Spit IIa

[Crumpp]

Unacceptable to Who ?

Any stability and control engineer in existence. Remember there was no such person when the Spitfire was designed.

There is a reason why the RAE added bob-weights to correct the stick force gradient. This fixed the control force issue but did not correct the instability itself.

As to NACA's evaulation of the MKV the RAE in Technical note No.Aero 1106 made a bit of a rebuttal on the NACA findings. This includes some criticisms in the way NACA carried out its tests. I guess both reports should be read to draw a balanced view. The RAE document refers to NACA reports ARC 6423 and ARC 6422.

I am aware of the RAE rebuttal. Keep in mind the British were one of the last to adopt any kind of standard on stability and control.

Of course they thought it was fine, there was no established basis for what was acceptable and what was not. A few fatalities later though, the RAE did something about the Spitfire's longitudinal instability. Again, it made it easier to control but did not eliminate the cause of the instability.