably dipped in pyrogen For the AccuFire to function as an ejection charge initiator the following electric matches could also be used 3 1 or 2 above without the pyrogen dip 4 BlackSky HiRMI Sensitive 5 DaveyFire N28B or 6 Oxral Other ignition devices WILL N
19. n Lightning Since the threaded inserts for the KS compatible retainers require a 3 16 hole drilled in the aft centering ring no retainer is available for a 2 5 diameter rocket using a 54mm motor mount The PMR retainers cannot be used with boattailed or minimum diameter rockets with the exception of our Bulldog kit which has enough exposed centering ring area at the boattail For ideas on other motor retention options for kits which cannot use a PMR system go to Rocketry Online at www rocketryonline com click on InfoCentral then on Construction then on Motor Retention PMR motor retainers should NOT be used on Loki motors The retainer will very slightly block the exit of the motor causing overheating of the retainer and or motor casing and potential failure of the retainer motor casing or both For retainers to use with Loki motors goto http www lokiresearch com retainer asp Extra PMR inserts are available separately so you can equip all your rockets for the motor retention system without having to buy a complete retainer system for every rocket We recommend installing the PMR after the rocket is built This gives the best support for the ID of the centering ring when drilling for the inserts The PMR 54 will work with many hybrid motors it does not work with a Hypertek J grain the hole ID on the PMR is about 1 8 too small The PMR system will work with Cesaroni Pro38 motors The PMR 29 38KS and PMR S54 use 8 32 screws The PMR
20. of body fin size number of fins and fin placement on the body tube CP can t be changed in kits However you CAN vary CG by adding more nose weight That s why the kit manufacturers specify CP so the owner of the rocket can find their CG and compare it against the CP to see if they need to add some nose weight to move the CG ahead of the CP for stability The CG will be dependent upon how you build and use the rocket which is why manufacturers usually don t specify CG Some people really use a bunch of epoxy others don t It s variable enough on how the person builds the rocket but even more so as what type of payload you have if any You can imagine that given the same kit design if someone were carrying some complex and heavy video electronics that the CG would be dramatically different from someone who flies no payload at all Once a kit is built and ready to fly with payload CG location is most dependent on the motors used Of course a G motor is much lighter than an I motor but a certain kit may be able to use G s H s and I s The motor is obviously in the back of the rocket and weight in the back of the rocket shifts the CG rearward so the bigger heavier the motor the worse the CG CP relationship will be Remember CP doesn t change any weight added to the rear of the rocket will move the CG back bad and weight added to the front of the rocket will move the CG forward good 02 24 07 38 74 PMLCompleteF
21. output IMPORTANT CUSTOMER ALERT For the AccuFire to function as a 2nd stage ignition device you MUST use 1 BlackSky HiRMI Standard electric match preferably dipped in pyrogen or 2 DaveyFire N28F preferably dipped in pyrogen For the AccuFire to function as an ejection charge initiator the following electric matches could also be used 3 1 or 2 above without the pyrogen dip 4 BlackSky HiRMI Sensitive 5 DaveyFire N28B or 6 Oxral Other ignition devices WILL NOT FUNCTION PROPERLY with the AccuFire Battery Testing is CRITICAL One thing that is CRITICAL that many customers do not do is to test their battery before EVERY FLIGHT Onboard electronics systems are very sensitive to appropriate voltage and current conditions a just slightly weak battery can cause the electronics to fail Given that you re flying hundreds of dollars of rocket electronics motor casing and motor reload taking time to test your 1 89 battery makes sense not only from a cost perspective but from a safety perspective as well It always amazes me how someone can walk out to a launch pad carrying 500 of rocket motor and electronics but wants to save money on batteries or igniters ematches on board The short story is make SURE you test your battery as noted in the manufacturer s instructions Test a NEW battery when you get it as well it doesn t happen often but sometimes a battery is bad right out of the box and test every b
22. product wouldn t it In our opinion it would make sense for the altimeter manufacturers to base their designs around fitting CPR and the scratchbuilders not using CPR can design mounting schemes for their altimeters as they always have We re in the rocket business not the altimeter business so we leave the altimeter issues to those that make them Third as you know there are many different sizes and shapes of altimeters available and it simply wouldn t be cost effective for us to produce all the altimeter mounts to fit each and every altimeter someone might like to use since we d sell very few of any particular adapter not enough to offset the tooling cost of the adapter It makes much more sense for the altimeter manufacturers to either a offer a version of their product ready made to fit CPR systems or b make altimeter mounts to fit CPR and sell them to promote use of their altimeters It s in their best interests to do either a or b to sell more of their altimeters and to support their customer base as we are with making CPR3000 compatible with what our customers already own Our CPR3000 altimeter bay is already designed in anticipation of altimeter manufacturers picking up the ball by designing it long enough and wide enough to accommodate any altimeter on the market at the time of it s introduction BlackSky has done so by making an adapter available for their ALTACC line of altimeters which we now sell as well So to summa
23. rocket for CPR See the CPR Systems page in our 02 24 07 13 74 PMLCompleteFAQ doc webstore for details including a graphic showing what modifications are required to use CPR with many of our kits What is CPR3000 The most complete Close Proximity Recovery System ever No need to purchase separate ejection systems external safety switch or drogue chute Also includes a 16 page fully illustrated comprehensive assembly and user manual These systems are perfect for retro fitting into your existing rockets or for incorporating into your new designs Here s what you get Complete altimeter bay assembly Complete Threaded Airframe Coupler assembly made from 6061 aluminum with a blue anodized finish All mounting hardware for the PML Co Pilot or Transolve P6 altimeter Mounts for Transolve P4 P5 Adept ALTS 25 and BlackSky ALTACC altimeters sold separately Two complete ejection systems including charge canisters and holders Designed for E matches Charge cylinders for flash bulbs sold separately One set of fore and aft altimeter O rings provided whether a CPR based full rocket kit or a CPR Retrofit kit for scratchbuild use Dual piston systems Drogue chute or streamer with tubular nylon shock cord External safety switch and lead wires 16 page fully illustrated comprehensive assembly and user manual See the CPR Systems page in our webstore for graphics and details IMPORTANT NOTE ON ALTIMETER FIT IN ALTIMET
24. software All these simulations are run on bone stock kits so if you add nose weight or make other modifications you will need to adjust accordingly Be sure to read the information on the first page of the chart thoroughly It explains the chart in detail as well as giving you helpful tips on kits motors and delays Keep in mind that these predictions were made with the flight day set as no wind no launch rod angle and with the launch site at 500 above sea level 70 F and 75 humidity Days with absolutely no wind are quite rare so be sure to compensate for flight conditions on the day you actually fly For example if it is a windy day and you ve added some launch rod angle the rocket s altitude will be lower and you may also need a slightly shorter delay Conversely if you re flying in a high altitude area Denver for example the air is thinner and therefore produces slightly less drag on the rocket In that case you may want to choose a slightly longer delay The essential thing to remember is that these are just simulations Launch conditions such as wind temperature and variations in motor impulse due to manufacturing variations in the motor can and WILL cause differences in actual flights PML recommendations for motors delays and altitude predictions are to be used only as a guideline to provide you a starting point for making 02 24 07 70 74 PMLCompleteFAQ doc your decision as to what motor and
25. the clear coat Don t let this deter you from using the clear coat it really is a benefit to use it Just go easy Usually 2 coats are sufficient though some people use three e Also be sure to always test clear coating metallic paints Often clear coats will dull the metallic look you are trying to achieve From the Ask Krylon feature of Krylon s website The only product you want to top coat the metallics with is the Krylon Living Color Latex Enamel Paint It will darken the paint a few shades but it will keep the metallic look If you use any of our lacquer clears the metallic look will be completely stripped out 02 24 07 33 74 PMLCompleteFAQ doc PML GENERAL INFO FAQ Getting Started In Higher Power Rocketry If you re completely new to rocketry as a hobby the National Association of Rocketry www nar org specializes in the beginning hobby rocketeer and the rockets best for getting started We d recommend a visit to the NAR site to start off One of the other great places to surf around whether you re new to rocketry or have flown lots of model rockets and are ready for something bigger is www rocketryonline com This site has all kinds of information and links about hobby rocketry including higher power However you re here to see what PML has to offer so below are some of the typical questions and answers for people just getting into high power rocketry What Do I Need to Get Starte
26. where the motor tube is wedged into the narrow end of the boattail without the use of a centering ring IE Bull Puppy Pit Bull 256 It will not work with the Bull Dog or Pit Bull 600 since these have a centering ring at the base See note 1 above for details 4 JB Weld Loctite Weld or similar must be used to secure the sleeve to the motor tube These epoxies have a high temp rating are not brittle and bond very well with phenolic and aluminum Common hobby epoxy may soften from the heat of the motor and fail Do NOT use standard hobby epoxy or even the epoxy PML sells for general kit construction The high temperatures generated by the motor can cause these epoxies to fail The motor retainer sleeve should be inspected after every flight to make sure the impact from landing did not loosen the retainer sleeve 5 For the KS washers to work with older KS kits already in the field both adapter tubes must be cut 1 8 to 3 16 by the user In the past we made the adapter tubes a bit long to aid in insertion and removal of the adapters within the mother tube This is not really necessary and now the adapter tubes are too long to work with the HAMR KS adapters The tubes can be easily cut by the user with a hack saw Dremel miter saw X Acto saw etc whether they are assembled or not Beginning in mid February 2007 we have changed the length of the KS adapter tubes to accommodate the use of these retainers This includes all KS kits that were i
27. 29 38 uses 4 40 02 24 07 43 74 PMLCompleteFAQ doc Other Motor Retention Solutions See the Motor Mounts FAQ for details on other potential positive motor retention solutions for PML kits 02 24 07 44 74 PMLCompleteFAQ doc PML HYBRID READY FAQ Hybrid Ready What makes a kit hybrid ready A long motor tube an electronic deployment system and or compartment and a venting hole The customer must drill the venting hole as motors differ as to where the hole should be located Hybrid Motor Mounts Hybrid motors require very long motor mounts Call us for specific assistance in obtaining a hybrid motor mount for a scratch build project We offer kits that are already designed specifically for hybrid motors see the Hybrid Ready section of the webstore Our 54mm kits can take Hypertek s Standard J and their New Hammerhead J Our 38mm kits are intended for Sky Ripper Hybrids and with the use of a 29mm adapter RATT Works hybrids Some customers ask why the Ion kit has a shorter 28 MMT than our other 38mm kits Simple to keep the price size and weight down for using smaller H and I hybrids and or smaller composite motors PMR Motor Retention System The PMR 54 38 and 29 38 will work with hybrid motors ERM System The Electronic Recovery Module ERM system is based on our CPR3000 system and is designed specifically for hybrid rockets ERM is designed for the PML AccuFire timer or PML Co Pilot alt
28. 4 is 3 5 1 L D ratio We also offer a Harpoon missile style 11 4 fiberglass nosecone e PML does not make custom nose cones e Some customers have asked about conical nose cones in larger than 1 1 29mm or 1 5 38mm diameter A suggestion would be going to a craft store and buying a Styrofoam cone used in craft projects and fiberglassing over it That might work out for you Or if you know a woodworker with a lathe have them turn you one Some rockets can benefit from some nose weight so the weight of the wood would be good e We cannot tell you with certainty whether our tubing is compatible with that of another manufacturer This also includes whether our couplers nosecones pistons CPR parts etc will fit another manufacturer s tubing With the variation in tubing from one manufacturer to another we simply cannot tell you with certainty if our components will match well with non PML tubing Nosecone Fits and Airframe Tubing After cutting airframe tubing it may be necessary to deburr the edges inside and out using 150 grit or finer sandpaper This is especially true with QT as the cutting process may squeeze the cut end ever so slightly making it tight for inserting a nosecone or for inserting the piston Deburring or chamfering the inside edge of a QT will eliminate those problems Plastic Nosecones PNCs HDPE high density polyethylene e Thicker wall than competitors less flex which reduces paint chipping
29. 5 Charge Holder 4 0 4 0 4 Charge Cylinder Ematches 4 0 4 0 4 Fore Altimeter Mount 2 0 6 0 6 Aft Altimeter Mount 2 0 3 0 3 Switch 6 screws 4 alt 2 sw amp wiring 2 0 2 0 2 O Rings 6 0 05 0 05 CPR2000 e CPR2000 is designed to use the Transolve P4 or P5 altimeter or the Adept ALTS25 We do not currently offer adapters to use electronics from other manufacturers e CPR2000 components are still available on our webstore for customers who may own CPR2000 kits and need replacement parts Differences in Mounts for CPR2000 and CPR3000 The mounts for the CPR3000 for Co Pilot and P5 or P6 are just more robust Basically the areas where the holes are located are thicker If you tried to mount a Co Pilot to a 2000 mount not only would the holes not line up but also there s more room than needed to clear the parts on the altimeter On the other hand if you tried to mount an ALTS2 toa 3000 mount the holes would not line up and there would be interference between the mount and components on the altimeter PML Co Pilot Altimeter for CPR3000 See the Electronics page of our webstore for more details on each device and other devices that may not be covered here PML currently carries the PML Co Pilot altimeter The Co Pilot altimeter was developed exclusively for Public Missiles Ltd by Missile Works Corp and was designed specifically for PML s CPR3000 Recovery System though it can also be used in other 02 24 07 17
30. AQ doc Mark the CP on the rocket then mark a point at least one body diameter ahead of the CP Make sure you prep the rocket as it ll be in flight with the motor you intend to use installed chute s installed payload installed etc before you do the CG CP check No need to add black powder to an altimeter or the delay area of a reload casing or to put in igniters they re not heavy enough to matter Now balance the rocket teeter totter style on a piece of dowel back of a chair something like that If the rocket balances level with the pivot point of the teeter totter arrangement at or forward of the CG point you marked you re good to go If not you ll have to add nose weight until it does Up to two body diameters is usually even better but don t go much over two diameters or the rocket will be overstable By the way this is what s meant by one caliber or two caliber stability It comes from wartime artillery terminology where the diameter of a gun is called the caliber so one caliber one diameter and so on Don t forget that if you use say a small H motor and set the CG that if you then decide to use a big J motor the J weighs more and you may have to add nose weight again to compensate That s why it s usually recommended to set the CG CP relationship with the largest motor you intend to use in the rocket If you don t have the biggest motor you intend to fly on hand or if you haven
31. ER BAY We ve gotten reports of customers sometimes having difficulty getting the altimeter with O rings fitted to slide into the altimeter bay properly We ve tested the fit of the CPR O rings in the altimeter tube using both latest batches and older batches of parts We ve combined them in all combinations In all cases the parts will NOT fit if no baby powder is used With baby powder applied as per the CPR instructions provided with your CPR Based kit or CPR RetroFit Kit all parts fit perfectly seal well and slide smoothly MISCELLANEOUS CPR CUSTOMER QUESTIONS INFORMATION 02 24 07 Some customers have asked if the altimeter vent hole should be drilled through the airframe only as our instructions tell you or through the altimeter tube as well The hole only needs to go through the airframe The air passes through the airframe hole works its way around the circumference of the altimeter tube and enters the altimeter bay through the large slot in the altimeter tube Also keeping the AF vent hole on the opposite side of the slot as the instructions direct provides a buffer against tiny spikes in the airflow for better altimeter operation 14 74 PMLCompleteFAQ doc Another question has been why is the drogue section of the rocket on the bottom and the main chute section on the top This is one of those questions where once you understand WHY you will never forget the answer Deploying the drogue from the nose could j
