miniAlt 25K User`s Manual
Contents
1. beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep beep ea beep beep beep beep Ea E E Table 3 numerical beep sequences As an example 12 560 would be reported as long beep pause beep pause beep beep pause beep beep beep beep beep pause beep beep beep beep beep beep pause beep beep beep beep beep beep beep beep beep beep long pause Installation Basic record only mode Your altimeter needs to be installed in a separate payload compartment sealed from the pressure and heat of the ejection charge gasses Itis not OK to tie it to the shock cord and pack it in with the chute The high pressure and heat encountered during ejection would damage the delicate pressure sensor s diaphragm If you are not using the electronic ejection features and are just interested in peak altitude determina tion the simplest mounting method involves adding a sealed payload compartment to your rocket This is just a section of body tube behind the nosecone with a sealed tube coupler connecting it to the main body tube see figure 5 Some rockets already have such a payload section and one can be added easily if yours does not Loose fit Glue Tight fit PES Wadding Sampling hole Altimeter Figure 5 Installation for reporting only You must drill a clean edged hole in the p2. masking tape to secure them to the outside of the tube Set the tube igniter assembly down open end up to prepare for the addition of black powder Making a stand out of a small block of wood with appropriately sized holes drilled in it will hold your tubes more securely during the filling sealing operation Add the appropriate amount of FFFFg black powder multiply the volume of the parachute bay in cubic inches by 01 to get grams of black powder and gently tap the side of the tube to distribute the black powder around the igniter head Using a section of 1 8 wooden dowel carefully press a small ball of flameproof wadding in on top of the black powder so that the powder is completely covered Do not press too hard or you may damage the igniter element Seal the end of the ejection charge with melted wax or a disc of tape The purpose of the seal is simply to hold the powder in You do NOT want to use something stronger like epoxy which would make the tube rupture upon ignition possibly damaging your rocket s airframe Using a wax or tape seal will keep the ejection charge tubing intact so that it can be reloaded and reused If you use molten wax melt the wax using a flameless method not a candle and keep it away from any open containers of black powder Your ejection charge is now complete Store loaded ejection charges in a safe manner with the igniter wire ends shorted together until immediately prior to use Since the actual amount o
3. switch OFF and correct the problem Do not launch if continuity is not reported properly Warning Launching your rocket before the continuity annunciation will result in failure Always wait until you hear the continuity beeps or silence if deployment is not being used before allowing your rocket to be launched When you recover your rocket the altimeter will be beeping to report the peak altitude attained Since this number is saved in nonvolatile memory you can safely turn the altimeter OFF at any time If you want to retrieve the altitude reading at a later time simply turn the altimeter back on and listen for the third number reported previous flight altitude Preflight Checklist D Check voltage of main and ejection charge batteries using an accurate voltmeter with the altimeter switched ON A 9V alkaline should read gt 9V a 6 cell NiCad should read gt 7 8V and a 7 cell NiCad should read gt 9 1V Replace recharge battery if voltage is low Prep rocket install engine do not install engine igniter Make sure arming switch is OFF Install ejection charges if used and wadding chute protection Connect ejection charge leads to altimeter s ejection charge terminals making sure that wires do not short together or short to anything else Do not swap wires to apogee main charges Have your rocket inspected by RSO if applicable install engine igniter and place rocket on launch pad Turn altimeter power switch ON If
4. the apogee and main ejection charge cables are not exchanged and that no wires are shorting together or to any conductive objects Also insure that adequate wadding or other protection is used to prevent the hot ejection charge gasses from burning your parachute and shock cord At this point you can have the RSO inspect your rocket if applicable and proceed to the launch pad Install the igniter in the engine and place the rocket on the launcher Turn the power switch ON and listen to the series of beeps from the altimeter A two digit number representing the Mach Delay switch settings will be reported first If you hear a continuous tone instead the altimeter s built in self test is indicating a problem Do not attempt to launch if this condition exists After the Mach Delay setting is reported the beeper will present a five digit number representing the main chute deployment altitude If the Mach Delay or Main Deployment settings are not reported as expected turn the altimeter OFF and inspect correct the switch settings Another five digit number will be reported after the main deployment altitude number This repre sents the peak altitude attained on the last flight as saved in the altimeter s nonvolatile EEPROM memory This reading is preserved even when the power is turned off and is not cleared until a new flight is made This allows you to retrieve post flight altitude data from the altimeter even if your rocket is hung up in a tre
