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rocket_recovery_system_failure_modes

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rocket_recovery_system_failure_modes [2016/05/01 21:17]
dw444
rocket_recovery_system_failure_modes [2016/09/02 14:29] (current)
dw444
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   - Shock cords about 5m to reduce shock loads.   - Shock cords about 5m to reduce shock loads.
   - Place chute so that nose and tail sections don't bash each other on decent.   - Place chute so that nose and tail sections don't bash each other on decent.
-  - Ensure chute compartment is sufficiently sealed so that it can pressurize, primarily between the altimeter bay which should be well vented. +  - Ensure chute compartment is sufficiently sealed so that it can pressurise, primarily between the altimeter bay which should be well vented. 
-  - Motor is retention inadequate, motor is ejected rather than chute.+  - Motor retention inadequate, ​resulting in motor being ejected rather than chute.
   - Flight computer must signal continuity on pad.   - Flight computer must signal continuity on pad.
   - Flight computer can signal continuity but have damaged capacitor so not fire, ground test firing circuit if possible.   - Flight computer can signal continuity but have damaged capacitor so not fire, ground test firing circuit if possible.
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   - Don't use smokeless powder, it is too pressure sensitive. Blackpowder substitutes behave differently and should be avoided  ​   - Don't use smokeless powder, it is too pressure sensitive. Blackpowder substitutes behave differently and should be avoided  ​
   - Make sure e-matches are well clamped in screw terminals.   - Make sure e-matches are well clamped in screw terminals.
-  - Use acceleration tolerant switches.+  - Use acceleration tolerant switches, key switches are good.
   - Align switches perpendicular to axis to avoid acceleration effects.   - Align switches perpendicular to axis to avoid acceleration effects.
-  - Shock cord not strong enough, assume 20g loads +  - Shock cord not strong enough, assume 20g loads (probably excessive) 
-  - Use good knots, ​bowline and barrel knots.+  - Use kevlar cord (heat resistant) next to ejection charge and nylon cord or tape to reduce shock load.  
 +  - Use good knots, ​bowlines, ​barrel knots and fig 8 for cord, tape knots and overhands for tape.
   - Use tape to pad kevlar cord where it leaves body tube to avoid tube damage "​zipper effect"​   - Use tape to pad kevlar cord where it leaves body tube to avoid tube damage "​zipper effect"​
-  - Ground test  +  - Ground test every deployment three times, to check for repeatability ​ 
-  - Ejection charges are best mounted centrally on bulkheads, use eyenuts on the end of studding.+  - Ejection charges are best mounted centrally on bulkheads, use eyenuts on the end of studding ​if required.
   - Only use masking tape to adjust fits, other tape generally binds worse.   - Only use masking tape to adjust fits, other tape generally binds worse.
   - Check friction in joints, it can change.   - Check friction in joints, it can change.
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   - Compartments vented so that reduced ambient pressure doesn'​t cause premature separation.   - Compartments vented so that reduced ambient pressure doesn'​t cause premature separation.
   - Vent altimeter bays symmetrically to avoid false readings from wind.   - Vent altimeter bays symmetrically to avoid false readings from wind.
-  - Ensure ejection charge not going to change due to acceleration.+  - Ensure ejection charge not going to change due to acceleration ​(ie use wadding).
   - Use nylon shear pins (M2) to stop main deploying at drogue deployment.   - Use nylon shear pins (M2) to stop main deploying at drogue deployment.
-  - A shear pin may stop the drag on the fins after motor burn out causing separation, has this ever happened? ​+  - A shear pin can be used to stop the drag on the fins at motor burn out causing separation, has this ever happened? ​
  
rocket_recovery_system_failure_modes.txt · Last modified: 2016/09/02 14:29 by dw444