32. ML s hybrid ready kits CPR3000 Component Weights The following lists approximate weights in ounces for CPR3000 parts for use in RockSim or other simulation programs 02 24 07 Aluminum Threaded Airframe Coupler 1 7 Aluminum Threaded Airframe Sleeve 0 6 Charge Holder 0 4 Charge Cylinder Ematches 0 4 Charge Cylinder Flashbulbs 0 6 Fore Altimeter Mount 0 6 Aft Altimeter Mount 0 3 Switch 6 screws 4 alt 2 sw amp wiring 0 2 15 74 PMLCompleteFAQ doc 3 O Rings 0 05 CPR MAX CPR MAX CPR3000 for Large Diameter Rockets Our CPR system has been available in 2 1 through 3 9 diameter sizes for years Our new CPR MAX system was developed for 6 and 7 5 rockets This system allows for redundant recovery system deployment for the purpose of safety and to protect your investment If you ve always wanted to add CPR3000 style recovery to your 6 0 or 7 5 inch kit CPR MAX is the answer The CPR MAX system uses the same components as the CPR3000 system but in a special design configured for large diameter 6 and 7 5 inch airframes CPR MAX also features twin altimeter design which can be used either as the backup required for Level 3 flights or as a safety backup for regular sport flying NOTE CPR MAX does not REQUIRE the use of two altimeters It can safely and effectively be flown with only one The second altimeter is a redundancy feature not a requirement The CPR MAX System contains nearly ev
33. OT FUNCTION PROPERLY with the AccuFire How Altimeters Work The following is a generalized discussion of how the PML Co Pilot and other barometric altimeters work It is not intended to be absolutely or entirely accurate just descriptive of basic operations as an educational tool 02 24 07 21 74 PMLCompleteFAQ doc The Co Pilot and all other barometric altimeters I know of takes an air pressure sample when you first turn them on and some like you to leave them on for a couple minutes so they can take multiple baseline readings They then set themselves to say OK this pressure reading I ll call zero Doesn t matter what the actual launch site elevation is it says OK this is zero I ll base everything I do from now on based on changes from this pressure reading So let s say your launch site is at 750 ASL above sea level and let s pick some arbitrary scale for altitude Let s say it ranges from 0 at sea level to 10000 at 10 miles altitude When you turn your altimeter on it takes the pressure reading at your launch site which being at 750 is say 15 It does it a few more times over the next few seconds 15 15 15 It says OK I keep getting 15 so I m now going to reset all my internal software to say 15 0 The next thing the Co Pilot does is look for a pressure drop corresponding to 300 AGL to determine a launch has really taken place so it should arm it s deployment circuits and look for apogee So now you l
34. PMLCompleteFAQ doc PML COMPLETE FAQ AIT Information Layout In This FAQ The information in this FAQ is laid out alphabetically The headings for each section such as PML AIRFRAMES FAQ are in all capital letters to help you find each section in the clickable Table of Contents Index on the left side of the screen For more information on any of the systems or components discussed in this FAQ always refer to the appropriate page on the website at www publicmissiles com Nearly all details available for any of these components or systems such as length weight wall thickness etc are shown on the website page where the component or system is sold Each Mini FAQ as available on that item s page in the webstore begins on a new page in this Complete FAQ This aids in being able to maintain the document and set up a structure that makes the PDF file easily searchable 02 24 07 1 74 PMLCompleteFAQ doc PML ADHESIVES FAQ We say so in all our kit instructions but make sure you lightly sand any area to be bonded This is important to get a good bite on the materials for the epoxy and will dramatically increase the strength of your finished rocket Adhesives Epoxy e PML epoxy is competitively priced Also buying PML epoxy is a convenience to the customer you can get everything you need for your high power kit from one place e We recommend using our epoxy because it s known to work well We ve used it
35. R3000 What is CPR e CPR is an altimeter based two step parachute deployment system Using a dual deployment altimeter the first chute a small drogue is deployed at apogee allowing for a fast but controlled descent At a user selectable approximately 200 400 600 or 800 feet refers to PML Co Pilot altimeter the altimeter fires a second charge deploying the main chute allowing for a soft landing e The altimeter is centrally located in a special compartment within the main airframe The drogue chute is ejected from a split point in the airframe just above the fin motor section while the main is ejected at the nose cone Both chutes are deployed using our exclusive Piston Ejection System e Once assembled the altimeter charge cylinder assembly can be easily moved to another CPR3000 rocket making it easy and cost effective since you only need one altimeter to fly CPR3000 e CPR 2 1 and 2 6 come with a 12 streamer cut to desired length instead of an 18 drogue chute which comes with larger sizes The chute is too large for these small diameters e ACPR based rocket must always be flown with the electronics installed A CPR based rocket cannot be flown with motor based ejection This is because the fin section coupler bulkplate assembly and the lower drogue piston block off the motor section from the rest of the rocket e PML offers both CPR Equipped kits and CPR Retrofit Kits for converting an existing PML kit or scratchbuild
36. a rockets w o payload nosecone only at other end of shock cord 3 yrds 1 2 TN e 2 1 and all 2 5 dia rockets w payload payload section and nosecone at other end of shock cord 4 5 yrds 1 2 TN e 2 5 dia rockets w payload payload section and nosecone at other end of shock cord and 54mm motor mount more weight and higher velocity harder to predict exact ejection time 4 5 yrds 1 2 TN e Most 3 0 dia rockets 4 5 yrds 42 TN Heavy or with large payload section 7 5 yrds Y TN e Economy 3 9 dia rockets 7 5 yrds 2 TN Heavy or with large payload section 7 5 yrds 1 2 TN e 6 0 and 7 5 dia rockets w o payload nosecone only at other end of shock cord 7 5 yrds 4 TN e 6 0 and 7 5 dia rockets w payload payload section and nosecone at other end of shock cord We usually have each section come down with it s own chute and use 7 5 yrds 34 TN for the booster and 4 5 yrds 34 for the payload 02 24 07 65 74 PMLCompleteFAQ doc PML ROCKSIM FAQ We offer RockSim files for every PML rocket and RockSim data on every PML component on the RockSim Page of our website PML was the first high power manufacturer to provide this to our customers and is still the manufacturer that provides the most simulation data and information to their customers What You Need To Know About Simulations We use RockSim as our tool because it s one that s readily available and that many mod
37. acetone nor MEK causes any problem on our plastic NCs used in moderation and for short term contact with the plastic of course e If you need to add noseweight for CG CP adjustments we recommend sand held in place by our Two Part Expanding Foam sold on the Adhesives Page of the webstore Custom PNC e Custom PNC means changes to standard PML PNCs we do not make custom cones e See our website at www publicmissiles com for current pricing on all custom work The prices below are shown only to give you a general idea of the pricing range for such work e Convert to boattail by cutting tip add 4 00 Customer must provide motor tubing size if base diameter is to be same as the motor tube or base diameter 4 00 charge includes cutting shoulder Customer must provide shoulder length e Slotting for 3 amp 4 only add 3 50 per slot Intellicones The PML Intellicone is intended to be used above a payload section to mount electronic equipment The Intellicone is not intended to have a shock cord attached to it the shock cord attaches to the payload section to which the Intellicone is screwed removably riveted or some other attachment scheme The cable is used to retain the payload section into the Intellicone Put the two ends of the cable into the cone put in the payload tube with the cables going into the notches in the hole in the cone then pull on the cable to wedge the payload tube into the Intellicone See the Nosecone
38. after the flight it just takes a little practice 02 24 07 40 74 PMLCompleteFAQ doc A more solid retention option is to use one of our PMR or HAMR motor retainers described below They work great and are really easy to use HAMR Motor Retention System PML has developed our own line of high quality threaded motor retainers The HAMR Highly Adaptable Motor Retainers system has been designed specifically for use with our rocket kits or any scratch built rocket using PML motor tubes These lightweight tool free threaded retainers are precision CNC turned from 6061 aluminum and anodized These retainers fit virtually all popular motor brands and types including Aerotech RMS CTI Pro XX Animal Motor Works Hypertech Kosdon Sky Ripper Loki and others The HAMR system can be adapted to existing rockets if the motor tube extends at least 3 8 beyond the aft centering ring The HAMR can also be used with boattail and tailcone rockets PML offers both a HAMR system for standalone single diameter motor mounts and a HAMR system for PML s popular Kwik Switch 54 28 29mm motor mount system General notes for retro fitting the HAMR system onto existing rockets and other important information 1 The motor tube must protrude 3 8 beyond the aft ring for the sleeve to fit If the rocket is already built and the motor tube is flush with the ring difficult but possible surgery is required for a retro fit Y
39. against the lower bulkplate The upper bulkplate cap has the LES holder attached to the topside and is removable for accessing the timer This cap is actually two bulkplates glued together in a fashion similar to the one on an Intellicone The G 10 plate with timer installed is held centered within the tube via two opposing wooden runners and can be slid out when the upper bulkplate cap is removed CPR3000 and Hybrids Using CPR3000 with a hybrid based rocket is usually impractical due to the excessive length that needs to be added to the rocket CPR3000 requires nearly 3 feet to be added to a hybrid based rocket effectively putting it out of bounds for use with hybrid rockets Our ERM system is a much better solution PML AccuFire and Hybrids The AccuFire Staging Timer is NOT affected by hybrid motor harmonics it s completely safe to use with hybrids 02 24 07 46 74 PMLCompleteFAQ doc PML IGNITERS FAQ Igniter manufacturers will specify the electrical usability ohms and volts range for their devices contact the igniter manufacturer for their specifications Igniters PML offers an igniter making kit Magnelite igniter kits which allow you to make your own igniters ranging from A size BP motors all the way up to M and larger motors depending upon the igniter wiring size purchased See the Igniters page in our webstore for more information Ematches vs Igniters The difference between e matches
40. an overall slot length limit of 22 However they must have 1 unslotted skip section for any continuous slot over 14 If there are more than four slots around the airframe they must have 1 unslotted every 10 This is necessary because once the first slot or two is cut it is difficult to keep the remaining slots straight due to the more flexible tubing Having a 1 skip section helps to be able to complete the remaining slots Example You need three 19 slots Since this slot is longer than 14 it must be interrupted for 1 at some point such as making a 12 slot a 1 gap then a 6 slot Your fin tang must be then be notched to bridge the gap and a CR should be installed at the gap Dado slots for any tube size in any length and in any type cannot be wider than 0 125 This is because the wider the dado the deeper you must go to get usable depth at the edges because the tube is round With dados wider than 0 125 you have to go nearly through the tube to get well defined edges Slot Tolerances The following slots are actually 0 015 larger than listed because of G 10 variations to ensure the G10 will fit even if it runs on the high side of thickness tolerances 0 062 0 093 and 0 125 The following slots are exactly as listed 0 188 0 25 0 375 0 5 Slot length tolerance 0 062 for 3 9 and smaller 0 125 for 6 0 and larger Slotting 3 9 tubes and sma
41. and a description of what could likely happen in the following scenarios a transonic to sonic flight w o Mach Delay b transonic to sonic flight w Mach Delay but delay time too short c transonic to sonic flight w Mach Delay but delay time too long A a You run the risk of mach pressure spiking b Same as a c Not a problem unless delay exceeds time to apogee One could also reverse these scenarios sonic to transonic and the same would still hold true Q When not using the Co Pilot for deployment is it best to fly with main and drogue connectors closed or open circuit Does it have an impact on battery life A It will work in either configuration If the outputs are open then no audible chirping on the pad if shorted then the unit will chirp The battery will be used up a bit sooner if the outputs are shorted Leave one output shorted and the other open for the best of both The MosFET outputs of the Co Pilot utilize an internal crowbar circuit to limit current flow so it makes them immune to shorts Opens are a don t care since no current flows Q Has PML considered using a RCA jack normally closed in place of the SPST switch Using a RCA plug allows a measure of safety remove me prior to launch and a pressure relief hole A We ve considered it but the RCA plugs can be less durable over time than a real switch Also you need to mount the switch such that the movable leaf will be forced INTO contact by th
42. and igniters is that ematches are intended to ignite an easy to burn substance quickly such as the BP used in rocket ejection charges However an igniter is intended and constructed to produce a large hot ball of flame for an extended period say 0 5 0 75 seconds to ignite a rocket motor Ematches typically will not ignite motors unaided as they do not produce a hot enough flame for long enough whereas igniters certainly could ignite BP Another significant difference between them which is critically important for onboard rocket electronic use is their current requirements Igniters typically require much more current than an e match the current requirements are usually more than altimeters can provide Therefore for onboard altimeters which need to ignite deployment charges ematches are needed For staging timers which need to ignite motors igniters are needed Be sure to always check to be sure an e match or igniter will work with your onboard electronic device 02 24 07 47 74 PMLCompleteFAQ doc PML MOTOR MOUNTS FAQ Kwik Switch e PML is the only company with the Kwik Switch quick interchangeable motor mount e The Kwik Switch 2000 increases the ease of use and positive retention features of the original Kwik Switch system e The standard Kwik Switch has 13 75 of usable length meaning motor cases less than 13 75 will fit the KS See the Motor Recommendations Chart on the Specs Page of our website for ca
43. and to the motor mount tube PML boattails vary in the following areas Number of slots 3 4 or 6 Slot width Length of slots The above details are described for each boattail on the Nosecones page of the PML website Also slotting charges are not included in the pricing of the boattail since it varies 3 4 or 6 Tailcones e All tailcones except Mini BBX are 1 75 exposed length with 3 16 to 4 shoulder See the Nosecones page of the website for Mini BBX tailcone details 02 24 07 59 74 PMLCompleteFAQ doc PML RECOVERY COMPONENTS FAQ Parachutes Construction Design PML chutes are made by a real parachute company are not just hobby parachutes All are multi panel chutes not a flat disc with shroud lines All are a 15 degree conical design All sizes use 1 9 ounce rip stop nylon coated with urethane for zero porosity Actual weight of the fabric is 2 6 ounces sq yard e The lines used on 36 and smaller chutes are braided polyester with a breaking strength of 180 pounds minimum e The lines used on 48 and larger chutes are flat braided nylon with a breaking strength of 300 pounds minimum e 60 chutes and above have heavier lines and every seam and edge is reinforced with high strength webbing Spill Holes e The spill hole provides straighter descent and reduces swinging or rotation of rocket under the chute while on descent the swinging occurs with non spillhole chutes
44. anges for strengthening Fully glassed airframe which requires phenolic as a starting point not QT You must special order your kit with phenolic as all kits 3 9 and under except Nimbus come standard with QT Thicker fins 0 063 should go to 0 093 0 093 should go to 0 125 Fin to airframe joints should be glassed 30 minute epoxy should be used throughout the build Some customers have asked if they can double up or sandwich two pieces of G10 to create a super thick fin for very high impulse flights We don t recommend it at high speed airflow can split them 02 24 07 30 74 PMLCompleteFAQ doc PML GENERAL ASSEMBLY amp PAINTING FINISHING FAQ General Assembly Tips We say so in all our kit instructions but make sure you lightly sand any area to be bonded This includes fins airframe inside and out motor mount etc This is important to get a good bite on the materials for the epoxy and is especially important in high stress applications It takes very little extra time to do this and the sanding dramatically improves overall strength Don t skip the sanding 1 After filling tube seams as described in the Airframes FAQ under Filling Phenolic Tube Spiral Seams unless you re using our Quantum Tube which has no seams assemble according to the kit instructions We recommend using a quality epoxy in all gluing procedures see the Adhesives FAQ for details Be sure to apply epoxy fil
45. as a thrust ring against the OD of the motor mount tubing That s typically how it s done and works just fine Motor Ejection Clip Regarding retaining the motor from ejection you have a few options In high power rockets there is no engine clip like you may be used to with model rocket sized products Many people use masking tape around the motor casing for a tight friction fit to the inside of the motor tube You need it to be tight enough that the motor will hold against ejection charges but not so tight you won t be able to get it out after the flight it just takes a little practice A more solid retention option is to use one of our PMR motor retainers described below They work great and are really easy to use PMR Motor Retention System e Regular non KS motor retainers use the lower centering ring as the anchoring point for the threaded inserts For Kwik Switch motor retainers they do not mount to the KwikSwitch adapters but actually span across to the CR that holds the KS Mother tube to the airframe Both KS retainers one for 29 38mm and one for 54mm have the same bolt hole pattern just the ID is different The reason is that the Medusa nozzle on the 54mm motors is larger in OD than a 29mm motor casing two different retainers with different ID s were required e The PMR 29 38 KS and the PMR 54 stainless steel retainers have the same hole pattern dimensions This means they can be interchanged on the same rock
