General Aircraft Monospar ST-25
The General Aircraft Monospar ST-25 was a British 1930s light twin-engined utility aircraft.
Design and development
The Monospar ST-25 was a low-wing cantilever monoplane with a fabric-covered metal structure. The monospar name came from the use of a single spar in the wing structure that had been developed by H J Stieger. The cabin was enclosed with five seats. It was based on the earlier GAL Monospar ST-10, with the addition of folding seat for a fifth passenger and the addition of a radio receiver. First flying on 19 June 1935, the type was named Jubilee, and also numbered 25, in honour of the 25th anniversary of the reign of King George V.[2]
Operational history
- The last flying Monospar ST-25 (ZK-AFF), of Piet Van Asch's New Zealand Aerial Mapping Ltd was lost in 1986 as a result of a hangar fire.[3]
- The last surviving Monospar ST-25 (OY-DAZ), an ST-25 Ambulance, was fully restored during 1989-1999, and now displayed in Egeskov Veteranmuseum at Egeskov Castle, Denmark.[4]
Variants
- Monospar ST-25 Jubilee
- (1935-1936) Single fin and rudder. 30 built.[2]
- Monospar ST-25 De Luxe
- One Monospar ST-25 Jubilee with large single fin and two Niagara II engines, later converted to the prototype Monospar ST-25 Universal, with twin fins.[2]
- Monospar ST-25 Ambulance
- Variants of both Monospar ST-25 Jubilee and ST-25 Universal, with a large door on starboard side to allow a stretcher to be loaded.[2]
- Monospar ST-25 Universal
- (1936-1939) Twin fin and twin rudder. 29 built, including the conversion of the De Luxe.[2]
- Monospar ST-25 Freighter
- A variant of the Monospar ST-25 Universal, with a large freight door but without the passenger seating.[2]
- GAL.26
- One modified Monospar ST-25 Jubilee, fitted with two Cirrus Minor I engines in 1936.[2]
- GAL.41
- One experimental aircraft based on the Monospar ST-25 Universal. A new fuselage was built containing a pressurized section with two seats. Its purpose was to test possible pressurization systems for a proposed airliner, the GAL.40. The GAL.41 flew for the first time 11 May 1939, and was grounded in 1941.[5]
Operators
- Australia
- Canada
- Eastern Canada Air Lines (5 × ST-25 Freighters, delivered in 1936)
- Denmark
- France
- New Zealand
- Romania
- Spain
- Spain
- Turkey
- Turkish Government (2 × ST-25 Freighters for parachute training delivered in 1937)
- Turkish Mapping Aviation
- United Kingdom
Specifications (Monospar ST-25 Jubilee)
Data from Jackson, 1973
General characteristics
- Crew: 1
- Length: 26 ft 4 in (8.03 m)
- Wingspan: 40 ft 2 in (12.24 m)
- Height: 7 ft 10 in (2.39 m)
- Wing area: 217 sq ft (20.16 m2)
- Empty weight: 1,680 lb (762 kg)
- Loaded weight: 2,875 lb (1,304 kg)
- Powerplant: 2 × Pobjoy Niagara II radial engine, 90 hp (67 kW) each
Performance
See also
General Aircraft ST-18 Croydon
Notes
Bibliography
- Howson, Gerald. 1990. Aircraft of the Spanish Civil War 1936-39. Putnam ISBN 978-0851778426
- Jackson, A.J. (1973). British Civil Aircraft since 1919, Volume 2. Putnam. pp. 215-220, 519-521 ISBN 0 370 10010 7
- Lumsden, Alec; Heffernan, Terry. Probe Probare, Aeroplane Monthly, February 1984
- Ogden, Bob (2009). Aviation Museums and Collections of Mainland Europe. Air-Britain. ISBN 9780851304182
- Stroud, John. Wings of Peace, Aeroplane Monthly, April 1988
External links
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