Originally Posted by rdrcrmatt
These are a terrible idea for engine heaters. Someone stuck one on our club's 172's block heater. I came out to fly and the engine wasn't warm. Reason was, a block heater draws a fair amount of current, which warmed up the ThermoCube, triggering it to turn off the engine heater. This cycled for who knows how long till I threw it out.
Interesting! I have used mine for 7 years with no issues like you describe, although I can see how that might happen. I suppose it might depend on how many amps your heater draws. Since this switch is closed all the time that the ambient temp is below 35 degrees, I use a lower power heater and it keeps my engine at about 55 degrees minimum with a cowl blanket and cowl plugs installed. No need for a high power heater if you use one of these - a 60W light bulb will do. Annual cost to run this way is about 10 or 20 dollars, and the plane is always ready to go.
One other benefit of this approach is that the engine is almost always significantly warmer than the air, so condensation on cold internal engine components on a humid day is unlikely to result.
Noah F, RV-7A
All men dream, but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find that it was vanity: but the dreamers of the day are dangerous menů for they may act their dream with open eyes, to make it possible. -T.E. Lawrence