From "The German Fighter since 1915" by Rüdiger Kosin, Putnam, 1988:
pp.142-144The Author...was design office group director and engineer pilot in the experimental flight section of the Ernst Heinkel aircraft company at Rostock-Marienehe. At the turn of the year 1936/37 same activity at the Arado aircraft works in Brandenburg on the Havel. From 1941 to the end of the war was director of the aerodynamic design division. From October 1945 to May 1946 wrote a report for the Royal Air Force. From May to October 1946 resided in the British Interrogation Centre in Wimbledon. November 1946 to July 1950 worked in France — Decize (Nievre) — in the Oestrich group on jet engine development. July 1950 accepted an offer from Fokker in Amsterdam. Design of a supersonic fighter. When the firm withdrew from the project, accepted an offer from the U.S. Air Force to work in America on the continuation of a development process in Germany interrupted by the war. From January 1952 to July 1955 worked in Wright Air Development Center in Dayton, Ohio. In July 1955 accepted an offer from the Northrop Corporation, Los Angeles, California. Worked as Research Scientist, director of the design office, project director and finally, until December 1968, as Technical Assistant, Vice President Engineering.
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From this comparison it is clear that the Fw 190 should have been the inferior aircraft, but it had two clear advantages: superior roll manoeuvrability and acceleration in a dive, which gave the pilot the chance to get into a firing position from an unfavourable situation, or to escape from the enemy if he was surprised. The Fw 190 gained a reputation for quite outstanding roll response. In contrast to the Bf 109, whose excessive aileron control forces at high speed were a constant source of complaint, the Fw 190's aileron force compensation was excellent. Both aircraft were fitted with ailerons whose leading edge was forward of the pivot axis. On the Bf 109 this part had a circular arc-shaped profile which was designed to keep the gap between aileron and wing as narrow as possible. The Fw 190 featured Frise ailerons, in which the aileron leading edge is extended to form a sharp edge. On the up-going aileron this part projects below the wing, and air pressure reduces the load produced by the top surface of the aileron. The Fw 190's wing also possessed great torsional rigidity. When an aileron is deflected, the wing tends to twist in the opposite direction. This tendency increases as speed rises, until the aileron reversal speed is reached, i.e. force is required to move the aileron, but its deflection has no effect. With stressed-skin construction the wing skin has to be strong enough to absorb the bending forces, and if this is the case the skin has an abundance of strength for the torsional loads, i.e. torsional stiffness is high. In contrast, the traditional Messerschmitt single-spar wing, as used on the 109, had plenty of strength in the bending plan, but relatively low strength in torsion. Torsional stiffness was further reduced by the large cut-outs and apertures in the wing skin for radiator, undercarriage and weapons installation.
The wingtip adopted for the 109F (and also for the Bf 110), was different from the previous version, but the change was not intentional. As an experiment a 109E wing was built with the span reduced by one metre. This machine, the Bf 109 V24, was tested and the wing found to be too small. Rounded wingtips were added to bring the wingspan up to around 10 m again, but the ailerons were not extended, and now ended at 87 per cent of the semi-span. The overall result was a further decline in aileron effectiveness. The illustrations show the fundamental differences in the wings of the two aircraft. The top and bottom shells of the Fw 190 wing were constructed separately, and connected by two widely spaced webs. The forces acting on the wing skins were transferred to a massive spar at the wing root, located at about one third of the chord. The spar was continuous from one side to the other, and formed the main attachment between wing and fuselage. The aft web extended as far as the fuselage side, where it was connected to a reinforced bulkhead. Full ribs were employed at the highly loaded points, where the undercarriage and weapon mountings were attached, with half-ribs used for the remainder.
The essential load-bearing element of the Bf 109 wing was a stout spar, at 45 per cent of the wing chord. It was located so far aft in order to accommodate the wheels. The upper wing skin was uninterrupted, and was stiffened with widely spaced ribs and longitudinal profile strips. A large proportion of the undersurface was covered with removable hatches, located between strong full ribs. The problem of transferring the forces around the various apertures called for some imaginative engineering, and was a daring piece of work. A powerful spar bridge was an integral part of the fuselage, and the two wing panels were attached to the fuselage sides at three points: the top and bottom spar flanges were connected to the spar bridge, while the third attachment point was part of the undercarriage spring strut fitting. The same fitting also held one end of the engine support strut; thus three substantial loads were transferred into the fuselage via a single component, albeit fairly complex and rather difficult to make.
