I hope I'm not wearing out my welcome yet... I've seen on a few vendor sites kits that were either multi-stage or clustered. I'd eventually like to get into those as well. I know how the multi-stage work, but how do the clusters work? I'm trying to figure out how you get all the engines to ignite at the same time, and how you wire them up. If I get a multi-stage, I'll probably only be able to fly it at a LARGE field. Which means a club launch. Which means I'll have to work fast to have one built by the August launch...
Hi Eldred, Please accept my personal thanks for guiding rmr back to it's intended purpose. Clusters... I betcha I've got a flight report of my cluster rocket, "USA". It was a scratch built bird from Estes parts. Like a Big Bertha with 3 motor tubes, only a bit longer, pointy nose cone and 3 fins with popsicle stick fin pods. (not like a BB at all really, but the same dia). Anyway, I launched it twice one day; once on 3 A8-3 motors and again on 3 C6-5 motors. I launched it off the Estes porta pad and the little yellow controller that came with it. A special clip whip can be used to wire up the igniters, but I simply twisted the ends together to form 2 sets of twisted triplets. Carefully twist one wire of each igniter to the others, and separately twist the other 3 together. All the + wires must not touch the - wires. It's easy for them to touch under the tape, so use your imagination and make sure you know they're not touching.
The Estes yellow controller with fresh AA batteries has enough juice to light 3 solar igniters.
Ah - wire 'em parallel. I was initially thinking serial, but on further reflection that would be dumb. As soon as the first igniter fred, it would break the circuit. Thanks! I like the launch reports some of you guys write. I never did launch logs when I was into rockets long ago. All I did for Saturday was date and engine. I don't know how high they went, or how far from the pad they landed.
I have a couple of cluster models that I can show you how to set up at MIS in August. It's not that hard really. The trick with the Estes engines is to:
1) Take a toothpick and clean out the motor nozzles. This will get rid of any clay that may block the igniter.
2) Hook up the igniters in a parallel circuit. I can show you a couple of 'clip whips' that I made to help with that.
3) Pick through the igniters for the ones with the most pyrogen (the black stuff) on the tips.
4) Use plenty of battery power. The small launch controller that Estes makes that use 4AA batteries will not provide enough current to reliably ignite clusters. I've used a modified Estes controller with two 6 volt lantern batteries with good results. And, of course, the club rack will give you plenty of juice.
I may also suggest that you pick up a copy of G. Harry Stine's book "Handbook of Model Rocketry". This is the Bible for us rocket guys. I can bring my copy to MIS for you to look at. It has everything you need to know.
It's also a good idea to put a meter on them and use the best looking igniters that also happen to have the exact same resistance.
Try switching up to a small 12v lead acid motorcycle battery. You can get one for around $30, it has the juice to launch clusters all day long, and is rechargeable for years. I've been using the same motorcycle battery for at least 6 years now.
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