The De Schelde S.21 was a proposed

Dutch Dutch or Nederlands commonly refers to: * Something of, from, or related to the Netherlands ** Dutch people as an ethnic group () ** Dutch nationality law, history and regulations of Dutch citizenship () ** Dutch language () * In specific terms, i ...

fighter of the late 1930s and early 1940s. It was a single-seat, single-engined, pusher

monoplane A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple wings. A monoplane has inherently the highest efficiency and lowest drag of any wing con ...

. A single prototype was under construction in 1940, but work was abandoned due to the German invasion.

Design and development

The Dutch shipbuilding company NV Koninklijke Maatschappij De Schelde of

Vlissingen Vlissingen (; ) is a Municipalities of the Netherlands, municipality and a city in the southwestern Netherlands on the island of Walcheren. With its strategic location between the Scheldt river and the North Sea, Vlissingen has been an importan ...

entered the aviation business in 1935, when it recruited most of the technical staff, including Chief Designer T. E. Slot, of

Pander & Son Pander & Son was a Dutch aircraft company based in The Hague, founded by Harmen Pander and his son Henk Pander. History Harmen Pander was the managing director of a furniture company which in 1924 bought the assets of the bankrupt ''Vliegtuig In ...

, which had failed in 1934. Early designs built by De Schelde were the

De Schelde Scheldemusch The de Schelde Scheldemusch was a single-seat pusher biplane designed in the Netherlands to be easy and safe to fly. It was one of the first light aircraft to use a tricycle undercarriage. Despite a sales campaign in the UK, only six were built, ...

, a lightweight single-seater pusher

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

Praga B The Praga B2 was a low powered aero engine suitable for very light aircraft. It dates from the mid-1930s. Design The Praga B2 was a dual ignition, air-cooled horizontal twin producing 40 horsepower (30 kW) aimed at lightweight aircraft. I ...

engine, and the Scheldemeeuw, a flying boat version of the Scheldemusch.Beeling ''Air International'' December 2015, pp. 73–74. In 1938, Slot started design work on two more advanced types which also followed Slot's preferred pusher configuration, the De Schelde S.20, a light cabin monoplane, and the S.21, a single-seat fighter, with construction of

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototype ...

s for both types beginning in early 1939.Beeling ''Air International'' December 2015, p. 74. The S.21 was a low-wing

cantilever A cantilever is a rigid structural element that extends horizontally and is unsupported at one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cantilev ...

of all-metal construction. It featured an

inverted gull wing The gull wing, also known as Polish wing or Puławski wing, is an aircraft wing configuration with a prominent bend in the wing inner section towards the wing root. Its name is derived from the seabirds which it resembles and from the Polish ai ...

, with the aircraft's tail carried on twin booms.Green 1961, p. 98. The compact

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

nacelle A nacelle ( ) is a streamlined container for aircraft parts such as Aircraft engine, engines, fuel or equipment. When attached entirely outside the airframe, it is sometimes called a pod, in which case it is attached with a Hardpoint#Pylon, pylo ...

carried the pilot, engine and the aircraft's armament. The pilot sat in a heavily glazed cockpit in the nose of the nacelle, with the engine, a

Daimler-Benz DB 600 The Daimler-Benz DB 600 was a German aircraft engine designed and built before World War II as part of a new generation of German engine technology. It was a liquid-cooled inverted V12 engine, and powered the Messerschmitt Bf 110 and Heinkel He ...

Ga liquid-cooled inverted

V12 engine A V12 engine is a twelve-Cylinder (engine), cylinder Internal combustion engine#Reciprocating engines, piston engine where two banks of six cylinders are arranged in a V engine, V configuration around a common crankshaft. V12 engines are more c ...

rated at for takeoff and at at , driving a three-bladed propeller was situated immediately behind the pilot. Slot recognized that to allow the pilot to bail out from the aircraft, the propeller would have to be jettisoned. A mechanism for doing this had yet to be decided on when work on the aircraft stopped. The engine was cooled by a radiator in the nose of the aircraft below the cockpit. A nosewheel undercarriage was fitted. Its armament consisted of a single Madsen 23 mm cannon on a flexible mount in the nose, together with four 7.9 mm FN-Browning machine guns in the side of the nacelle. The cannon was intended to be fixed during air-to-air combat, and during ground strafing operations, it would be released and aimed manually by the pilot, with an automatic stabilizing system controlling the aircraft's

aileron An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement aroun ...

s and

elevators An elevator (American English) or lift (English in the Commonwealth of Nations, Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive tracti ...

to aid the pilot in keeping control of the aircraft while busy aiming and firing the cannon.Beeling ''Air International'' December 2015, p. 75. The prototype S.21 was almost complete when Germany invaded the Netherlands in May 1940, with the De Schelde factory and the prototype S.21 being seized by German troops. Development was abandoned, with the prototype being tested to destruction at

Utrecht Utrecht ( ; ; ) is the List of cities in the Netherlands by province, fourth-largest city of the Netherlands, as well as the capital and the most populous city of the Provinces of the Netherlands, province of Utrecht (province), Utrecht. The ...

. Although abandoned, artist impressions of the S.21 were presented in the wartime aviation press as the fictional Focke-Wulf Fw 198.

Specifications (Performance estimated)

References

Notes

Bibliography

* * {{cite book, last=Green, first=William, title=War Planes of the Second World War: Volume Three Fighters, year=1961, publisher=Macdonald, location=London

External links

S.21
(in Russian) Single-engined pusher aircraft Scheldemusch Inverted gull-wing aircraft Low-wing aircraft Twin-boom aircraft