What's a pyrotechnic squib?
Posted: Fri Jun 30, 2017 11:43 pm
Regarding the safety rule at http://www.wra2.org/Water_Rocket_Safety_Rules.php which says "Reco.very system cannot contain black powder, fireworks, or pyrotechnic 'squibs'."
What is a pyrotechnic squib? Is that like an Estes pyro engine igniter, which consists of a wire that heats up to ignite a coating on it, which in turn ignites the engine?
What about a very thin wire that simply melts in a fraction of a second? Would that count as a "squib"?
I ask because I was in a conversation with the Eggtimer altimeter folks about water rocket recovery possibilities, using the onboard altimeter's deployment signal. The Eggtimer's deployment signal can be programmed to supply full battery power for as little as 1 second, which is enough to drive a servo controller. For that matter, you don't even need a servo, just a motor and a gear would be lighter. Or a simple hand-made solenoid actuator may be even lighter. Then he asked, why not just use that battery power to melt a very thin wire to release the nose cone? He clarified he wasn't talking about a rocket engine igniter, just a thin wire (like from an electronics fuse) that melts quickly.
Would fuse wire be considered a "squib" according to the competition rules? I could even encase it in a small glass tube so the melting material never touches anything.
A side question is, are the deployment signals built into some altimeters allowed for deployment systems on water rockets and still be compliant with competition rules?
What is a pyrotechnic squib? Is that like an Estes pyro engine igniter, which consists of a wire that heats up to ignite a coating on it, which in turn ignites the engine?
What about a very thin wire that simply melts in a fraction of a second? Would that count as a "squib"?
I ask because I was in a conversation with the Eggtimer altimeter folks about water rocket recovery possibilities, using the onboard altimeter's deployment signal. The Eggtimer's deployment signal can be programmed to supply full battery power for as little as 1 second, which is enough to drive a servo controller. For that matter, you don't even need a servo, just a motor and a gear would be lighter. Or a simple hand-made solenoid actuator may be even lighter. Then he asked, why not just use that battery power to melt a very thin wire to release the nose cone? He clarified he wasn't talking about a rocket engine igniter, just a thin wire (like from an electronics fuse) that melts quickly.
Would fuse wire be considered a "squib" according to the competition rules? I could even encase it in a small glass tube so the melting material never touches anything.
A side question is, are the deployment signals built into some altimeters allowed for deployment systems on water rockets and still be compliant with competition rules?