General Aircraft Monospar ST-25
|Monospar ST-25 Jubilee of Eloy Fernández Navamuel during the Spanish Civil War|
|National origin||United Kingdom|
|Manufacturer||General Aircraft Ltd, Hanworth|
|First flight||19 June 1935|
|Developed from||General Aircraft Monospar ST-10|
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 GAL Monospar ST-10, with the addition of a folding seat for a fifth passenger, extra side windows, and the addition of a radio receiver. On 19 June 1935, the prototype (G-ADIV) made its first flight at Hanworth Air Park. It was designated Monospar ST-25 Jubilee, to honour the 25th anniversary of the reign of King George V.
- The last flying Monospar ST-25 (ZK-AFF), of Piet Van Asch, the owner of New Zealand Aerial Mapping Ltd, was lost in 1986 in a hangar fire.
- The last surviving Monospar ST-25 (OY-DAZ), an ST-25 Ambulance, was fully restored during 1989–1999, and is now displayed in Egeskov Veteranmuseum at Egeskov Castle, Denmark.
- Monospar ST-25 Jubilee
- (1935-1936) Single fin and rudder. 30 built.
- Monospar ST-25 De Luxe
- One Monospar ST-25 Jubilee with a large single fin and two Niagara II engines, later converted to the prototype Monospar ST-25 Universal, with twin fins.
- Monospar ST-25 Ambulance
- Variants of both Monospar ST-25 Jubilee and ST-25 Universal, with a large door on the starboard side to allow a stretcher to be loaded.
- Monospar ST-25 Universal
- (1936-1939) Twin fin and twin rudder. 29 built, including the conversion of the De Luxe.
- Monospar ST-25 Freighter
- A variant of the Monospar ST-25 Universal, with a large freight door but without the passenger seating.
- One modified Monospar ST-25 Jubilee, fitted with two Cirrus Minor I engines in 1936.
- 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.
- Adelaide Airways
- Eastern Canada Air Lines (five ST-25 Freighters, delivered in 1936)
- Armée de l'Air (2 ST-25 in Indochine (Vietnam) in November 1945)
- Van Melle's Confectionery Works, Breskens (one Jubilee, PH-IPM "Dubbele Arend", delivered in 1935)
- New Zealand Aerial Mapping
- Royal New Zealand Air Force
- General Command of Mapping (Turkey)
- Turkish Government (two ST-25 Freighters for parachute training delivered in 1937)
- Crilly Airways
- Royal Aircraft Establishment (two Jubilees used for radio development)
- Royal Air Force (impressed civil aircraft used during the second world war)
Specifications (Monospar ST-25 Jubilee)
Data from Jackson, 1973
- Crew: one
- 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 (20.2 m2)
- Empty weight: 1,680 lb (762 kg)
- Gross weight: 2,875 lb (1,304 kg)
- Powerplant: 2 × Pobjoy Niagara II 7-cyl. air-cooled radial piston engine, 90 hp (67 kW) each
- Maximum speed: 142 mph (229 km/h; 123 kn)
- Range: 585 mi (508 nmi; 941 km)
- Service ceiling: 16,000 ft (4,900 m)
- Rate of climb: 800 ft/min (4.1 m/s)
- Howson, 1990
- Jackson 1973, pp. 215–220
- PIET VAN ASCH – New Zealand's Aerial Mapping Pioneer at wings.net.nz
- Ogden (2009)
- General Aircraft Monopar ST-25 – British Aircraft of World War II accessed 1 July 2017]
- http://www.geschiedeniszeeland.nl/tab_themas/themas/luchtvaart/rond_vliegveld/ (in dutch)
|Wikimedia Commons has media related to General Aircraft Monospar.|
- Howson, Gerald. 1990. Aircraft of the Spanish Civil War 1936–39. Putnam ISBN 978-0-85177-842-6
- 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 978-0-85130-418-2
- Stroud, John. Wings of Peace, Aeroplane Monthly, April 1988