Daidalos Team's Room -QUESTIONS AND REQUESTS ONLY on IL2 Authorized Addons

[JG27CaptStubing]

Originally Posted by IvanK

Capt Stubbing .

In your reply you state that you are seeing the effects start at 300mph but don't state at what altitude. Well that could be the case depending on altitude. Its not an IAS but a Mach number problem. In the chart you post note that at 30,000feet the limit is in fact 290Kias this equating to 0.68Mach. The limit of onset values (at 1G) is solely Dependant on Mach number. This is exactly what is happening in Il2. I have the luxury of real time Mach number display in the tests I perform. So far in what I see the onset of compressibility in the P38 is almost exactly on the documented numbers..

That was at 14K and below. I think your right that the "tuck under" does start at the right IAS or close to it but prior the planes elevator effectiveness is so reduced it may as well be part of the compression problem or some other mythical cement elevator. Read the statments above about how these problems were solved and they virutually had no issues 15K and below.

Originally Posted by IvanK

As to why the other aircraft don't have the same issue. Well many of them didn't in real life suffer quite the same problem as the P38. The design of the P38 resulted in a fairly low (by comparison with the other types) Critical Mach number (Mcrit). Further complicating this was the design of its tailplane, a large surface immediately behind and in the combined downwash of the inner wing cockpit cuploa area. So the P38 had an inherently lower Mcrit than the others types. There is for example documented cases of late model Spitfires achieving Mach 0.92.... a speed no P38 would ever approach.

What you're saying is all true but it also depends upon what version of the plane and if it had the changes mentioned above which supposedly got rid of some of those problems.

Originally Posted by IvanK

You also state:

"The flaps we have in the game are nothing more than a Speed Brake which slows the plane down and causes some sort of lifting action. "

I disagree, again the documentation on the P38 describes the effects of the Dive flaps resulted in up to a 4G pitch up raising the nose and assisting the pilots recovery. Sure the increase in Drag will assist in deceleration but the prime function of the P38 Dive brakes was to get the nose pitching up. It does exactly that in IL2 as well. (BTW don't forget that dive flaps of almost exactly the same design were fitted to late model P47D's and other types). To test in Il2 get yourself to Vmax at sea level and activate the Dive brakes what happens ? just a decel or decel + pitch up ?

Lets be clear... They are "Dive Recovery Flaps" not Dive Brakes. In my earlier post where I quoted they are not meant to be dive brakes is very true. It was a device meant to move the center of lift back over the wing area instead of the tail area hence the problem. Since I'm not a P-38 pilot I can't comment on what it would be like to use them in real life. By the accounts given Olegs version does seem about right after reading through it again. Though I still think the problem starts with the cement elevators very early on and continue throughout the dive.

Originally Posted by IvanK

I do agree with you that some types P47,D9 and Tempest do end up at huge Mach numbers (1.15 in my tests) which are unrealistic. Rest assured this is being looked at. The Il2 FM was never really designed to model compressibility to the nth degree. The DT team is aware of this and is discussing this and other things.

I agree you can tell the sim wasn't meant to really be a study sim about compression problems.

Since you're at it what about some of the other issues I mentioned?

Accuracy of 50 cals on wing mounted 6 gun platforms? I think their hitting power is fine by the way.

Horse Power on the F6F which seems to be anemic at best. I need to do some real testing here but I think this plane has been ignored for sometime now.

Antons losing all 3 control axis from a single shot even with pushrod accuated control surfaces. Antons non self-sealing fuel leaks or what I call a fuel leak bug which empties the plane in a matter of minutes.