Anna-Elizabeth (@tankgrrl)
This is looking very good. Keep it going !
As far as answering your question about the engine cowling flaps: It would likely be based on several things. If it was a winter time based Corsair in the Solomon's I would say most likely go with opened. Keep in mind the South Pacific has seasons just the opposite of what we have here in the USA. Our winter time is their summer, and vice versa.
Since you are building a plane based / operated from an aircraft carrier, closed would likely be more fitting.
It depends on the engine's cylinder head temperature, and also the engine oil temperature, as to when these cooling flaps were actually opened up by the pilot. The flaps were kept closed when the engine was first started and warming up to operating temperatures.
If the plane has just landed, and the engine shut down has just happened, I would go with the closed position as well, because it was common to close the flaps before exiting the plane. This allowed easier warm up on the next time the aircraft was started up.
Even though Tamiya has you build this kit with the landing flaps lowered, they were most often raised before the pilot exited the plane.
Personally though, I like how the Corsair looks with the flaps dropped. I also like how the engine cooling flaps look when they are opened up. In the end it comes down to personal choice. Do what makes you happy.