GRUNHERZ,
It is interesting, but it doesn't match the timeline of the Spitfire development. It is quite possible that the author made some assumptions and messed up the timeline by doing so.
Once the mock-up of Type 300 was completed at the end of April 1935, officials and designers were unanimous, when they viewed the model: It was to be a great success.
Some alterations were necessary and the Ministry of Aviation quickly made the money available. Amongst other things the wing design was to be changed. The resulting characteristic elliptical shape produced very thin wings, which were still able to hold the fuselage and weapons, and could withstand the strains of air battle. It was planned to arm this aircraft with eight American Browning-MG's.
This bit here is simply wrong. No mock up of Type 300 was ever done without elliptical wings. Further, the first drawings of Type 300 with elliptical wings appear in September, 1934.
In my books I have found this passage:
The 14th Paris Aero Show opened during November, 1934 and Shetstone submitted notes of his visit to the design office. He mentioned, in particular, the Heinkel 70 calling it the most outstanding exibit and considered it to be- "One of the most efficient (aerodynamically) aeroplanes in the world." He also commented favorably on the Gallay radiator, quoting the manufacturer's claim that it saved 17% in weight and drag over the standard British type.Mitchell decided the wings of Type 300 would be elliptical during the second or third week of November, 1934. Therefore there is no way that a mockup of Type 300 could ever have appeared, much less in 1935, without the elliptical wings.
During constructions great emphasis was placed on reducing air resistance. Extremely smooth surfaces were created. Rivets were not going to mar the performance of this aircraft.
In achieving this, Supermarine engineers took on board results, made available by the German designer Ernst Heinkel. While the Aérosalon 1932 took place in Paris, Mitchell wrote a letter to Heinkel with the following question: "Was the skin of the aircraft exhibited in Paris made of metal or was plywood used to cover the fuselage?" He also showed an interest in British research about the He 70 with new English aircraft engines: "We found to our consternation that despite its vast dimensions your plane is markedly faster than our fighters."
This I have no problem with, other than the description of the He 70 participating in the Aérosalon 1932. The He 70 first flew in December, 1932 and entered service in 1934. I think it far more likely that the Supermarine representative, Shetstone, first saw it at the Paris Aero Show in November, 1934.
And after this exchange a Rolls-Royce Representative did get in touch with Heinkel in Warnemünde. He suggested the Germans to purchase an He 70 in order to fit her with the new 810 h.p. Rolls-Royce engine Kestrel V and offer her globally. There simply would be no faster plane on earth.
Heinkel was not averse to this proposal and suggested a deal: an He 70 in exchange for the licensing rights of the Kestrel V. The London Ministry of Aviation was soon in agreement, however the new rulers in Berlin were not prepared to give their consent to this idea. This is why Rolls Royce bought a Heinkel He 70, which reached a speed of 420km/h with the Kestrel engine.
The aircraft was checked over thoroughly by the Royal Aircraft Establishment in Farnborough. And this is when Supermarine became interested. The elliptical wing shape of the He-70 convinced even Mitchell.
Mitchell had already settled on the elliptical wings, quite probably based on Shetstone's recommendations after observing the He 70 in the Paris Aero Show, well before Rolls Royce aquired an He 70. I can see the He 70's structures being examined and some technical strengthd being taken from it for the Type 300, but I can just as easily see the Type 300 being no more influenced by the He 70 than it was in November, 1934 because of Shetstone's recommendation.
The fact is that the Type 300's development simply cannot have happened as described in the article you posted. The He 70 wasn't at the 1932 Paris show and the Type 300 already had elliptical wings in November of 1934.
It seems to me the likely limit of the He 70's influence on the Type 300 is Shetstone's recommendation in November 1934 and the replies Heinkel gave to Mitchell's letters. The Rolls Royce purchase is simply too late to have much, if any, effect.
