The P-51 radiator does not produce thrust; that is a myth. What it does is reduce the cooling drag. In the case of the P-51, it can eliminate most, but not all the cooling drag. So the P-51 flies as though the raduiator is mostly not there. It isn't thrust, it is drag reduction. There cannot BE a positive thrust from the P-51 radiator.
There might be from the Republic Rainbow exhaust system, but that is NOT a cooling system producing thrust, that is exhaust thrust, which is possible and several aircraft have taken advantage of it.
Radiators will never produce thrust, only more or less drag.
Neo is so wrong below that I don't really know where to start. I seriously wonder if he hasd ever operated an air-cooled piston engine in an aircraft. I think he is Gaston or a close cousin. Maybe he is The Pipe. Hello, The Pipe here. Remember him? He was about to start posting in third person when he mysteriously disappeared. Maybe he is back.
At low speed and low power, such as when you are gliding toward landing on final or coming down base, the cooling flaps are usually mostly closed, and your ramblings won't change that. As you increase power and the temperature rises, the cooling flaps are progressively opened to keep the temperatures in the green. If you open the cooling flaps at low power, you usually shock-cool the engine and it gets expensive due to cracked cylinders. Better stay away from aircraft with air-cooled engines Neo. You'll buy a few before you are done, if you fly them the way you post. Best stick with the engine manufacturer's recommendations in the pilot's operating handbook.
Edited by GregP, 08 May 2012 - 03:48 AM.