Here`s - Champlain Region Model Rocket Club
Contents
1. Lu O lt x x 2 m Secondary Circuits Wires are Solid Colors w Black Stripe Backup 1 Second Drogue Charge 26 Avionics Bay Assembly Procedure Bulk Plates Using the outside edge of the Body Tube Bulk Plate cut out two gaskets from the gasket material Using a 4 tube cutout the center of the gasket Using CA glue glue the gaskets to the bulk plates Epoxy the Coupler Bulk Plates to the Body Tube Bulk Plates using a bolt through the center holes of the two plates center the plates and compress the epoxy Cut out 2 hole drilling templates on page 21 Tape the templates in place over the assembled Bulk Plates and drill the various holes See SL SK Assemble and attach the various U Bolts wire terminals and charge holders Pem Nuts M Using a large C Clamp compress the Pem Nuts in to the Avionics Coupler Tube Y Using JB Weld epoxy on the inside of the tube the Pem Nuts in place Altimeter Sled Cut the G10 material to the specified dimensions Using the drilling template supplied with the altimeters as well as the battery pack and switch bracket drill the required holes Cut two pieces of the brass tubing to specified length Temporarily assemble the two threaded rods through the bulk plates to be used as an alignment aid for attaching the brass tubes to the G10 sled material Using JB Weld epoxy the brass tubes to the sled Note that one tube is on the front while the other is on the back2. CR 1 CR 2 weigh 40z each and CR 3 CR 4 Weigh 1 50z each D REGION TOMAHAWK 13 Booster Assembly Procedure Continued Final Assembly Epoxy the Fin Can into the Body Tube Use small C clamps at the body tube CR 1 joint Fill the booster fin joint with epoxy Sand smooth Cut the Bulkhead Stop Ring from scrap 5 tubing and epoxy to the inside top of the coupler ring Weigh the couple tube and bulk plate Weight 200z Insert the Coupler into the Body tube but do not epoxy at this time Mount the Bulk Plate and temporary secure with nuts Insert RMS 75mm 5120 Motor Case Test fit the motor retention bolt Remove the Bulk Plate and Motor Case Epoxy the coupler tube to the body tube Add a generous fillet of West System Epoxy to the topside of CR 4 Re attach the Top bulk plate Epoxy the 1 Y washer to the top of the bulk plate 4 YE S S SS S Scale Raised Detail N Cut the Fin Fillet from hard wood stock and epoxy in place N Cut the body tubing raised details from PML Quantum tubing and epoxy in place N Finish Sanding all surfaces and spray a coat of Krylon Grey Primer Y Weigh the final Booster Weight 144 50z D REGION TOMAHAWK 14 Fin Fillet Cross sectional Detail x Fin Fillet End detail Drawing Scale 1 1 20 16 t ST on su 9m 15 8 a 16 BW 11 2 E Q Fin shown for reference _ Calculations for Raised Detail Widths 3 Tube Circumference 5 15 3 14159 16 18 Less Fins Wid
3. Igniters Pack cooler with Gator Aid and snacks READING GLASSES L U D D U U D O L D REGION TOMAHAWK 88 Launch Site Pre Flight Advance Planning _ Schedule a launch date with Mike Dutch _ Verify availability and type of launch rail 1515 or Unistrut _ Verify launch site waiver is above 10 500 feet _ Assemble all required paperwork for certification D REGION TOMAHAWK Pre Flight Checklist Jeffery H Oppold 2 25 2012 89 D REGION TOMAHAWK Appendix Black Powder Calculator 56 Chemical Reaction of Black Powder A4KNOs s C7H40 s 2S s gt 2K2S s 4CO2 g 3CO g 2H20 g 2N2 8 Where KNO3 Potassium Nitrate Saltpeter C7H 0 Charcoal S Sulfur K2S Potassium Sulfide CO Carbon Dioxide CO Carbon Monoxide H20 Water Vapor Steam N2 Nitrogen After much research decided that the above chemical reaction for the combustion of black powder made the most sense There are many similar equations found in text books and on the internet for this reaction most are simplified by treating charcoal as pure carbon which isn t correct However the chemical reaction that occurs during the manufacturing of charcoal is not well known either but did find the following 1 C21H32014 gt C7H40 9CO 5CHa 4H20 Best Guess of Charring Process Where C21H32014 Wood cellulose T lignin C7H40 Charcoal CH Methane D REGION TOMAHAWK 56 Molar
4. I Kevlar Strap o Wildman Rocketry KEV1 D REGION TOMAHAWK 1 Fold Under Recover Harness 32 Jeffery H Oppold 2 25 2012 Deployment Bag Protective Flap Folds over to protect Shroud Lines Bag Opening 25 x 4 Diameter Chute Compartment 1 Wide Elastic Bands Used for Packing Chute Shroud Lines CI Retention S Strap Connected to Nose Cone D REGION TOMAHAWK 1 Loop Opening Deployment Bag Deployment Bag Jeffery H Oppold 2 25 2012 33 Deployment Bag Parts Detail k 63 gt Back Side Body Piece Ia Seam Bottom Piece Kevlar Cloth Allowance Kevlar Cloth J Blanket Stitch Retention All Edges Strap Kevlar Strap es gt N Top Side 50 Body Piece 7 gt lt in 30 1 Wide Elastic Band Kevlar Cloth R 7 Long Stitched Outside of Seam Line 20 Blanket Stitch All Edges 15 Double Stitched down 23 amp 412 Blanket Stitch 10 All Edges Y Seam Allowance Y Seam 5 Allowance 0 D REGION TOMAHAWK 34 Deployment Bag Retention Strap Retention Strap Loop Detail Kevlar Thread 69 Double Stitched 1 Box 5 Y gt Side View a gi gt gt 1 Loop 1 Fold Opening Under Loops are sewn on BOTH ENDS Strap is sewn so that one loop is just inside the bag with the other loop and the majority of strap is outside of the bag see next page D REGION TOMAHAWK 35 Retention Strap shoul
5. Nuts AirFrames Avionics Bay started work on the avionics bay by installing the eight PEM nuts in its coupler tube see page 16 for drawing used the fin alignment guide on page 7 to mark the vertical lines shown and used a heavy paper wrap to draw the circumferential line 2 4 down from the top of the mid airframe tube then placed the coupler tube half way inside the mid airframe tube taping it in place while drilled the four holes for the PEM nuts then marked the lower part of upper airframe tube in the same manner as did the mid airframe tube secured the coupler tube to the mid airframe with several nuts and bolts placed the upper airframe tube on the top portion of the coupler tube and once again drilled the four holes for the PEM nuts then placed an alignment mark to aid in final assembly Pem Nuts Jeffery H Oppold 2 25 2012 63 D REGION TOMAHAWK Pem Nuts O Air Frame placed the Mid Section Air Frame over the booster coupler and aligned it so that the avionics port holes are 90 out of phase from the rail guides very important as need to be able to access the switches inside when on the pad With that alignment intact then drew fin alignment marks up the p side placed tape across these marks and marked the tape removed the tape measured for the center point and the placed the tape back on the body tube and transferred the center mark to body tube then use