5. you hear a continuous tone turn altimeter OFF and do not fly Confirm Mach Delay and Main Deployment settings Last flight altitude will be reported as well I Turn arming switch ON Ejection charge continuity will be annunciated by a series of one two or three beeps Ejection charges should be considered to be armed at this point and body parts kept clear Q If continuity is being reported as expected attach launch system leads to engine igniter and launch O O C u Testing A simple apparatus for ground testing the entire ejection system can be made with a small 1 dia plastic suction cup and a 15 feet of 1 8 plastic hose Drill a hole in the center of the suction cup and insert one end of the plastic hose Glue hose in place if friction fit is not achieved Tape the suction cup to the outside of the rocket s airframe such that the air sampling hole in the airframe lines up with the plastic hose i d Prep the recovery system as in the checklist above omitting the rocket engine and its igniter Place the rocket on a slightly angled launchpad with the nosecone pointing away from people and other objects After the system is armed and ready for launch suck on the free end of the plastic hose to create a low pressure region within the payload compartment The altimeter will sense this as a launch condition When you stop sucking on the hose the altimeter will sense apogee and the payload section should be eject
6. ands in untinned stranded wire can escape during wire insertion and make contact with adjacent terminals After inserting the wires and tightening the connections tug the wires with a pair of longnose pliers to insure that they are gripped tightly You do not want these connections to loosen in flight Connecting Switches External power and arming switches are connected to the appropriate terminal blocks They should be normally open in the off position and capable of handling the expected load current Bear in mind that most switches are rated for switching current making breaking a contact rather than hold ing current allowable current without switching Since the arming switch is always turned on off with no current flowing through it switching is handled by the altimeter you can generally use a switch with a lower current rating than the expected igniter current The igniter current is typically present for a very short period of time reducing switch heating further Selection of the power switch is easier due to its minimal current requirement 0 01A The important consideration with the power switch is that it be bounce free you do not want the switch to turn off momentarily during vibration or acceleration as the altimeter would reset and deployment would fail Both the power and arming switches should be mounted with the switch movement perpendicular to the travel of the rocket This will minim
7. apogee peak altitude When the derived rate of ascent decreases to zero apogee is detected and a power MOSFET is turned on to supply power to the apogee event ejection charge igniter The peak altitude reading is also stored in nonvolatile memory for later retreival Altitude readings continue to be taken during descent and are compared with the main deployment threshold that was read from the switch bank on power up When the altitude has decreased to the main deployment level another power MOSFET is turned on to supply power to the main parachute ejection charge igniter At this point the peak altitude is reported continuously at ten second intervals via a sequence of beeps Getting to Know Your Altimeter Refer to figure 1 below to identify the following items A Power switch terminals B Arming switch terminals C Ejection charge power terminals note polarity D Apogee ejection charge terminals E Main ejection charge terminals F Audio beeper G Mach delay switch bank switches 4 6 H Main deploy switch bank switches 1 3 I Pressure sensor element Al Figure 1 Parts identification Powering the Altimeter The altimeter s electronics are powered by a standard 9V battery connected to the attached battery clip Make sure that both of the clip s snaps are gripping the battery terminals firmly to prevent power interruption due to vibration The larger battery terminal or clip terminal can be compressed inward if
8. at an accidentally ejected nosecone can severely damage anything in its path Many kinds of ejection charge igniters are suitable for use with the miniAlt altimeter Standard Estes igniters work well and are readily available put a dab of epoxy with glass microballoon thickener between the tape and the igniter tip to make them more durable Commercially available electric matches can also be used a listing of several appears in the appendix Flashbulbs are sometimes used but are fragile expensive bulky and prone to accidental triggering by weak electrical currents Since the igniter will be in direct contact with the ejection charge s black powder all that is really needed is a thin wire element that glows red hot when a current is passed through it Basic ejection charges can be made in the following manner Cut a section of cardboard tube the tubing from shirt hangers works well about 1 long and use hot melt glue to fill in a plug at one end Work the glue in from the end that you want to plug rotating the tube between your fingers until a solid seal is attained Set the tube glue end down on a piece of paper until the glue cools When cool cut away the excess paper and inspect the plug for uniformity of thickness 3 16 to 1 4 is good and lack of holes Insert your ejection igniter in the open end of the tube being careful to not damage the delicate ignition element wire Bend the lead wires over the lip of the tube and use
