The Göppingen Gö 9 was a German research aircraft built to investigate the practicalities of powering a plane using a pusher propeller located far from the engine and turned by a long driveshaft.

Design and development

In 1937,

Claudius Dornier Claude (Claudius) Honoré Désiré Dornier (born in Kempten im Allgäu on 14 May 1884 – 5 December 1969) was a German-French airplane designer and founder of Dornier GmbH. His notable designs include the 12-engine Dornier Do X flying boa ...

observed that adding extra engines and propellers to an aircraft in an attempt to increase speed would also attract a penalty of greater drag, especially when placing two or more engines within

nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...

s mounted on the wings. He reasoned that this penalty could be minimized by mounting a second propeller at the rear of an aircraft. In order to prevent tail-heaviness, however, the engine would need to be mounted far ahead of it. Dornier

patent A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an enabling disclosure of the invention."A ...

ed this idea and commissioned a test plane to evaluate it. The aircraft was designed by Dr Ulrich Hütter as a 40% sized, scaled-down version of the

Dornier Do 17 The Dornier Do 17 is a twin-engined light bomber produced by Dornier Flugzeugwerke for the German Luftwaffe during World War II. Designed in the early 1930s as a '' Schnellbomber'' ("fast bomber") intended to be fast enough to outrun opposing a ...

's fuselage and wing panels without the twin-engine nacelles, and built by

Schempp-Hirth Schempp-Hirth Flugzeugbau GmbH is a glider manufacturer based in Kirchheim unter Teck, Germany. History Martin Schempp founded his own company in Göppingen in 1935, with the assistance of Wolf Hirth. The company was initially called "Sportfl ...

. The airframe was entirely of wood and used a retractable

tricycle landing gear Tricycle gear is a type of aircraft undercarriage, or ''landing gear'', arranged in a tricycle fashion. The tricycle arrangement has a single nose wheel in the front, and two or more main wheels slightly aft of the center of gravity. Tricycle g ...

– one of the earliest non- Heinkel-built German airframe designs to use such an arrangement. Power was supplied by a

Hirth HM 60 The Hirth HM 60 was a four-cylinder inverted air-cooled inline aircraft engine designed in 1923 and first sold in 1924. The engine was of very high quality, and its sales success contributed to Hirth's rapid pre-war expansion. It was a popula ...

inverted, air-cooled inline four-cylinder engine mounted within the fuselage near the wings. Other than the engine installation, the only other unusual feature of the aircraft was its all-new, full four-surface

cruciform tail __NOTOC__ The cruciform tail is an aircraft empennage configuration which, when viewed from the aircraft's front or rear, looks much like a cross. The usual arrangement is to have the horizontal stabilizer intersect the vertical tail somewhere ...

, which included a large ventral fin/rudder unit of equal area to the dorsal surface. This fin incorporated a small supplementary tailwheel protruding from the ventral fin's lower tip that assisted in keeping the rear-mounted, four-blade propeller away from

tailstrike In aviation, a tailstrike or tail strike occurs when the tail or empennage of an aircraft strikes the ground or other stationary object. This can happen with a fixed-wing aircraft with tricycle undercarriage, in both takeoff where the pilot rot ...

damage against the ground during take-off and landing. The Gö 9 carried the civil registration D-EBYW.

Operational history

Initially towed aloft, flight tests began in June 1941, but later flights operated under its own power. The design validated Dornier's ideas, and he went ahead with his original plan to build a high-performance aircraft with propellers at the front and rear, producing the

Dornier Do 335 The Dornier Do 335 ''Pfeil'' ("Arrow") was a heavy fighter built by Dornier for Germany during World War II. The two-seater trainer version was called ''Ameisenbär'' ("anteater"). The ''Pfeil''s performance was predicted to be better than other ...

. The eventual fate of the Gö 9 is not known.

Specifications (Gö 9)

References

Citations

Bibliography

* *Selinger, P E. ''Segelflugzeuge Vom Wolf zum Discus''. Motor Buch Verlag, Stuttgart 1989

External links

Video of Do 335A and Göppingen Gö 9 tests
{{DEFAULTSORT:Goppingen Go 9 1940s German experimental aircraft Mid-engined aircraft World War II experimental aircraft of Germany Single-engined pusher aircraft Schempp-Hirth aircraft Aircraft first flown in 1941 Glider aircraft