radiator cowl?

[Hans S]

I was trying to think on how to shed the extra radiator weight for a liquid cooled engine. Has anyone tried to build the lower cowl as a radiator? What I'm thinking is aluminum sheet with channel walls welded in, then another aluminum sheet welded on top. It would be similar to a honeycomb panel, but with a channel snaking between the sheets. The whole underside would be in the airflow and small fins could be added for extra heat sink dissipation. You'd lose the weight of the original lower cowling by replacing it with the radiator cowling. It would be a pretty labor intensive to form the aluminum sheets, though a plug could be made from the original to form it. Air wouldn't be forced through it like a normal radiator, it would pass over, so drag would also be reduced. I only thought of the bottom, for if you do top and bottom, it would be a nightmare to get at the engine without opening up the cooling system. Granted, I have no idea how much heat could be dissipated this way, but there would be a lot of surface area. And because the prop would always pull air over it, an electric or mechanical fan wouldn't be needed.

 

I kind of kicked around the idea that the top cowling half could double as a inter-cooler for a turbo/supercharger.

 

And, you wouldn't have to paint it. Shiny aluminum.

[Steve Innova]

At that point in the fuselage (extreme aft end), the boundary layer of air would be probably be too thick to exchange sufficient heat.

 

Vortilons placed ahead of the cowling/radiator fins might help...

[Hans S]

Has anyone ever had that measured? I'm guessing it would have to be done in a wind tunnel to get some accurate feedback.