Quote:
Originally Posted by 6S.Manu
(Post 446764)
In my opionion this thread demostrate that Spitfire had some characterics who actually were dangerous if the pilot was not experienced... the ability to reach a great amount AoA in so little time (given the low stick forces) CAN BE dangerous if the pilot is not really well trained.
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The Spitfire
was flown by pilots who were not well trained by modern standards. The need to get pilots into action meant that training was relatively short and pilots were entering action with only a few hundred hour on type. However, I'm not aware of accounts describing the Spitfire's elevator response as a major challenge to the pilot. I'm certainly not aware of any reports of pilots pulling the wings off or losing control because of the elevator response. It would be interesting to find some if they exist.
I suspect some of the confusion evident in this thread is because:
i) Some posters (including, it appears, the OP) seem to regard stability as existing only in extreme values, so that an aircraft is either stable and thus perfectly safe, or unstable and thus horribly dangerous. However, the truth seems to be that while the Spitfire was indeed longitudinally unstable, this instability presented almost no problems even for relatively inexperienced pilots. IIRC, one of Crumpp's posts also describes the DC-3 as being unstable. Again, it probably was, but there is little evidence that this caused problems for its pilots. In fact, it's worth noting that
most aircraft actually are spirally unstable (i.e., left to themselves they will ultimately end up in a spiral dive), but the instability mode is so slow to develop that the pilot isn't even usually aware of it.
ii) Some posters regard instability as a desireable characteristic for a fighter aircraft as if it promotes manoeuvrability. But in technical language "unstable" is not the opposite of "unmanoeuvrable" (if by the latter we mean not agile). An aircraft can be simultaneously unstable and unmanoeuvrable (DC-3), or it can be stable and manoeuvrable (Pitts Special) or it can be unstable and manoeuvrable (Spitfire), or stable and unmanoeuvrable (almost any large aircraft). Unfortunately, popular accounts and casual useage mix these terms up and sometimes use unstable to mean manoeuvrable, or imply that instability is necessary for manoeuvrability. It isn't.
Whether any of this can be represented in a flight sim is a different matter. The lack of force-feedback, short PC joysticks and the need to allow response curves all suggest to me that it would be tricky at best.
FWIW, there have been attempts to relate the pilot's experience of how easy an aircraft is to fly to deficiences in stability or other aerodynamic deficiencies of the design. One such method is the Cooper-Harper scale for evaluating aircraft flying qualities (often used by test pilots). The scale considers the aircraft characteristics and how they impose demands on the pilot in selected tasks or required operation. The scale runs from 1 (good) to 10 (very bad), with 1 defined as "pilot compensation is not a factor in desired performance" and 10 meaning that "control will be lost during some portion of required operation". On the scale, 3 is defined as an aircraft characteristic which exhibits "some mildly unpleasant deficiencies" and imposes demands on the pilot such that "minimal pilot compensation (is) required for desired performance". The scale defines 4 as requiring "moderate pilot compensation". The division between deficiencies warranting improvement is at the 3/4 boundary (not required for 1-3, required for 4-10). I suspect that the longitudinal instability of the early Spitfire if assessed on the scale would be on that 3/4 boundary - i.e., it warranted improvement but was not seen as a major deficiency.
It would have been useful if the OP had clarified some if these matters at the start.