6. hole guide on page 9 and marked CR 1 wanted all the holes to precisely line up so placed CR 2 CR 3 CR 4 and ABP 1 inside a small piece of body tube and held them in place with a smaller body tube Using a drill press drilled the four holes through all rings at the same time l also placed alignment marks on the rings so that can place them on the body tube in the same orientation as they were when the holes were drilled just in case my drilling was slightly off however it wasn t Next using the Aero Pack retainer as a guide drilled the 12 holes for the threaded inserts into CR 1 D REGION TOMAHAWK Centering Rings Centering Rings Jeffery H Oppold 2 25 2012 53 Motor Tube Assembly amp Fin Attachment cut the motor to the correct length using a hack saw and sanded the ends square Using the template on page 10 marked the fin locations with respect to the holes drilled for the threaded rods on CR 1 CR 2 and CR 3 Using JB Weld epoxy then glued CR 1 to the bottom of the motor tube making sure the fit and location was compatible with the Aero pack Then using a fin for alignment marked the locations for CR 2 and CR 3 and then glued them in place using a threaded rod to make sure the holes were aligned as well as a square to align the fin location markers then added fillets of epoxy to each ring tube joint 1 Here s the fins mounted on the motor tube It took a bit of doing
7. of sled material Apply a generous fillet to the joints Assemble all components onto the Sled and wire per the schematic on page 24 Weigh the assembled Avionics Bay Weight 59 00z Re EH AEA RH D REGION TOMAHAWK 27 5 Fiberglass 3 1 Ogive Performance Rocketry N Garmin Astro DC 40 GP Tracker see next page for mounting detail Zinc Plated Coupling Nut 20 x4 McMaster Carr 90264A437 Note Coupling Nuts are attached with Soller Composite 1 Carbon Fiber N Biaxial Braided Tape and Epoxy a 20 Stainless Steel Pan Head Bolt CBP3 5 Fiberglass Coupler Bulkhead McMaster Carr 914004257 Performance Rocketry N S Stainless Steel 2 U Bolt w Mounting Plate McMaster Carr 8896T94 da e Mm e L y Bottom View D REGION TOMAHAWK Drawing Scale Nose Cone Jeffery H Oppold 2 25 2012 28 Retention Bolt M3x16mm 0 50 Pitch D REGION TOMAHAWK Drawing Scale 1 1 29 Garmin Astro DC 40 Aluminum Mounting Bracket 1 1 2 Holes S aa Through Both Plates A MN D REGION TOMAHAWK Drawing Scale 1 1 GPS Mounting Bracket Jeffery H Oppold 2 25 2012 30 Nose Cone Assembly Procedure Bulk Plates Drill the four holes in the bulk plate Use the inside of the shoulder for alignment Temporary attached the bolts and coupler nuts to the back side of the bulk plate For each coupler nut align a flat edge to the outside flush with the ed
8. view A perfect 12 edge D REGION TOMAHAWK Fin Construction 45 Jeffery H Oppold 2 25 2012 Fin Construction Plywood cuts are Done Here s a look at the fins after all of plywood cuts have been completed They each weigh 7 5 ounces Next step is to fill in the drilled holes rough edges and any other imperfections Ml use JB Weld for this as want them good and strong Fin Construction Jeffery H Oppold 2 25 2012 D REGION TOMAHAWK Fin Construction 46 Fin Construction Carbon Fiber Overlay The first step in the carbon fiber process is to cut the carbon fiber cloth into the pattern of the fins Nice scissors are a must but it s actually pretty easy to cut However it unravels real easy so cut the cloth about 1 bigger on each edge and then use masking tape to hold it Se a E That s me on the floor cutting 3 FON the carbon fiber cloth The bolt K n lS 60 wide and expensive so want to minimize waste 7 A Try TS HA aa lt Here s what the patterned carbon fiber looks like after it s been cut and the edges taped had to cut 8 pieces D REGION TOMAHAWK Fin Construction Fin Construction Jeffery H Oppold 2 25 2012 47 Fin Construction Carbon Fiber Overlay The second step is to cut the release fabric and batting The release fabric is placed right on top of the epoxied carbon fiber so that when compressed the excess epoxy passes through i
9. zz D REGION TOMAHAWK Drawing Scale l Jeffery H Oppold 2 25 2012 17 K Sheer Pins 1 y Drill 4 holes 90 apart Tap for 2 56 Nylon Screws 4 McMaster Carr 93135A079 20 2 1 al ka nna _ _ Nose Cone Shoulder Depth O S _ 0 125 diameter pressure vent holes 3 O co 45 a _ Avionics Bay Coupler Height 5 Pem Nut Attachment Access Holes Screw holes x 4 in line with fins Note With the Nose Cone attached drill the shear pin holes all the way through the airframe and the Nose Cone s Shoulder Increase the size of the shoulder hole to main D REGION TOMAHAWK Drawing Scale al Jeffery H Oppold 2 25 2012 18 Air Frame Assembly Procedure Pem Nuts Holes Use the fin alignment guide on page 7 to mark the fin locations at the top of the Mid Section Air Frame Extend the marks down 2 from the top of the body tube Secure the Avionics Bay s Coupler inside the body tube up to the half way point Drill the 4 holes for the Pem Nuts through both tubes Use the fin alignment guide on page 7 to mark the fin locations at the bottom of the Upper Section Air Frame Extend the marks up 2 from the bottom of the body tube SE RARA Secure the Avionics Bay s Coupler inside the body tube up to the half way point taking care to align the fin locations with those on the Mid Section Air Frame Drill the 4 holes for the Pem Nuts iS Mid Section She
10. 1 53 grams gt Design for 2 grams Air Frame Upper Section L 35 in Gp 0 0003535 x 10 20 x 52 x 35 3 2 grams gt Design for 4 grams 2 Rocketry Online Info Center Black Powder Usage http www info central org article 303 D REGION TOMAHAWK 56
11. Aeropack 75mm Retainer SkyAngle Parachute CERT 3 Xlarge Kevlar Shock Cord 50 1 Kevlar Strap Shock Cord In Stock 25 1 Kevlar Strap Rouse Tech Discount Hobby Center Motor Case RMS 75mm 5120 Forward Seal Disc RMS 75mm 5120 Carbon Fiber Soller Composites Tape Fabric In Stock 6KPW50 50 x 1 vard Northern Hardwoods Birch Veneer Plywood Sheet 5 x5 PerfectFlite Altimeters Hardware In Stock 1 miniAlt WD Mounting Stand offs Launch Lugs Unistrut Extreme Rail Buttons x2 In Stock D REGION TOMAHAWK Parts List Jeffery H Oppold 2 25 2012 75mm ASSEMBLY Flange RA75 RT 070 RT 081 Biaxial Braided Tape 1 x 10 1515 Delron Rail Buttons x2 G12 5 0 48 108 x2 216 G12 3 0 48 68x1 68 G12CT 5 0 40x2 80 FBP5 0 S6x3 18 FCBP5 0 S6x3 18 FCR45 0 3 0 7x2 10 FNC5 0 3 10 70x 1 70 52x1 52 C3 X 189 x 1 189 KEV1 S1 ft S 50 KEV1 S1 ft 5 25 5399 27 399 5 27 0 94 ft 9 40 S31 yard 31 41 73 MAWD MH44 100 x 2 200 S1 5x2 3 S12 pair 12 S10 pair 10 39 Stainless Steel McMaster Carr Threaded Rod 8 32 Thread Size 36 98847A009 2 59 x4 10 36 Hex Nuts 8 32 Hex Nuts 90257A009 8 39 x 100 8 39 U Bolt 2 Mounting Plate 8896194 4 16x 4 16 64 Sheer Pins 2 56 Nylon Screws 93135A079 4 99 x 100 5 4 99 Threaded Rod Y 20 12 988044487 2 41x2 4 82 PEM Nut
