(I don't come to this group very often but just check it out once in
a while.) The basic item to understand is that with fairly low resistance,
you get a lot of current flow so you get more heat than with much
higher resistance. It's the same principle they use when making
heating elements for your stove or room heaters. Since the last
time I looked at igniters, I saw they also had a low resistance
through a small wire, then I could say that the best bet is just
heavier wire for the leads to make sure that their resistance is
very small in comparison so that you don't get much heat dissipating
in them. Thicker wire is lower resistance, thinner wire is "higher"
resistance. It is the same reason that car stereo enthusiasts use
"monster cable" which is quite thick, so that it minimizes the
resistance losses in the wire. I always used copper lamp chord
when I shot rockets back in high school. When I used telephone
wire it got quite warm. I also soldered all the connections except
the final connection to the igniter. Once a wire gets hot its
resistance gets higher which will make it hotter even faster. If you
can get the resistance numbers for the wire you propose to use,
the igniter, and the batteries, I could help you calculate the energy
lost (Watts) in the wire, the igniter, and batteries.
Be sure to check how warm the batteries get when you launch. Because
the time is small I doubt that they would get too warm on a single launch,
but just the same, since NiCads have fairly low resistance, they could
get warm in a hurry if you send a lot of current out of them.
>I use an Estes Command Control Launcher to fire off
>everything from 1/4A's to G80's, and I'd like to start
>using it for some low end HP launches (instead of using
>borrowed pads). I always use 12 freshly charged NiCd's, and
>I was wondering if anyone has had any success with it using
>50-100 feet of wire? I'm not a student of Ohm's Law, but I
>do know that resistance increases with greater lengths of
>wire. Any suggestions as to the best wire to use to
>minimize resistance losses?
>Scott Depot, WV
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