46. attery before every flight It s asking a lot of an inexpensive battery to run an onboard computer and fire two ematches every flight make sure it can do it and replace it often 02 24 07 23 74 PMLCompleteFAQ doc Ni Cad Batteries for Electronic Systems We recommend Radio Shack s Hi Capacity Ni Cad battery part 23 299 as a good Ni Cad for onboard electronic systems unless specified otherwise by the instructions provided for the device Ematches vs Igniters The difference between ematches and igniters is that ematches are intended to ignite an easy to burn substance quickly such as the BP used in rocket ejection charges However an igniter is intended and constructed to produce a large hot ball of flame for an extended period say 0 5 0 75 seconds to ignite a rocket motor Ematches typically will not ignite motors unaided as they do not produce a hot enough flame for long enough whereas igniters certainly could ignite BP Another significant difference between them which is critically important for onboard rocket electronic use is their current requirements Igniters typically require much more current than an e match the current requirements are usually more than altimeters can provide Therefore for onboard altimeters which need to ignite deployment charges ematches are needed For staging timers which need to ignite motors igniters are needed Be sure to always check to be sure an e match or igniter will work with you
47. aunch it sees 15 16 17 18 and up let s say 17 equals 1050 or 300 above your launch site altitude It says OK there s 17 that s 300 above the ground so this is a real launch I m going to start running the software to monitor when to deploy my chutes now OK the rocket s still going up is near the top of it s flight and it sees 800 801 802 on our arbitrary scale 802 803 804 804 803 802 OK it says I saw 804 as the highest reading I ever got but now I see 803 and then 802 Must be I m over apogee and falling back to earth Deploy Deployment Charge Igniter Selection PML s Electronic Deployment Devices can work with flashbulbs electric matches or igniters Flashbulbs are not recommended though due to their much lower reliability and great variability in firing current requirements Also electric matches are preferred over igniters due to the relatively low current requirements compared to most igniters intended for motor ignition The resistance reading of what you intend to use is important Here s why E I x R where E is Voltage I is Amperage and R is resistance We know the Voltage involved depending on the onboard battery We also know from the specifications of the unit that the ignition device must fire with a certain amperage range So we need to find R the Resistance to determine which ignition device can work successfully with the device we intend to use Below is an example of how to do the calcula
48. d in High Power Rocketry Many people see that PML offers kits and single use 29mm motors but also ask about launch pads launch controllers bigger motors flying fields etc High power rocketry is a little different than model A through D motors and midpower E through smaller G rocketry The equipment is larger and more expensive the flying fields must be bigger and therefore harder to find and there are regulations governing where large rockets can be flown and what altitudes are allowed We always recommend joining a NAR National Rocketry Association or TRA Tripoli Rocketry Association club in your area They ll already have the launch equipment they ll have suitable launch fields lined up they ll know local regulations they ll already be filing the paperwork necessary to fly big rockets FAA waivers and they ll also be more than willing to help you out Besides it s always more fun to fly with other people that enjoy the hobby and can help you out as you move along so joining a club is the way to go in keeping costs down finding good flying fields and complying with regulations Be sure to visit the www nar org and www tripoli org websites They have detailed information about local clubs the motor certification process required for flying H motors and above and much more Really join a club it Il make your higher power rocketry experience a LOT easier and more fun I ve Flown Lots of Model Rockets
49. deep enough but also not so deep you come through the side of the dowel Now get a washer from your local hardware that ll capture the edge of the motor when it s installed on the woodscrew and you re done You may need to get what s called a fender washer They re just like a regular flatwasher but with a much larger OD for the size of the center hole With careful installation of the woodscrew each flight to make sure you don t strip the threads this will work very well for you If you spend a little time shaping the retainer as well you can make it blend in and look like it belongs there rather than just an add on piece If you use a harder material for the retainer than wood you can actually thread the hole and use a threaded machine screw instead of the wood screw I ve done em both and they both work 02 24 07 52 74 PMLCompleteFAQ doc Yair har weet Cree Bostisll Figure 1 Boattailed Kit Motor Retainer Bullpuppy On my Bullpuppy and all my minimum diameter rockets I thread the inside of a piece of brass tube In this case choose tubing to fit a 6 32 screw Then I drill a hole in the tail cone parallel to the axis of the rocket Be sure it is located far enough from the aft closure of the motor to allow the screw to just clear it I epoxy the brass tube in the tail cone and to the motor tube With a little filling you can blend this into the tail cone and it is almost invisible on the finished rocket I use 6 32 all
50. delay to fly for the launch conditions at the time of flight Information is also shown in the chart regarding motor kit combinations that should be strengthened or otherwise require special treatment This is explained in the chart and additional information can be found in the Kit Strengthening section of the Airframes FAQ Data Sheets The Data Sheets are available for nearly every kit PML makes and are available by clicking on a link under the description of the kit in the webstore These sheets show a photo of the kit list the kit s features and specs and have a mini Motor Recommendations Chart on them all on a single printer friendly page Of course we recommend you always look at the full Motor Recommendations Chart on the Specs Page of the website for the latest information 02 24 07 71 74 PMLCompleteFAQ doc PML STAGING FAQ Interstage Couplers Interstage Couplers are used to house staging timers and to connect the upper and lower stages together The Interstage 3000 the latest version from PML is used in our two stage rocket kits but is now available for scratchbuilders designing their own staged rockets Using an IS3000 system from PML is a quick simple solution to an often difficult design problem Interstage 3000 kits are ready to ship in 2 1 2 5 3 0 and 3 9 diameters To use an IS 3000 system the booster needs 3 regardless of diameter at the top just like a regular rocket would for a pa
51. e PML fiberglassed tubes are manufactured using the latest high temperature compression process to guarantee superior laminate bonding and the best possible cloth to resin ratio read highest strength lowest weight It comes to you pre 02 24 07 4 74 PMLCompleteFAQ doc glassed initially sanded and almost ready to paint If you want the best or need ultimate strength PML pre glassed phenolic is for you QT Kits Phenolic Kits All kits from 2 1 3 9 diameter except Nimbus come standard in QT All kits 6 0 and larger are phenolic as QT is not available larger than 3 9 Any of our QT kits can be special ordered in phenolic Contact PML Central about it at 586 421 1422 9 5pm EST Mon Fri or pmlhighpowersales compuserve com for pricing and delivery details It usually costs a little more and takes longer since it s a special request Premium Kraft Phenolic Tubing e Tests show nearly 5x greater compression strength than cardboard e Doesn t fray when cut or fuzz when sanded Phenolic is more brittle than cardboard but e Damage is localized impact damage doesn t travel up the tube like cardboard e No accordion damage like cardboard with compression loading again damage stays localized and is easily repaired by cutting off the damage and splicing on a new piece Accordion damage ruins the entire tube with cardboard in most cases e Phenolic is waterproof good for wet sanding or if rocket lands
52. e G forces of launch rather than 180 deg from that where the launch will try to separate the switch Also the size of the altimeter pressure hole would determine the size of the plug needed so you d need to maybe use a big plug on a small rocket to get the size of the plug hole 26 74 PMLCompleteFAQ doc you need One other thing is that all altimeter manufacturers I m aware of recommend that the pressure relief hole s be smooth and flush to the airframe All RCA plugs I ve seen use a threaded ring to tighten them on which makes a turbulence inducing obstruction right before the hole and also by definition makes the hole not flush to the airframe Q I just noticed browsing Missile Works web site that the Co Pilot is 25 bucks more than an RRC2 What makes the Co Pilot worth the extra bucks besides the PML brand name A Designed specifically to interface with the CPR 3k system 02 24 07 Minor revision to apogee detection software Better layout of terminals for easier connections Clear markings for all connections and switches Lower altitude main chute deployment range available Superior documentation instructions Q What is the Co Pilot s altitude report out accuracy A The software interpolates and reports to the nearest foot On a low flight it is easily within 5 2K AGL and the accuracy increases from there as peak altitude increases then it rolls off again Missile Works states that 3
53. e MMT holes in the ring and boat tail line up When it comes time to install the boat tail apply epoxy as directed and also apply epoxy to the base of the studs and to all the joints so the assembly can t come unscrewed Slip the boat tail over the studs and install the complete assembly into the rocket I made my own retainer from aluminum sheet and it looks a lot like PML s retainer except that it only has 2 tabs Socket head screws hold it onto the studs which are recessed slightly into the boat tail For the Sudden Rush you may have to modify this approach by allowing the screw threads to project through the boat tail and anchor the retainer ring with nuts Not as pretty but effective Another approach might be to install blind nuts into the aft centering ring and use really long screws to hold the retainer ring in place Sudden Rush amp Slimline Motor Retainer If anyone else ever asks the slimline tail cone does create problems with the Sudden Rush kit Details The Slimline Tail Cone is shorter than the PML tail cone In addition the design of the retainer has the end of the motor tube about 3 8 inch inside the tail cone The combination of a shorter cone and the motor tube being inside the cone pushed the 02 24 07 54 74 PMLCompleteFAQ doc motor tube s top centering ring close to 1 5 inches further up the body The result is that the 5 inch coupler that is used to form the top of the fin section can only be inserted ab
54. e a complex thing and do definitely require special considerations experience and lots of what if thinking and simulation 02 24 07 74 14
55. ec 97 issue of High Power Rocketry Magazine There s a good article on how to make a Self Contained Altimeter Bay that ll make the altimeter easily removable to switch back and forth between rockets However you ll have to modify the HPR Magazine design slightly due to differences in altimeter layout from the ALTS2 altimeter used in the article design Fitting ST 2 Timer to 1S3000 The PML AccuFire is the recommended staging timer for the IS3000 system the two were designed together to complement each other The Transolve ST 2b will also fit directly The ST 2 can be used if the customer drills holes in three of the corners of the board However using an ST 2 can be potentially unsafe as it only has one set of two screw terminals requiring the customer to install a switch in series with the electric match to safe the system from firing on the ground Everything else uses off board power and will not fit the IS3000 system Customer Q amp A and Miscellaneous Co Pilot Information 1 Q there was a cold solder joint on one of the sensor leads A Customers have noted that they think that some of the joints on the Co Pilot are cold soldered i e bad connections The sensor terminals and discharge capacitor are all hand soldered so they will look different than the wave soldered joints Only the circuit side components can be placed for wave soldering and the sensors cannot be washed hence they are added post wave The joints may
56. econe but not the chute as can happen in non piston rockets especially the larger diameter ones 02 24 07 61 74 PMLCompleteFAQ doc e The operation of the piston system is quite simple The piston sits in the airframe over the motor and under the parachute It is attached to the motor mount via a nylon blend strap which is epoxied to both the motor mount and the piston itself When the ejection charge goes off the pressurization between the motor and the piston bottom pushes the piston upward which separates the rocket and pushes the chute out That s all there is to it No special prep needed nothing to do just push in the piston load the chute and you re done e We use metal D rings with a butt welded joint for shock cord attachment to the piston on all kits up to and including 4 On 6 and larger kits we use Kwik Links Fitting the Piston e After cutting airframe tubing it may be necessary to deburr the edges inside and out using 150 grit or finer sandpaper This is especially true with QT as the cutting process may squeeze the cut end ever so slightly making it tight for inserting a nosecone or for inserting the piston Deburring or chamfering the inside edge of a QT will eliminate those problems e Phenolic pistons should slide easily in or out with just a little push or pull from you Sand until you achieve this fit and chamfer round the edge of the upper and lower portion of the piston We also recommend
57. elers have Real life conditions in flight like temperature launch site altitude humidity launch lug drag on the rod winds a biggie and variation in actual motor performance from the perfect motor RockSim uses another biggie are going to affect the real flight sometimes substantially Motor performance can vary up to 15 from manufacturer s specs and still achieve certification Also the user s ignition technique and or device can make a big difference as well A motor chuffing a bit on the pad can make a big difference in an actual flight performance vs the simulation which of course ignites perfectly every time Also note that an altimeter you may use to evaluate the accuracy of the simulation prediction can be off by 10 15 as well RockSim or any simulator is just that a simulation so use it as a guide not a gospel We ve provided the information to assist our customers in motor and delay selection but everyone needs to understand that it is indeed only a simulation However since we do use RockSim for all our simulations and also include the files we use on our website the individual modeler can download the files and run their own simulations for the flight conditions they usually experience As noted on the front page of our Motor Recommendations Chart Data was produced from RockSim simulation software with 500 elevation launch site 70 humidity 75 deg F 0 mph wind O deg launch rod angle These are clearly relat
58. en you just need to realize that the colder it is the more likely you ll have a problem with plastic cracking due to the cold There is no perfect material but we truly believe our QT is the best all around material for airframes on the market especially for the price If we thought there was something better we d be selling it 02 24 07 7 74 PMLCompleteFAQ doc Pressure Relief Holes There are many debates about the necessity of pressure relief holes We think it is only necessary in extremely fast burn motors with rockets that will pass 5000 very very quickly If you are unsure or don t want to take any chances then drill the following holes One 1 8 hole just above the uppermost centering ring of the MMT one 1 8 hole near the top of the main airframe but below where a coupler or nosecone shoulder might be and one in the payload section This should work with most sub sonic rockets of 4 dia or less Working with PML Airframe Tubing Cutting Phenolic or Quantum Tubing Cutting phenolic tubing is a little different than cutting cardboard First of all put away your X ACTO knife and get an X ACTO razor saw It is possible to cut phenolic with a knife but it will take a dozen or so passes to get through You should use the razor saw to do almost all of your cutting A hacksaw with a fine toothed blade can also be used A good tip to ensure a straight cut is to put an automotive style hose clamp around the tubing when c
59. enough epoxy in this fashion you can then pull the dowel toward you making a fillet with the fingertip shaped round profile of the dowel It may be beneficial to use masking tape to cover the inside of the bottom of the airframe and the outside of the motor mount tubing while applying the epoxy inside This will make it easy to peel off the tape to remove any epoxy drips that may get on the airframe and or MMT and hinder you from installing the lower centering ring when your internal fillet work is done Another easy and strong option is to use our Two Part Expanding Foam available on the Adhesives page of the webstore No internal fillets are needed See the PDF on the Adhesives page for details on using the foam Some customers are concerned that the small canard fins at the top of the Bullpuppy kit appear too long for the slot This slight over length is intentional It would be difficult to fill in the slot and make it look good if the fin were too short so we make them a touch long to ensure that will never happen Go ahead and mount them then when the epoxy has cured use sandpaper or a small file to knock them back flush with the top of the airframe Customers sometimes ask Is it OK to put the launch lug in the corner of a fin root and the main body The instructions say to put it in between two fins but it would produce less drag near a fin root and would be stronger also This can be done if you re careful but by putting the
