Radial Engine Cooling

[JtD]

Originally Posted by ElAurens

Oh, and take a look at the placard on the panel that says to keep the engine cowling flaps closed above 150 mph. Do that in game and you will have a toasted R-2800 in very short order.

Opening up the engine cowl flaps above that speed caused turbulence and the plane became unflyable due to elevator fluttering. That's why they had to be closed. The engine still overheated when flown at high power settings and would get damaged when done excessively.
In game, however, there's no disturbance from the cowl flaps and up to 4.101 the plane could be flown around for all eternity at 110% power rads closed no overheat provided you were flying at a higher altitude.