9. ayload section to allow outside air pressure to be sampled by the altimeter This hole should be as far away from the nosecone and other body tube irregularities as possible 3X the body tube diameter or more to minimize pressure disturbances being created by turbulent airflow over the body tube Sand the area around the hole as necessary to eliminate flashing or raised edges Exact sizing of the hole is not critical refer to the following table for suggestions Table 4 Payload Section Size vs Sampling Port Hole Size While not strictly necessary the single sampling hole can be replaced by several smaller holes distrib uted around the airframe s circumference This will minimize the pressure variations due to wind currents perpendicular to the rocket s direction of travel If you are not using additional batteries or ejection charges mounting is not critical Simply place the altimeter in the payload section it does not matter which end of the altimeter faces up Use pieces of foam rubber in front of and behind the altimeter to prevent it from shifting under acceleration and deceleration A wrap of foam weather strip around the battery portion of the altimeter will provide a snug fit in 24mm BT50 size body tubes and a sleeve made out of standard foam pipe insulation can be used for larger size tubes Make sure that your foam rubber pieces do not block the path from the air sampling hole to the altimeter s pressure sensor ele
10. e for weeks with a dead battery At this point the arming switch should still be OFF and the altimeter will be silent If you are using electronic deployment never launch if the altimeter is silent A lack of beeps at this point indicates that the arming switch is OFF or that there is no continuity through the ejection charge igniters Now we will arm the ejection charges From this point on you should exercise extreme caution as you will be working with live charges Keep your hands face and other body parts away from the ejection charges and the nosecone If the charges should blow prematurely you do not want to be in the path of the forcefully ejected nosecone or payload section Turn the arming switch ON This provides primary arming for the ejection charges secondary arming occurs after the altimeter detects launch conditions of 160 AGL altitude If you have ejection charges connected properly the altimeter will signal continuity with a series of beeps A single beep every second indicates proper continuity on the apogee charge two beeps indicates continuity on the main charge and three beeps indicates continuity on both charges The continuity beep annunciation will continue until the rocket is launched If continuity is being reported as expected you can connect the engine s igniter to the launch system Your rocket is ready to launch If continuity is not reported as expected turn the arming switch OFF turn the altimeter power
11. ed from the booster As you release the vacuum from the hose the altimeter will sense the lower apparent altitude and will eject the nosecone from the payload section If the sections do not separate with a reasonable amount of force additional black powder should be added to the ejection charges to insure reliable separation Cautions Do not touch circuit board traces or components or allow metallic objects to touch them when the altimeter is powered on This could cause damage to your altimeter or lead to premature ejection charge detonation Exercise caution when handling live ejection charges they should be considered to be explosive devices and can cause injury or damage if handled improperly Do not expose altimeter to sudden temperature changes prior to operation The resulting circuit drift could cause premature ejection Do not allow strong wind gusts to enter the airframe pressure sensing hole this could cause premature launch detection and ejection Do not allow the altimeter to get wet Only operate the altimeter within the environmental limits listed in the specifications section Check battery voltage s before each flight and replace recharge if low Do not rupture pressure sensor diaphragm with excessive pressure or sharp object Always follow proper operational sequencing as listed in preflight checklist Appendix Igniter Sources Estes Industries EST2301 Igniter 1295 H Street Penrose CO 81240 Countd
12. ee ia eas ta 12 Pr flight checklist i ietie ct En cn re it iaiia 13 On ground testing sseeseseesseeseseesseesessesseescssesseesoesessessoeseesossoeseeseesoe 13 COUNOMNS sonion E S 14 Append Daiei N AEA 14 Mounting Hole Template 15 SIECIFICGHONS sarsana eana E OET 16 Warranty sn ns de t en ossoa iissa 16 Congratulations on your purchase of the new miniAlt rocketry altimeter Please read these instruc tions carefully before attempting to use the altimeter to insure safe and successful operation Your new altimeter provides two primary functions gt Peak altitude determination After a flight with the altimeter installed your rocket s peak altitude apogee will be reported via a series of audible beeps This will allow you to study the effect of various design parameters fin nose cone shape fin airfoil number of fins etc on your rocket s performance It can also be used by clubs for altitude contests compete to see who can get the most altitude out of a given engine size etc gt Electronic deployment of recovery devices The altimeter provides electronic outputs for firing ejection charges at two points during flight apogee and secondary adjustable from 300 feet to 1700 feet above ground level Firing the first charge exactly at apogee insures that the recovery system is deployed while the rocket is traveling at the slowest possible speed This minimizes the l