12. However since the Tomahawk has a 3 5 margin of stability can safely assume that it would still be stable in these conditions as it would lose about 1 caliber of margin leaving 2 5 Jeffery H Oppold 2 25 2012 82 Booster Separation Charge Test s bn Sr I KANA nas AER Above is a series of time lapse frames from the charge test for the booster had calculated that needed a little over 1 5 grams of powder which appears to be correct Check out the explosion in the top frame D REGION TOMAHAWK Jeffery H Oppold 2 25 2012 83 Nosecone Separation Charge Test 4 PES GAWA m EZ OES an es aad DE te Y a N WA 4 a aie Above is a series of time lapse frames from the charge test for the nosecone had calculated that needed a little under 3 5 grams of powder which appears to be correct for 2 shear pins was happy to see the deployment bag shoot out and not have to completely rely on the nose cone chute D REGION TOMAHAWK Jeffery H Oppold 2 25 2012 84 Altimeter Test tested my dual PerfectFlite Altimeters in my scale Patriot using the exact altimeter settings that I ll be using on my Level 3 certification flight All charges occurred as planned and the flight was a complete success SET are the initials of the Scott Turnbull a CRMRC member and acting RSO for the launch Below is a scan of the flight card for that launch Guld LAUNCH RECORD Ele L g R L l
13. Layout and Rough Cut cut out a template of the fins from poster board This allowed for an easy transfer of the fin pattern to the plywood surface It turned out that could lay out 2 fins within the 20 height as shown below and saved a lot of material Cutting was done on a table saw don t own a table saw sol had a friend help me D REGION TOMAHAWK Fin Construction 43 Jeffery H Oppold 2 25 2012 Fin Construction Sanding and Cutting Centering Ring Slots It is most important that all four fins be identical so we aligned the root edges clamped the 4 fins together then drilled 3 holes and bolted the fins together This kept them tightly together when the edges were sanded and the centering rings cut We decided we needed the holes anyway so that each individual fin could be attached to a guide for cutting the 12 knife edge on the leading edge see next page Clamped and on the drill press After sanding the edges and cutting the slots for the centering rings Fin Construction D REGION TOMAHAWK Fin Construction 44 Fin Construction Cutting the Knife Edge My friend came up with a really good idea on how the hold the fins so that we would get a perfect knife edge We built a half box as a guide so that we could attach the fins to it then used the ripping fence to align the box and fin to the blade Guide box with the fin attached and aligned to the ripping fence Blade side
14. NAR Level 3 Certification Project Jeffery H Oppold 66 Westall Drive Ext Richmond VT 05477 NAR 88251 Member Champlain Region Model Rocket Club Overview One of my main interests in High Power Rocketry is the construction and flying of scale models When searching for a rocket to build stumbled upon a scale drawing of the Thiokol Chemical Corporation s D Region Tomahawk missile page 3 After studying this design and the availability of the various components required to construct this rocket decided on a 5 9 scale version The main body tubes will be made from Performance Rocketry s G12 fiberglass tubing 3 1 Ogive fiberglass nosecone and birch plywood fins reinforced with carbon fiber surfaces It will use an Aerotech RMS 75mm 5120 Motor Case which allow for the use of an L sized engine for a test flight as well as an M sized motor for the certification flight The estimated weight loaded is 31 5 lbs and when launched with an M1500G motor the rocket should achieve an altitude of 10500feet Recovery will use a dual set of PerfectFlite miniAlt WD logging dual event altimeters The main chute will be Sky Angel Cert 3 XLarge and will provide a rate of decent of 27 ft sec D REGION TOMAHAWK Overview Overview Jeffery H Oppold Design Specification D REGION TOMAHAWK NOISIA O LAW OUYLSY e eee N 1 NOILVUOdNOD TVOINSHD HONOIYLS TiV130 MIVDS TVD TG
15. TIVLIO GVOTAVd ONY ONQYHS NIJ TEMA 904 TWIS oz si 0nN0Y4HS DIJUM 3811 INGI 1 1 VOLIY 001 S 9 H 4 SMBIIS pNOJUS y uid 1929 An M9J3S y Ujj N ES S y gt A op A ELF om aa C TET SMP EN TELS 189 mi yl ES ETTE ERTE ol 5 0 go 158 ES K RL L 4 A a ue 22V3p 3UI uI 1 00 Si 0 196 2 25 2012 409 2_sourys 120 01 D REGION TOMAHAWK Original Blueprint Jeffery H Oppold Drawing Scale 0 085 1 Scale 0 57222 1117 D REGION TOMAHAWK Scaled Blueprint Scaled Blueprint Jeffery H Oppold 2 25 2012 Material Birch Veneer Plywood Carbon Fiber Reinforced lj y gt Soller Composites 6KPW50 54 7 in 2 16 4 54 lt gt Fin Tang Width 64 34 2 14 oa 52 h T 12 13 13 O Y 10 k i D REGION TOMAHAWK Drawing Scale 1 Jeffery H Oppold 2 25 2012 KW y Aerotech RMS 75mm 5120 Motor Case S taS e o S N 2 A E x SS L Ke 451 H pa e9s suimeiq ALAAAAALAALAAAJA A AABALAA AAA AALAAAL AS COROLLA L P GE SES SES SS A A A A A A A A A O A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A AO A A A A A A A A A A A A A A A A A A A A A A A A AO A A A A A E ae TES SR RRR SS SRR RK RRR KR KIRK KR RRR KKK OOO OOOO S AA a A a a a a WP AN RRR RRRR RRR Note Taken from the Aerotech web site http www aerotech rocketry c
16. Weight of the Combustion Products Right Side gt 2K2S s 4CO2 g 3CO g 2H20 g 2N2 g 2 110 3 4 44 01 3 28 01 2 18 01 2 28 01 572 71 g mole So 1 gram of Black Powder produces 572 71 g mole of gas and solid products Now we need to calculate the weight of just the gas products Weight of each gas product 4CO2 176 04 572 71 0 3074 g 3CO 84 03 572 71 0 1467 g 2H20 36 02 572 71 0 0629 g 2N 56 02 572 71 0 0978 g Which allows us to calculate the gram moles of the gas products Moles of each gas product ACO 0 3074 44 01 0 006985 gram moles 3CO 0 1467 28 01 0 005237 gram moles 2H20 0 0629 18 01 0 003493 gram moles DN 0 0978 28 01 0 003492 gram moles 0 019207 gram mole of gas product D REGION TOMAHAWK The point of the calculations on the previous page were so that we can now use the Universal Gas Law to develop an equation that has pressure and thus force as a function of the amount of Black Powder used First a definition of the Universal Gas Law is in order Using the Universal Gas Law PV nRT where P Pressure in lbs in2 V Volume in in nr D 2 L where D BT Diameter L BT Length n number of gram moles of power 0 019207 R Universal Gas Constant 1545 4 ft lb lb mol R T Gas Combustion Temperature 1300 C for 10 Sulfur 2832 R Breaking up the variable n into two part such that n Ggpn where Gae grams of black powder n n
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18. ainless Steel 2 U Bolt w Mounting Plate McMaster Carr 8896194 Sealing Rubber McMaster Carr 99604A1119 11 16 OD Terminal Strip Radio Shack PN 274 678 Sealing Screw 8 Terminals cut down to 2 McMaster Carr 98070A470 1 18 80 10 32 Thread x2 Side View 1 CPVC End Plug gt 5 Bulk Plate Rubber Gasket 5 Coupler Bulk Plate Threaded Rod McMaster Carr 98804A487 20 12 x2 D REGION TOMAHAWK Drawing Scale T lt Avionics Bay Top gt Avionics Bay Top Jeffery H Oppold 2 25 2012 21 Top View Stainless Steel 2 U Bolt w Mounting Plate McMaster Carr 8896194 Sealing Rubber McMaster Carr 99604A1119 11 16 OD a Sealing Screw Terminal Strip Radio Shack PN 274 678 McMaster Carr 980704470 1 18 80 10 32 Thread x2 8 Terminals cut down to 2 IS CPVC Tubing 2 High ______ gt Side View Ya CPVC End Plug ar Ce B o N L l 5 Bulk Plate SS AAA AE AAA aka a 5 Coupler Bulk Plate f E El D REGION TOMAHAWK Drawing Scale 1 Avionics Bay Bottom Jeffery H Oppold 2 25 2012 22 Drilling Template O 13 64 Diameter 50 Diameter 1 4 Diameter 6 C 1 8 Diameter O D REGION TOMAHAWK q Drawing Scale lt Jeffery H Oppold 2 25 2012 23 Altimeter Sled 5 i Mounting hole for ALTIMETERONE E
