I think what is being overlooked here is the useability of flaps in actual combat: It is a grey area that shows large inconsistencies according to aircraft type in actual combat reports; it is not all an issue of pilot proficiency or inclination. Some aircrafts do like to use flaps a lot in real-life combat (most prominently of all the P-51!), some don't (like the Me-109, Spitfire and P-47).
I think what is not realized is that the effectiveness of the flaps is greatly diminished by the deceleration they create in real-life: In a test against the Oscar I, the P-38J's flaps actually slowed down the P-38's speed enough to make the Oscar gain MUCH faster, but that reflects the Oscar's lack of speed retention in a far smaller turn radius: Against a Me-109G there might be a short-term turn gain with flaps because here a turn radius advantage can become for a short while more important than the sustained turn performance...
Surprisingly enough, at 20 000 feet exactly, and at a wide range of speeds (150 to 300 MPH ias), IF altitude was maintained in flat turns, the Oscar would NOT gain on a P-38J, as long as the P-38 did NOT use its flaps... Any altitude loss while turning would instantly help the Oscar's puny engine and gain the Oscar a big turning advange... (The Oscar1's level turn advantage disappeared above 19 000 ft, but always remained in a downward spiral.)
I agree with Thorsim using the flight manual as the final word is not realistic, but using the structural limit might not reflect the way flaps were actually used either. On the 109 flaps were slow to deploy manually, and on the P-47 they seemed not to have been much used except for the deliberate purpose of slowing down, but not actually turning as such...
I think the ability to sustain speed in turns, similar amoung many types, should determine the useability of flaps at higher speeds, so that all aircrafts are treated on an even footing: I think Thorsim's idea of a midway between the Pilot's Manual's 200 MPH limit and the 400 MPH structural limit is a good idea, allowing variations for the limiting reality of slow manual deployment on some types, and maybe giving a high speed deployment advantage to some types that display unusually good speed retention in turns at high speed because of their inherent aerodynamic slickness.
The only reason the P-51 is sometimes quoted as using flaps at 400 MPH while most other types don't, is that the Mustang's surprisingly good speed retention in turns (compared to its so-so climb rate) made the speed loss of 10° of flaps seem less onerous to the pilot compared to other types. Yet certainly the FW-190A could use flaps to some advantage up to 300 MPH, as pilots often did. Beyond that speed, the FW-190A was a poorer turner and had less acceleration in turns than many other types, and in actual combat the flaps were then most often used to slow down and try to trick the pursuer in slipping ahead...
Still, the most common use of flaps for the Mustang is actually at medium to very low combat speeds, similar to most other types but maybe with a bigger gain since it is generally an inferior-turning aircraft at these speeds. In the word of a Polish pilot: "It helped the turn, but made the stall dangerous".
I think it is a grey area and should be treated as such, and not defined by the cut-and-dried limits of a pilot's manual.
In general flaps were not massively used in combat, even on the deck, except by the P-51 when it needed a brief catch-up at some risk... So if in a simulation they define relative turn performance for all aircrafts, it does sound odd.
Gaston
