The Hendon Mk.I was in essence the Handley Mk.III with a longer fuselage. Powerplant was a 450 hp Napier Lion IB twelve-cylinder water-cooled W-engine. Armament consisted of a trainable 0.303 in (7.7 mm) machinegun, and one torpedo or two 520 lb (236 kg) bombs.
Six aircraft (s/n N9724 to J9729) were ordered in November 1923 and the first of these flew on July 7, 1924. The type was not placed in service, but the aircraft went through a series of modifications that played a major part in the development of the fully automatic slot system. With an improved slot operating system the type was designated Hendon Mk.II, and with interlinked ailerons and slots it was designated Hendon Mk.III.
Span: 46 ft 0 in (14.02 m)
Length: 34 ft 6 in (10.52 m)
Wing area: 526.0 sq.ft (52.21 sq.m)
Max takeoff weight: 6,970 lb (3,160 kg)
Max speed: 110 mph (177 kmh)
Service ceiling: 9,500 ft (2,940 m)."