Ok,I guess It's time for me to chime-in here and straighten-out all of you![sm=bananahead.gif]After getting my master's degree in aerodynamic engineering from the prostegeious university of TLAR back in 1964,I have come to the conclusion that rounded wing tips were a combination of all of the above!Aeroplanes back then were still in there infantcy-they were still learning.As for the ground loop thing,take a look at the wing tips of the Sopwith aircraft---especially the beloved "PUP".This plane was trully loved by it's pilots!!!No other plane that I know of at the time had such a reputation.It got that rep. due to the fact that it was a VERY user friendly bird to fly!Also it could manuver very well and was reasonably successful as a fighter during the period.It was,however,a little low on firepower-only 1 gun.Of course,By adding the second gun and the additional amo increased the weight and therefore required more power(can you say-"vishous-circle")The other plane that comes to mind is the Russian Mig 3.This fighter was feared by the Luftwaffa and orders were given to---avoid engageing the thing at all costs at high altitude!It also had very little firepower compared to most other fighters of the time.BTW,Since the Mig 3 was designed years before the famous P51,one has no choice but to come to the conclusion that it most definitely must have influnced the engineers at North American Aviation,due to the fact that they designed the Mustang in such a very short length of time!Just look at the Mig and the Mustang and it should be obvious.As you can see by now,I'm no expert,but this subject just got me going.