13. ere Ejection charge Loose fit Tight fit Wadding ling hol Altimeter and Sampling hole eject battery Figure 6 Installation for apogee deployment Choose a motor with a delay that is a few seconds longer than you would normally use with the specific motor rocket combination The motor s charge will then serve as a backup in the event of a primary ejection malfunction Installation with dual event deployment Again there are many possible variations of the following installation scheme Careful attention to the design of your installation will make the difference between a successful installation and a failure Ground test your setup before launching to insure proper separation and deployment of recovery devices The basic premise is that you want two separable parachute compartments and a single sealed electronics bay Perhaps the simplest method involves a basic setup similar to the apogee deployment system described above with an additional sealed chute compartment behind the nosecone see figure 7 A small parachute or streamer is ejected from the compartment aft of the payload electronics section at apogee and a larger chute is ejected from the compartment between the payload section and nosecone at a lower altitude set by the Main Deployment switch bank The ejection cable leading into the forward parachute compartment should be sealed in the same manner as the aft one to prevent eject
14. f black powder necessary can vary based on a number of parameters powder type nosecone coupler to tube friction etc you should test your ejection charges on the ground before flight Start with a little less powder and increase the amount until the airframe separates reliably Then add 50 as a safety factor to account for variations in friction due to humidity etc Operation To insure proper operation of your altimeter and any associated deployment systems you must observe and adhere to the following sequence of events If you launch before the altimeter is ready ground level will not be sampled properly and deployment will not function properly If you forget to arm your ejection charges the recovery devices will not be deployed and serious rocket property damage can occur Sequence of events Prepare your rocket and install the engine before setting up the altimeter Do not install the igniter into the engine until you are at the launch pad If you are not using electronic deployment just using the altitude reporting function you can ignore the sections of the following text that deal with ejection charges If you are using electronic deployment the apogee and main ejection charges and associated igniters should be loaded into your rocket and the wires connected to the altimeter s ejection charge terminals The power and arming switches should be OFF open circuit and the battery or batteries should be connected Make sure that
15. for setting mach delay time and main recovery device deployment altitude The switches are only read on power up so their status cannot be altered by flight induced vibration or shock Any intentional modification of the switch settings should be done with power off so that they are read properly the next time the altimeter is turned on The mach delay setting is used to prevent premature deployment of the apogee recovery device as the rocket makes the transition between subsonic and supersonic flight During this period the pressure surrounding the airframe will increase suddenly which could be interpreted as a decrease in altitude triggering the apogee deployment event If you think that your rocket will go supersonic a computer simulation should be run to determine the time at which flight returns to subsonic speeds Add ina safety factor of 20 30 and enter the resulting time on switches 4 5 and 6 according to the table below The time that you enter should always be less than the simulation s reported time to apogee Important If your rocket is not expected to exceed Mach 1 the mach delay time should be set to zero switches 4 6 OFF This will allow apogee detection to occur at the proper time The altitude at which you would like your main recovery device to be deployed is set using switches 1 2 and 3 Set the altitude high enough to insure that the chute will deploy fully in time to slow the rocket s final descent but low enough to
