P-47 Actions 29 Mar 44 near Berlin

[drgondog]

Both North American and USAAF dive tests established the .76 Mach 'Do Not Exceed' limit for the Mustang (same for A, B/C, D and K) which was about 475mph TAS and 280 IAS at 20,000 feet. Obviously this isn't too far from the Mcrit of those models Laminar Flow airfoil at .82.. I believe, opinion wise, that several example exist where higher speeds were attained (and survived) but they weren't documented under rigid scientific framework.

I also know the P-51H exceeded 500+ TAS in a dive but I haven't been able to put my fingers on the data - it also had a thinner laminar flow wing and 1,000 pounds lighter - and seem to recall the Mcrit was .85 for the thinner wing but not sure.

The P-51 was just plain 'cleaner' aerodynamically than any operational piston engine fighter in WWII... which is why I seriously doubt that any spitfire came close to 600mph in a dive much less 500 w/o ripping it's drawers.

Franek - where can we look to see what you have seen on the test data?

My sources are the North American data published in Mustang by Robert Gruenhagen, and Mustang Designer by Ray Wagner - which is as much about Edgar Schmued (Head of NA Design and father of P-51).

Regards,

Bill

[Franek Grabowski]

Originally Posted by Six Nifty .50s

Another strange notion not sustained by facts. RAF test pilots were first to admit the maximum speed of the Spitfire declined rapidly when diving into denser air -- reduced to about .67 Mach at heights just below 20,000 feet. Not very impressive, and probably overoptimistic for anyone but highly experienced pilots. That explains why the 109s and 190s could out-accelerate Merlin-powered Spitfires if the dive was started from heights below 30,000 feet.

Well, a look at respective angle of dive column proves any discussion with you is just a waste of time. Bye.

Bill
Mustang was cleaner, no doubt, but Spitfire dived better.
When I cope with recent projects, I will make some sort of order with my papers and then let you know exact details. IIRC (this may be in archive) Mustang's top speed was around M=0,8 and Thunderbolt's - M=0,7 but I may be wrong.

[Six Nifty .50s]

Bill, according to Eric Morgan the data you seek was published in a report by RAE Farnborough in June 1945, based on trials the previous year. The purpose was to measure profile drag measurements on the Spitfire's wing at high speeds. The test aircraft was Spitfire Mk XI serial number EN409. The chief test pilot was Squadron Leader Tony Martindale.

If not interested in the original report you could can read summaries in The Spitfire Story by Alfred Price or the hefty Spitfire: The History by Eric Morgan.

The second edition of the Price book contains a photo of EN409 after it was seriously damaged in the controversial dive of 27th April 1944, in which the pilot claimed to have reached 606 mph, and Mach .89. After the motor was destroyed he made a successful landing, wheels down, minus propeller and parts of the engine.

[Six Nifty .50s]

Originally Posted by Franek Grabowski

a look at respective angle of dive column proves any discussion with you is just a waste of time.

So would your attempt to explain it further.

Franek, it's true that any discussion with you is a waste of time. My responses were not specifically directed at you, since you are usually quarrelsome and unwilling to be civil.

According to Alfred Price, Jeffrey Quill carried out diving trials with Spitfire K5054, although in this case he began his dive from only 20,000 feet. A landing gear fairing flew off after Quill reached the "maximum allowable speed" which was quoted as "a true airspeed of 465 mph".

[John Beaman]

Cool it guys or this thread is frozen and maybe gone. Stick to the issues.

[Six Nifty .50s]

I know that dive angles vary according to the chart but I also know that at lower heights there were greater limits on dive speeds, especially if the angle was 45 degrees or more. The pilot could tear the wings or tail off the aircraft and many Spitfires were structurally damaged when pulling out from dive-bombing runs.

There is a good reason why Martindale dived his Spitfire from 40,500 feet. If the Spitfire could be safely dived from a 45 degree angle at a speed substantially greater than .67 Mach (when below 19,500 feet) I don't think it's unreasonable to demand some proof.

[Graham Boak]

I suggest you consult the records concerning the diving trials carried out at Boscombe down by Sq.Ldr. Martindale, where a dive Mach of around 0.91 was achieved. The tail stayed on but the reduction gear broke and the propellor came off. He was able to bring the aircraft to a safe landing - a photograph has been published.

I'm far from clear why a Spitfire's tail should come off but a 190's stay on?

[Graham Boak]

Apologies for the duplication: for some reason my machine wasn't picking up the later parts of this discussion when I first entered it. No doubt my fault.

However, as the appropriate test results are presumably still available, perhaps a visit to the National Archives is called for?

[Franek Grabowski]

Originally Posted by John Beaman

Cool it guys or this thread is frozen and maybe gone. Stick to the issues.

John
I simply leave this discussion. In my opinion, if one uses speed after recovery from a dive as an argument against high dive performances, it is an indicator not to waste time anymore.

[Slybirdsx]

To all concerned, my name is john, and I am the son of the first pilot listed, Glenn G. Callans. I have most of my fathers records and will search for the event listed. I will post it if any information relates to it. Regretably, my father passed April 9, 1994. However I know if he were here he would with out a doubt be apart of this forum. He loved reuniting with his former "Thunderbolt" and other flight buddies.