Photograph:
General Aircraft Monospar ST.12 VH-UTH (c/n ST12/36) at Bankstown, NSW in 1958 (David C Eyre)
Country of origin:
United Kingdom
Description:
Four-seat twin-engine cabin monoplane
Power Plant:
Two 104 kw (140 hp) de Havilland Gipsy Major I four-cylinder in-line inverted air-cooled engines
Specifications:
- Wingspan: 12.25 m (40 ft 2 in)
- Length: 8.04 m (26 ft 4 in)
- Height: 2.42 m (7 ft 10 in)
- Wing area: 20.15 m² (217 sq ft)
- Max speed: 254 km/h (158 mph)
- Cruising speed: 229 km/h (142 mph)
- Service ceiling: 5,923 m (19,400 ft)
- Initial rate of climb: 376 m/min (1,233 ft/min)
- Range: 660 km (410 miles)
- Empty weight: 835 kg (1,840 lb)
- Loaded weight: 1,304 kg (2,875 lb)
History:
Following the success of earlier models of the Monospar series, General Aircraft produced the ST.12. This was a progressive development of the earlier models and was introduced to the market in 1935, being described as a four-seat general purpose monoplane. This model was similar to the ST.10 but was fitted with a folding seat for an occasional fifth passenger, an additional cabin window, a radio receiver and a homing device as standard.
General Aircraft then built ten aircraft with fixed undercarriages fitted with the de Havilland Gipsy Major engine as the ST.12, these being similar to the ST.11.
Four ST.12s were imported to Australia. One VH-UTH (c/n ST12/36 – ‘Captain Cook’) was registered to New England Airways in May 1935. It is known to have changed hands at least fourteen times, owners including P H Moody Air Taxis of Rockhampton, QLD in June 1938; Butler Air Transport Company of Sydney, NSW in March 1941; and the Tasmanian Aero Club at Launceston in October 1949. It was eventually obtained by Dr J Morris of Forrestville, NSW, who flew it to the United Kingdom, where it was sold. It became derelict but has been under restoration with the Newark Air Museum for many years and was nearing completion to static display in early 2020.
New England Airways received a second ST.12 VH-UTK (c/n ST12/38 – ‘Captain Phillip’) in May 1935. Ownership was transferred to Airlines of Australia Ltd in January 1936 but it was destroyed in a fire at Mackay, QLD on 1 July 1938.
Monospar ST.12 VH-UTM (c/n ST12/41 – ‘Captain Flinders’) was registered in August 1935. It entered service with Eastern Air Transport on 15 July 1935, going to Airlines of Australia in January 1936. Ownership was transferred to Australian National Airways in December 1938, then back to Airlines of Australia in April 1940, and Transcontinental Airlines in August that year. It crashed at Orford Bay, QLD on 16 February 1942 on a flight from Horn Island.
The Australian agent then imported an ST.12 VH-UTZ (c/n ST12/42) in July 1935, which was operated by Eastern Air Transport from Mascot, NSW from July 1935. The following month ownership was transferred to Australian Transcontinental Airways Ltd. However, it crashed between Barrow Creek and Alice Springs, NT on 6 September that year.
In 1945 Airlines (WA) Ltd of Perth obtained Monospar ST.11 VH-UAZ (c/n ST.11/33), which was fitted with Pobjoy engines. In October 1935 it was used in the search for the missing de Havilland DH.86 VH-URT which had disappeared in Bass Strait. It was flown in one day from Melbourne, VIC to Perth,WA in 21½ hours and during an overhaul the company sought approval to fit it with de Havilland Gipsy Major engines and the undercarriage from a de Havilland DH.90 Dragonfly. This would have brought it close to ST.12 configuration. In the event the overhaul was not completed, the Gipsy engines were not installed and the aircraft was sold. Its ultimate fate is not known.