8/5/08

Current Project Update

I've been working hard on my second practice high-power rocket, for my MN State Fair exhibit. It hasn't been named yet, naming rockets has never been one of my best areas in rocketry. But it is similar to my last one in that it has a cluster of 2 "G" motors, the same payloads, and similar weight, but a different airframe shape.

It's almost done, I just have to wait for the nosecone to come in the mail. I ordered it on the 15th of July and it's still not here. I'll have to call.

So excited! There's a good chance it'll fly on Saturday the 9th!

6 comments:

R2K said...

Clusters are hard... no way around that fact. What kind of igniters will you use?

DTH Rocket said...

Not sure. Last time I used First Fire Juniors, but that failed. So I'm going to talk to some of the rocket people there and see what igniter they suggest.

DTH Rocket said...

"There" as in the next hpr launch on the 9th

R2K said...

Well I can tell you, I use the aerotech copper igniters!

They are almost universally hated, but you know what here is the secret:

Put the metal end (the non burning side) in a light flame like lighter, candle, stove until the insulation holding the two thin copper sheets together burns. They will gently peel apart (not too much heat plz). Now they work like normal igniters, you can just clip on to them. One great part of these igniters is the physical shape of the pyrogen head: its folded to greatly increase the burning surface area and add new ballistic trajectories to the burning pyrogen.

Anyway they work for me... but my largest composite cluster to date was a G55 with two E-15s, or E-30s. I think I flew that once perfectly, and once with an E not burning.

DTH Rocket said...

You mean that it doesn't short out without the insulation? Huh. That's interesting.

R2K said...

Yeah do you have copperheads?

They use two thin sheets of copper in place of two ends of wire... and these are pressed together with an insulating glue between. This means you either have to buy the clip from aerotech, or make your own by taping alligator clips (remember + needs to be on one side, and - on the other of the strip). Or you can also burn them apart gently, and then use them like normal igniters.

The insulation remains in the parts that still touch, but you have spread the bottom apart and they dont need insulation as long as they dont touch.

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