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Portable Preheaters: Propane vs. Electric

If you live where the weather rarely falls to 20 degrees, you probably cant justify an expensive installed preheater of the type we reviewed in the March 2007 issue of Aviation Consumer. But if you still need an occasional preheat, where does that leave you? A heated hangar is one option and portable preheaters are another. Assuming the hangar is out, for this article, were examining two portable options: the old standby Red Dragon from Flame Engineering and a new gadget called AeroTherm, an electric preheater.

Jim Cavanagh
Verified

If you live wh

ere the weather rarely falls to 20 degrees, you probably cant justify an expensive installed preheater of the type we reviewed in the March 2007 issue of Aviation Consumer. But if you still need an occasional preheat, where does that leave you? A heated hangar is one option and portable preheaters are another. Assuming the hangar is out, for this article, were examining two portable options: the old standby Red Dragon from Flame Engineering and a new gadget called AeroTherm, an electric preheater. Obviously, portable heaters work differently than

Red Deagon Preheater

their permanently installed counterparts. Rather than heating by direct contact through heated elements, plugs or pads, the portables simply blow hot air into the engine compartment, raising the temperature until the engine is warm enough to start.

This has some pros and cons. On the plus side, you use the heater only when you need it, so youre not wasting fuel. There’s nothing to install on the airplane, so you don’t have to fool with an A&P nor any kind of FAA approvals. Last, a portable-at least a propane model-blows a fiery blast of heat, so its faster than installed elements.

On the downside, portables take up space in the hangar and propane versions need refueling and require storing that fuel in the hangar or elsewhere, which can be hazardous. Portables can be carried in the airplane, but doing so isn’t especially practical and there’s always the worry about propane in the cabin. (The electric AeroTherm doesnt have that problem.)

Last, portable preheat can be problematical. It does a terrific job warming up cylinders but not much for that 20-degree slug of cold oil in the crankcase, unless

Jim Cavanagh