19. aq eng M IDOSTIA 101d WIS 90 0007 000 1 or rr 5 0009 R Ti D rr baa 0008 DODOT 000ZT D REGION TOMAHAWK RockSim Results 77 2 25 2012 Jeffery H Oppold Drogue Deploy 24 8 sec Apogee Altitude 10560 ft Velocity 4 0 ft s Main Deploy 96 0 sec Altitude 1100 ft Velocity 129 7 ft s Coast 21 2 sec Boost 3 6 sec Velocity a 995 0 ft sec Touch Down 135 sec Velocity 27 4 ft s Launch 0 sec D REGION TOMAHAWK 78 Stability Considerations found this safety report on line at the NAR website and used it as a reference for determining my required take off velocity In it the report recommends a simple rule of thumb that the take off velocity should be at least 4 times the wind speed A 4 1 ratio limits the angle of attack to 14 degrees which Dahlquist found to give 1 caliber of CP shift where one body tube diameter is referred to as one caliber This ratio can be achieved using more thrust lighter weight or a longer rod RockSim divides the wind speed into several ranges and I ve calculated the minimum take off speed for each range using the above ratio of 4 1 RockSim Wind Speed WindSpeed Take off Velocity Setting mph ft sec ft sec Calm 0 2 9 4 2533 17 0132 Light 3 7 9 11 5867 46 3468 Slightly Breezy 8 14 9 21 8533 87 4132 On the following three pages are the RockSims results for the above wind conditions l ve assumed a Uni st
20. ar Pins Pressure Vents M Draw an alignment mark directly centered between each fin and make a mark 4 up from the bottom 7 Drill a shear pin hole and tap screwing in a shear pin before drilling the next hole Drill all 4 holes in this sequence Y Drill the pressure vent holes Y Weigh the final Mid Section Air Frame Weight 35 00z Upper Section Shear Pins Pressure Vents Extend the fin alignment marks drawn in the Pem Nut assembly procedure down the full length of the tube Find and mark the center point between each of these marks 1 down from the top Drill a shear pin hole and tap screwing in a shear pin before drilling the next hole Drill all 4 holes in this sequence Drill the pressure vent holes Weigh the final Mid Section Air Frame Weight 59 00z RE WEA amp D REGION TOMAHAWK 19 Main Chute Charge Holders PEM Nuts x 4 in line with fins McMaster Carr 10 24 94648A350 Threaded Rod x2 McMaster Carr 98804A487 20 12 Note Use JB Weld to secure PEM Nuts 11 to the inside of the Avionic Bay coupler 5 Diameter G12 Coupler Tube 11 Long PEM Nuts x 4 in line with fins McMaster Carr 10 24 94648A350 a L Altimeter Sled Retention Nuts CBP 1 nma 2 aE n ABP 2 El Vol A Apogee Charge Holders Top and Bottom Charge Holder details are on next two pages D REGION TOMAHAWK Drawing Scale 1 Avionics Bay Jeffery H Oppold 2 25 2012 20 Top View St
21. ation is correct w r to the Aero Pack Using the 8 32 Threaded Rod as an alignment aid epoxy in place CR 2 amp CR 3 Using the fin guides tack epoxy the fins 4 Minute JB Weld to the motor tube Verify that each fin is 90 w r to each fin on its left and right amp is 90 w r to the body tube Drill the correct size hole in the center of each rail guide ring and screw in the threaded inserts Using Elmer s Carpenter s Glue glue the rail guide rings to CR 1 amp 4 Clamp until dry Using Loctite Hysol epoxy put a good size fillet along each fin body tube seam Form the internal fin fillets by using the carbon fiber tape amp WS epoxy Epoxy in place CR 4 but omit the top fillet as the coupler tube needs to fit flush against this ring Install the threaded rod and nuts Secure nuts with Loctite Blue 242 Threadlocker Weigh the final assembly Weight 86 00z A ISS Lal S SL l LS RRA Subtract 4 x weight fin and total weight of the rings from the above measurement This is the motor tube epoxy carbon fiber rods rail guides weight Updated Motor Tube Weight 28 402 Body Tube Cut the body tube to length from 5 G10 Fiber Glass Tubing Cut the 4 112 slots for the fins Fit the final Fin Can assembly inside the booster tube Mark the rail guide locations on the outside of the body tube lt lt Sh IS El Remove the Fin Can and drill the holes for the retention screws Weight 27 000z 1 Boat Tail
22. d exit between the bottom and back side pieces seam centered on the back side piece with one loop just inside the bag lt Deployment Bag 1 Wide Elastic Band 635 Long Double Stitched down J 3 4031 9 U 32 p T16 amp 32 20 gt Double Stitched 15 gt Bottom View 25 10 gt 5 D REGION TOMAHAWK DeploymentBag Deployment Bag Jeffery H Oppold 2 25 2012 36 Preparation Stand Side View Y PVC Cap S 1 PVC Cross DO Y PVC Pipe 6 Long Y 1 D Pipe Insulation lt IR PVC 90 Elbow E D REGION TOMAHAWK Drawing Scale Preparation Stand Preparation Stand Jeffery H Oppold 2 25 2012 37 Preparation Stand Front View d gt d h R aa WAH Y PVC Pipe ji W E a 24 Length Not Shown to Scale gt T T d ra Y 1 D Pipe Insulation Y PVC 90 Elbow Parts List Y PVC Cross x 2 2 PVC Round Cap x 4 Y PVC 90 Elbow x 4 Y PVC Pipe x 10 ft Y 1 D Pipe Insulation x 3ft D REGION TOMAHAWK Drawing Scale AE Jeffery H Oppold 2 25 2012 38 Body Performance Hobby Airframe 5 0 Glass Tube 48 Motor Tube 3 0 Glass Tube 48 Booster AVbay Couplers 5 0 Glass Coupler 10 Airframe Bulk Plates 5 0 Airframe Bulk Plate Coupler Bulk Plates 5 0 Coupler Bulk Plate Centering Rings 5 0 to 3 0 CR Nose Cone 5 0 Ogive 3 1
23. d this mark as the vertical alignment for the shear pin locations then measured 1 up from the bottom on each shear pin vertical alignment line and drew a mark for the shear pin hole Then in sequence drilled a hole for the 2 256 tap tapped the hole and then screwed ina shear pin then repeated this sequence at each shear pin location This resulted in perfect alignment of the 4 pins then increased the hole in the coupler to 7 64 Finally drilled the 1 8 pressure relief holes The Upper Air Frame is assembled in a similar manner D REGION TOMAHAWK AirFrame O Air Frame Jeffery H Oppold 2 25 2012 64 Avionics Bay then compressed the PEM nuts into the coupler tube using a large C clamp Using JB Weld epoxy permanently secured the nuts to the coupler tube You can see in the picture that roughed up the inside of the tube around each nut so that epoxy would have more surface area to adhere to Also it s important to use something like JB Weld because it works so well with metal In the sequence of pictures at the bottom show how cut the sealing gaskets that are placed between the Avionics bay s coupler bulkheads found the gasket material at ACE Hardware it looks like nylon but is very compressible its normal use is for lining the bottom of drawers used the coupler bulkhead for the outside guide and a 4 PML tube for the inside D REGION TOMAHAWK Avi
