Hawker Horsley
The Hawker Horsley was a British single-engined biplane bomber designed by George Carter and Sydney Camm for Hawker Aircraft. Built first in wood, then in mixed wood-and-metal construction and finally all-metal, it served the Royal Air Force as a day bomber and torpedo bomber from 1926 to 1935, was sold in small numbers to Greece and Denmark, and briefly held the world distance record in May 1927. Production totalled 124 aircraft, including two prototypes, six for Greece and two Dantorps for Denmark. After retirement the type flew on as an engine testbed, including early trials of the Rolls-Royce Merlin, and no example is recorded preserved in a British museum.
Why It Mattered
The Horsley was a rare bomber from Hawker, and the last wooden aircraft the company produced before it introduced its famous metal construction system. George Carter and Sydney Camm designed it for Air Ministry Specification 26/23, a requirement for a fairly standard medium bomber. A later torpedo-bomber specification asked the same basic design to carry a torpedo of up to 2,800lb. Its construction charted the change: the Mk I was all wood, the Mk II mixed wood and metal, and the final aircraft were all metal. In May 1927 a Horsley briefly held the world long-distance record, and the type served the RAF as a day bomber and torpedo bomber until 1935.
Design Notes
The Horsley was a large single-engined two-bay biplane whose upper wing was larger than its lower. Its crew of two sat in tandem open cockpits, the pilot forward and the gunner aft; the gunner also aimed the bombs and operated the radio, and had a Lewis gun on a Scarff ring and a prone bomb-aiming position. A fixed forward-firing Vickers gun completed the armament, and the load was one torpedo or up to 1,500lb of bombs. Production Horsleys were powered by a single Rolls-Royce Condor IIIA engine of 665 hp. The three methods of construction had their own mark numbers: Mk I for the all-wooden aircraft, Mk II for the mixed material, and Horsley III, unofficially, for the all-metal aircraft. Some aircraft were fitted with floats.
Operational History
The first prototype, J7511, made its maiden flight in March 1925. The Air Ministry's first production order came in March 1926 and covered thirty aircraft: ten Mk Is on the all-wooden first prototype's pattern and twenty Mk IIs. No. 100 (Bomber) Squadron was the first unit to get the type, starting its conversion in August 1926; No. 11 Squadron followed in mid-1927 and a re-formed No. 33 Squadron in 1929, while No. 504 Squadron of the Special Reserve flew Horsleys from 1929 until February 1934. On 20 May 1927 Flight Lieutenant Roderick Carr took off bound for India; forced down in the Persian Gulf after 3,420 miles, he had beaten the previous distance record, only for Lindbergh's Atlantic crossing to break it within hours. Work on a torpedo version began in 1926 with J8006, modified to carry a 2,069lb torpedo; a contract at the end of 1927 covered the first twelve all-metal torpedo-bombers, and two further orders for 18 aircraft followed. The Coast Defence Torpedo Flight received the first production torpedo aircraft in August 1928; two months later it was renamed No. 36 (Torpedo Bomber) Squadron. No. 36 Squadron later moved to Singapore, helped suppress a rebellion in Burma, and flew its Horsleys there until the Vickers Vildebeest replaced the type in 1935. Denmark bought the torpedo version in small numbers as the Dantorp, two of them Hawker-built aircraft with Leopard II engines, and Greece bought six standard Horsley IIs. Denmark also bought a licence to build ten more at the Danish Naval Workshops, but none was built owing to a shortage of funds. Production came to 124 aircraft in all, including the six machines supplied to the Hellenic Naval Air Service and the two Dantorps built for Denmark. In the day-bombing role the type lasted until 1934.
Afterlife
The Horsley was retired in 1935, but individual aircraft worked on as engine testbeds. The original prototype tested versions of the Condor, the Eagle VIII and the H.10 for Rolls-Royce, and then the Napier Lion; later aircraft flew with the Armstrong Siddeley Leopard, the Rolls-Royce Buzzard and even a Junkers Jumo. The most important trials were flown between 1934 and 1937 by S1436 and J8611, which flight-tested the Merlin 'C', 'E', 'F' and 'G' variants and the Merlin X; Merlins went on to power the Whitley V and Halifax bombers. The final flight of any Horsley came on 7 March 1938, when the Merlin-powered testbed flew for the last time at RAE Farnborough. No example is recorded in preservation: the British Aircraft Directory lists none preserved in British museums.