|Home made preheater that doesn't require Electricity or preheat with a Torpedo heater|
Cold starts are not a good thing for aircraft engines because as the engine components get colder, the clearances get less until no clearances exist. I preheat from 40 degrees F and lower.
Ever since I bought my aircraft, I had the concern of preheating and what type of preheater to use. There are band heaters for the cylinders and pad heaters for the oil pan and so forth and so on. Each type of preheat applications had it's own problems. Some of those problems are long term so damage is done before symptoms show.
Some say the pad heaters cause rusting of the oil pan and eventual oil leaks and condensation on the cylinders walls that promotes rust. The band heaters have their own problems so what's an aircraft owner to do? Make your own!
The object is to provide heated air that will fill the cowling. This will increase the temperature of the block and with the hot air entering just under the oil pan, will also heat the oil. Heating both the oil and the engine block is important.
I use cowl plugs and the opening behind the spinner provides a little air flow through the cowl. The entire engine is bathed in warm air.
I made my preheater because I wanted a unit that didn't require electricity and had a decent output. You may find how I made my unit interesting.
I had some idea of what I wanted so I roamed through the home improvement centers until I came across a convection heater at Lowe's. It was the right size and had a lot of output BTUs and used LP Gas. Perfect!
The heater housing had holes in the top because it was a natural convection type heater. I had to plug some of these holes so I used a cookie tin lid for this purpose. Any sheet metal will work.
I used a ductboard adaptor and a reducer to convert from the heater housing to a 4 inch scat tube. That required cutting a hole in the cookie tin lid and the top of the heater housing.
One can see this heater is good for a tail dragger that stands tall like my C180 so the application is limited. If one is able to adapt the scat tube directly from the top of the heater, you might be able to use it on tri-gear aircraft.
The top photo shows the parts and Lowe's skew numbers. I hope they are still good. This project is about 10 years old and the numbers may have changed. You still get the idea, however, and that's the purpose of this article.