24. e a Altimeter Test D REGION TOMAHAWK Altimeter Test 85 D REGION TOMAHAWK Pre Flight Checklist not complete yet 87 Shop Pre Flight Advance Planning _ Schedule a launch date with Mike Dutch _ Verify availability and type of launch rail 1515 or Unistrut _ Verify launch site waiver is above 10 500 feet _ Assemble all required paperwork for certification Deployment Charges _ Select 8 e matches 4 primary 4 Backup Verify continuity with ohm meter 1 ohm _ Construct 4 charge holders using Micro Centrifuge tubes and JBWeld epoxy _ Verify that have enough 4F black powder in my powder can 120z Altimeter Sled Assemble Altimeter Sled Install fresh batteries Check Altimeter deployment settings Make sure backup drogue is programmed to apogee 1 second Test Altimeters for proper Beep sequences If all good remove batteries and pack Install AltimeterOne O O O O D L Pack instructions for both the Perfectfite and AltimeterOne altimeters Packing Assemble Shock Cords and Quick Links Pack Main Drogue and Nose Cone Parachutes as well as deployment bag Secure GPS Transmitter and Receiver from CRMRC Club Charge batteries Assemble Tool Box tapes tie down cables grease paper towels table and chair Place motor casing inside body tube Include forward seal ring Pack unassembled motor and liner tube Don t forget assembly instructions Pack at least four 4
25. er holes and attached it temporarily to the sled then marked the place for the ties removed the holder and drilled the end holes of slot filing out the rest of the slot with a hobby files The last thing was to affix labels to aid in the identification of the circuit and various wires Altimeter Sled Jeffery H Oppold 2 25 2012 68 D REGION TOMAHAWK Altimeter Sled Altimeter Sled When attached the battery holder noticed that it was Sagging from the tension of the bolts because the stand offs are only in the corners To fix this cut out two strips of plastic with the proper thickness glued them in place and drilled the holes B Here s the assembled Sled sans the battery In hind sight wish would have swap the locations of the bottom wire exit holes at it would have provided a much more clean exit path thru the bulkheaerds Not a big deal but something to think about Jeffery H Oppold 2 25 2012 69 Nose Cone The nose cone arrived with a very warped shoulder and would not fit into the body so had to come up with a way to fix the warp With a lot of force was able to get a scrap piece of body tube around the shoulder which forced the shoulder round To hold the now round shoulder in place used auto body filler Bondo built an inside trowel out of popsicle sticks and keeping is tight against the outside was able to mold a pretty decent band of filler keeping the inside ro
26. erts and installed them then installed the threaded rods being careful not to stress the fiber glass rings thumb tightened top and bottom nuts and then alternately tightened the top and bottom nuts to maintain a systematical torque This was a rather long and tedious task but when finished could tell this results in an incredibly solid fin can construction Internal Fin Fillets D REGION TOMAHAWK Internal Fin Fillets 58 Booster Coupler cut a Y piece of fiberglass from a scrap piece of 5 G12 tubing cut it to fit the inside diameter of the coupler tube and secured it to the top recessed down the thickness of the bulk plate with epoxy This provides a stop ring for the bulk plate to rest on flush to the top of the coupler tube used epoxy again to secure the bulk plate to the ring via a generous fillet then attached the slotted booster body tube to the fin can using epoxy at CR 1 and around the fins To attach the booster coupler put generous amount of epoxy on top of CR 4 forming a fillet where the coupler will rest on top of it then simply slid the coupler over the threaded rods and held it in place with some weight until cured bolted down the threaded rods with two nuts and secured with epoxy High Temp JB Weld The next page show the competed booster without the body panel detail Booster Coupler D REGION TOMAHAWK Booster Coupler 59 Fin Slots On the left
27. ge of the bulk plate Using JB Weld epoxy quick cure place a small amount on the edge of the coupler nut that is flush with the bulk head outer edge Slide the assembly inside the nose cone shoulder and allow the epoxy to cure Carefully remove the bolts and bulk head The coupler nuts should be perfectly aligned Using the carbon fiber tape and West System Epoxy thicken to mayonnaise consistency carefully wrap the tape around the inside of the shoulder covering the coupler nuts Take care not to the get epoxy on the inside threads of the nuts Drill the two holes for the U Bolt Cut a piece of G10 for the GPS mounting plate Place the G10 sheet inside the mounting bracket and mark the location of the holes and drill Using the back piece of the GPS unit mark where the holes for the attachment screws go and drill Assemble all components to test for fit and function Weigh the assembled Nose Cone Weight 29 60z S SSL SSL S BRA BAAR D REGION TOMAHAWK 31 Recovery Harness Booster to Mid Section Drogue Chute Quick Link 3 16 x 2 Booster Mid Section Quick Link E Quick Link J lT D D Upper Section to Main Chute Upper Section Main Chute Quick Link Quick Link y N D P Quick Link Loop Detail Loops should be tight but still allow for Stainless Steel Triangle Quick Link the Quick Links to be removed McMaster Carr 3709732 Kevlar Thread 69 Double Stitched 3 Folded O
28. h the switches mounted on the altimeter sled re used the 90 alignment marks used for the PEM nut alignment ran a piece of masking tape between these marks and marked the tape then removed the tape and found the center point between these marks placed the tape back on the body tube and placed a mark 2 down from the top of the airframe mid section With the Avionics Bay inserted into the airframe drilled the port hole then repeated the above for the airframe upper section placing the port hole 180 from the mid section s port hole and from the bottom That completed the construction of the Avionics Bay D REGION TOMAHAWK Avionics Bay Avionics Bay Jeffery H Oppold 2 25 2012 67 Altimeter Sled After cutting the G10 material to the specified dimensions used JB Weld epoxy to attach the brass tubing to opposite sides of the G10 base To get the proper alignment of the tubing attached the top and bottom bulk plates of the avionics bay with the threaded rod and used it to hold the brass rods in place while the epoxy cured The layout of the altimeter sled consists of a primary and backup circuit with each circuit mounted on opposite sides of the G10 sled The PerfectFlite User s Manual had a hole template for the altimeter so used that For the switch mounting bracket and battery holder simply used them as a template For the battery cable ties first drilled the battery hold