60. ents are made available to you in the Adobe Acrobat Portable Document Format pdf We make them available to you in this format so the document can be viewed or printed either online or offline using your monitor and your own printer If needed the PDF viewer is available through a link on our site as well On rare occasions customers report they cannot view a PDF file while on the website this seems to usually be from unusual user computer configurations We would like to remind you that you can always right click on a file and save it to your local hard drive and open it from there Kit Specifications The purpose of this chart is to show you various specifications customers are often interested in such as length weight diameter fin thickness Center of Pressure launch lug size stock parachute size and other information Motor Recommendations Predicted Altitude and Ejection Delay Chart The purpose of the Motor Recommendations Chart is to give you an example of possible altitudes that can be attained with various rocket motor combinations All motors shown except hybrids are made by Aerotech Motors of different total or average impulse or motors from other manufacturers may work as well Consult your favorite motor manufacturer or dealer Match motor to rocket for approximate altitude and ejection delay time Optimum delay time is printed after the estimated altitude The numbers on the chart are from simulations run using RockSim 4 0
61. erk the rocket enough to pull apart the lower section and deploy the main Deploying the drogue from the middle doesn t jerk the nose away from the chute compartment PML recommends that the fore and aft altimeter O rings be used for only two flights then thrown away and replaced with new O rings This will help ensure good sealing of the altimeter bay and protection of the altimeter from pressure spikes and black powder residue We offer a 12 pack 6 fore 6 aft O rings on the CPR ERM of the webstore under part number CPR3K OR PK One set of fore and aft altimeter O rings is provided with the CPR3000 system initially whether a CPR based full rocket kit or a CPR Retrofit kit for scratchbuild use T ordered the charge cylinder for flash bulbs but the flash bulb is very loose inside the charge cylinder Put a tissue packing around the flashbulb Roll a small tissue square preferably Estes wadding since it s flameproof about 1 5 x 1 5 into a tooth pick shape then form it into a ring and use a small screwdriver to pack it around the bulb once installed Kind of like a tissue donut with the flashbulb in the hole of the donut CPR3000 and Hybrids Using CPR3000 with a hybrid based rocket is usually impractical due to the excessive length that needs to be added to the rocket CPR3000 requires nearly 3 feet to be added to a hybrid based rocket effectively putting it out of bounds for use with hybrid rockets This is certainly true of P
62. erything you need altimeters epoxy ejection powder and additional airframes if required not included to convert your existing rocket or as an enhancement to your own design The Bulldog AGM 600 and Pterodactyl kits would require over 2 feet of airframe tubing to be added to use the CPR MAX system which would change their appearance so substantially that PML does not recommend CPR MAX for these kits The information below is intended as a guide for determining the proper amount of ejection powder used with various diameter CPR MAX rockets using a piston ejection system and a 24 fore or aft recovery airframe o 6 0 diameter 1 0 to 1 3 grams o 7 5 diameter 1 2 to 1 5 grams CPR MAX Component Weights The following lists approximate weights in ounces for CPR MAX parts for use in RockSim or other simulation programs This does NOT include the weight of the pistons KwikLinks or piston straps only the core components of the CPR MAX system The weight is for one part so if more than one is used be sure to multiply the weight by the quantity of parts 02 24 07 COMPONENT QTY 6 0 7 5 CT 6 0 1 10 75 15 75 CT 6 0x8 1 6 9 10 2 CT 6 0x1 5 2 1 3 1 9 16 74 PMLCompleteFAQ doc PT 6 0x2 1 1 5 2 3 Aluminum Threaded Airframe Coupler 2 1 7 1 7 Aluminum Threaded Airframe Sleeve 2 0 6 0 6 PT 1 5x10 2 1 7 1 7 Birch Bulkheads Mounting Plates 2 3 65 3 95 Charge Caps Vinyl 4 0 05 0 0
63. et However they will NOT interchange with the hole pattern for a PMR 29 38 Said another way if you have a rocket that can use a 54mm and a 38 or 29mm EVEN IF IT DOES NOT USE A KWIK SWITCH SYSTEM you must buy the PMR 54 and PMR 29 38 KS The non KS PMR 29 38 and the PMR 54 do not have the same hole pattern the PMR 29 38 KS and PMR 54 do 02 24 07 50 74 PMLCompleteFAQ doc e PMR 29 38 should not be used on CR 2 1 1 5 1 5 38mm and CR 2 5 2 1 2 1 54mm as there is not enough wood for ample insert anchoring PMR 29 38KS and PMR 54 should not be used in a Quasar kit or with any CR 2 5 2 1 application e CR 2 1 1 5 kits Callisto 38mm Io 38mm Phantom X Calibur Phobos 38mm e CR 2 5 2 1 kits Black Brant VB 38mm Explorer 38mm Quasar Small Endeavour Tempest Thunder n Lightning e Since the threaded inserts for the KS compatible retainers require a 3 16 hole drilled in the aft centering ring no retainer is available for a 2 5 diameter rocket using a 54mm motor mount The PMR retainers cannot be used with boattailed or minimum diameter rockets with the exception of our Bulldog kit which has enough exposed centering ring area at the boattail For ideas on other motor retention options for kits which cannot use a PMR system go to Rocketry Online at www rocketryonline com click on InfoCentral then on Construction then on Motor Retention e Extra PMR inserts are available separately so you can equip all your rockets for t
64. exposure to UV will make any plastic brittle This may take years though Modern plastics like QT may also have some UV blocking additives blended in to delay the deterioration further The color pigments in the plastic are the first to break down hence the yellowing Paint stops the breakdown process DO NOT skimp on the shake the can for at least two minutes after the ball rattles step This is a mistake many people make If you need to stand in front of a clock while you shake the can Getting all the paint in the can well mixed is a very 02 24 07 31 74 PMLCompleteFAQ doc important step that should not be rushed Also as it notes on the can shake it for a few seconds every minute or so while you re painting to help keep it well mixed e Four or five light coats are better than one or two heavy coats You will reduce the risk of runs and sags in the paint dramatically and it will dry faster as well e For the very first coat apply a very light coat of your base color You re really not trying for any color coverage at all just getting a bit of the paint stuck to the surface of the rocket to allow the subsequent coats to bond to it Allow this coat to dry for about 5 minutes before applying more coats This first very light coat seems to set the stage for following coats so they won t run as easily e For the best finish let each coat dry and sand lightly with 320 or 400 grit sandpaper you should let each coat dry
65. fering with the piston Usually there is dead space in the booster area so we glue and screw there If the screws might interfere with the piston travel or other functional item we simply epoxy it in place Motor Retention Thrust Ring High power kits don t use a thrust ring in the front of the motor mount like Estes class rockets do because high power motors can vary greatly in length Therefore if you glued in a thrust ring you d be stuck flying only that length of motor If you use a reloadable motor for high power flights the lower closure has an OD larger than the OD of the motor mount tube so that provides the thrust ring by transmitting the force against the bottom of the motor mount tube If you re using a single use motor as opposed to a reloadable you ll need to wrap masking tape around and around the base of the motor until you ve built up maybe 1 16 3 32 thickness of tape to act as a thrust ring against the OD of the motor mount tubing That s typically how it s done and works just fine Motor Ejection Clip Regarding retaining the motor from ejection you have a few options In high power rockets there is no engine clip like you may be used to with model rocket sized products Many people use masking tape around the motor casing for a tight friction fit to the inside of the motor tube You need it to be tight enough that the motor will hold against ejection charges but not so tight you won t be able to get it out
66. foam in large batches as it generates enough heat in large batches to deform a fiberglass nosecone We recommend multiple smaller batches about 4 6 ounces at a time to fill large areas 02 24 07 3 74 PMLCompleteFAQ doc PML AIRFRAMES FAQ Airframe Tubes Our tubing is specified by ID Be sure to add 2x the wall thickness if you need to determine the OD Stock full length tube length tolerance 0 00 0 25 Airframe Selection Criteria Quantum Tube airframes are the best choice for most sport rocketry applications QT is very easy to work with and finish with no spiral grooves to fill It s very strong for most rocket flying and is also very forgiving to the impacts of rough landings However QT is NOT a replacement for fiberglassed phenolic it is simply an easier to use material in applications that do not require the specific features of phenolic PML parts such as nosecones centering rings couplers etc all fit QT just as well as they fit phenolic However there are some limitations with QT 1 It comes only in 2 1 2 5 3 0 and 3 9 diameters 2 Itis not intended for near mach transonic or above mach supersonic flights See our online FAQ for information on mach and near mach flying 3 It is not intended to be used as a base for fiberglassing Kevlar or other typical tube strengthening methods 4 Itis not intended for use in minimum diameter rockets rockets where the airframe IS the motor mount the mo
67. ghts of the tubes We ve tried fiddling with the 1 05 number but then once one tube is right say the 2 1 at 10 7 oz another tube is off by enough that the fiddling of the density in the RockSim materials database is no good What we suggest you do is just build the kit in RockSim from phenolic then add a mass object right at the CG point for the difference in weight The weights of the tubes are shown in our webstore Here s a quick reference of tubing weight differences all for 36 pieces of tubing Airframe Size PT Weight QT Weight Difference 2 1 8 7 OZ 10 7 oz 2 0 oz 2 5 10 3 oz 11 3 oz 1 3 oz 3 0 12 1 oz 15 2 oz 3 1 oz 3 9 15 3 oz 18 0 oz 2 7 OZ Also keep in mind that RockSim 4 0 doesn t take into account the weight of fin tabs through the airframe wall epoxy paint etc There s also no way to easily add piston strapping or shock cord We took care of these difficulties in the RockSim RKT files we provide by adding a mass object to bring the RockSim weight of the kit up to our measured weight of the actual kit The minor weight difference you re going to get between RockSim and QT is going to be different from what the real rocket weighs when you build it anyway since build techniques amount of epoxy painting etc will vary from builder to builder What we suggest is to use RockSim as a design tool to figure fin sizes needed etc then build the real rocket Weigh the completed
68. gine is protruding from the tailcone the red shows to U shaped lengths of 1 mm steel that are glued into small holes drilled into the lip of the tailcone between the engine and the 38 mm tube shown with brown dots The steel Us can be bent outwards see arrows to allow changing the motor Bullpuppy I ve started working on the Bullpuppy and I wanted to let you know that your assistance was invaluable I decided to go with the Aeropack retainer Fortunately Aeropack is 02 24 07 51 74 PMLCompleteFAQ doc based right here in San Diego so I was able to get the retainer directly from them In fact Bob Mosley the owner met me personally to deliver it Bob had a great suggestion which I have used and I thought I would pass on to you The outer diameter of the retainer is slightly larger than the boat tail I shortened the boattail by 3 8 so that the diameters matched very clean look The motor tube extends the shortened boat tail by 3 8 to allow attachment of the ring so the motor is actually in the same position as the stock kit The outer diameter of the Aeropack ring was a nice snug fit in the shortened boat tail Bullpuppy Little Lunar Express Lunar Express I ve made a minor modification to my full size Lunar Express that may work for you as well I ve also done it to my Bullpuppy it works for any boattail kit I ll try to describe it to you but bear with me I ve attached a crude JPG drawing that ll help make sen
69. grams 1 Ounce 28 3 grams 1 Kilogram 2 2 Pounds 35 2 ounces Stability Center of Pressure CP stands for Center of Pressure You re probably aware of the center of gravity this is the point on a rocket or any object where all the weight seems to be centered The center of pressure is similar it is the point on the rocket where the corrective force of the fins is centered The center of pressure must be a minimum of one body diameter behind the center of gravity on a rocket fully prepped for launch to ensure stability CP doesn t vary it s controlled by the design of the kit CP specifications given in the PML catalog and on the website spec sheet are measured from the nose tip However you CAN vary CG by adding more nose weight That s why we specify CP in the charts so the owner of the rocket can find their CG and compare it against the CP to see if they need to add some nose weight for stability A very generalized rule of thumb CP moves about 75 80 of the length of airframe added to a rocket Example A rocket is stretched by adding 10 of airframe The CP will move rearward about 7 5 around 75 of the 10 that was added A quick description of CG vs CP and how to properly adjust the relationship can be found at www rocketryonline com Go to the InfoCentral section then to Rocketry Design then to CG CP Relation The information is repeated below for your convenience It is somewhat simplistic but was
70. hat does not go all the way through a tube Used in minimum diameter kits for fin mounting also used for some canard type fins Building Construction G10 is sanded most easily using 80 120 grit cloth backed aluminum oxide sandpaper Scuff all areas where epoxy will be with 80 120 grit sandpaper Use 220 or 320 on fin surfaces that will be painted G 10 is extremely abrasive Do not try to cut it with common shop tools as it will damage or destroy most common blades very quickly The cost of having PML make your G 10 fins for you on custom jobs is probably cheaper than buying the tools that will allow you to cut the G 10 yourself Fins leading trailing edges do not need to be shaped Simply lightly sand the edges to remove any manufacturing burrs If you do choose to shape the fin edges protect your power tools from the abrasive sanding dust and wear a dust mask Mounting Be sure to apply epoxy fillets to the fins at all three of the following areas Motor Mount inside airframe where fin passes through slot outside airframe fin joint People have asked how to make internal fillets to the fins deep up into the airframe One technique we ve had luck with is to use a piece of 1 4 3 8 or 1 2 dowel as appropriate Mix your epoxy and load up the end of the dowel with a blob of epoxy then stick the dowel into the airframe and onto the fin joint you re working on After 02 24 07 28 74 PMLCompleteFAQ doc depositing
71. he motor retention system without having to buy a complete retainer system for every rocket Install inserts in all your rockets and you can use the PMRs in whichever rocket you re flying e We recommend installing the PMR after the rocket is built This gives the best support for the ID of the centering ring when drilling for the inserts e The PMR 54 will work with many hybrid motors it does not work with a Hypertek J grain the hole ID on the PMR is about 1 8 too small The PMR system will work with Cesaroni Pro38 motors e The PMR 29 38KS and PMR 54 use 8 32 screws The PMR 29 38 uses 4 40 Other Motor Retention Solutions Many of the following are emails from PML customers with solutions they have come up with for retaining motors in PML rockets PML has not tried these solutions themselves and does not endorse them as viable safe and effective solutions They are presented here simply as thought starters for you in coming up with your own solutions to motor retention concerns you may have PML cannot will not be able to comment on using any of the information below with your rocket Mini BBX and Terrier Booster If possible I d like to find an alternative to friction fitting the upper stage engine I know this subject has been discussed before on RMR I haven t but will do what Daniel Flury from Switzerland has done http www shuttle endeavour de webimg bbx_tailcone jpg The blue circle shows where the 29 mm en
72. hinner or acetone on the Quantum Tube either will melt or distort the tube CA cyanoacrylate super glue may be used with QT but only in normal amounts Heavy amounts of CA may distort the QT Pistons QT Tubing and Cold Weather Flying The first time you fly a QT rocket in cold weather take it with the piston OUT to the launch site with you and set it outside while you re doing other things Once the rocket s come to ambient temperature try to fit the piston it ll probably be too tight Sand it until it has the nice slip fit you d expect Voila you re done Your QT rocket is now ready to go now and forever Basically once you sand the piston for cold flying conditions it ll fit well then and also will be fine in warmer weather as it s nearly impossible to sand a piston so much it s too loose Think of it sort of like setting CG CP when you build the rocket you add as much weight as the heaviest motor you ll fly to the tail then adjust the noseweight once until it s right It s something you do one time to make sure you re set for the future Same thing with the piston It s no secret that all materials get brittle in the cold plastics in particular It s not that QT becomes unusable at temps below say 30 degrees it s just that it s not as forgiving when things go wrong as it is when it s warm Customers have asked us to specify a temperature at which QT should not be flown but there s no specific number to be giv
