Cowl Inlet Door

Cylinder head temp problems are not unusual, but I have a different twist. My CHT's are too cool. I can only recall once or twice that a cylinder head ever got to 400F. Most run 350F to 390F during hot, hard climbs, but at cruise, and running lean of peak, it's not unusual for 2 to be below 300F and the rest just barely over 300F.

I had the same problem years ago and solved it with a variable inlet. I live in Dallas and summer time climbs were brutal, but later, cruise temps were too cold. I have a NACA scoop on the bottom though. Heres a drawing of what I did 18years ago.... By the way if in cruise, and your cylinders are too cold, your openings are too large.

Vance Atkinson
EAA Tech and Flt Advisor

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