[NZtyphoon]

Originally Posted by Kurfürst

My point is basically the difference how the Spitfire and 109 behaved when getting near the stall. Both gave plenty of warnings, but the difference was as I see it is that once riding the stall, the Spitfire gave very little margin before you actually stalled, and once stalled it went medieval on you.

NACA report Spitfire Va stalling Characteristics with reference to the concluding remarks on page 9...

The airplane possessed some unusual characteristics in stalls that are not required in reference 1. The motion beyond the stall was not violent and an unusual
amount of lateral control was available in many flight conditions, even when full up elevator was applied. The good stalling characteristics allowed the airplane to be
pulled rapidly to maximum lift coefficient in accelerated maneuvers in spite of its neutral static longitudinal stability.

From Spitfire Va Flight Characteristics

Characteristics of the elevator control in accelerated Flight: (pages 8 & 9)

The elevator control was found to be powerful enough to develop either the maximum lift coefficient or the allowable load factor at any speed....(page 8 )

The Spitfire airplane had the unusual quality that allowed it to be flown in a partly stalled condition in accelerated flight without becoming laterally unstable. Violent buffeting occurred, but the control stick could be pulled relatively far back after the initial stall flow breakdown without causing loss of control. With the gun ports open, lateral instability in the form of a right rolll occurred, but not until an up-elevator deflection of 10° had been reached and unmistakeable warning in the form of buffeting had occurred. This subject is discussed more fully in reference 2.

The excellent stall warning made it easy for the pilots to rapidly approach maximum lift coefficient in a turn so long as the speed was low enough to avoid undesirably large accelerations at maximum lift coefficient.
The excellent stall warning possessed by the Spitfire was obtained at the expense of a high maximum lift coefficient. The maximum lift coefficient in accelerated flight was 1.21, while the average lift coefficient throughout a stalled turn was usually about 1.01 (9)

The report goes on to state:

In turns at speeds high enough to prevent reaching maximum lift coefficient because of the excessive accelerations involved, the small static longitudinal stability of the Spitfire caused undue sensitivity of the normal acceleration to small movements of the stick. As shown by the time histories of high-speed turns (figs. 15 to 18 ), it was necessary for the pilot to pull back the stick and then ease it forward almost to its original position in order to enter a turn rapidly without overshooting the desired normal acceleration. Although this procedure appears to come naturally to a skillful pilot, flight records from other airplanes show that a turn may be entered rapidly and the desired normal acceleration may be held constant by a single rearward motion of the stick provided the static stability of an airplane is sufficiently large. By careful flying, the pilot was able to make smooth turns at high speed, as shown by figures 17 and 18. Ordinarily, however, small movements of the stick caused appreciable variations in the normal acceleration, as shown in figures 15 and 20.

This hardly speaks about a deadly stall and it certainly doesn't mean the Spitfire was inherently dangerously unstable as claimed by Crumpp. It would be interesting to know whether this Spitfire, as tested, might have been marginally unstable, because, as noted, the cg position was not accurately known. It would also be interesting to know how the elevator control was affected by the extended mass balances described by Jeffrey Quill.

Getting back to flight qualities in CloD, how would it be possible to replicate these qualities?