Quote:
Originally Posted by winny
You keep saying that it's unstable but I still don't know What you actually mean.
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Hey Win, here's the laymans
I'm flying staright and level, trimmed for cruise and hands off in an aeroplane and I hit a pocket of rough air. The right wing drops a fraction:
Stable: aircraft will settle back to it's trimmed state automatically thanks to inherent clever design - basically it's to do with differing lift vectors and their strength and direction. This is great for trainers, light aircraft and commercial machines as it means a minimum of pilot effort to fly the plane in straight lines. However it also means that the plane will resist slightly manouevres initiated by the pilot, cos it just wants to fly straight and level! Not great for fighter aircraft.
Neutrally stable: The plane will stay at that angle of bank and unless controls are manipulated will not return to it's original attitude. More workload for the pilot but generally not hard to fly, just requires more attention.
Unstable - the aircraft continues or even accelerates the wing drop to the right. Without pilot interaction/correction the manoevre would continue or even amplify till 'bad things' happen. Aircraft of this nature are tiring to fly because you're constantly fighting the plane - like being balanced on a pin and in asituation where even your control inputs are being amplified. Not fun. A good example of this is the P-51B/D with the rear fuselage tank full; it pushed it's CoG back far enough that it took it to the limit of acceptable controllability - there is a quote by Bud Anderson where engaged before he could empty this fuel tank he ended up in a turning fight with the nose still pitching up and round but he had nearly full forward stick input to try and keep it from throwing itself into a spin.
Now Crummps agenda is based on
one report of a Mk. V with which he wishes to tarnish the handling of all Spitfires, despite reams of evidence to the contrary.
In truth there were some issues with Mk Vs being not correctly loaded (they carried quite a bit more kit in them than the earlier Mks) and a short term measure of intoducing bobweights into the elevator control circuit ('g' acting on the bob weight during pitching manoevres actuallly weighted the control column to provide a resistance to up elevator input). As this problem was investigated, and it's catalysts understood, better and more careful loading instructions, and ultimately a redesigned elevator mass blance made the bob weights obsolete.
Was the Spitfire's CoG range small? Yes. And it didn't take much to put it close to or beyond them. However, if you've done your reading nearly every one who's flown the thing, in whatever Mk, speaks glowingly of it's handling. Sure there were lemons and I suspect the NACA variant was an old war weary machine not in best of trim, but it seems foolish to take the evidence of one report against a veritable sea of contrary opinion.