General Aircraft Monospar

The General Aircraft Monospar was a British family of aircraft built by the General Aircraft Company to exploit the new cantilever wing developed by the Monospar Wing Company Limited.

Design and development

After producing a number of experimental cantilever wings based on the work of Swiss engineer H.J. Steiger the Monospar Wing Company designed a light low-wing aircraft designated the Monospar ST-3 and built by the Gloster Aircraft Company. After successful testing of the ST-3 a new company General Aircraft was formed to use the new Monospar wing in new designs.

The first design was the ST-4 a twin-engined low wing monoplane with a fixed tailwheel landing gear. Powered by two Pobjoy R radial engines the first aircraft (registration G-ABUZ) first flew in May 1932 and was followed by five production aircraft. The ST-4 II an improved variant with minor differences followed with a production run of 30. In 1933 the ST-6 appeared, a similar aircraft to the ST-4 with manually retractable landing gear and room for an extra passenger. The ST-6 was only the second British aircraft to fly with a retractable landing gear (the first the Airspeed Courier was flown a few weeks earlier). Another ST-6 was built and two ST-4 IIs were converted.

The Croydon factory closed down in 1933 and a larger factory was opened in 1934 at Hanworth where the company produced a developed version the ST-10 externally the same but powered by two Pobjoy Niagara engines an improved fuel system and aerodynamic refinements.

Operational history

The ST-10 prototype (G-ACTS) won the 1934 Kings Cup air race at an average speed of 134.16 mph. Only one other ST-10 was built along with two similar ST-11s with de Havilland Gipsy Major engines for export to Australia. A production batch of ten ST-12 aircraft was based on the ST-11 with fixed landing gear.

Variants

Monospar ST-3

Experimental cantilver monoplane, one built.

ST-4

Experimental cantilever monoplane, seven built.

ST-4 II

Improved variant of ST-4, 22 built, two later converted to ST-6 standard.

ST-6

As ST-4 with manual retractable landing gear, two built and two conversions from ST-4 IIs.

ST-10

Improved variant with two Pobjoy Niagara engines, two built.

ST-11

de Havilland Gipsy Major engined variant, two built.

ST-12

Fixed landing gear variant with two de Havilland Gipsy Major engines, 10 built.

Survivors

• One ST-12 (registration VH-UTH) is held by the Newark Air Museum, England

See also

Related development

• General Aircraft Monospar ST-25

References

Bibliography

• The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). London: Orbis Publishing, 1985, p. 2158.
• Jackson, A.J. British Civil Aircraft since 1919, Volume 3. London: Putnam, 1974. ISBN 0-370-10014-X.

External links

• British Aircraft Directory ST-3
• British Aircraft Directory ST-4
• British Aircraft Directory ST-6
• British Aircraft Directory ST-10
• British Aircraft Directory ST-11
• British Aircraft Directory ST-12

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "General Aircraft Monospar".