Country of origin:

United Kingdom

Description:

Four-seat light twin-engine low-wing monoplane

Power Plant:

Two 63 kw (85 hp) Pobjoy R seven-cylinder [2835 cc] geared, air-cooled, radial engines

Specifications:

History:

The General Aircraft ST.4 Monospar was aimed at the market for a light transport feeder liner and for operation by private owners, being a twin-engine light low-wing monoplane with Pobjoy radial engines. It was basically the production model of the ST.3 and was produced by General Aircraft Ltd at its facility at Croydon in Surrey in the United Kingdom. It had a tubular steel framework forward with a single girder to the tail and was fabric covered. The wings were monospar with triangular bracing and ribs formed of duralumin, being fabric covered.

In 1933 a new model known as the ST.4 Mk II was released with some refinements and modifications, including a landing-light in the nose. The prototype G-ABUZ (c/n ST.4/1) was first flown in May 1932 and four further Mk I production aircraft were delivered, being G-ABVO, which became VT-ADT; G-ABVP which later became X9434, G-ABVR which became CH347; and G-ABVS. After production moved to the Mk II a further 24 examples were delivered.

The ST.4 series was powered by the Pobjoy R seven-cylinder geared air-cooled radial engine built by Pobjoy Airmotors & Aircraft of Hooton, Cheshire. This engine had a low weight, providing 1.75 lb/hp, had a bore of 77 mm (3.03 in) and had a stroke of 87 mm (3.43 in). It had steel barrels which were screwed into duralumin heads, two valves per cylinder operated from a cam-ring at the rear of the engine through push-rods and ball-bearing rockers. The diameter of the engine was 64.77 cm (25½ in), it weighed 61 kg (135 lb) and it provided 62 kw (85 hp) at 3,000 rpm using 0.57 pints of fuel per bhp/hour. The engine was popular in light aircraft in the 1930s and was fitted to the Comper Swift also.

Fuel was contained in four tanks, two in the wing root of each outer wing section, and one on each side of the monospar wing with a total capacity of 191 litres (42 Imp gals).

One example of the ST.4 came to Australia. This aircraft was the second of the ST.4 Mk 1C models built and became G-ABVN (c/n GAL/ST4/2). It was initially registered in the United Kingdom in March 1932, receiving Certificate of Registration 3689, and was operated with Portsmouth Southsea and Isle of Wight Aviation Ltd of Shanklin. In due course it was obtained by an Australian couple, Mr Colin Dalrymple Kelman and his wife Mary ‘Penny’ Kelman (nee McKillop).

During December 1936 and January 1937 the Kelmans flew the aircraft to Australia in what has been described as a leisurely flight. They were both involved with aircraft and over the years owned and operated a number. In addition to the Monospar they operated de Havilland DH.60G VH-UIC in 1935; Percival Proctor 3 VH-ABN in 1951; de Havilland DH.82 Tiger Moth VH-BIN in 1953; Auster J-5 VH-AFT in 1954; Beech C17L VH-BOU in 1955 and Cessna 182A VH-CMK in 1958.

Mr Kelman managed the pastoral property ‘Malaraway’ at Moree, NSW and later owned ‘Glenberrie’ at Julia Creek, QLD. As set out, they both were pilots and owned and operated a series of aircraft, so the ultimate fate of the Monospar after its arrival in Australia is quite strange. ‘Peggy’ Kelman was born in Glasgow as Mary Margaret McKillop, was raised in Orange, NSW, and worked with aviatrix Nancy Bird during barnstorming operations in western NSW in 1935. She met Mr Kelman at ‘Malaraway’ station near Moree. They travelled to and were married in London. After her husband died she set up Central Highlands Air Taxi Service with her son. She was a member of the Australian Women Pilots Association and was awarded an OBE for services to aviation.

The ST.4 Monospar G-ABVN was purchased by the Kelmans on 4 December 1936, the aircraft and the crew leaving Heston in  Hounslow, Greater London, on 18 December 1936, arriving in Darwin, NT on 11 January 1937. It later flew on, arriving at Moree on 15 January. Shortly after, the aircraft was sold due to the downturn in wool prices at that time.

Thereafter the aircraft remained at Mascot aerodrome in Sydney, NSW. In June 1945 the Department of Civil Aviation (DCA) was informed by Mr R E Turner of Sydney of an intention to purchase the aircraft, stating it was in excellent condition but was missing the compass, seats and some instruments. For reasons unknown the aircraft was never registered in Australia and may not have been flown again. Little is known about its time in Australia thereafter, but during World War II it was used as an Instructional Airframe by the RAAF. By 1954 it was in a derelict state at Bankstown, NSW and was subsequently broken up.