73. his FAQ Some customers have thought that QT is a replacement for glassed phenolic This is not the case Quantum Tubing is not intended for super high stress applications It is intended as a replacement for standard phenolic for sport rockets QT makes it easier and faster for flyers to achieve a nice finish and to eliminate some of the problems of plain phenolic in high impact situations like landing on rocks cold weather flying etc Fiberglassed phenolic is the best product for high stress flights Also follow the 02 24 07 6 74 PMLCompleteFAQ doc recommendations in the Kit Strengthening section of this FAQ if the flight will be near or exceed 0 85 Mach Do s and Don ts for Quantum Tube QT Do s Before applying paint to the QT lightly sand the outside of the QT using 320 or 400 grit sandpaper Sand the fin fillet area on each side of fin slots using 150 grit sandpaper before applying epoxy to fin and tube Use the edge of an X Acto knife to de burr cut ends of QT This will remove minor deformation of the ID of the tube when it is cut Sand the inside area of the QT using 120 or 150 grit sandpaper wherever parts are to be epoxied to the QT Sandpaper flappers on a drill sandpaper glued to a large wood dowel sandpaper on the end of a stick etc can be used to prepare the inside of the QT for epoxy Using alcohol or mineral spirits will not damage the gloss finish on the QT Don ts Do not wipe or spill lacquer t
74. ht at the nail the CG Push on the rear of the rocket and it spins right at the nail the CG That s a good way to think of the CG it s the nail that your real rocket will turn around in flight Now think about if you put fins on the back end of your stick rocket Though it s not completely true say that the CP is exactly where you stuck the fins on your rocket it s true enough for this example If that stick was flying through the air front end first and wind pushes on the rocket the fins will push on the stick The stick will rotate around the nail CG Since the fins are on the back the rocket straightens back out and continues nose forward Now remove your imaginary fins from the back of the rocket and put them only on the front near the nose cone end of your rocket OK now it s flying again and wind pushes on the fins push on the fins of your imaginary rocket What happens The nose of the rocket turns around the nail CG and the front end flips over and turns into the rear end This is bad Of course you want the front end of the rocket to stay the front That s the general reason why the CG must be ahead of the CP keeping the CP behind the CG makes sure the front of the rocket stays the front Many manufacturers specify the CP location on their kits CP doesn t vary in kit rockets it s controlled by the design of the kit CP is affected by such things as the rocket s body diameter length
75. if it is a windy day and you ve added some launch rod angle the rocket s altitude will be lower the speed of the rocket at apogee will be higher since it will be going at an angle instead of straight up and you may also need a slightly shorter delay Conversely if you re flying in a high altitude area Denver for example the air is thinner and therefore produces slightly less drag on the rocket In that case you may want to choose a slightly longer delay The essential thing to remember is that these are just simulations Launch conditions as mentioned above can and WILL cause differences in actual flights PML recommendations for motors delays and altitude predictions are to be used only as a guideline to provide you a starting point for making your decision as to what motor and delay to fly for the launch conditions at the time of flight RockSim 5 0 and Higher People sometimes ask if we intend to offer PML RKT files and component data for RockSim 5 0 or higher We worked with Apogee before they released version 5 0 so updated PML data files are ALREADY in 5 0 and above We updated our component data files on the PML website at the same time 5 0 was released so if you download our component data you ll have the latest as well Regarding updating our Motor Recommendations Chart simulations with 5 0 or higher the differences between 4 0 and 5 0 or higher files for generalized altitude and delay predictions with various motors
76. ik Switch locking tab design It comes standard with a 54mm adapter the 75mm adapter can be purchased separately 75 54 Kwik Switch PML carries a 75 54mm Kwik Switch motor mount based on the original Kwik Switch locking tab design similar to the Giant KS discussed above The KS 75 54 system comes standard with the 54mm adapter though it can also be purchased separately Friction Fit Adapters Friction fit adapters are available for those who do not want the KS system or for kits that are not equipped with the KS system Available adapters are ADPTR 38 29 ADPTR 54 38 ADPTR 54 29 PML recommends you purchase the 38mm mount option for all kits that can be purchased standard with a choice of 38mm or 29mm motor mount and also purchase an adapter for 29mm ADPTR 38 29 This allows maximum flexibility in motor selection since if you build with 29mm that s all you can use If you build with 38mm you can always install the 29mm adapter if you want to step down to smaller motors but can also fly 38mm as well Some people have asked why the PML 29 to 38mm adapter ADPTR 38 29 costs more than the one from LOC and why is ours worth the extra money Our adapter is built up of various tubing sizes so it ends up like a double thickness tube LOC s is a standard 29mm tube with centering rings to adapt out to the 38mm tube Ours are worth the extra money for two reasons 1 It s easier to friction fit ours because you have the entire tube area
77. ill fail through less impact specifically because of their flexibility Their flexibility allows the tubing to flex and the layers to delaminate with an impact that our tubing would take without damage Said another way once you get to a certain point our tubing will crack or chip but ours will take a bigger hit for it to suffer 02 24 07 5 74 PMLCompleteFAQ doc any damage at all For this reason we believe our tubing to be better overall because it can absorb the smaller impacts that will begin hidden structural damage with competitor s flexible phenolic tubing Better to have an airframe chip or crack on the ground where you can see it and fix it first than to have the whole rocket destroyed under the stress of flight from hidden structural damage PML Pre Glassed Tubing Service PML offers a fiberglassing service for our phenolic airframe tubing All tubing is vacuum bagged The fiberglassing service leaves the tubes with a smooth finish ready for priming and painting with little if any prepwork required Our pre glassed tubing is available on the Airframes section of the webstore e Airframe tubes 2 1 through 3 9 get 3 wraps of 6 oz cloth e Airframe tubes 6 0 through 11 4 get two wraps of 16 oz cloth Quantum Tube These great airframe tubes are made in the USA from a special blended polymer that is extremely durable and easy to use Quantum Tube can be squeezed dropped or even thrown and will not suffer any damage
78. imeter though others may work All of our hybrid ready rockets except Aurora Tempest and Nimbus use the ERM System Here s what you get with the ERM system e Complete altimeter timer bay assembly e Complete Threaded Airframe Coupler assembly made from 6061 aluminum with a blue anodized finish e All mounting hardware for the PML Co Pilot or Transolve P6 altimeter Mounts for Transolve P5 or P4 and Adept ALTS 25 altimeters sold separately e Acomplete ejection system including charge canister for e matches and holder Charge cylinders for flash bulbs sold separately e Rear deployment piston system e External safety switch and lead wires See the Hybrids page of our website for graphics of ERM and additional details 02 24 07 45 74 PMLCompleteFAQ doc ERM Complete vs ERM Retrofit Systems The ERM Complete includes the recovery airframe and the pre cut nosecone All you will need with this is the MMT fin section to make a rocket The ERM Retrofit does not include the recovery airframe nor the nosecone This is good for retrofitting an existing kit ESH 54 Timer Housing An ESHS4 is a timer housing made from a 54mm coupler tube a couple of bulkplates a removable G 10 plate that you mount the timer to and an LES holder The tank of a Hybrid motor is approximately the same diameter as the ID of the coupler tube This allows the ESH to slip over the tank must be friction fitted by a distance of about 1 2 to 1 and butt
79. in 48 72 hours of your order There are no returns on custom items unless we made a mistake Custom items are by definition unique specialized parts and they cannot necessarily be resold to another customer We welcome customers forwarding us RockSim files of their projects as it sometimes helps us understand what you re after However YOU STILL MUST PROVIDE US A DETAILED PARTS LIST OF WHAT YOU NEED INCLUDING CUT LENGTHS DIAMETERS ETC YOU MUST PROVIDE US WITH THE SAME LEVEL OF DETAIL AS IF YOU HAD NOT INCLUDED THE ROCKSIM FILE We will not decipher the RockSim file to determine exactly which parts it contains Look at the RockSim file as a way to help us understand your parts list not a way to produce your parts list and measurement data 02 24 07 20 74 PMLCompleteFAQ doc PML ELECTRONICS FAQ Onboard Electronic Devices Altimeters Timers Etc See the Electronics page of our webstore for more details on each device and other devices that may not be covered here PML currently carries the Co Pilot altimeter The Co Pilot altimeter was developed exclusively for PML by Missile Works Corp and was designed specifically for PML s CPR3000 Recovery System though it can also be used in other applications as well such as scratch built deployment systems The Co Pilot is based upon Missile Works RRC altimeter though it differs in important ways such as location of electronic components which allow
80. in water or if rocket is lost and is exposed to the elements until found Real PML phenolic tubing has the PML logo printed inside the tubing If it doesn t have the logo it s not real PML tubing Beware of imitations because all tubes are not the same One manufacturer s 4 tube may not be the same size as another PML Tubing Component Compatibility With Other Brands We cannot tell you with certainty whether our tubing is compatible with that of another manufacturer This also includes whether our couplers nosecones pistons CPR parts etc will fit another manufacturer s tubing With the variation in tubing from one manufacturer to another we simply cannot tell you with certainty if our components will match well with non PML tubing PML Phenolic Tubing vs Flexible Phenolic Tubing The so called flexible phenolic tubing available from others is nothing more than plain cardboard with an inside and outside skin of phenolic or interlaced layers of phenolic and cardboard In our testing the tubing was not nearly as flexible as the claims would lead you to believe and doesn t have the characteristics of true PML phenolic that have made ours the industry standard for high power rockets for the last 10 years The flexibility features of the other tubing do not prevent damage they simply damage differently Our tubing takes a big impact to fail at all and fails by obvious cracking or chipping The competitors w
81. intended to introduce the newbie to the concept of CG CP t4 4 The CG Center of Gravity and CP Center of Pressure are very important fundamental design and flight parameters of any rocket and have an important relationship to each other The general relationship between the CG and CP is as follows the center of pressure must be a minimum of 1 body diameter BEHIND the center of gravity on a rocket fully prepped for launch to ensure stability Now we ll explain why it must be this way and what you can do to make sure your rocket meets this requirement whether it s a kit or a scratchbuilt design 02 24 07 37 74 PMLCompleteFAQ doc You re probably aware of the center of gravity CG this is the point on a rocket or any object where all the weight seems to be centered The center of pressure CP is similar it is the point on the rocket where the corrective force of the fins is centered OK now imagine just a simple stick a piece of dowel 12 long This is your rocket with one end the nose end and the other the motor end It weighs the same on the first 6 as it does on the rear 6 that s why the CG is exactly in the middle at 6 That s what the CG means where the weight or more correctly mass of the item is centered Now drive an imaginary nail into your stick rocket into the table it s sitting on right at that CG point of 6 OK now push on the front of the rocket and it spins rig
82. is a typical accuracy 3 5K AGL No barometric unit we know of for HPR currently compensates for local ambient pressure conditions so as that fluctuates you ll get some slight variance in readings only for extreme fluctuations 27 74 PMLCompleteFAQ doc PML G10 FINS FAQ Fins Material and Usage G10 is a highly compressed fiberglass laminate in a high temp epoxy resin It looks very similar to computer circuit board material It is extremely tough waterproof and solvent proof It is very rigid yet has just enough flex to keep it from snapping under most loads When scuffed with sandpaper epoxy bonds readily to it and primers and paints adhere well to it too Fins can be made much thinner much less drag when made of G10 and still be stronger than most other materials especially wood It is a very consistent material and does not have any of the hidden structural flaws that wood may have PML was the first to use G10 fiberglass for fin material G10 was exclusive to PML for many years though now other manufacturers have recognized the benefits and offer it as well G10 is used on every PML kit Most other manufacturers use wood especially in larger sizes All PML kits except minimum diameter use through the wall to the motor mount fin mounting design for strength Minimum diameter kits use dado slots in the body tube with fiberglass reinforcing patches for the fin to tube joints Dado A groove or channel t
83. ively perfect conditions to allow repeatability in producing our charts Sure 0 mph wind might be unrealistic for most people s flying conditions but what is realistic 5 mph 10 Depending on the launch sites you personally fly at anything from 2 to 20 mph might be a typical wind condition So the only fair way for us to produce the chart is to set it at known conditions clearly state what those conditions were and leave it to the user s experience or THEIR copy of RockSim to make adjustments to the data we provide as they deem prudent Motor Recommendations Chart The numbers on the Motor Recommendations Chart available on the Specs Page of the website are from simulations run using RockSim software All these simulations are run on bone stock kits so if you add nose weight or make other modifications you will need to adjust the file accordingly to match your situation We recommend you weigh 02 24 07 66 74 PMLCompleteFAQ doc your kit when you re done building and painting and enter that weight into RockSim to get the most accurate simulation results Keep in mind that these predictions were made with the flight day in the simulator set essentially perfect as mentioned above and the real world isn t Your actual flight will likely be different than the simulated one Days with absolutely no wind are quite rare so be sure to compensate for flight conditions on the day you actually fly For example
84. ize the chute in your kit Nearly all of our kits have an Upgrade Chute option listed right next to the kit itself in the webstore 02 24 07 60 74 PMLCompleteFAQ doc Upgrade pricing will vary depending upon the base and upgrade chute There is a fairly large jump in upgrade pricing to move from a 54 to 60 chute This is because the 60 and up PML chutes are a totally different construction Lines are heavier and every seam and edge is reinforced with high strength webbing RockSim a popular rocket design and flight simulation program has a parachute descent calculator as one of it s features The parachute descent calculator function routinely over recommends what size PML chute is necessary said another way RockSim will report that the chute we ship with a kit is far too small rocket descends too fast according to RockSim Apogee admits that the descent rate calculation in RockSim 4 0 uses a fixed Cd which may lead to incorrect chute sizing calculations Here s their reply when we asked them about it This is one of the things we expect to change in a future version of RockSim We want to allow the user to change the Cd for the particular parachute Right now it is fixed and it may be too high or too low depending on the parachute People sometimes ask us for a chute size calculator We don t really have any hard and fast rules on chute sizing We do it by gut feel and experience We suggest you l
85. ke positioning the decal easier This is NOT recommended for the decals from PML they are self adhesive and the soapy water will make them not stick e PML offers both replacement decal sheets for our kits as well as PML logo decals on the Decals Page of our webstore Customers often order AMRAAM or Bulldog decal sheets for their scratchbuild military look rockets as those sheets have items that can be used to mix n match a military look to your own design e We recommend a clear coat of some sort to help protect the decals as well as seal their edges to help prevent them peeling off There are three general gloss levels of clear coat spray available in order of decreasing gloss Crystal Clear very shiny glossy finish almost a wet look Matte or Satin not shiny but not extremely flat dull Testor s Dullcote very flat dull finish most realistic look to missiles etc e When using any clear coat put on only VERY thin light coats and wait at least 5 minutes between coats The clear coat can damage your decals or paint if you put it on too heavily or don t wait long enough between coats This is especially true for the first coat you can go a little heavier after the first one is dry There seems to be something about the solvent used in the clear coat that will eat the decals or base 02 24 07 32 74 PMLCompleteFAQ doc paint if there s too much clear coat on at a time Please go easy on
