Cabin Heat

[Dave Black <asterisk@idsonline.com>]

Rene',

> If both oil coolers are mounted in the wing for the IO-540 per Alan's
> rec., what choices in cabin electric heat is there?  Or could heat be
> routed back up the fuselage conduit tube with outlet for hot air front
> and rear floor?

Electric heat is just not practical for anything more than preheating the cabin
while you're doing the preflight. It could not hope to keep the cabin warm in
flight unless you could stop nearly all air movement through the cabin. Keep in
mind that a 12 volt, 60 amp alternator will put out a total of 720 watts.
Subtract the wattage of all the other equipment you will be using and see how
much remains for heating. It'll probably be around 500 watts -- which is 1/3 of
a typical household electric space heater. Also consider how much sooner your
alternator will fail when supporting this extra load.

I believe you should either duct the hot air from one or both of the coolers
into the cabin OR you should put a third cooler inside the cabin and run hot oil
to it specifically for cabin heat. If you use the inside-cabin cooler, you'll
need a blower to circulate air across that cooler and a valve system to direct
the hot oil to the cooler(s) of your choice. Either of these methods will make
good use of heat which is abundant, free and already available.

But each method also has its' failure modes: In the event of an engine fire, the
hot air system could bring flames right into the cabin. In the event the hot oil
plumbing broke, hot oil could leak (squirt?) into the cabin. It's a personal
choice, but I like the hot oil system better, since your choice of plumbing
layout gives you control over where the leaks might occur.

> Should the Nav lights' wiring be shielded using a single wire with the
> two conductors to avoid interference with the nav and com antennae
> mounted in Alan's lovely wings.

There is no need to shield the nav light wiring, but there's nothing wrong with
doing it, either. The nav lights are simple resistive filament light bulbs, so
they make no electrical noise. Now Strobe Lights are another matter...

Dave Black
SW RG Classic (TopDoor)