Perry Mick wrote:

Power in the resistor is I^2*R, so if we assume it takes
10W to destroy a 5W resistor, I=sqrt(10W/.35Ohm), which
is an average current of only 5.3 amps.  Probably realistic.
It's probably the peak current that is killing it though.
If the coil were to saturate, that would take out the
resistor real fast, because it would start to see the full
14V.  14*14/.35=560W.  But that would also damage
wires so doubt that is happening.

I'm guessing mine has survived so far because my
flight rpm range is 4700-5100.  But I also like to
drive my car in 4th gear around 4000 rpm continuously,
with no problem.
--
Perry J. Mick
Duckt N7XR
http://www.ductedfan.com

There are some cooling air holes in the cover. If you mount it horizontally
instead of vertically the chimney affect can not work.

I am not so sure it is a ballast resistor. Why is there not one in
the trailing unit? I would have to see a schematic of the igniter
and be privy to the stock trigger pulse width to be sure what
is going on. For that matter why does the leading unit require two
coils and the trailing unit only need one?

Paul Lamar
 
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