De Havilland DH 18
The designation D.H.17 was allocated to a project for a twin-engined 16-passenger biplane which was not built. The next type number, de Havilland D.H.18, was allocated to a large single engined biplane accommodating eight passengers in an enclosed cabin; the pilot was seated in an open cockpit behind the wings.
During 1920 the Aircraft Manufacturing Company, which had been building de Havilland designs, was re-formed as the de Havilland Aircraft Company Ltd. The new organisation built two modified aircraft at Hendon designated D.H.18A for lnstone Air Line, followed by a third.
The D.H.18 first flew early in 1920 and was delivered to Aircraft Transport & Travel Ltd This D.H.18 had a short life, terminated by a forced landing near Croydon in August of the same year.
These were kept busy on Croydon-Paris service until the first, having accumulated high flying hours, was withdrawn from use in September 1921; another was lost in a crash only two months after delivery. The third production D.H.18A, delivered to Instone in June 1921, was passed to Daimler Hire Ltd in April 1922, only to be destroyed over France a few days later in a mid-air collision with a Farman Goliath.
The last two aircraft were designated D.H.18B, and had plywood-covered fuselages and increased weights; they served with Instone for a short time before the second was dismantled in 1923. The first was used in Air Ministry flotation tests, being deliberately landed in the sea off Felixstowe in May 1924. Strangely, the last surviving D.H.18 was the first production aircraft which, following its withdrawal from Instone's use in 1921, was delivered to RAE Farnborough for test purposes. It was finally scrapped in 1927.
Engine: 1 x Napier Lion inline piston engine, 336kW
Take-off weight: 2956 kg / 6517 lb
Empty weight: 1833 kg / 4041 lb
Wingspan: 15.62 m / 51 ft 3 in
Length: 11.89 m / 39 ft 0 in
Height: 3.96 m / 12 ft 12 in
Wing area: 57.71 sq.m / 621.18 sq ft
Max. speed: 206 km/h / 128 mph
Cruise speed: 161 km/h / 100 mph
Ceiling: 4875 m / 16000 ft
Range: 644 km/ 400 miles