The H.P. 54 Harrow was the production version of the earlier Handley Page H.P.51 design, itself a monoplane conversion of the three-engined Handley Page H.P.43 biplane. The two monoplanes were both designed by Dr. G.V. Lachmann. Initially Handley Page intended to offer the H.P.51 to Air Ministry specification C.26/31 for a bomber-transport, then saw the H.P.54 as a more likely winner. In the end neither type was a candidate for C.26/31, since in June 1935 the Air Ministry, anxious to expand and modernise the RAF wrote specification B.29/35 around the Harrow, emphasising its bomber role though retaining its transport capability. On 14 August, months before the first Harrow flew, the Ministry put in an order for 100 aircraft. Powered by Bristol Pegasus X engines of, the first Harrow flew on 10 October 1936 from Radlett. The Harrow was designed to have powered nose and tail turrets, with a manually operated dorsal turret. The nose and dorsal turrets were armed with a single Lewis gun, while the tail turret carried two Lewis guns.. A bombload of up to could be carried under the cabin floor, with the aircraft being able to carry a single bomb.
Operational history
The first Harrow was delivered to No. 214 Squadron RAF on 13 January 1937, with all 100 delivered by the end of the year, with five bomber squadrons of the RAF being equipped with the Harrow. The Fleet Air Arm ordered 100 Harrows but Handley Page lacked the production capacity to supply them. Despite being fitted with cabin heating by steam boilers using exhaust heat, the Harrow gained a reputation of being a cold and draughty aircraft, owing to the turret design. As the delivery of more modern bombers increased, the Harrow was phased out as a frontline bomber by the end of 1939 but continued to be used as a transport. 271 Squadron was formed on 1 May 1940 with a mixture of Harrows, Bristol Bombays and impressed civil aircraft. While the other aircraft equipping 271 Squadron were replaced by Douglas Dakotas, it retained a flight of Harrows as transports and ambulance aircraft until the end of the Second World War in Europe. Harrows were used occasionally to operate risky flights between England and Gibraltar, two being lost on this route. Harrows also operated in support of Allied forces in their advance into north-west Europe, evacuating wounded from the Arnhem operationin September 1944. Seven Harrows were destroyed by a low level attack by Luftwaffe fighters of JG 26 and JG 54 on Evere airfield as part of Unternehmen Bodenplatte, the German attack on Allied airfields in northwest Europe on 1 January 1945, leaving only five Harrows, which were eventually retired on 25 May 1945. The Harrow also served in a novel operational role at the height of The Blitz against Britain in the winter of 1940–1941. Six Harrows equipped No. 420 Flight RAF which used lone Harrows to tow Long Aerial Mines into the path of enemy bombers. The LAM had an explosive charge on the end of a long cable and the unorthodox tactic was credited with the destruction of 4–6 German bombers. The experiment was judged of poor value and the planned deployment of Douglas Havocs in the LAM role was cancelled. Nine Harrows were also used by 782 Naval Air Squadron, Fleet Air Arm as transports. After flight refuelling trials, three Harrows were operated by Flight Refuelling Limited and refuelled Short EmpireFlying Boats on transatlantic services, two from Gander, Newfoundland and one based in Foynes, Ireland. In 1940, the two aircraft based at Gander were pressed into service with the Royal Canadian Air Force.
