RRC3 Help Needed

Last Sunday while attempting a dual deployment flight with a Missile Works RRC3 the main chute failed to deploy. The drogue worked perfectly and fired right at apogee. However the main charge never fired at the programmed altitude. The charge and igniter were completely intact but the altimeter had recorded firing the main at 47 fps. while attempting to trouble shoot the problem we checked every connection from the igniter to the battery. Everything was tight and correct. We also tested the igniter that failed to fire during flight but it fired perfectly in the test. We also tested the altimeter itself after the flight with a static main test fire and that worked perfectly. The only questionable piece of evidence we could come up with was a recorded voltage drop when the main fired. During the drogue firing the battery dropped .5 volts but during the attempted main firing the voltage drop was 8 volts. I have included a screen shot of the voltage drop recorded buy the RRC3. Any help with this would be greatly appreciated

Give Jim a call at Missile Works I am sure he would help you out.

To get a voltage drop like that you had to have a short, or possibly a faulty battery.

What sort of battery are you running? By 8v drop I'm thinking 9v. Was this the maiden flight of this RRC3?

My guess is that you were using a 9v battery that wasn't new. I run only 7.4v rechargeable li-po batteries when running my electronics and have never had an issue. My RRC3 has performed time and time again using this battery.

I concur that it looks like a short. I question if there is anything wrong with the battery as it worked fine 27 seconds earlier and was back to normal voltage after the failed event. It was 9.3 when the event occurred and that would have fired the match.

markkoelsch said:

To get a voltage drop like that you had to have a short, or possibly a faulty battery.

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Not a rocketry expert, but as an instrumentation tech and e-fire fireworks guy, I'd say this likely wasn't an issue with the altimeter. Perhaps, but many other possibilities as well. Keep us posted.

Thank you everyone for your input. We did contact Jim and he also suggested a short. To answer a few questions. Yes it was the maiden flight on the RRC3 and the battery was a new out of the box Duracell 9 Volt (we only use batteries once). Upon looking closer at the e match there is a very small area of the lead wire that is uninsulated near the head. The charge canister was copper I believe that the uninsulated wire made contact with the copper canister and shorted out.

Padseven said:

Thank you everyone for your input. We did contact Jim and he also suggested a short. To answer a few questions. Yes it was the maiden flight on the RRC3 and the battery was a new out of the box Duracell 9 Volt (we only use batteries once). Upon looking closer at the e match there is a very small area of the lead wire that is uninsulated near the head. The charge canister was copper I believe that the uninsulated wire made contact with the copper canister and shorted out.

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I would agree it would be possible and that is the reason I quit using metallic charge canisters. I use 1/2" CPVC pipe caps and short sections of 1/2" CPVC Pipe. The pipe that I use is 1/2" CTS Genova CPVC 4120 HI-TEMP 0.623" OD/0.467" ID. I use the pipe caps as holders for the charge canisters. Makes for quick turnarounds.

Sailorbill said:

I would agree it would be possible and that is the reason I quit using metallic charge canisters. I use 1/2" CPVC pipe caps and short sections of 1/2" CPVC Pipe. The pipe that I use is 1/2" CTS Genova CPVC 4120 HI-TEMP 0.623" OD/0.467" ID. I use the pipe caps as holders for the charge canisters. Makes for quick turnarounds.

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Similar to above...PVC end caps...a large one bolted to the bulkhead and the next size smaller end cap that holds the charge.This smaller cap is held in place with a wood screw. Agree with using non metallic charge canisters. Using the two end caps allows for having the canisters prefilled in advance of the launch and very easy ebay prepping. The end caps are inexpensive and reusable...have not shattered and avoid any chance of shorting as originally discussed by Padseven.