86. l fillets on your fins or when you know your rocket is going to see super heavy duty flights and you want every bit of strength you can get PML Expanding Foam is a simple inexpensive and easy way to do it There is a PDF document on the Adhesives Page of our website explaining how to use the Expanding Foam The website PDF mentions that open flame and hot wire cutting can produce dangerous fumes but the heat of a motor casing next to the foam is not a concern Don t be fooled into thinking the expanding foam in a can you can buy at the hardware is the same stuff it isn t The main problem with it is unlike our foam it needs air to cure which you don t have inside the rocket in a foam filled area The can foam often doesn t completely cure or even can stop curing and reactivate months later when you get the rocket in the hot sun PML foam stops expanding after 4 5 minutes It will NOT expand any more with heat sunlight etc The PML Expanding Foam features are Expands up to 25 times its liquid volume Dependant on temp and humidity High temp formula Perfect for fin root encapsulation High adhesion rate Two equal part by volume mix ratio Does not need air contact to cure Fast curing Light weight Easy to cut and sand Very carvable Shelf life of 1 year at moderate 70 80 F temps 2 yrs if kept cool and dry Great for strengthening thin wall nose cones or securing nose weight However take care when using the
87. l notches to hold the altimeter to the CPR module The Alt Acc uses a jumper to turn the unit on amp off The system is normally armed by closing a screw on the circuit board again via another hole in the airframe and the status of the unit is determined by looking at a LED on the circuit board via a hole in the airframe I went a couple of steps further and wired the jumper block on off jumper tothe CPR switch mounted on the body tube This allows the AltAcc to be armed without accessing the altimeter directly I also drilled another hole in the altimeter bay so I could view the LED indicator to determine the status of the altimeter 02 24 07 19 74 PMLCompleteFAQ doc PML CUSTOM WORK FAQ Custom Work All specifications requirements for custom work are described in the FAQ for the item in question For example Custom airframe slots See the Airframes FAQ Custom centering rings See the Centering Rings amp Bulkplates FAQ See our website at www publicmissiles com for current pricing on all custom work Check the appropriate page for the type of custom part involved Example for custom centering ring hole boring check the Centering Rings page PML does not make custom nosecones PML offers more custom work options than any other manufacturer Most others only offer fins and centering rings PML also offers quick turnaround time on custom work except for very unique items Custom work is usually shipped with
88. ld TN e Strength Ratings 3 8 1000 9 16 2100 34 3 100 e You may need to clear out flashing from manufacturing in the nosecone eyelets to pull the shock cord through use an X Acto knife If you must open up the eyelet to allow the shock cord to pass through easier do it toward the body of the nosecone not toward the edges of the eyelet that will weaken the eyelet An easy way to pull through a shock cord strap is to put one corner through the eyelet and pull the strap through using pliers e We have a guide to properly tying tubular nylon available on the Recovery Page of our webstore Regarding why we have you attach the chute to the shock cord and not to the nosecone if you attached to the cone and the cone came off the shock cord the whole rocket would plummet If the chute is attached to the shock cord and the cone comes loose only the nose cone falls The reason it s one third of the way up is that if it were exactly halfway the nosecone would bang into the rocket on descent since they 02 24 07 64 74 PMLCompleteFAQ doc were both equidistant from the chute With it at 1 3 and 2 3 respectively they are separated on descent Shock Cord Selection Criteria We use the following as general guidelines for kits For scratchbuilders more and wider shock cord may be better if it fits We recommend using our 12 Tubular Nylon for kits up to 4 diameter with 4 Tubular Nylon for larger than 4 e 2 1 di
89. lets to all critical areas especially the fins Spray the entire rocket with a scratch filling sandable primer Let dry then sand with 220 grit sandpaper Keep repeating the spraying and sanding process until all defects are gone Some people use alternating coats of gray and white primer to help identify particularly high or low areas Use white primer as the final coat for rockets you intend to finish in light colors especially white and the various fluorescent colors Gray is better for rockets you intend to finish in dark colors It is all right to sand through the primer except on the last primer coat Also the last primer coat may be sanded with even finer sandpaper Even better is using a green 3M ScotchBrite pad Now is the time to touch up any dings that may have occurred during assembly Dab a bit of automotive spot putty on the affected area let dry and sand smooth Final Finishing Painting Stay with the same brand of paint throughout the process primer base color accent colors and clear coat Paints seem to work best as a system so use those from the same company to ensure compatibility We ve had good luck with Krylon and it comes in a wide variety of colors However the relatively new Krylon latex enamel sprays can be rather globby Be sure to test them first before using them on your big project Some customers have noticed unpainted QT yellows slightly after long exposure to sunlight Here s why Prolonged
90. ller PT and QT Minimum start point from end of tube 0 375 Maximum uninterrupted slot length is 12 except for 0 188 wide slots the maximum slot length for these is 8 If a longer slot is required we must leave a minimum of a 1 gap in slot Example You need a 14 slot Since this slot is longer than 12 it must be interrupted for 1 at some point such as making a 6 slot a 1 gap then a 7 slot Your fin tang must be then be notched to bridge the gap and a CR should be installed at the gap Maximum total slot length is 18 again except for 0 188 wide slots the maximum slot length for these is 8 02 24 07 9 74 PMLCompleteFAQ doc e The following slot widths are available for tubes 3 9 and smaller PT QT and glass 0 062 0 093 0 125 0 188 and 0 250 e For fiberglassed tubes only 0 062 0 093 slot widths are available with a maximum of 10 slot length e For fiberglassed tubes only 0 125 0 250 slot widths are available with a maximum of 18 slot length Slotting 6 0 tubes and larger e Minimum start point from end of tube 0 75 e Maximum total slot length is 26 e The following slot widths are available for NON glassed 6 0 and larger 0 062 0 093 0 125 0 188 0 25 0 375 and 0 5 e The following slot widths are available for fiberglassed tubes 6 0 and larger 0 093 0 125 0 188 0 25
91. lug at the fin root you limit the size of the fillet If you make the fillet too big the epoxy will block the ends of the lug Also it just makes it harder to sand that area of the rocket while painting One customer asked and the upper fins have some small amount of twist in them All flat stock materials are warped to some degree and I mean ALL except glass as in window pane and stone and G 10 is no exception At PML we know how to cut the sheet so as to minimize the warpage Fin Tolerances Variations in G 10 thickness 0 012 0 003 PML sends back to manufacturer any G 10 with greater variations A very small degree of warpage is common with G 10 but nowhere near the degree of warpage in any wood product and does not adversely affect the aerodynamics of the rocket Fin dimension tolerance stock and custom 0 050 Matched fin sets accuracy 0 010 FYI a human hair is about 0 004 Custom Fins You MUST use the custom fin template downloadable on either the Custom Work or Fins page of our website for a custom fin order Be sure to fill it out completely to avoid delays Minimum custom fin size is 2 by 1 maximum size is 48 by 36 02 24 07 29 74 PMLCompleteFAQ doc Kit Strengthening As mentioned on the first page of the Motor Recommendations Chart on the Specs Page of the website chart cells are highlighted for kit motor combinations that require strengthening We recommend the following ch
92. n stock at that time Keep in mind that dealers may have older kits on their shelves for an extended period of time If all of the tubes in the Kwik Switch set Mother tube and both adapter tubes are the same length then you have the new version This change will not affect the use of the original PMR KS version 6 The bonding surface of the sleeve must be sanded with 80 grit sandpaper to thoroughly scuff the anodized surface The anodizing does NOT have to be removed that s almost impossible anyway just scuffed 7 The motor tube must be sanded with 80 grit as well The retainer sleeve should fit loosely on the motor tube IE It should just fall off when tipped This will assure that the JB Weld or similar is not just pushed out of the way when mounting the sleeve on the tube The sleeve s bonding surface and the tube should be coated with the epoxy and then the sleeve should be pushed onto the tube with a slow twisting motion Any epoxy squeeze out can be removed when the epoxy gels but before it cures 8 After and only after the adapter sleeve is epoxied to the rocket the threads can be lubed with a tiny bit of grease for smoother threading of the 2 pieces and to prevent future galling however unlikely The grease should not be applied before assembly since even the slightest bit accidentally smeared on the bonding surface will weaken the epoxy bond 02 24 07 42 74 PMLCompleteFAQ doc PMR Motor Retention System Regular
93. non KS motor retainers use the lower centering ring as the anchoring point for the threaded inserts For Kwik Switch motor retainers they do not mount to the KwikSwitch adapters but actually span across to the CR that holds the KS Mother tube to the airframe Both KS retainers one for 29 38mm and one for 54mm have the same bolt hole pattern just the ID is different The reason we had to do this is that the Medusa nozzle on the 54mm motors is larger in OD than a 29mm motor casing two different retainers with different ID s were required The PMR 29 38 KS and the PMR S54 stainless steel retainers have the same hole pattern dimensions This means they can be interchanged on the same rocket However they will NOT interchange with the hole pattern for a PMR 29 38 Said another way if you have a rocket that can use a 54mm and a 38 or 29mm EVEN IF IT DOES NOT USE A KWIK SWITCH SYSTEM you must buy the PMR 54 and PMR 29 38 KS The non KS PMR 29 38 and the PMR 54 do not have the same hole pattern the PMR 29 38 KS and PMR 54 do PMR 29 38 should not be used on CR 2 1 1 5 1 5 38mm and CR 2 5 2 1 2 1 54mm as there is not enough wood for ample insert anchoring PMR 29 38KS and PMR 54 should not be used in a Quasar kit or with any CR 2 5 2 1 application e CR 2 1 1 5 kit examples Callisto 38mm Io 38mm Phantom X Calibur Phobos 38mm Explorer 38mm Black Brant VB 38mm e CR 2 5 2 1 kit examples Quasar Small Endeavour Tempest Thunder
94. of 30 of the standard price of the FNC Example FNC 6 0 is 84 95 30 x 84 95 25 49 an extra strength FNC 6 0 would be 84 95 25 49 110 44 This is only an example Always check the webstore for current FNC pricing e See our website at www publicmissiles com for current pricing on all custom work The prices below are shown only to give you a rough idea of the pricing range for such work Convert to boattail by cutting tip add 6 00 for 6 Add 10 00 for 7 5 and 11 4 Slotting for 6 only add 6 00 per slot Slotting for 7 5 and 11 4 is done and charged on a per order basis meaning the charges are not standard They will be quoted when the slotting job is specified Boattails Boattails are long ogive shaped components that are attached to the tail end of the rocket and serve to reduce drag and can add a retro look to the rocket PML boattails are made by modifying our existing line of nosecones 2 1 through 3 9 boattails are made of plastic while our 6 0 and 7 5 boattails are fiberglass Centering rings are included In most cases the tip of the nosecone is cut off at the point that will allow the motor mount tube to fit through the opening In the larger 6 0 and 7 5 boattails various motor mount sizes can be used with the appropriate centering ring placed in the opening at the base of the boattail Unlike tailcones the fins of the rocket are usually mounted through the boattail
95. on kits and prototypes we ve built e PML can answer questions on our epoxy because we use it and have experience with it We can t answer questions about epoxy from other manufacturers e PML does not recommend use of CA cyanoacrylate super glue in most of our kits Experienced modelers may find uses for CA but do not use it in our kits unless specifically instructed to do so or unless you know for sure from experience that it s OK CA should never be used as a replacement for epoxy it should be used as an assembly aid as opposed to as the main bonding agent unless specified otherwise in the kit instructions NEVER use CA on or near piston strapping or shock cords The CA may attack the strapping and dramatically reduce the strength e General Rule of Thumb Slower setting time epoxy stronger finished kit e 5 min epoxy can be used on all PML kits due to the precision fit of components and interlocking design but 12 min is often recommended for those who don t have the experience to complete a procedure before the 5 min type sets up We recommend 12 minute or 30 minute epoxy for all super strength needs e Finishing epoxy e More brittle but also more sandable e Is very thin and good to use when fiberglassing because it wets the glass cloth well e Should not be used for structural work e It takes 12 24 hours before fully setting up and becoming sandable e Mix ratio of the epoxy provided with the Nimbus
96. ook at the Kit Specs sheet on our website and find a rocket of comparable size and weight to what you re working with and select a chute of similar size to what we ship with that kit We also have a Parachute Size vs Weight chart on the Recovery page of our webstore that can help Sometimes we will upsize a chute one notch from what a similar kit might ship with because the kit in question has something special about it that might need to descend slower For example if a kit that would normally ship with a 30 chute has some protrusions particularly big fins or fins that extend well below the airframe we might ship it with a 36 instead to help it descend and land a little softer Folding Packing Flying We have a guide to properly folding packing PML chutes on the Recovery Page of our website We no longer recommend use of the Gradual Deployment feature on our larger chutes Successful operation of the system is too dependent on specific flight conditions and exact setup of the system We have not sold shipped parachutes equipped with Gradual Deployment for a number of years but some customers may still have some Gradual Deployment chutes Piston systems Design Operation Very efficient design captures 95 of ejection gases A PML first and exclusive to PML for years Esssentially guarantees the chute will eject from rocket and will not be damaged from the ejection charge Ejection gases can t leak past the chute and eject the nos
97. ou will have to Dremel out the aft ring Dremel back the fin tabs about 1 4 then insert a new ring to the proper depth to expose 3 8 of the motor tube This is beyond what most people would want to do In this case the best solution is the original Public Missiles Ltd PMR If the motor tube protrudes more than 3 8 the motor tube can be cut back to fit Depending on how much tube needs to be removed you can use a hack saw X Acto razor saw or a coarse sanding block 2 For years we have only sold the PMR for motor retention Hence all of our kit instructions state that the motor tube should be flush with the aft centering ring But as stated in note 1 above the motor tube MUST protrude beyond the aft centering ring by 3 8 You can confidently ignore the kit instructions and make the required adjustment to facilitate the HAMR system There will be no adverse effects to the rocket it s assembly or it s flight characteristics However it is always prudent to check the CP CG relationship on any rocket before flight 3 It is actually a very simple matter to retro fit a rocket that uses a boattail or tailcone Simply scribe a line around the boattail or tailcone 3 8 from the base and cut this section off with a Dremel cut off wheel leaving the motor tube intact and exposed Of course 02 24 07 41 74 PMLCompleteFAQ doc you can perform the cut with a hacksaw blade or X Acto razor saw just as easily This method works with kits
98. out 3 4 inch into the top of the fin section before it hits the top centering ring I doubt that a 3 4 shoulder is a good idea that close to the business end of the rocket Solution Since the SlimLine retainer was not cheap I m determined to use it I plan to sand the top centering ring on the motor tube until it fits INSIDE the 5 inch coupler I ll attach the strap to the motor tube per the instructions I ll then dry fit everything With everything dry fit in place I ll glue the motor tube into the coupler I ll them assemble the rest of the bulkhead per the instructions I ll now have a bulkhead with the top of the motor tube glued inside I ll then prep the outside of the coupler and the inside top of the body apply the epoxy and slide the whole assembly into place dry fitting the tail cone to ensure that it is all in the right place Once all that sets I ll pull the tail cone and install the fins per instructions Make sense I figure this will have a plywood to phenolic bond for the top centering ring and a 2 5 inch wide phenolic coupler to quantium tube bond for the coupler bulkhead That combo should be strong as steel Modification of PMR 29 38 motor retainer for CR 2 1 1 5 kits PML Io As described in the PML Hardware FAQ there is not enough wood in the aft centering ring of the CR 2 1 1 5 kits e g the Io with a 38 mm motor mount to hold the brass inserts that come with the PMR 29 38 motor retainer A solution is to
99. overnight before sanding Also wet sanding is best to sand paint because the water acts as a lubricant and a coolant and flushes away the paint that s sanded off keeping the sandpaper cleaner Make sure you have sandpaper that s made for wet sanding and dip it in the water bucket at least every 30 seconds or So e Apply the last color coat as heavy as possible without running or sagging There s no way to say how much is too much or too little it s just something you develop with practice This is another reason to stick with one brand of paint because you develop a feel for how the paint sprays and adheres to other layers and can learn how much is just enough before it will run e Let the paint cure for at least 48 hours before handling This is difficult to do but will really pay off in the long run Even though the paint feels dry it is still quite soft underneath the top layer and will be easily damaged until it s fully cured e Once the paint has cured you can apply your decals or self adhesive Monokote accent stripes available at most hobby shops Many hardware stores also carry various colors of vinyl tape what most people call electrical tape We ve used red blue green yellow and white as well as the usual black electrical tape for stripes It s a little thicker than Monokote or paint for stripes but is very fast and easy If using water type decals wet the area where the decal goes with slightly soapy water to ma
