Black Powder Charge for Model Rocket Dual Deployment

[BareRocketry]

I'm having good luck with these home made black powder deployment charges:

Black Powder Charge for Model Rocket Dual Deployment

Any ideas on how to improve this technique?

 

[lr64]

What would you like it to do better? I've read, but it's only been on line, that grain of wheat bulbs may be reliable for this, and use less power. My own igniters have to fit in smaller places and not clog tiny nozzles.

Richard Nakka discusses some related igniters, and others:
https://www.nakka-rocketry.net/igniter.html
https://www.nakka-rocketry.net/articles/Nitrate_based_igniters.pdf

Recently, I made an igniter that used a bit of something approximating Nakka's RNX propellant stuck over the resistive element, which was graphite and, I think, Beacon 527. It made a little fireball (quarter inch? half inch?) that persisted for several seconds. After one or two, though, it fell off the igniter. (This was in the open air.) On the scale of the usual igniter, it would probably make a medium sized fireball. The nice thing about that is you don't have to mess with anything that goes off easily. It may require a pretty good battery. A 9V alkaline probably won't cut it, but I imagine a small capacity 3S lipo would. I had a 1400 mAh one around, but I'm pretty sure that's overkill. The 30 gauge magnet wire connecting the igniter would have glowed red hot long before the battery's current capacity was reached.

 

[Rocketjunkie]

He's using the BP for dual deployment. Use the MJG BP motor starters (small ematches).
https://electricmatch.com/rocketry/see/23/6/bp-rocket-starters

 

[lr64]

I suppose the extended life of the fireball might not be particularly useful for that, now that you mention it! Some of the Nakka stuff I linked to is about ejection charges, though.

 

[cwbullet]

He's using the BP for dual deployment. Use the MJG BP motor starters (small ematches).
https://electricmatch.com/rocketry/see/23/6/bp-rocket-starters

Ditto. Going cheap or homemade is likely going to increase failures/.

 

[BareRocketry]

Great feedback, Gang. Thanks.

To answer Ir64's question, "What would you like it to do better?", I was looking for an inexpensive way to do lots of ground testing. Having used the CTLI (Christmas tree light ignitor) many times on the ground I became more and more confident in using them for live flights.

First step: use CTLIs for low altitude (< 1000') apogee deployment with a motor charge backup. Low altitude flights make it easy to spot redundant charges at apogee. Good results.

Next step: Dual deploy with CTLIs using oversized drogue at apogee in case of main charge ignition failure. Good results.

Over time the goal changed from having a cheap deployment charge to having the most reliable solution possible. E-match still takes the crown. But CTLIs have been very reliable. Crazy as it sounds, most often the tungsten filament is still intact and continuity is still good post launch.

 

[SolarYellow]

I like your little cutting jig.

I also like the Richard Nakka CLI version, as it eliminates the bulk and weight of the base and socket. I'm interested in running these in the smallest rockets I can fit them in. The lights are 100 for $3 at Walmart in season, probably less at post-season clearance price.

I've found paper drinking straws that are a draggy slip fit on the bulbs I have. I plan to use those rather than plastic.