I am working on a Monogram 1/48 P-61 and want to model it in flight. How do I need to change the cowl flaps? Should they be open or closed in flight? Whats the easiest way to do this?
I belive they were closed in flight.
[#ditto] I think the cowl flaps on almost all aircraft were closed once in flight.
Open for ground except cold weather warm up, open for take-off, climb and perhaps hot days low in cruise, closed or slightly open (in trail is the usual term) in cruise, closed for descent and landing.
As Jon explained, a C-46 heavily loaded climbing out of India would have these as open as possible, as would a fully loaded C-97 in cruise over the Pacific if running at some speed. Otherwise in trail vs. open depending on where the engine was in its temperature vs. output;and with the 4360 very problematic. Should have probably had a couple of rows.
Take a look at most flap arrangements- they had interlocking leaves so that there would not be a clear slot open.
Very rarely closed on the ground. A/c would be left in most ways set up for take off, in which case closed flaps would be a bad thing. No real reason to close them unless the a/c was in storage, in which case the big open front of the engine would be tarped- a more important consideration.
For big multi-engined a/c, the position of the cowling flaps is an impact on air speed.