Does IL-2 simulate the shapes of wing like straight wings are good at lower speeds
and swept wings are good in more higher speed and does it simulate the effects of
near supersonic speeds like a P-51 Mustang's wing will break of at a much lower
speed than the Me-262's.
The effect you're talking about is compressability, where the aircraft begins causing supersonic shock before actually going supersonic, due to a low speed design.
The issue in il2 AFAIK (I haven't played it nearly as much as everyone else around here) is that the il2-modelled structural failure tends to occur more at low altitude than high altitude and this would be therefore related to IAS which is the mundane type of structural failure caused by force of airspeed (which is measured by the pitot). Compressability is the opposite since it is related to TAS and is inversely proportionate to air density (so it is measured by a Mach meter and engineering guidelines for the aircraft).
It is very difficult for aircraft, even modern jets to reach supersonic speeds near sea level because of air density, compressability is rarely an issue. But it is very easy for any aircraft, even piston aircraft with a high dive speed, to approach supersonic speeds at high altitude. For an example, consider that at 30,000ft the speed of sound is less than 425mph IAS.
Now this does bring up a problem with il2 modelling when performing high altitude missions. Point in fact, Republic Aircraft listed the maximum dive speed of the Thunderbolt at 550mph. Now even if this was adjusted by the pilot to TAS the figure would still be 0.81 Mach when diving from altitudes higher than 30,000ft (something B-17 escorts might very well do). That's definitely fast enough to rip the wings off that plane (Charles Lindbergh tested the P-47 himself and said it was unstable from 440mph at 15,000ft if I recall correctly).
So firstly this element is not modelled in detail in il2 obviously. Many aircraft can well exceed 450mph IAS at high altitude in a dive, of which most of them would break up a little over half that speed in reality. When you get lower they tend to start losing ailerons and elevators.
But secondly il2 sturmovik is a ground attack simulator that got expanded. The original programming engine just wasn't designed for all this. I'd expect this kind of modelling for SOW:BoB however, since the historical Battle of Britain was mostly aerial combat at altitude. The problem with SOW is that it won't have anything like the variety of flyables and mission generation possibilities as il2 for several years to come. Think of it as the 2002 version of il2 in a new programming engine, rather than taking up where il2 left off.
So ultimately compressability isn't really modelled in il2 per se and that's just something we all have to put up with for some time. It is possible individual damage models for the aircraft in il2 might be modified to simulate compressability effects, but I don't know the first thing about modding il2 so I don't even know if that's possible.