29. ike The West System Epoxy is unbelievably strong when used with the carbon fiber tape I ve used this type of fin joint on three level two class rockets and have never had a fin joint failure not even on the flight where had a partial chute failure D REGION TOMAHAWK Internal Fin Fillets Internal Fin Fillets Jeffery H Oppold 2 25 2012 56 Fin Slots Here s the box that my friend and designed and built to router the fin slots We made it adjustable up to 6 inches so that it can be used multiple times Notice the grooved slot on the upper left this will hold the router sled We built the sled out of plexiglass so that it would allow for viewing of the cut as it is being made Note the rail guide on the right It fits and slides in the groove slot shown above Here s an action shot and a quick look at WA the start of the second pass on the router Two passes because the G12 is a tough material to route ee a y y y TS f LA A Y a Fin Slots Jeffery H Oppold 2 25 2012 57 D REGION TOMAHAWK Fin Slots Rail Guides amp Threaded Rods used a plywood center ring cut into 6 pieces for the rail guide anchors placed the booster body tube over the fin can and drilled the holes through the fiber glass body and into the plywood ring so that would have perfect alignment then removed the body tube and enlarged the holes to accommodate the threaded ins
30. is the booster body tube with the fin slots and on the right is the completed booster without the body detail D REGION TOMAHAWK Body Tube Raised Detail cut the fin fillets out of maple and used Loctite Hysol epoxy to secure them in place This was actually a pretty difficult step as the fillets were quite small to cut on a table saw resulting in rough surfaces with lots of a blade marks that filled with Elmers wood putty seen as white blotches on the fillets Since couldn t get clamp on these used masking tape to hold them place checking them often to make sure they hadn t moved cut the raised detail pieces and used the templates to round the ends to the correct contours using a dremel tool with a sanding disk tested several glues and found that PVC cement worked best for attaching the plastic details to the fiberglass body tube Once again had to use my hands on the far end to hold the pieces in place but the PVC cement dries pretty quick so this wasn t a big deal D REGION TOMAHAWK Body Tube Raised Detail Once all the pieces were in place and the cement had dried sanded the details to cleanup any stray cement then used a plastic model panel line scriber tool to widen and cleanup the lines between each of the raised detail panels Below it the raised detail ready for primer and paint D REGION TOMAHAWK Body Tube Raised Detail Jeffery H Oppold 2 25 2012 62 Pem
31. l E red E S L ES L L E L S S E ra E 2a reel pas pa ES al pal E 2 Cc gt O Ju gt E S QU 20 O a ae r UN l O cn p 3 3 lt O E 2 H E H 7 2 Cc O Sa LL 3m 8 1 UA AA III MANAT m All Holes are lt D REGION TOMAHAWK O A x INOYSLOWILIE 5 Diameter G10 Coupler Tube 11 Long Aluminum Bracket for 2 Pole Detent Switch Aligned with pressure neutralization holes Altimeter PerfectFlite miniAlt WD attached using PerfectFlite mounting hardware Ya Inside Diameter Brass Tubing d G10 Fiberglass Sheet 7 5 x 4 5 ni Altimeter Sled Retention Nuts Threaded Rod McMaster Carr 98804A487 20 12 x2 Battery Held on with Plastic Cable Ties Top View Drawing Scale gt 24 Aluminum Bracket Detail al k es 12 14 Z D REGION TOMAHAWK Drawing Scale 1 1 Avionics Bay Altimeter Bracket Jeffery H Oppold 2 25 2012 25 Primary 1100FT Main Charge Avionics Top Bulkhead e Missile Works O 2 Pole Detent Switch qe 110 OFF q 220 ON E N 105 DURACELL Avionics Bottom Bulkhead Primary Drogue Charge D REGION TOMAHAWK Avionics Bay Schematic Jeffery H Oppold 2 25 2012 Primary Circuits Wires are Solid Colors Backup 900FT Main Charge
32. nce Fairly constant speed 0 01 Frequency 0 010000 rad second Wind starts at altitude 0 00000 Ft Launch guide angle 0 000 Deg Launch guide data Launch guide length 120 0000 In Velocity at launch guide departure 78 5266 ft s The launch guide was cleared at 0 260 Seconds User specified minimum velocity for stable flight 46 3468 ft s Minimum velocity for stable flight reached at 40 8599 In Here the take off velocity is about 1 7X pretty safe The stable flight velocity is attained about a third of the way up the launch rail D REGION TOMAHAWK 81 Stability Considerations Launch conditions Altitude 0 00000 Ft Relative humidity 50 000 Temperature 59 000 Deg F Pressure 29 9139 In Wind speed model Slightly breezy 8 14 9 MPH Low wind speed 8 0000 MPH High wind speed 14 9000 MPH Wind turbulence Fairly constant speed 0 01 Frequency 0 010000 rad second Wind starts at altitude 0 00000 Ft Launch guide angle 0 000 Deg Launch guide data Launch guide length 120 0000 In Velocity at launch guide departure 78 5266 ft s The launch guide was cleared at 0 260 Seconds User specified minimum velocity for stable flight 87 4132 ft s Minimum velocity for stable flight reached at 151 6107 In Here we might have a problem as the rocket does not reach the Stable flight velocity until about 2 5ft after it has left the rail So would either need a longer rail or lighter winds since can t change this motor
33. om customersite resource_library aerotech_rms_ext_dim_dwgs 75mm_hp_rms hp_75 5120 pdf 1 6 S Drawing Scale D REGION TOMAHAWK RMS 75mm 5120 Motor Case Jeffery H Oppold 2 25 2012 8 32 Stainless Steel Hex Nuts x 36 McMaster Carr 90257A009 Stainless Steel 3 8 EYE Bolt McMaster Carr 33045T52 1y3819H qn Jajdnoy 37 ll d y D O 5 ee VU a gt O Y bD m Y oS L E S C o gt Y O c O n Y O dU lt O op O O C O c E G OD we n A bp 258 55 Ye S UM O N we D x 00 A a a E A 3 L A oO O M EE a LU sai vo Zo O 205 iL T N SNS LL ja e A E iz Ow co Y o G eo t ee e e Y O sE 30 g v o Z O lt O Z Y Z A lt E SES N WS SPO POOP E WS PRR RRR RRR KKK RRR RK KK RK KKK RK KKK ROKK RK AKON NG aaa OO A A e BF E E F a ee ee ll al a ll ll ll ll E E de de le ld ll _ o Ly L A k PE e nnn s n T ds T Aw i KKK 5 Diameter CR 3 Bulk Plate Stop Ring G12 Coupler Tube 10 Long Y Wood Center Ring Carr 90192A114 10 x 2 Stainless Steel Threaded Insert w 10 24 Screw Stainless Steel Threaded Rod x4 McMaster Carr 98847A009 McMaster RMS 75mm 5120 Motor Case 21 14819H aqn Apog D REGION TOMAHAWK Booster Section Aero Pack RA75 Boat Tail 2 25 2012 Jeffery H O
34. one for the bag one for the drogue chute and one for the nose cone chute DIA ia AU Yi D REGION TOMAHAWK 72 Painted Jeffery H Oppold 2 25 2012 D REGION TOMAHAWK Painted o 73 D REGION TOMAHAWK Simulation amp Ground Testing 75 vel3 rath er 3125 h Diameter j Mass 555 4180 Oz Se lected a ass gt 7 i Tomahawk _level3 Simulation results Engine selection M1500G Launch guide data Launch guide length 120 0000 In Velocity at launch guide departure 78 5265 ft s The launch guide was cleared at 0 260 Seconds Max data values Maximum acceleration Vertical y 662 587 Ft s s Maximum velocity Vertical y 995 0146 ft s Maximum altitude 10559 50304 Ft Recovery system data Parachute Main Deployed at 96 039 Seconds Velocity at deployment 129 6941 ft s Altitude at deployment 1099 88214 Ft Parachute Drogue Deployed at 24 815 Seconds Velocity at deployment 4 1780 ft s Altitude at deployment 10559 50303 Ft Time data Time to burnout 3 600 Sec Time to apogee 24 815 Sec Optimal ejection delay 21 215 Sec Landing data Time to landing 134 925 Sec Velocity at landing Vertical 27 4282 ft s D REGION TOMAHAWK RockSim Results RockSim Results Jeffery H Oppold 2 25 2012 76 oul UC L DOT 06 09 OF UC 0 j 0 DUC DUE S o ct kad ynowwng TI D D cr u 009 ami 008 aabody 000T gpr qMeyeulo y U99S9q yo ayey Aojd
