Spitfire supposed to dive better than the 109?

[NZtyphoon]

Originally Posted by Glider

I wouldn't set too much store in the 0.92 Mach no. It was reached but it was a test pilot and the machine basically fell apart around him, the prop came off, the engine almost fell out.

Mind you the wings stayed on

Alex Henshaw's account of experiments conducted on a Mk V are interesting: pilots were complaining that the engines were over-revving in a dive, so Castle Bromwich test pilots conducted some test flights:



Here's an account by an aerodynamicist regarding the fabric ailerons:

Originally Posted by ATAG_Dutch

Both true. In fact when I did my dive tests, I pulled out using the trimmer exclusively. In the high speed dives, I need a lot of down trim and a lot of rudder trim, but got up to at least 440mph, maybe 450, but by that time I was more concerned with where the ground was.

P.S. I also brought prop pitch down to fully coarse, i.e. lowest revs.

From Pilot's Notes Spitfire IIA & IIB

DIVING

21. The maximum permissible diving speed is 450 m.p.h. A.S.I*. Note the following:

(i) Constant-speed airscrew. - At maximum r.p.m., 3,000 , the throttle must be 1/3rd open. The pitch control need not be brought back to reduce r.p.m., the range of pitch is enough to hold down the r.p.m. at any airspeed.

(ii) The flaps must be up at over 120 m.p.h A.S.I.

(iii) The aeroplane should be trimmed in the dive, i.e. the trimming control tab should be set to give no load on the elevator. This will lessen the possibility of excessive "g" being induced in easing out of the dive, particularly if the pilot should release his hold on the stick owing to "blacking out' or any other reasons. No difficulty is experienced easing out of the dive will be experienced even if the aeroplane is trimmed in the dive as the elevator is comparatively light and recovery is not resisted by excessive stability in pitch. Elevator tabs may be used, very carefully, as described in para. 14.

(iv) The rate of descent is very great, so ample room for recovery must be allowed.

* Note Henshaw's comment on speed being pegged at 470 m.p.h. A.S.I so one wonders whether this was a misprint in the Pilot's Notes.

[janpitor]

Maximum permissible actually doesn´t mean maximum that the aircraft can sustain. A safety factor is used in aircraft construction and also in manuals/permissible maneuvers.

[NZtyphoon]

Originally Posted by janpitor

Maximum permissible actually doesn´t mean maximum that the aircraft can sustain. A safety factor is used in aircraft construction and also in manuals/permissible maneuvers.

Originally Posted by jf1981

I would be pleased that they tune up what a human can stand in a fighter aircraft so that one cannot abuse the very high followed by negative Gs.

At the present time, one can handle very high Gs for some time but even a low neg G for long time results in sort of blackout.

Agree 100% with both comments - for interest the Pilot's Notes General, which were always issued and used in conjunction with the Pilot's Notes, say this about g forces and blackout thresholds:



I remember reading somewhere that 109 pilots had slightly higher blackout thresholds because their seats had a greater backward angle than the British - RAF fighters later adopted two-step rudder pedals for similar reasons.