"The Spitfire wing has washout and doesn't depart in that way. The root departs first and gives a clear buffet long long before the tips go."
Yes it does. The wash-out gives warning when the turn is tightened gradually but if you pull it too fast the stall will be total.
"A larger rudder is needed with added torque and thrust, you are implying it was a design flaw."
I'm not. It was determined that such rudder was adequate for keeping the plane flying straight and in normal power off stalls and it was, if you began the corrective inputs right away. In power on stalls and in spin if the tail got its inertia built up it was probably of little help.
"I think your reasoning is faulty. The significant change in this Mark IX was to it's CofG by way of the rear tank. Your view is not supported by the flight tests of normal (no rear tank) Spitfires I have read where they had to be held in a spin, letting go of the stick would allow the aircraft to correct itself."
By all means. If the aircraft has a tendency to stay in turn by itself or even tighten the turn itself it strongly indicates that in other than straight flight its MAC tends to move forward if its not there already, add some weight to the rear and the tendency is pronounced. Maybe that is why Spitty had rather big elevators, that is to keep it flying straight despite its CoG being aft of CoL.
"Look at the comments in your paper about the aircraft tightening up in turns. If the CofG is much farther to the rear than designed for then the tail is dropping harder in the turn and this causes an autonomous tightening of the turn. This makes it much harder to ride the turn and would make the aircraft more difficult to handle and more likely to depart unexpectedly. Then you are in a world of pain once departed because your CofG is behind your CofL (without any shifting of CofL). Presumably that is one of the reasons they considered this rear tank dangerous."
Yes, that is why I posted it, the point is in such unstable aircraft such condition was dangerous. However, such condition was hardly unique for Spitty. All I'm implying is that it was less manageable if the pilot lost control due to its inherent unstableness. As the CoG was moving forward in later versions such as IX due to bigger heavier engine, there was room, CoG wise, to make a rear tank as well, although it was advisable to empty it first before flying into combat...
Testing the Spitty 1 offline I found the power off stall to be just as described in existing documentation. In fact even a power on stall is surprisingly benign. I don't really see what is the problem? Accelerated stall? That is a totally different thing to stall tests conducted in normal flight testing.
-C+