16. ikelihood of rocket damage due to zippered body tubes and stripped parachutes which occur when deployment occurs at higher velocities Electronic deployment is preferable to using the engine s built in timed ejection charge which can vary from engine to engine and is usually limited to two or three specific time delays which may not be optimal for your particular engine rocket combination While it is often adequate to use single event ejection at apogee a two event deployment option is also provided This involves ejecting a small parachute or streamer at apogee allowing your rocket to fall at a fast but controlled rate to the secondary deployment level of 300 to 1700 feet AGL switch selectable At this point a larger main chute is deployed to bring your rocket slowly and safely down for a soft landing This has the significant advantage of reducing the distance your rocket drifts on windy days making safe recovery easier and more certain Theory of Operation The miniAlt altimeter determines altitude by sampling the surrounding air pressure during flight and comparing it with the air pressure at ground level As the altitude increases the air pressure de creases and the onboard microprocessor converts the pressure difference to altitude When the altimeter is turned on it reads a bank of configuration switches and saves their values in memory It then checks the barometric pressure sensor to make sure that the pressure readi
17. ion gas entry into the payload compartment Two additional precautions should be made First the joint between the payload section and the forward parachute compartment should be either a very tight friction fit or preferably a positive retention system like screws or retain ing pins can be employed This will prevent the shock of the main chute deployment from separating this joint and ejecting the electronics Second the fit of the nosecone to the upper parachute compart ment should be tight enough to prevent inadvertent separation at apogee but loose enough to allow separation upon main chute ejection charge firing Seal cable here Seal cable here Main chute G Apogee drogue ejection charge ejection charge _ Drogue chute Wadding i Altimeter and Sampling hole eject battery Loose fit Tight fit Main chute Wadding Figure 7 Installation for dual event deployment 1 Ejection charges The ejection charges used to deploy your recovery devices can be purchased commercially see appendix or made at home Since ejection charges contain a quantity of explosive black powder extreme care must be exercised while constructing and handling them Keep your face and hands away from the end of any ejection charge that has been loaded with powder Do not look into or reach inside rocket airframes with live ejection charges loaded and keep in mind th
18. ize the forces placed on the switch during acceleration deceleration which could inadvertently move the switch to the off position If the switch is on the outside of the airframe or near any of the recovery device rigging a cover should be fabricated for the switch to prevent it from being bumped to the off position due to impact with the rigging A simple and effective switch can be made using a lever plunger switch eg Omron SS 10T a small piece of brass tubing and a length of brass rod with a sharpened end The brass tubing is secured to the top of the switch housing with a small amount of epoxy do not use CA as the outgassing during curing will get into the switch and ruin its contacts such that when the sharpened end of the brass rod is inserted into the tubing it depresses the plunger The switch assembly is mounted inside the altimeter bay with a hole for the brass rod leading to the outside The Normally Closed terminals of the switch are used in this case so when the rod is inserted and the plunger is depressed the switch turns off opens A remove before flight flag can be hung from the end of the brass rod to remind you to turn on the altimeter One advantage to using a Normally Closed switch is that failure of the external mechanical assemblies brass tube during flight will NOT turn the altimeter off rod out switch on rod in switch off Configuring the Altimeter Two sets of switches are provided
19. ment A channel can be cut in pipe insulation for this purpose make sure that the channel lines up with the sampling hole and the sensor s air inlet Your payload section should close securely so that the altimeter is not ejected upon motor burnout deceleration or chute deployment shock Setting up the altimeter for use as a recovery device with apogee only or two stage deployment is necessarily more complex You may want to gain some experience with your altimeter in reporting only mode before using it for deployment Then begin with a simple apogee only deployment application and move on up to two stage deployment after you ve gained experience with electroni cally fired ejection charges The following suggestions can be used as a starting point and should be adapted to suit your specific application To insure the highest degree of safety all recovery systems should be ground tested prior to launching Using redundant backups e g motor ejection charge in addition to electronic deployment is always a good idea whenever possible Installation with apogee deployment Installation with apogee only electronic deployment is similar to the standard installation noted above The altimeter is mounted in the sealed payload compartment along with an ejection charge battery and a small hole is drilled through the rear bulkhead for the ejection charge cable see figure 6 Route the ejection charge cable through the bulkhead with
