I tested quite a few of the fighters and I could get almost all them to do this. The P-51 does it the easiest, the c205 and the P-38 hardly not at all.
What I notice is that the slower you go the more rudder authority you get. Try starting this knife edge loop at 300 vice 175ias. Start the manuver with a slightly nose up attitude, so that your speed will be dropping as you commence the manuver.
What I noticed is that at 300ias the rudder has little effect, which I more or less expect. At slower speeds the rudder can and has alot more effect.
In fact some planes that I tried, like the 109G-10, absolutely crawl over the top. Quite amazing really to watch out the six view. I am still able to maintain a rudder only knife edge loop, correcting with counter aileron and some down elevator. On the way down when speed picks up the rudder loses almost all of its control and you have to go wings level.
This I notice is also true for spin recovery. If I recover from my spin early, before speed gets to high I can use the rudder effectively to counter the spin rotation. If speed is higher then spin recover is alot more difficult, because the rudder has lost alot of authority.
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Mino
The Wrecking Crew
"My Motto: Just have fun!!!! "
Swager
[This message has been edited by Minotaur (edited 09-10-2000).]