100. p Go to http mx blastzone com mailman listinfo pmInewsletter to manage your PML News subscription The above URL is also on our Newsletters page of our website at www publicmissiles com so if you forget it some day in the future when you need to do something with your subscription just visit the Newsletters page Glossary Abbreviations Terminology Misc BP Black Powder used for ejection charges CG Center of Gravity the point on an object where it balances where all the weight seems to be centered See additional information under the section Stability CP Center of Pressure the point on a rocket where all the corrective action of the fins seems to be centered See additional information under the section Stability Dado A groove or channel that does not go all the way through a tube Used in minimum diameter kits for fin mounting also used for some canard type fins G 10 A type of fiberglass used in all PML kits for fins Similar to circuit boards ID Inside Diameter 02 24 07 36 74 PMLCompleteFAQ doc KS KwikSwitch motor mounting system LES Loadable Ejection System system used with altimeter for deployment charges MMT Motor Mount OD Outside Diameter VHA Very High Altitude a line of PML kits This abbreviation used on our website and our catalog Inches x 25 4 Millimeters Millimeters 25 4 Inches 1 Pound 4 45 Newtons 1 Pound 16 ounces 454
101. parately Piston Strapping Selection Criteria e 10mm tubular for 1 5 rockets like the Cirrus e 0 75 for 2 1 through 3 9 rockets strap 5 long for these diameters e 2 0 for 6 0 and larger rockets strap is 6 long for 6 0 and 7 5 Piston Strap Heat Resistance Nomex Protectors We sometimes get questions about whether the piston strapping needs to be protected from ejection heat First the strap is a nylon blend not pure nylon so it s relatively resistant to the short term heat of an ejection charge Regarding strap protection PML has sold more than 20 000 kits over the past 10 years That s probably 100 000 flights assuming only 5 flights per kit which is probably substantially too low but for the sake of argument that s what we ll use We ve only had two piston straps returned because of burn through damage That s a 0 00002 failure of piston straps due to heat damage Clearly customer experience has shown there s no need to add piston strap protection it only adds unnecessary weight and cost Also to be perfectly honest most people will lose their rocket to either drifting away on a very windy day a motor cato super late ejection or some other problem long before degradation of the piston strap becomes a concern Shock cords Tubular Nylon Shock Cords e We offer three sizes of tubular nylon shock cords 3 8 9 16 and 34 actually the 3 8 isn t tubular but it is should be used just as you wou
102. phenolic airframe reinforced with fiberglass cloth and have the fins upgraded to a thicker G 10 material There may be other considerations as well it depends upon the specific application See the Kit Strengthening section of the Airframes FAQ for information on when and how to strengthen Extended Kwik Switch and J570 The super long 38mm casing J570 19 2 does not fit the Extended KS We do NOT recommend a super extended even longer KS to be used with the J570 We do not believe the urethane KS mother tube and adapter tube mounts should be used with the high thrust profile of the J570 motor For super long casing mounts such as the J570 or custom motor mounts we recommend our ADPTR 54 38HD shown on the Motor Mounts page of our webstore 02 24 07 48 74 PMLCompleteFAQ doc This adapter is similar to ADPTR 54 38 on our Motor Mounts page with additional larger OD centering rings on the bottom of the adapter This allows the thrust of the motor in the adapter to be transferred directly to the 54mm mother tube instead of through the urethane adapter interface This will stand up to J570 and other high thrust 38mm motor thrust profiles assuming of course that the motor mounts were built and installed per instructions GIANT Kwik Switch PML also carries a Giant KS motor mount This mount uses a 98mm mother tube and can be equipped with both a 75mm and 54mm adapter tube This Giant KS is based on the original Kw
103. purchase some 4 40 nuts from a hardware store and epoxy them to the back of the aft centering ring before gluing the centering ring in place 1 Center the motor retainer on the centering ring and mark the position of the screw holes on the centering ring 2 Drill a small pilot hole 5 64 drill bit Hold the centering ring securely GO SLOW and BE CAREFUL if you rush this step or the next one you could split the centering ring 3 Carefully enlarge the hole to the proper diameter for the bolt to pass through 7 64 drill bit 4 Line up a 4 40 nut with the hole in the centering ring You probably will find the nut is slightly wider than the centering ring In this case grind or file off part of the outside edge of the nut until it s the same width as the centering ring a Dremel tool works fine 5 Scuff up both sides and edges of the nut with 100 150 grit sandpaper to help epoxy adhere to it 6 For each of the 3 holes in the centering ring insert a 4 40 bolt through the hole and attach the nut on the other side of the centering ring don t use the bolts that came with the retainer since you might ruin them during the following steps Use a small amount of epoxy to tack the nut in place on the back of the centering ring the bolt is used to center the nut and pull the nut back against the centering ring while the epoxy sets While the epoxy sets carefully back off the bolt a turn or two while holding the nut secure to f
104. r I m holding a PML tailcone that has an Aeropack motor retainer that looks like it belongs there Sudden Rush I believe it was Darrell Mobley Darrell can you confirm that epoxied a short piece of 54mm airframe inside the boattail then screwed the boattail onto the airframe sandwiching the rear closure of the reload between the 54mm MMT and the short piece of 54 in the boattail BBX Sudden Rush I incorporated positive retention into my PML Black Brandt X The BBX is a 4 kit while the Sudden Rush is 3 but I believe you can find a variation on what I did that will work I can t remember whether it was part of the kit or if I had to add it but you need a centering ring that will go immediately in front of the boat tail Drill two holes 180 degrees apart for retaining screws On the BBX I inserted long screws use washers to keep from crushing the plywood ring and threaded 3 hex joiners these are used to join threaded rod and can be obtained from Home Depot onto each of them 3 happens to be the number that equals the length of the BBX boat tail The tip of the screw should be about half way into the final joiner so you have room to screw in the retaining screw when finished Resting the boat tail s aft end on the table of my drill press I drilled two holes 180 degrees apart that match the locations of the screws This allows the boat tail to be slipped over the studs we have created on the centering ring Make sure th
105. r onboard electronic device Our Magnelites are definitely igniters and likely cannot be used in onboard systems due to the current requirements issue The sample calculations above and manufacturer s recommendations can be used to determine if a particular e match will work with your altimeter PML recommends that all flash bulbs and electric matches have the electrical wires twisted together until just before installation in the rocket system This can help prevent accidental ignition of the device due to static discharge or radio frequency interference RFD The Daveyfire N28BR Electric Match works perfectly with the CPR3000 system for parachute ejection charge ignition The N28BR fits perfectly into the CPR3000 Ejection Charge Cylinder Of course the N28BR can also be used in scratchbuild ejection systems as well Not intended for motor ignition our Igniters Page for Magnelite motor igniter kits The Daveyfire N28F Electric Match works perfectly with onboard staging timers for second stage ignition of G 80 single use motors The N28F can also be used for ignition of other popular rocket motors For best results for motor ignition dip N28F one time into a Magnelite pyrogen mixture sold on our Igniters page Electric matches will usually require extra pyrogen for successful motor ignition CAUTION When dipping take care so that resulting match head will pass easily into the motor grain hole Blocking motor hole can cause over pressu
106. ree up any epoxy that may have found its way into the hole in the centering ring or between the nut and bolt 02 24 07 55 74 PMLCompleteFAQ doc T7 02 24 07 After the epoxy has set build up a shoulder of additional epoxy around the nut to firmly anchor it to the centering ring Make sure some the epoxy actually goes up and over the edge of the nut It will be difficult not to get epoxy between the nut and bolt at this stage but if you occasionally turn the bolt a turn or two while the epoxy cures you ll break any bond that forms Make sure you turn the bolt in the direction that won t pull additional epoxy down into the threads of the nut After the epoxy has cured remove the bolt It may be helpful to use a fresh bolt and run it back and forth a couple of times through the nut to remove any epoxy that found its way into the threads Attach the centering ring to the aft airframe motor mount per the kit instructions Make sure the side of the centering ring with the nuts faces INTO the airframe and that the holes are NOT in line with the fins 56 74 PMLCompleteFAQ doc PML NOSECONES FAQ All PML nosecones except as noted below are 4 2 1 length diameter ratio with a true ogive shape Sizes indicate the size tubing they fit i e the ID of the tubing they fit e 1 1 amp 1 5 diameter are solid urethane both are conical shape 2 15 2 56 3 3 9 are plastic 6 7 5 11 4 are fiberglass 11
107. rization of motor which can rupture motor 02 24 07 24 74 PMLCompleteFAQ doc Other Ignition Devices e We also offer the Robby s Rockets Loadable Ejection System LES kit for those who prefer flashbulb ignition This kit comes with everything you need for ten ejection charges using flashbulb ejection ignition except the FFFFg 4F black powder which can be purchased locally in sporting goods or gun shops especially those that cater to antique firearms such as muzzleloaders Everything but the prewired flashbulbs can be used over and over again This kit is intended primarily for CPR2000 based rockets e However we recommend use of electric matches over flashbulbs for onboard electronic systems Flashbulbs are not recommended due to their much lower reliability and great variability in firing current requirements CPR2000 and CPR3000 A CPR based rocket must always be flown with the electronics installed A CPR based rocket cannot be flown with motor based ejection This is because the fin section coupler bulkplate assembly and the lower drogue piston block off the motor section from the rest of the rocket e PML doesn t sell an altimeter housing kit but we do have an altimeter and LES tube mounting kit that goes along with our CPR2000 based systems Many have used this system in their scratchbuild electronic deployment rockets Check out the website at www publicmissiles com in the CPR Systems section Also check out the D
108. rize we strongly believe in supporting our previous customers and would expect that the altimeter manufacturers can and should do the same by making their products work with CPR either through the base design or through offering CPR compatible mounts for their products 02 24 07 18 74 PMLCompleteFAQ doc BlackSky AltAcc Adapter Modifying AltAcc to work with CPR3000 PML now sells a BlackSky ALTACC adapter which fits all ALTACC models up to and including the 2C the CPR3K ALTACC ADPTR which is available on the CPR Systems Page of the PML website If you have any questions about using the ALTACC with CPR3000 contact BlackSky If you have an older ALTACC with a green board 1 16 has to be sanded off each end of the board for the CPR3K ALTACC ADPTR brackets to fit Prior to the availability of the adapter some customers modified the CPR3000 mounts to fit the ALTACC The following information about modifying the mounts for ALTACC is from a PML customer We can neither confirm nor deny that it works but provide it to you here for your reference I called and talked to Scott at Blacksky and he stated that all you had to do was cut or file four notches in the edge of the circuit board were the screws for the CPR mounting would engage and hold the altimeter in place The copilot altimeter has holes in the circuit board but the AltAcc has 2 metal standoffs that normally hold it to the body tube I took a triangular file and made 4 smal
109. rocket add a mass object at the CG to make the RockSim rocket weigh what the real one does THEN do your simulations That way your simulator rocket weighs exactly what your real one does so you don t have to worry about build differences and slight component weight differences in the RockSim component database Also there s going to be enough difference in RockSim s idealized perfect motor thrust and how your real motor burns wind and temperature humidity etc that the little bit of difference between QT and phenolic isn t going to matter much You shouldn t worry about dialing in RockSim to the n th degree because it s just a simulation a real life flight is going to be different no matter how perfect your input into RockSim is CPR Systems and RockSim See the Close Proximity Recovery CPR Systems FAQ for information on CPR component weights for use in RockSim We recommend creating a Mass Object or Objects with the weight of the CPR components involved 02 24 07 68 74 PMLCompleteFAQ doc Parachute Sizing and RockSim Descent Rate Calculator RockSim has a parachute descent calculator as one of it s features The parachute descent calculator function routinely over recommends what size PML chute is necessary in 4 0 Said another way RockSim 4 0 will report that the chute we ship with a kit is far too small the rocket descends too fast according to RockSim Apogee admits that the descent rate calculation in RockSim 4 0
110. s page of the webstore for a click here graphic showing more detail Fiberglass Nosecones FNCs White epoxy surface coat 6 two layers of fiberglass cloth one layer 100z one 60z 7 5 and 11 4 one layer 180z one 60z Molded in one piece not two halves that are then joined One piece is much stronger All fiberglass cones use a U bolt into a 1 2 thick ply bulkplate for chute and shock strap attachment due to the size and weight of the cones Scuff fiberglass cones with fine sandpaper to paint Fill imperfections in fiberglass cones w Bondo automotive spot putty etc When using epoxy in a fiberglass cone to retain nose weight do just a little at a time allowing the epoxy to cool between batches This will prevent the resin used in manufacture of the cone from breaking down due to the heat of the setting epoxy 02 24 07 58 74 PMLCompleteFAQ doc When you put a lot of quick set epoxy into the tip of the cone the heat generated during curing can exceed 200 degrees F The resin the cone is made of begins to deteriorate at 170 degrees Better yet use a slow setting 24 hour epoxy or our Two Part Expanding Foam sold on the Adhesives page of the webstore Custom FNC e Custom FNC means changes to standard PML FNCs we do not make custom cones e If more strength is required an additional layer of 16 oz fiberglass can be added to our FNC 6 0 7 5 and 11 4 during fabrication for an additional charge
111. se of what I ll describe What I did was to take about a 3 long piece of 3 4 dowel you may want to go smaller for the Little Lunar Express and cut it lengthwise from corner to comer Imagine taking a piece of flat wood 3 long by 3 4 wide and drawing a line lengthwise from the lower left to the upper right corners then cutting along that line It s the same idea with the dowel Then tape a piece of sandpaper to the boattail of the rocket at the bottom end Now take the dowel you cut and moving the dowel up and down along the centerline of the rocket sand the flat area from the cut until it conforms to the shape of the boattail Now sand the boattail area well where the retainer will go and epoxy it in place You might even want to drill a few holes through the boattail under the retainer before installing it to allow epoxy to seep in and rivet the retainer to the boattail The most important thing is to ensure you get a very good bond of the retainer to the boattail since epoxy doesn t bond as well to the plastic as it does to other materials In my full size LE I also slotted the front of the retainer to fit over the fin but you can also put it between fins Whatever looks good to you Now that it s mounted drill a hole for a woodscrew parallel to the centerline of the rocket Drill it small enough that the woodscrew will cut threads into the dowel when you install it but large enough that it won t split the wood Be careful to go
112. sing lengths of various motors e The Kwik Switch 2000 whether as a stand alone part for scratchbuilds or used in kits comes with the 54mm main motor tube and 38mm and 29mm adapters included e The Kwik Switch 2000 ships with the 29mm adapter threaded piece screwed into the mother tube mating half This is done for shipping purposes Some customers have thought the 29mm piece was missing because they didn t notice it already screwed in EXTENDED Kwik Switch The 54mm 1706 reload casing K185W K550W K1100T will not fit the standard KS2000 system For 5 00 you can upgrade to an extended KS2k system that will fit The standard extended KS is 17 which is long enough for a 54mm 1706 K185W K550W K1100T case Also you do not need an extra third centering ring with the extended KS for the center of the longer adapter tubes If you have already purchased a kit and wish to upgrade to the extended KS you must return your original unbuilt KS2000 components with the 5 00 Keep in mind that you may also need to have a longer airframe to compensate for the additional length of the KS EXT depending upon the kit That would also be additional cost and or we d need to ship you some coupler and airframe extension pieces at additional cost to upgrade your standard length kit Some of our rocket kits require strengthening from their stock configuration to fly certain larger motors that would require an Extended KS These rockets MUST use