20. miniAlt 25K User s Manual HE 4s MINTALT2SK_ Perfectriile miniAlt 25K User s Manual A miniature peak reporting altimeter with two event deployment capabilities for high power rockets Perrectriite URL www perfectflite com Sales sales perfectflite com Support support perfectflite com 15 Pray Street Amherst MA 01002 Voice 413 549 3444 FAX 413 549 1548 Contents Preface 55 nnn E 1 Theory of Operation 1 Preliminary Sep sistema antancioisi ts 2 Getting to know your altimeter 2 Powering the altimeter sccsscssssssssssssssscssssssssssccssscsssssnsscnssssscssees 3 Connecting external switches scssccsscssssssscssssesscssssesssesssessenses 5 Configuring the altimeter R 6 Numerical reporting method 7 Installation Basic payload module seseeseessesoesoessesoeseessesoesoesseesesoesseesessesseesessess 7 Sampling hole size chart eeseesesseesoesessessoesessoesoesessoesosseesoesoeseesoesoe 8 Adding recovery device deployment 9 Apogee only deployment ss 9 Dual event deployment sscsssssscssscssssssssssscsescesscssssssssssssessees 10 Ejection Charges Ejection charge igniters eessessesoesseeseseesseesossesseesoesessessoesessessossoese 11 Making ejection charges 11 Operation Sequence of events SU NS
21. necessary to insure a snug fit The ejection charge igniters can be powered by the main battery low current igniters only or by an additional battery connected to the separate ejection power terminals When using a single battery a jumper wire must be connected from the ejection power terminal to the power switch terminal as shown in figure 2 below When size and weight considerations allow a two battery installation is always preferrable This is due to the fact that when the igniters fire the additional current drain on the battery can cause the microprocessor s supply voltage to drop possibly resetting the altimeter If the altimeter is reset when the apogee charge fires the main charge will never fire Using a separate battery for the charges isolates the microprocessor power and eliminates this problem The ejection charge battery is connected to the terminal block at the end of the altimeter figure 3 below Battery selection is dependent on the igniter types that you will be using In general NiCad batteries will provide the most current for successful igniter firing Nickel Metal Hydride NiMH batteries should not be used their internal resistance is significantly higher than NiCads and as a result they are not able to provide as much current Make sure that you observe proper polarity when connecting the battery or the charges will not fire to main charge _ to apogee charge E s e ec ain to charge batte
22. ng is within normal limits If an abnormal condition is detected an error is reported If pressure readings are normal the values of the mach delay and main deployment level switch banks are reported via the built in beeper The peak altitude of the previous flight is then retrieved from nonvolatile EEPROM memory and reported Next the ground level elevation is sampled and the ejection charges power and continuity status is checked and reported as the altimeter awaits launch The continuity is rechecked and reported approximately once per second during this period The microprocessor also looks for a sudden decrease in pressure signifying a rapid increase in altitude launch detection When the altitude exceeds a preset threshold 160 feet above the ground reading launch is detected While awaiting launch the ground level will be updated if a slow change is detected to compensate for thermal and barometric drift If a mach delay value was entered into the configuration switches the altimeter waits for the pre scribed time to elapse before beginning to check for apogee This prevents a sudden increase in pressure due to the transition from subsonic to supersonic flight from being interpreted as a false descent apogee so that the apogee chute is not deployed prematurely After any Mach Delay period has elapsed pressure readings are taken every second and converted to altitude above ground level The altitude results are inspected to determine
23. own Hobbies dealer 7 P T Barnum Sq Bethel CT 06801 1838 203 790 9010 www countdownhobbies com Funa Techiman nissan aa ani Oxral 148 Moon Drive Owens Cross Roads AL 35763 256 725 4224 www pyropak com Davey fire sah racists eeen iere tie an Daveyfire 7311 Greenhaven Drive Suite 100 Sacremento CA 95831 3572 916 391 2674 14 Performance Hobbies dealer 442 Jefferson Street NW Washington DC 20011 3126 202 723 8257 www performancehobbies com FireFox FX w ceccccccccesseeessecesseseesees 11612 N Nelson Pocatello ID 83202 208 237 1976 www firefox fx com EE A Various igniter products Rocketflit i 5ssm innneninn nn Magnelite 836 Houston Drive New Haven IN 46674 FAX 703 783 5838 Le 3 675 x oN uy 3 425 Figure 8 Mounting hole template Specifications miniAlt 25K dimensions 0 85 W x 3 68 L x 0 45 T weight 24 grams without battery operating voltage 9V nominal 6V 10V operating current 11 ma typical eject charge battery voltage 3 6V to 27V firing current 3 0A for 50ms 1 1A for 1000ms with protection diode firing current 17A for 1000ms protection diode shorted continuity check current 8 2HA V maximum altitude 25 000 feet MSL launch detect 160 feet AGL event 1 output apogee event 2 output selectable 300 1700 feet AGL altitude accuracy 5 typical operating temperature 0C to 70C Warranty All assembled PerfectFlite