35. onics Bay Avionics Bay Jeffery H Oppold 2 25 2012 65 Avionics Bay Using epoxy attached the bulkhead gasket to the bottom of the top bulkhead pieces x2 then attached the bottom bulkhead pieces to the gasket side of the top bulkheads bolted the two bulkhead assemblies together and then cut out the bulkhead drilling template on page 16 and taped it to the top bulkhead Using the specified drill bit sizes drilled all the required holes on my drill press Left picture below removed the bolt and filled the center holes with JB Weld and then sanded them smooth when it had dried The center picture below shows the under side of one of the bulkheads highlighting the sealing gasket The picture on the right shows a completed bulkhead sans the wiring From the PerfectFlite User s Manual the recommended atmospheric pressure sampling port hole size for the miniAlt WD is calculated as follows Hole Diameter Tube Diameter X Tube Length X 0 006 5 0 X 10 5 X 0 006 0 315 Diameter or 0 078 in Area need two holes to access each of the altimeter power switches so given know the area the minimum diameter of these two holes is calculates as follows D REGION TOMAHAWK Avionics Bay Avionics Bay Jeffery H Oppold 2 25 2012 66 Avionics Bay 1 1A Hole Diameter 2x 2 TE 1 30 078 _ 0 039 22 0012414 2x0 11142 0 22284 3 14159 3 14159 MEN 64 To get these port holes aligned wit
36. ppold Print out and place tube on top marking slot location on outside of tube Fin Slot is 11 5 8 long starting 1 2 from the bottom and is in width D REGION TOMAHAWK Drawing Scale 1 0 1 0 Top View O D 5 150 lt ID 4 00 O D 3 125 Cut Down Cut Out Side View Glue to bottom of CR 1 N ih T y EM 15 Cut Down Depth E Material Birch Veneer Plywood D REGION TOMAHAWK a Drawing Scale 1 0 1 0 10 Top View Make an Alignment Mark here on all fins Drill 11 64 Holes D REGION TOMAHAWK Drawing Scale 1 0 1 0 11 Top View Transfer to Top of CR 1 Placement of 1 6 circle ring used CR 2 and bottom of CR 3 for Rail Guide mount Center line for threaded insert D REGION TOMAHAWK Drawing Scale 1 0 1 0 12 Booster Assembly Procedure Fins Centering Rings Cut the fins out of the Birch Plywood Weight Fin 7 500z Carbon Fiber the fins Use West System Epoxy Bondo Filler Weight Fin 10 650z Cut four holes for the 8 32 Threaded Rod in each Centering Ring amp Top Bulk Plate Install the threaded inserts for the Aero Pack into CR 1 Total Weight 15 002 Cut the Motor Tube to the correct height Motor Tube Weight 16 00z Dry fit in place CR 1 CR 2 amp CR 3 on to the motor tube Using the template on page 10 mark the fin locations on CR 1 CR 2 amp CR 3 Epoxy CR 1 to bottom of the motor tube making sure its loc
37. rut rod length of 10 feet 120 inches 1 Launching Safely in the 21st Century Final Report of the Special Committee on Range Operation and Procedure to the National Association of Rocketry http www nar org pdf launchsafe pdf 2 B Dahlquist Wind Caused Instability High Power Rocketry March 1998 Updated version available at http www apogeerockets com education instability asp D REGION TOMAHAWK Stability Considerations Jeffery H Oppold 2 25 2012 Stability Considerations Launch conditions Altitude 0 00000 Ft Relative humidity 50 000 Temperature 59 000 Deg F Pressure 29 9139 In Wind speed model Calm 0 2 9 MPH Low wind speed 0 0000 MPH High wind speed 2 9000 MPH Wind turbulence Fairly constant speed 0 01 Frequency 0 010000 rad second Wind starts at altitude 0 00000 Ft Launch guide angle 0 000 Deg Launch guide data Launch guide length 120 0000 In Velocity at launch guide departure 78 5266 ft s The launch guide was cleared at 0 260 Seconds User specified minimum velocity for stable flight 17 0132 ft s Minimum velocity for stable flight reached at 5 6892 In Lots of margin with these conditions 4 6X no surprise D REGION TOMAHAWK 80 Stability Considerations Launch conditions Altitude 0 00000 Ft Relative humidity 50 000 Temperature 59 000 Deg F Pressure 29 9139 In Wind speed model Light 3 7 9 MPH Low wind speed 3 0000 MPH High wind speed 7 9000 MPH Wind turbule
38. s 10 24 Captive Nut 94648A350 S6 34x10 6 34 Sealing Washer Silicon 11 16 OD 99604A119 11 84 x50 11 84 Sealing Screw 1 18 80 10 32 Thread 98070A470 S8 30x10 S 8 30 Coupling Nut Zinc Y 20 1 Length 90264A437 1 80x4 7 20 Pan Head Bolt 20 2 Length 91400A257 5 46x10 5 46 Quick Link Triangle 3709T32 S7 50x4 30 00 Eye Bolt 3 8 16 33045T52 21 66x1 21 66 Epoxy McMaster Carr High Strength Epoxy Loctite Hysol E 20hp 6430A19 12 16x2 24 32 Applicator Gun 74695A71 527 74x1 27 74 Bayonet Mixer Nozzle 5 9 L with 1 4 Taper Tip 74695412 50 91 x 121 10 92 Threadlocker Loctite 242 0 34 oz 91458A112 12 39x1 12 39 Giant Leap Chute Swivel In Stock Eyelet 1500 Ib test S6 00 x1 6 00 Custom Made Center Rings 5 0 to 3 0 Birch Ply 10 00 x2 20 00 D REGION TOMAHAWK PartsList Parts List Jeffery H Oppold 2 25 2012 D REGION TOMAHAWK Construction Construction Jeffery H Oppold Construction 41 Fin Construction Y Birch Plywood 5 x 5 Sheet ENN MANA SAN had the lumber dealer cut the sheet into 3 20 wide so that could get it home in my car My plan is to cut 5 or 6 fins and pick the best of 4 out of them Note the direction of the wood grain as l Il want the outside ply s grain to be perpendicular to the root edge D REGION TOMAHAWK Fin Construction Jeffery H Oppold 2 25 2012 42 Fin Construction
39. t and is absorbed by the batting which is placed over the release fabric Once the epoxy cures the release fabric is easily peeled off leaving a smooth a surface D REGION TOMAHAWK Fin Construction Fin Construction Jeffery H Oppold 2 25 2012 The release fabric is actually harder to cut than the carbon fiber Experience tells me to iron out the wrinkles because they ll end up ruining the surface if don t The batting is Y inch thick and was purchased ata local fabric store In both pictures I m using a fin as a guide 48 Fin Construction Carbon Fiber Overlay The third step is to epoxy the carbon fiber cloth to the plywood fins use West System 105 Resin and 205 Hardener mixed the epoxy in pudding cups and use cheap sponge paint brushes to apply Notice that have rubber gloves on as well A club member recently redid his kitchen counter tops in granite and let me borrow two slabs to use as a press have them covered in waxed paper Once the carbon fiber is saturated in epoxy cover it with the release fabric and gently smooth it out The slabs were big enough for me to do two fin surfaces ata Time D REGION TOMAHAWK Fin Construction Fin Construction Jeffery H Oppold 2 25 2012 49 Fin Construction Carbon Fiber Overlay IE e Wr put the second slab over the fins which weighed about 50 pounds The tool box then added another 20 pounds Tha
