Excellent article on the Spitfire Mk VIII, with a touch of the Saint-exupery and Richard Bach but, although it may seem a bit pedantic, as folk tales and myths become the ‘truth’ if repeated enough times, can we please finally shoot the old ‘canard’ that the Spitfire was influenced by the Heinkel 70?
Let’s look at Supermarine’s situation in 1934. Back in 1931 Mitchell had designed the S6B floatplane that won the Schneider Trophy and subsequently set a World Air Speed Record at 407.5mph. His new single-seat fighter (the Type 224) was no faster than the Gauntlet biplane it was intended to replace. Mitchell wanted speed, at whatever cost in complexity. Aerodynamic theory, proving that an elliptical wing offered a reduction in induced drag over any other planform, had been available since the twenties (Lanchester, Prandtl, Joukowski et al) and the new generation of monoplanes could usefully take advantage of that benefit. Mitchell had a brilliant young Canadian aerodynamicist (Bev Shenstone) who burnt the midnight oil with three-dimensional calculus, log tables, and slide rules (no computers then) to convert the concept into reality. Speed is also a function of wing thickness and here Joe Smith (Chief Designer after Mitchell’s death) provided a novel wing structure allowing T/C ratios of 13% root, 6% tip that still enabled combat stresses to be absorbed, not a requirement for the He70 airliner. The RAE chipped in with a cooling system design that actually provided thrust rather than drag ( the Meredith effect — Ed).
So, rather than being a ‘warmed over He70’, the Spitfire was a team effort pushing the bounds of technical knowledge. Was the effort worthwhile?
Martlesham Heath reports show that the Spitfire prototype achieved 349mph, while the Hurricane managed 315mph. Both powered by the Merlin C. Case proven!
Other aircraft that had elliptical wing forms, but probably not the same sophisticated design, include: Anf-mureaux 190 f.f 1936 (France) — fighter; Boeing XF7B-1 f.f. 1933 (USA) — fighter; Nieuport Delage 121 f.f.1932 (France) — fighter; Piaggio Pc7 1929 (Italy) — Schneider Trophy Racer; Seversky SEV-1XP f.f. 1935 (USA) — fighter (which evolved into the P-47 Thunderbolt); Short-bristow Crusader 1927 (UK) — Schneider Trophy Racer.
Did their designers all form an orderly queue outside the Heinkel design office?
As for the elliptical wing being adopted to cover the armament, no way. With the originally-specified four gun requirement, it can be seen that we have a nice, compact group just outboard of the wheel wells. When this was increased to eight, numbers five and six are still reasonably placed but seven and eight are out near that thin tip; when pulling ‘g’ I do wonder where the bullets went!
One final thing: Shenstone never worked for Heinkel! He did spend some time with Junkers but, more importantly, he helped Dr Lippisch on the aerodynamic calculations for the DFS 194 all-wing research aircraft that developed into the Messerschmitt ME163 rocket fighter.
There, I feel better now. Mik Sansom, Seaton What a joy to be able to read Maxi Gainza once again in Pilot! And not once, but twice. Firstly the vintage piece in the 50th anniversary issue and then the article on the Spitfire Mark VIII in the November issue. The fact that we old readers have been graced over the years by numerous articles on the Spitfire does not detract from the freshness and readability of this piece. I particularly enjoyed and shared the consideration that we pilots can find merits even flying the proverbial barn door.
All in all a very enjoyable read that brought me back to years past when Maxi was a regular contributor to this magazine and was writing informed articles in his beautiful linear English that only a foreigner can muster. I am looking forward to reading the next instalment in the December issue. Alex Burani