Black Powder Cluster Ignition

[thomas]

That looks like sticky match or quik match. Pyro guys use it in displays

Thanks, I did not know how it was called in English. It is exactly this stuff.

 

[dpower]

With my small 12V relay system, I've flown up to 7 motor clusters with Estes Solar Igniters. Twist the closest ones together, then use a 3x clip-whip. Haven't tried this with the new Estes "Model Rocket Starters", though.

 

[Reinhard]

On the power supply side, I personally don't understand why capacitors have never made it into this hobby.

The troubles of transporting high amps across distance aren't new. Wasn't Mr Edison building power stations every 4-6 blocks before Mr Tesla demonstrated a rotating magnetic field that could create AC? But at the end of the day, it was converting low voltage into high voltage for the 'journey' and back into the desirable voltage at the other end that was perhaps the largest breakthrough.

Back to today's model rockets- if we combined a simple step-up transformer, with a capacitor, even a single AA battery could light a cluster.

As an owner of camera gear I notice that my on camera flashes step 4 AA's to ? a rather high voltage. Canon's 8 AA battery booster packs deliver 330v and these aren't that much larger than many of the hand held lauch controllers out there (still fit comfortably into one hand). Again, add a 330v capacitor and as long as the nichrome wire based ignitors didn't melt outside of the motor, and I don't imagine you'd need a relay system for the vast majority of applications.

Has anyone tried this?

I've tried something similar. 2000µF @ 400V, controlled via a SCR. That's enough to turn a yellow LED ultra violet, if only for a very short time. ;-)

For ignition purposes, it is problematic though. The most obvious issue is safety, but the high voltage will also lead to other problems. For example, at 400V I could dump more than 1000A through an ematch with about 1-2 Ohm, because after a very short time, the bridge gets evaporated and you end up with an arc discharge. As a result, an ematch that can be fired with just 6mJ consumed more than 100J, which is quite inefficient. If you don't pay enough attention to the igniters and how they are connected, the ignition system might fail to ignite all the igniters even if there should be enough energy in theory.
That being said, if the details are taken care of, high voltage capacitor discharge based systems can work very well and they are often used in professional applications.

Reinhard

 

[Micromeister]

I built and have been using a semi-self-contained, Solar Cell Charged, 12V, 56000mf - 15v Capacitor Discharge Launcher sinced 1991. Heavy duty (45lbs) it can handle large and small rockets. 36" launch rods, custom controller and 50ft of 16/2 cable & 36" external power leads store in the 2" x 2" x 42" Sq Alum tube legs. The Alt/Az. head can handle any launch rod or rail up to 1/2". I'm sure it's been noticed in many of my Cluster liftoff photos.

It's wonderful for single motors and small 2 or 3 motor clusters ignition. That said; it just doesn't quite have enough juice to activate the relay coil and heat 4 or more igniters. After a lot of bigger cluster igniter attempts, I added an external battery drop cable for larger cluster relay ignition with an external 12V Hi/Amp gel-cell battery. Now this launcher can do just about anything I ask it to launch.

I don't talk or type about this launcher much because "Relay Ignition" is the most important part of reliable cluster motor flying. All others methods are simply inferior attempts to accomplish what we know is the best and most reliable way to get all motors thrusting.