40. t should provide sufficient compression to make sure the fins cure flat D REGION TOMAHAWK Fin Construction Fin Construction Jeffery H Oppold 2 25 2012 These two pieces of plywood have a 12 angle on them acting as a press on the knife edges They re covered with waxed paper Notice how excess epoxy is oozing through the release fabric The batting is placed over the release fabric which is then covered with waxed paper 50 Fin Construction Surface Finishing Here s a fin after the epoxy has cured and I ve cut and sanded the edges smooth This task is awful the dust gets into everything SO wearing a good mask and safety glasses is amust The 12 leading edges came out great They look really good They re flat and hard as a rock All that s left is to fill the cloth grain with filler to get a super smooth surface like auto body filler Bondo as it s easy to apply cures quickly and sands to a super smooth finish Fin Construction Fin Construction Jeffery H Oppold 2 25 2012 51 Fin Construction Surface Finishing Here s a fin after two passes of Bondo and sanding It s been primed and sanded with 400 grit paper Noticed that left the tang raw so that the epoxy joint to the body tube has a rougher surface to adhere to Fin Construction Jeffery H Oppold 2 25 2012 52 D REGION TOMAHAWK Fin Construction Centering Rings cut out the centering
41. th 0 25 4 15 18 p i Final Detail Area 4 3 795 ae ae ae Less Fin Fillets 2 0 3125 3 17 1 x Want 2 1 2 Detail Width Ratio 5 0 634 Outside Detail Width 0 634 2 1 268 Inside Detail Width 0 634 l LA la I Bottom of Body Tube tan sesa nang nee gaa aa wane nae een nan wee Ssss eee wang nee waa ween gesa nae eee an eee Dana eee nang une Kava Sassa Ssss Ssss gaga Ssss tes bai wee ih ag as aans D REGION TOMAHAWK lt e N N Drawing Scale gt Jeffery H Oppold 2 25 2012 15 Raised Detail Templates OLE JUL Print on Card Stock and Cut Out D REGION TOMAHAWK s ate Drawing Scale 1 1 16 DE S Pem Nut Attachment Access Holes T y Screw holes x 4 OD lt 16 D in line with fins T K DO dada lt Avionics Bay Coupler Depth 5 5 O ca 27 lt lt 0 125 diameter pressure vent holes de a ol E Booster Coupler Height 57 T 6 4 Sheer Pins v Drill 4 TA holes 90 apart Tap for 2 56 Nylon Screws McMaster Carr 93135A079 Anti zipper steel band embedded i flush with fiberglass surface Note With the Booster Section attached drill the Band is 0 500 wide and 0 025 thick shear pin holes all the way through the airframe and Hose clamp band the booster s coupler tube Increase the size of the E TN coupler s hole to
42. to get them square but in the end they are right on the money Using the 4 minute JB Weld to tack the fins in place worked out well as only had to hold them for a short time and if the alignment wasn t perfect they snapped right off and tried it again then used the Loctite Hysol epoxy to permanently attach the fins This stuff is great the applicator gun makes it easy and the epoxy is as tough Motor Tube Assembly as nails Jeffery H Oppold 2 25 2012 54 Internal Fin Fillets Here s a close up of the Loctite Hysol epoxy fillets Were going to cover these with carbon fiber tape and West System epoxy to form a incredibly strong and light weight joint first cut the carbon fiber tape to the right fins with masking tape to keep any unwanted epoxy off Here I m mixing the West System epoxy save all my apple sauce containers as they make great mixing bowls Also check out the rubber gloves my wife said it looks like have Mickey Mouse hands D REGION TOMAHAWK Internal Fin Fillets Internal Fin Fillets Jeffery H Oppold 2 25 2012 55 Internal Fin Fillets Each of the four pieces of tape are the same length so carefully poured about a quarter of the epoxy on them length wise Using my fingers worked the epoxy into the tape until it is evenly saturated also adjusted the tape so that it had equal coverage on the fin and body tube Here s what the final joint looks l
43. umber of moles of gas and substituting into the universal gas law yields PV GppnRT Solving for G yields Gp PV nRT Charge Calculating Equation D REGION TOMAHAWK 56 Using the Charge Calculating Equation G PV nRT and substituting real values and correcting for units yields our ultimate equation for the number of grams of black powder as a function of the pressure and the internal tube volume Gap P x 3 14159 x D x Lx 0 25 x 454 1545 4 x 12 x 2832 x 0 019207 P x 356 5716 x D x L 1008730 005 0 0003535 xP xD x L Finally we ll need to determine just how much pressure is required to generate the needed force to sever the shear pins and pop out the nose cone Pressure Calculator Pressure Ibs in x Area in Force Ibs solving for pressure Pressure Force Area D REGION TOMAHAWK 56 We now have all the equations that we need to calculate the amount of black powder for both the apogee separation ejection charge air frame mid section and the main chute separation ejection charge air frame upper section Using an on line force calculator determined that 200lbs of force would provide enough margin to assure a clean separation Tomahawk Calculations Tube Diameter 5 Radius 2 5 Area nR 3 14159 x 2 52 19 635 in Pressure 200 lbs 19 635 in 10 20 lbs in Gun 0 0003535 xP x D x L Air Frame Mid Section L 17 in Gun 0 0003535 x 10 20 x 5 x 17
44. und so that the nose cone bulk head could rest against it had to use a hack saw blade to get the scrap piece off but with a little sanding was finally able to get the shoulder to fit D REGION TOMAHAWK NoseCone Nose Cone Jeffery H Oppold 2 25 2012 70 Nose Cone drilled the 4 holes in the nose cone bulk plate and temporarily bolted the coupler nuts to the bulk head To get the coupler nuts aligned properly used a small bit of JB Weld Quick epoxy on each outside edge of the nuts inserted the bulk plate into the nose cone and let the epoxy cure then removed the bolts and bulk head and checked that the alignment was what wanted Then using the carbon fiber 1 tape and West System epoxy thicken to mayonnaise consistency wrapped the nuts in the tape working it tight and into the crevices cut the G10 fiber glass sheet and drilled the holes to mount the GPS unit to the aluminum bracket then mounted the bracket and tested the fit lIl wrap plastic ties around the GPS unit through the holes when get ready to launch This really came out nice Nose Cone D REGION TOMAHAWK Nose Cone A 71 Recovery Harness Deployment Bag A local leather repair shop sewed the Kevlar recovery harness and made my deployment bag Both came out perfect The bag when stuffed full with the main chute slides right out of the tube also had him make me 3 hexagon chute protectors
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