Have a friend with 3 RCV .60s powering a scale JU-52--He is having trouble with the engines overheating and losing about 600RPM on the top-end--the outboard engines seem to have a large inflow and outflow area for air--Has anyone out there experienced overheating problems with RCV engines and was a solution found?

I have the .90sp which I am installing in a GP Stuka....broken in but no flown yet......they do recommend installation of baffles to direct the air especally over the front bearing area.
I am installing a balsa baffle covered with epoxy in the cowl to help direct the air. Also opening the rear to allow a bigger space to allow the air to escape.
With the cylinder laying down rather than in the airstream some means of redirecting the cooling air must be provided.

Hello, Reverend.

Congrats on the Hornet's success. Sorry I missed it.

Hadley e-mailed me regarding his problem. I told him he was going to have to baffle/duct those puppies.

Were those cowls resonating again? You left before the maiden last week-end; when he took the cowls off, the engines sounded "normal", instead of like they were going to eat themselves. I just wonder if they are inducing some sort of harmonic vibration...

See ya Sunday.

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Having a large inflow area is not always desirable. You want at least 1-1/2 times as much exit as intake for cooling air. As air gets warmer, it expands considerably.

We know that.

The problem is the design of these RCV engines. They do not have a cylinder head protruding at a right angle into the air flow.

My bet is that the air is flowing PAST the engines, as opposed to OVER them. Hence, the need for baffles or ducts.

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