cluster ignition without fuse?

Doug Sams wrote:
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Agreed. ALL my BP cluster launches involve Solar igniters.
I use lamp cord (18ga ?) clip whips, though, and scrape the propellant grain on every motor to ensure no clay is present. I also take an emery board or nail file to *copper* clips (not the silver colored ones) to ensure good connectivity. The club launcher uses a large 12v lead-acid battery and my personal controller uses a 12v sealed gel-cell motorcycle battery. Very high reliability. I believe a low resistance current path is the biggest factor in BP cluster reliability, rather than the igniter type. YMMV.
--

Gary

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Good addition. I forgot to mention that. It's important for clusters AND staging.

Yep. Same here. Every range box should have some emery boards.

Exactly. We want most of the resistance to be the ignitor and not some bad connection elsewhere.
My move away from clip whips was prompted by two things - seeing someone else using extender wires (with insulating tape on the junctions) and struggling too often to get all the clips to stay attached and not touch each other.
Doug
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Doug Sams wrote:

Yeah, doing a 7 motor BT-80 cluster gets tight. I used to have some heavy gauge jumper wires with the plastic insulator covers over the clips. "Great!", I thought, "A solution to shorted clips." Worked like a champ. Once. ;)
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Gary

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shockwaveriderz wrote:

Ya just did a high-warp flyby... I know what flashpan ignition is, though I'd probably put enough powder in to orbit the rocket without motors; though I'm sure experienced guys like yall could tell me how much you generally use for a given cluster size and the pan size or configurations. But WHAT is a spider or quickmatch?? Never heard of either of these. What do they look like, how are they set up, where do you get them, etc.
How about flashbulb ignition?? Is that used anymore or did that go out like cold propellant rockets?? I never used flashbulb; to a high schooler it looked terribly sophisticated but having re-read about it now it seems a rather elegant solution. Thanks! OL JR :)
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OL JR wrote:

A spider is a set of thin tubes stuck in a cap that goes over a pan of BP. This pan of BP is essentially like what you'd see for flashpan ignition--the difference is the cap with tubes. The rocket with the motor cluster sits on top of the spider such that each motor is right over one of the tubes. When the BP is lit, fire squirts up each tube and up the motor nozzle.
It's a way to make flashpan ignition safer (no "overspray"), cheaper (need less BP), and more reliable (direct and concentrate the flame where it's needed).
Flashbulb ignition is still used (saw it most recently at NARAM 47 in 4xA cluster altitude), but is used less and less as time goes by.
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