Updraaft cooling?

[coenvanwyk]

I am building a kit aeroplane, a CH 701, and am thinking of putting a VW engine in it, probably a 2.1 liter. It seems to me that, with all the fresh air, and the big fan in front, that cooling it by opening the bottom, maybe with a moderate scoop, and providing exits on the top/sides of the engine compartment, with appropriate baffling, might work.

I understand that the exhaust valves need cooling, and this configuration would provide the maximum exposure, I think,

Do list members have any ideas or comments?

Coen van Wyk

[Tony Z]

rather do it from the top to the bottom... the original system was designed to allow airflow in that direction. Plus, heat travels upwards, to the hottest parts ore at the top so you would rather have cooler air there. Not to mention the deflector plates (vital for cooling the bottom of the cylinders) will be in the way of good airflow from the bottom.

[fig]

If you don't have a lot of experience of ACVW engines in aviation applications I'd say get a new Rotax engine.

[4agedub]

Volkspares does sell fiberglass engine covers for beetle aviation engines. You do not run a fan at all, the air coming from your prop also cools the engine.