Quote Originally Posted by Frank Giger View Post
Well, yes, they keep the same cooling system.

Let's look at the VW engine, which is opposed cylinders cooled in the automobile with air coming from above and down through cooling fins.

In an aircraft, it's the same, but done slightly differently. The air coming into the cowling from the front is cut in two horizontally, with baffling put between the layers. The top section is blocked off, making it high pressure, and the air has only one place to go - through the cooling fins of the cylinders. It works really well.

If RPMs are too high for the desired propeller, a Prop Speed Reduction Unit is used. It's essentially two pulleys of different sizes (the prop being put on the larger one) being driven by a belt (or even a gear).
I just checked out the 914 VW engine maybe is you talk about, the vw company has several differet types of engines. 1991 cc, 81 kW (110 PS; 109 hp) at 5800rpm. I really want to know the actually temp during take off and cruise. Taking off usually use full power for approximately 5 min, I had see some auto oil cooling engine overheat during 5 min by output 100%power(ground test). And how many time can VW engine run as 80%power? I dont thinks without cooling upgrade It can keep normal temp too long. Because the performence like this will never be applied on automobile. Otherwise can i say air cooling has higher efficient than oil cooling?