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 Something about using electric power systems for model airplanes
has never filled sufficiently the 'hole' left by not hearing an internal combustion engine screaming.
I switched over to electric more than a decade ago when the energy output of brushless motors and Li-Po
batteries hit parity with glow engines. I have to admit that the reliability and ease of use of electric
systems has its attractive features, not to mention no fuel mess to clean off the model. After finally
deciding to start using Cox .049 engines again, I needed to re-acquire the field support equipment that
was sold on eBay more than a decade ago.
 Looking at the
original set for my custom Chameleon Field Box, you can see that
a Royal power panel was on one end. I tried to find an exact replacement, but to no avail. This new-in-box
vintage Tower Hobbies Deluxe Power Panel was available, however, and it fit right into the hole for
the Royal panel. The Tower Hobbies panel is a step up from the Royal panel because the glow plug supply
is electronically driven by a pulsed current circuit that is somewhat regulated. An
HA17555 Precision Timer integrated circuit is used to generate the current pulses,
while a power transistor in a TO-220 heat-sink package provides the drive to the glow plug/head. The
Royal panel only had a 10 W resistor in series with the output. Otherwise, they both have outputs
for the glow plug, and electric starter, and a fuel pump (with Fill/Empty switch and pushbutton operation).
A 12V gel cell battery sits below the power panel in the field box. For convenience, an additional
set of banana binding posts and a set of spring-loaded jacks were added.
 
Posted January 14, 2017
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