24. prevent excessive drift In most cases a setting of 500 to 900 feet is appropriate If you have any doubt as to the time it will take for your chute to deploy choose a number towards the upper end of this range and gradually reduce it if deployment speed allows For small fields loosely packed chutes and windy conditions you may want to drop back to 300 feet When the altimeter is first turned on the current mach delay and main deployment settings are reported via the beeper see the next section for details This allows you to confirm that the correct settings are entered even if the altimeter is hidden inside your rocket The mach delay is reported as a two digit number and the main deployment altitude is reported as a five digit number swa sws sws off off off off off off Table 1 Mach delay settings Table 2 Main deployment settings off off 1100 feet AGL n off 1300 feet AGL Numerical Reporting Numbers are reported as a long beep separator followed by a pattern of shorter beeps With the exception of the two digit Mach Delay setting all numbers are reported using five digits a series of beeps for the first digit tens of thousands of feet a short pause another series of beeps for the next digit thousands of feet etc Ten beeps are used to indicate the number zero if zero beeps were used you would not be able to differentiate between 2200 feet and 0220 feet beep beep beep beep beep beep beep beep beep beep
25. products include a full three year 36 month warranty against defects in parts and workmanship Should your PerfectFlite product fail during this period call or email our Cus tomer Service department for an RMA number and information about returning your product The warranty applies to the altimeter only and does not cover the rocket motor or other equipment This warranty does not cover damage due to misuse abuse alteration or operation outside of the recom mended operating conditions included with your product Broken pressure sensor diaphragms due to puncture or exposure to ejection charge pressure hot gasses are NOT covered under this warranty Liability Due care has been employed in the design and construction of this product so as to minimize the dangers inherent in its use As the installation setup preparation maintenance and use of this equipment is beyond the control of the manufacturer the purchaser and user accept sole responsibility for the safe and proper use of this product The principals employees and vendors of the manufac turer shall not be held liable for any damage or claims resulting from any application of this product If the purchaser and user are not confident in their ability to use the product in a safe manner it should be returned to the point of purchase immediately Any use of this product signifies acceptance of the above terms by the purchaser and user 16
26. ry negative to charge battery positive to power switch to power switch to arming switch seo Figure 2 Single battery connections Figure 3 Dual battery connections High current igniter note The altimeter has a built in polarity protection diode to prevent spontaneous igniter firing in the event of a reverse connected battery The diode can handle 1 1 Amperes of current on a continuous basis and up to 3 0 Amperes for short duration pulses typical igniter duty If you expect to exceed these specifications a shorting wire can be soldered across the diode terminals on the bottom of the board as shown in figure 4 below If you install the shorting wire you must observe proper polarity when connecting the ejection power battery Failure to do so reverse polarity on the ejection power terminals will cause the charges to fire immediately upon closure of the arming switch Figure 4 Jumper for high igniter current applications Terminal Block Note To attach wires to the terminal blocks loosen the retaining screw facing outward from the board insert the stripped wire end from above and retighten the screw Make sure that you strip enough insulation from the wire 3 16 so the bare wire not the insulation is gripped by the contact Do not allow an excess of bare wire above the terminal as it could short circuit to adjacent parts or wires Always use solid wire or tin any stranded wire ends with solder the loose str
27. the altimeter connector end in the payload section leaving sufficient wire aft of the bulkhead to allow connection of the ejection charge Seal the point where the ejection charge cable passes through the bulkhead with silicone epoxy or hot melt glue to prevent ejection charge pressure from entering the payload compartment Make sure that the altim eter battery and wires are mounted securely so they will not shift under the high G forces experienced during acceleration and burnout deceleration Leave some slack in the cables to prevent the plugs from pulling out of the terminal blocks if things do shift Prior to launch you will attach the ejection charge s leads to the loose ejection charge cable ends twisting them tightly and taping them to prevent shorts The ejection charge will then be loaded into the rocket s airframe immediately in front of the motor with flameproof wadding inserted after it to protect the chute Pack the chute next being careful to position the shroud lines and shock cord away from the ejection charge cable to minimize the likelihood of tangling Then join the main airframe and payload sections making sure that they are sufficiently loose to allow separation when the ejection charge fires The altimeter should not be switched ON and armed until your rocket is loaded onto the pad to prevent wind gusts etc from prematurely firing the ejection charge See the Preflight Checklist section for more details Seal cable h
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