113. spreader will force the filler into the grooves and will scrape away any excess on the body tube outside the seams Wipe off any globs that occur Allow to dry for an hour 3 Sand the filler with 120 grit sandpaper until it is even with the surrounding surface Usually you will need a second coat since the filler shrinks somewhat After the second coat let dry and resand 4 If needed you can apply a final coat using automotive spot putty again available at automotive stores Only squeeze out a little at a time and recap it because the solvent in it evaporates quickly and any unused portion will become thick and globby You 02 24 07 8 74 PMLCompleteFAQ doc want the spot putty to be very spreadable since it has a finer material grain size than the Elmer s filler and will provide a very smooth final finish 5 Sand the entire surface smooth using 220 grit sandpaper Do not apply any primer coat at this time as the epoxy used in assembly must adhere to the raw tubing Custom Work Custom Tube Slotting Pricing of custom tube cutting and slotting is covered in the Airframes section of the webstore There will be additional charges for the following slotting set ups Unequal slot spacing around circumference of tube odd number of slots except and 3 and or variations of slot width length or start point from one slot to the next on same tube For tubes with four slots or less around the circumference of the airframe all slots have
114. system 02 24 07 72 74 PMLCompleteFAQ doc Two Stage Rocket Booster Delay Timing Shortly after the release of our Terrier Booster for our Mini BBX kit a customer wrote with the following question What motor delay times do you recommend for the Mini BBX Terrier booster Short medium or long Does it matter which upper stage motor ANSWER I think what you re asking is more correctly not what delay time is necessary for the booster but we ll talk about that too but when the upper stage motor should be ignited Well as in lots of rocketry it really depends The general rule or situation you need to look for is if at booster motor burnout the rocket is not moving quickly i e doesn t have a lot of kinetic energy to keep it coasting you want to get the upper stage motor lit NOW If it has a lot of velocity and can coast for a second or two you can set your sustainer stage ignition to be a little later The idea is that you don t want the rocket slowing down to the point where the fins aren t providing good guidance for it before the upper stage gets lit and gets everything under power again When considering when to ignite the sustainer motor also don t forget that the motor may require a bit of time to come up to pressure and really begin a thrusting burn You have to figure that into it too which depends upon the upper stage motor you ve selected Also take into consideration the composition of the second stage motor and acco
115. t reached a certification level where you can buy one check out the weight of the propellant you intend to use and the reload casing from the manufacturer Many times that information is available on the manufacturer s web site Simulate the weight of the casing and propellant in the motor mount tube Use one or more rolls of coins a baggie with dirt in it whatever you can come up with that s similar to the weight of the motor and casing 4 4 02 24 07 39 74 PMLCompleteFAQ doc PML HARDWARE FAQ Launch Lugs e All our round tubular launch lugs under 34 are thin wall brass tubing like a brass soda straw 34 lugs are thin walled copper tubing e The round lug sizes refer to the size rod they fit For example if a kit has a 3 8 launch lug that means it loosely fits a 3 8 launch rod e Customers sometimes ask Is it OK to put the launch lug in the corner of a fin root and the main body The instructions say to put it in between two fins but it would produce less drag near a fin root and would be stronger also This can be done if you re careful but by putting the lug at the fin root you limit the size of the fillet If you make the fillet too big the epoxy will block the ends of the lug Also it just makes it harder to sand that area of the rocket while painting e Our Linear Rail Lugs can be screwed or glued or both Any epoxy will work but JB Weld is strongest Some customers ask about screws inter
116. that you keep some sandpaper in your range box to adjust the fit at the field if necessary The first few times you fly you may need to tune the fit for differing temperature and humidity once you ve gotten it dialed in you should be good for the life of the rocket Sometimes it just takes a bit of tweaking the first couple of times out e The first time you fly a QT rocket in cold weather take it with the piston OUT to the launch site with you and set it outside while you re doing other things Once the rocket s come to ambient temperature try to fit the piston it ll probably be too tight Sand it until it has the nice slip fit you d expect Voila you re done Your QT rocket is now ready to go now and forever Basically once you sand the piston for cold flying conditions it ll fit well then and also will be fine in warmer weather as it s nearly impossible to sand a piston so much it s too loose Think of it sort of like setting CG CP when you build the rocket you add as much weight as the heaviest motor you ll fly to the tail then adjust the noseweight once until it s right It s something you do one time to make sure you re set for the future Same thing with the piston e A little baby powder on the ID of the body tube and OD of the piston helps lubricate the piston assembly Only do this when the rocket is completely finished The baby powder may prevent glues and paints from adhering Piston Systems and Black Powder Ejection Charges
117. thread rod for the actual retainer I cut a piece long enough to engage most of the treads in the brass tube plus about 1 2 inch I then bend it 90 degrees about 1 2 inch from the end Thread the rod in the tube and turn it down until it firmly holds the motor in It works It is cheap and easy It takes up very little room It is a low CD approach t4 4 t4 4 Bullpuppy Attached is a photo of a big external motor clip one customer made looks like aluminum stock to me With this one you d have to work with some retaining nuts etc on the inside of the boattail before assembly but it may be an idea you d like Figure 2 Bullpuppy Aluminum Retainer Clip Thunder n Lightning I think maybe I found a solution to retaining the motor in the booster for Thunder amp Lightning I acquired an Aeropack motor retainer I took a spare piece of pml 38 mm motor mount tube and rubber cemented a strip of 220 grit emery paper The same width as needed around one end I then inserted the other end into the aft end of the tail cone and rotated to remove material from the inside of the aft end The forward extension of the tube keeps the assembly square and by rotating the relief is constant when the Paper loads up pull it out and clean it with a brush when the strip is all inside the cone pull it out clean it and glue on another strip Try not to get glue on the working side of 02 24 07 53 74 PMLCompleteFAQ doc the emery pape
118. tion though if the manufacturer of the electronic device specifies requirements for the ignition devices connected to it follow the manufacturer s specifications over the calculation Co Pilot Altimeter Battery 9 volts Current 1 25 amps E I1xR 9 1 25 x R rearranging we get R 9 1 25 or 7 2 ohms The ignition device must be 7 2 ohms or more to work properly with the Co Pilot 02 24 07 22 74 PMLCompleteFAQ doc Igniter manufacturers will specify the electrical usability ohms and volts range for their devices contact the igniter manufacturer for their specifications We strongly recommend that you check each igniter you intend to use before flight to determine that it is good and within the ohm range needed We also strongly recommend that you ground test the electronic device you intend to use with the ignition device you intend to use before committing that combination for use in an actual flight Ground testing instructions are included in our detailed instruction package provided with each of the Electronic Deployment Devices we sell Timer Ignition Device Selection The AccuFire is designed to work with electric matches or igniters and outputs up to 1 25 amps to the pyro circuit Flashbulb based igniters are not recommended due to their much lower reliability and great variability in firing current requirements The AccuFire pyro channel output circuit is a closed loop feedback amplifier with a limit of 1 25 amps current
119. to work with instead of just the two thin contact spots of the centering rings 2 If you happen to have the misfortune of a motor blowing up the super thick tubing of our adapter will tend to contain and absorb the explosion usually leaving the rocket without damage Hybrid Motor Mounts Hybrid motors require very long motor mounts Call us for specific assistance in obtaining a hybrid motor mount for a scratch build project We do offer kits that are already designed specifically for 54mm hybrid motors see the Hybrid Ready section of the webstore 02 24 07 49 74 PMLCompleteFAQ doc Currently our Hybrid Ready rockets are only 54mm We sell the Tempest and Aurora as Hybrid Ready which can both take the Standard J and the New Hammerhead J Motor Retainers Thrust Ring High power kits don t use a thrust ring in the front of the motor mount like Estes class rockets do because high power motors can vary greatly in length Therefore if you glued in a thrust ring you d be stuck flying only that length of motor If you use a reloadable motor for high power flights the lower closure has an OD larger than the OD of the motor mount tube so that provides the thrust ring by transmitting the force against the bottom of the motor mount tube If you re using a single use motor as opposed to a reloadable you ll need to wrap masking tape around and around the base of the motor until you ve built up maybe 1 16 3 32 thickness of tape to act
120. tor casing touches the airframe directly If your rocket does not fit any of the above special applications and about 90 of most fliers rockets don t QT s right for you Phenolic airframe tubing is the staple of high power rocketry It was first introduced because it is much stronger than cardboard tubing with almost 5x the compression strength It also comes in all sizes from 1 1 to 11 4 It fits all PML components such as nosecones centering rings and etc perfectly It is also a very good base for rockets that will require the strengthening of fiberglass Kevlar carbon fiber or similar materials For this reason we recommend phenolic as the appropriate tubing for rockets that are 6 0 7 5 or 11 4 in diameter or rockets that will require strengthening for the rigors of transonic or supersonic flight We also recommend phenolic for transonic or supersonic flights in kits of 2 1 diameter as phenolic can withstand those flights without strengthening in most instances Fiberglassed phenolic is THE choice when high stress flights of transonic supersonic or BIG motor flights are planned Level 3 flights should all begin with fiberglassed phenolic as the airframe tubing as should any rocket above 2 5 diameter that will fly greater than 950fps see our online FAQ in the Kit Strengthening section for more Fiberglassed phenolic tubing is extremely strong and able to handle nearly any flight profile you can imagin
121. ulkplate was broken off Is this a common failure Is there anything I can do to prevent it from happening again I showed it to someone else at the launch and they indicated the same thing had happened to them This damage to the piston is the classic indicator of too much BP used for the ejection charge What s happening is the piston is ejecting with so much force that it s coming to the end of the piston strap at tremendous velocity then snapping back against the top of the airframe and voila chunked piston skirt In phenolic airframe this is usually manifested by a cracked or chunked top of the airframe too QT can sometimes crack from this problem Look carefully at the top of your airframe and you may find a small indentation or other witness mark of where the piston hit Follow the directions on how much BP to use on the sheet that was packed in your piston kit baggie or as shown above Post Flight There are debates as to whether the piston and airframe need to be regularly cleaned of black power residue All of us at PML occasionally run a damp cloth in the airframe and around the OD of the piston ust like wiping off dirt and let them dry If necessary wrap the cloth around a stick to reach inside 02 24 07 63 74 PMLCompleteFAQ doc Piston strapping Piston retaining strapping 10mm tubular approx 500 1b 3000 Ib 3 4 and 6000 Ib 2 The piston strapping comes with a PML piston kit if you buy the piston kit se
122. unt for that in the timing as well For example a Blue Thunder motor will ignite and come up to pressure far quicker than will a Blackjack It also depends on what you re trying to achieve the absolute maximum altitude of a certain kit A successful two stage flight but staying under a certain waiver Etc It all depends on what you re trying to do Honestly your best bet would be to simulate a number of different delay scenarios to see which one provides the flight profile you re looking for but always keeping in mind a generous safety factor of timing to account for problems like a slow pressurizing motor etc Sometimes an immediate ignition of the second stage motor is best but other times that can actually decrease the ultimate altitude due to pushing the flight profile into a higher drag situation It depends is the honest answer You really need a simulation program to help determine what you want need to do depending upon what motor combos you re using since of course the power level of the booster motor and the weight of the entire rocket which of course depends upon what motors are installed play a big factor in it We d suggest RockSim available at http www apogeerockets com index asp since we already have the data files for the MiniBBX Terrier available for RockSim on our RockSim Data page in our website Now regarding actual booster motor ejection times that of course depends somewhat on the above now that you understand that
123. uses a fixed Cd which may lead to incorrect chute sizing calculations Here s their reply when we asked them about it This is one of the things we expect to change in a future version of RockSim We want to allow the user to change the Cd for the particular parachute Right now it is fixed and it may be too high or too low depending on the parachute PML has been designing and flying high power rocket kits for nearly 12 years as of this writing We have a pretty good handle on how to size chutes for our kits and tens of thousands of customer flights have proven that out so we recommend ignoring the chute descent rate calculator feature of RockSim Custom Work and RockSim Files We welcome customers forwarding us RockSim files of their projects as it sometimes helps us understand what you re after However YOU STILL MUST PROVIDE US A DETAILED PARTS LIST OF WHAT YOU NEED INCLUDING CUT LENGTHS DIAMETERS ETC YOU MUST PROVIDE US WITH THE SAME LEVEL OF DETAIL AS IF YOU HAD NOT INCLUDED THE ROCKSIM FILE We will not decipher the RockSim file to determine exactly which parts it contains Look at the RockSim file as a way to help us understand your parts list not a way to produce your parts list and measurement data 02 24 07 69 74 PMLCompleteFAQ doc PML SPECS PAGE FAQ Specification Sheets PML provides various specification sheets on our website for customer convenience Public Missiles specifications docum
124. utting to act as a guide for the hacksaw If you have access to power wood working tools they can be used to cut PML tubing We have used band saws miter saws and table saws all with very good results After cutting it may be necessary to deburr the edges inside and out using 150 grit or finer sandpaper This is especially true with QT as the cutting process may squeeze the cut end ever so slightly making it tight for inserting a nosecone or for inserting the piston Deburring or chamfering the inside edge of a QT will eliminate those problems Filling Phenolic Tube Spiral Seams Over the years we have tried just about every kind of filler imaginable Our favorite is Elmer s Professional Carpenter s Wood Filler It is easy to apply inexpensive dries quickly and sands easily One can will finish at least 8 average rockets 1 The wood filler sometimes is a little dry and chunky It is water soluble so you can put some into a separate container and add water literally a drop or two at a time Water goes a long way in thinning the filler if you make it too thin add a little more filler and mix it up again 2 Spread the filler over the areas you want to fill using a putty knife your finger or an auto body filler Bondo spreader You can find Bondo spreaders in any automotive store or store like Kmart that has an automotive section Using the spreader push the filler into any seams or grooves you want to fill Using the
125. yload coupler or nosecone shoulder The sustainer upper stage also requires 3 clear at the bottom The Staging page of the website has a PDF file that illustrates design requirements for the upper stage if you are designing a scratchbuilt two stage rocket There is also a PDF file that shows design requirements for the Terrier IS3000 system 1S3000 Specifications Weight The weights given below are without the timer See the Electronics Page on the PML website for timer weight information e IS 3000 2 1 5 5 oz e IS 3000 2 5 6 8 oz e IS 3000 3 0 7 0 oz e IS 3000 3 9 9 3 oz e IS 3000 Terrier 7 5 oz The urethane transition piece weighs 1 30z with the rest of the system weighing 6 2 oz Length The timer enclosure tube which comprises the entire length of the IS 3000 is 5 for all systems except the IS 3000 TERR Terrier system in which it is 8 long Fitting ST 2 Timer to IS3000 The PML AccuFire is the recommended staging timer for the IS3000 system the two were designed together to complement each other The Transolve ST 2b will also fit directly The ST 2 can be used if the customer drills holes in three of the corners of the board However using an ST 2 can be potentially unsafe as it only has one set of two screw terminals requiring the customer to install a switch in series with the electric match to safe the system from firing on the ground Everything else uses off board power and will not fit the IS3000

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