The Vernon was a development of the Vimy/ Vimy Commercial, having much the same wing plan, and being powered by the same type of engine - the 375 h.p. Rolls-Royee Eagle VIII. First flying in 1921, instead of a bomber style of fuselage, with gun-rings fore and aft, the Vernon carried no defensive armament, and had a spacious hull designed to carry troops and stores. It was, however, fitted with bomb racks and could be used as a bomber.
The Vernon served from 1922-26 with Nos 45 and 70 Squadrons of the RAF in India, Cyprus and Iraq. Apart from its role in the evacuation of sick British troops from Iraq in 1922, the Vernon was the chief transport aircraft used on the celebrated Cairo-Baghdad air mail service in the mid-1920s. In 1923, when Squadron Leader A. T. Harris commanded the Squadron, he cut away a hole in the nose and fitted a high-altitude drift bomb-sight. This, with a bomb-aimer using the prone position, made the Vernon a very fine bomber indeed, capable of far greater accuracy than any other contemporary aircraft.
The maker's figure for the maximum all-up weight of the Vernon was 12,000 lb, but this had been increased by Middle East Headquarters to 12,500 lb. In order to give them sufficient range to make the desert crossing safely from Ziza to Ramadi, a cylindrical tank holding 150 gallons temporarily fitted inside the hull.
Vernon Mk I aircraft (20 built) differed little from the Vimy Commercial, but the Vernon Mk II (25) introduced 336kW Napier Lion II engines and the Vernon Mk III (10) had Lion III engines, increased fuel tankage and oleo-pneumatic landing gear. The Vernon was superseded by the Victoria from 1927.
Engines: 2 x 375 hp Rolls-Royce Eagle VIII (later 450 hp Napier Lion II)
Wing span: 68 ft 1 in (20.75 m)
Length: 42 ft 8 in (13.00 m)
Gross weight: 12544 lb (5,690 kg)
Max speed: 118 mph (190 km/h) at S/ L with Lion engines
Accommodation: Crew of 3 plus 11 passengers
Typical range: 320 miles (515 km) at 80 mph (128 km/h)