[Franek Grabowski]

Originally Posted by Six Nifty .50s

This has nothing to do with measuring the greater air resistance against the plane and propeller at lower heights. There is simply no way that a Spitfire or any other aircraft could attain the same Mach Number or accelerate as quickly if the pilot began his dive in denser air; in this case 12,000 feet below the original starting point.

I am afraid you cannot understand simple laws of physics. If an aircraft reaches Mcr at low level, increasing it will not change anything! Mcr is constant non-dimensional value non dependant on AS.

Whose analysis? It's always reckless to draw general conclusions based on the results of one pilot and one plane. But if you insist, anyone can play that game ...

Yup, let's go. Please, prove me that M=0,83 that Herb Fisher was unable to exceed is more than M=0,89 achieved by Martindale.

Boscombe Down January 1941. Spitfire P7525. Complaints by No. 66 Squadron over handling qualities included a diving speed restricted to 320 mph in spite of full forward trim. Flew left wing low and had airflow problems with the tailplane. Modifications made to improve handling.

Every aircraft that was reported to have poor handling qualities or performances was tested at Boscombe Down. In most cases this was caused by poor servicing - apparently this was the case of this Spitfire, which was damaged at 66 Sqn, then rpaired and sent to BD.

Farnborough June 1942. Spitfire P7251. Failures of tailplanes had occurred in high speed dives, usually breaking off at Frame 19, and tests were started to locate the cause. Out of 36 accidents under investigation at the time, the tail unit broke off in mid-air 24 times and 15 pilots were thrown out of the aircraft. A new mainplane was fitted to P7251 together with recording instruments used to measure tail plane deflections. Two pull outs were made at 300 mph and one at 400 mph and there was some twisting of the fuselage near the tail. The terminal velocity of the Spitifire was quoted at "560 mph True Air Speed, corresponding to about Mach .79".

There was no Spitfire with such serial.

Farnborough April 1944. Spitfire EN409. This aircraft was dived from a height of 40,000 feet and reputedly reached a True Air Speed of 600 mph, which destroyed the engine and propeller.

Farnborough August 1944. Spitfire PL827. This aircraft was dived from a lesser height of 36,000 feet, but the pilot was unable to complete his high speed run because the supercharger exploded and the aircraft was set on fire.

Ridiculous. Making complaints because the aircraft reached the top speed for a propeller driven aircraft and this caused a few malfunctions? Fisher achieved TAS=560, a little bit less than Martindale, I would love to see what would have happen with Thunderbolt flying with TAS=600.

Farnborough November 1944. Spitfires NL345, NH476, PT357. These aircraft were fitted with recording instruments to assess structural damage caused by dive-bombing, although the pilots did not dive at particularly high speeds, nor at excessively steep angles (usually 45 to 60 degrees). The test was prompted by complaints from No. 125 Wing which experienced a large number of buckled mainplanes within a few weeks.

This was also reported by Polish pilots. I am not sure what it has to dive speeds but eg. Mustangs also suffered such failures. They were fatal however, so no such aircraft was ever tested.

I really don't think that anyone is interested in reading responses such as: "This cannot be true because I seem to remember talking to a Polish pilot who never mentioned this to me".

You may like it or not but PAF was the greatest foreign operator of Spitfires. Thus, I may conclude Polish stats or observations would be representative for the type.

I doubt it, unless the Focke-Wulf had an engine failure. And you're the one who implied that we should not question the findings from RAF tactical trials.

RAE Farnborough and AFDU Duxford tested Oberleutnant Arnim Faber's FW 190 A-3 against the Spitfire V and the Spitfire IX. The Focke-Wulf ran away from both in dive performance, even though Faber's plane was not exactly tip-top. It had a derated engine which did not deliver maximum potential power and level speed, and the BMW also ran rough because of bad spark plugs.

I do not know if you do that willingly or not but it was clearly noted that Fw 190 was able to escape (Split-S) due to excellent ailerons' efficiency and superrior roll rate. This was improved in later Spitfires, starting with Mk XII.

I don't know if the RAF tested a Griffon-engined Spitfire against a Jumo-engined FW 190D, but former Luftwaffe pilots have said that the Dora 9 accelerated faster in a dive than the FW 190A.

I doubt if Fw 190D had much different Mcr than Fw 190A, this means their maximum speeds must have been similar.