Quote:
Originally Posted by 41Sqn_Stormcrow
I don't understand your point, Kur.
Yes, the Spit may have had a sensitive elevator. Yes, in case it went into a spin it may have done so in a violent manner.
But again, there is abundant indications by pilots that flew the spit that the airframe provided pilots with sufficient warning before this dangerous behaviour occured. This is, as I explained above, due to the fact that the spit had cranked wings with the inner sections of the wing stalling before the outer sections. The resulting buffeting provided a warning to the pilot.
Stalling on the inner section is in no way dangerous as long as it is approximately symmetrical. I've seen with my own eyes during an experimental flight on a piper that also had cranked wings that basically this plane needs only 1/3 of its wing unstalled to provide sufficient lift. It will have been similar for the spit.
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Stormcrow's comments are borne out by
NACA report Spitfire Va stalling Characteristics
I also note the following conditions in the Wright Field report quoted by Kurfurst:
NACA report Measurements of the Flying Characteristics of the Spitfire Va
Quote:
(Tests, Results and Discussion, page 5) All of the flying qualities tests were made with the
center of gravity at a distance of 31.4 inches behind the
leading edge of the wing at the root. The mean aerodynamic
chord of 85 inches was computed to be 4.80 inches
back of the leading edge of the wing at the root. The
center of gravity was therefore at 31.4 percent of the
mean aerodynamic chord. Because no accurate drawings of
the Spitfire were available, the calculated location of
the mean aerodynamic chord may be somewhat in error.
The center-of-gravity location with full military
load is not known.
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According to the cg diagram of an earlier Spitfire I (attached) the cg was a maximum of 7.6" aft of the datum point, which is 19.5" aft of the wing leading edge, a total of 27.1" aft of the wing leading edge, or 4.3"
forward of NACA's calculated cg.
while
here the cg for a Spitfire Va tested at a loaded weight of 6,450 lbs by the A&AEE was 6.2" aft of the datum point, or 25.7" aft of the wing trailing edge, almost 6"
forward of NACA's calculations, making their Va tail heavy, albeit their Spitfire weighed 6,184 lbs, which should not be enough of a difference to affect the cg that much.
How is it possible for a report to determine elevator characteristics when the cg of the test aircraft may not be set up properly? Nor do we know how the Spitfire in the RAE tests was set up.