Robelander

My Feedback: (5)

Looking for some input. I have a Lanier Edge 540 that I carefully trimmed out the cowl for a Saito 180. I trimmed out the head area for the engine and I trimmed out a oblong hole for the exhaust. I am using an ss exhaust tube from Mac's so the hole is about 1/2 in wide by 1 in long oval. I hate like heck to cut anymore out of this beautiful cowl but I was concerned that there wouldn't be any air flow for engine cooling. I was thinking of either making 2 long slots about 2 1/2 in by 1/2 in or just cutting out a large semi circle. What do you think? Thanks

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iflircaircraft

Rule of thumb for cooling :
Air cooled engines require approx. a 3 to 1 ratio for cooling.
1" inlet...3" outlet.
In my experience if I don't cut out the cowling, I flair the aft end of the cowl on the underside by cutting 3 slots and bending the flaps to let the hot air to escape.
IMHO

Tom

MinnFlyer

My Feedback: (4)

Yup.

Tis better to cut up your cowl, then ruin your engine.

djlyon

Cut it. I've found the simi circle works well at the fire wall or in the case of cheek cowls a triangle cut on the sloped in section of the cheek. Your inlet is probably hugh so don't worry about the ratio. The main thing is to try do draw air over the cylinder and head.