The Handley Page Heyford was the last biplane heavy bomber to see service with the RAF. It was an unusual looking aircraft, chiefly because the fuselage was attached to the upper wing, rather than the lower wing, as was more normal in biplanes. The main advantage gained by this configuration was good visibility for the pilot, dorsal and nose gunners, as good as that provided by later monoplane bombers. The Heyford also features a retractable ventral “dustbin” turret that covered the vulnerable spot below and behind the aircraft.
The price paid for this good visibility was that the pilot’s cockpit was seventeen feet above the ground when landed – pictures of the Heyford on the ground resemble later pictures of the Short Stirling, looming dramatically over ground crew. Another result of the configuration of the wings was that the Heyford carried its bombs in a wide bomb bay in the lower wing, completely inaccessible from the main fuselage.
The Heyford was designed to an Air Ministry specification issued in 1927 (B.19/27), which also produced the Fairey Hendon. The Heyford had a metal airframe with a fabric-cover, designed for easy access and maintenance – the rear section of the airframe was hinged, and could swing aside to give access to the interior of the tail. The entire aircraft was designed with ease of use in mind – Handley Page claimed that the time between 900 mile flights was only thirty minutes (although when you remember that that 900 mile flight would have taken at least eight hours, it is not entirely clear how useful that feature would be).
The prototype Heyford first flew in June 1930. A production order was issued in 1932, to specification B.23/32. The Heyford Mk I features a few changes from the prototype, including the use of 575 hp Rolls Royce Kestral IIIS or IIIS-5 engines and a stronger undercarriage, that on the prototype having collapsed in tests.
The aircraft carried a crew of four. The navigator/ pilot/ front gunner sat in a compartment in front of the pilot. The pilot had an open cockpit in front of the wings. Behind him was the rear gunner, whose job was to main the ventral turret, but who normally sat in the mid-upper gun position. The radio operation had a position inside the fuselage, just behind the pilot, but in combat would move back to man the mid-upper turret. The position of the bombs in the lower wing meant that the fuselage was relatively empty, making movement between positions comparatively easy.
The first production aircraft took to the air on 21 June 1933, just in time to take part in that year’s Hendon Air Show. Tests revealed it to be a generally successful aircraft, and a distinct improvement on its predecessors. It entered service with No. 99 Squadron, at Upper Heyford, which switched to the new aircraft between November 1933 and March 1934. In all eleven front line bomber squadrons would receive the Heyford.
The Mk I was followed by the very similar Mk IA which featured an engine powered generator to replace the wing powered type used on the Mk I. The Mk II and Mk III were both powered by the 640 hp Kestrel VI engines, although they only operated at full power in the Mk III. Despite some experiments with enclosed cockpits, that innovation was never used in a production Heyford.
The Heyford was very much an interim design. Its front line career was limited to the four years between 1933 and 1937, by which time it was obsolete as a heavy bomber. A shortage of more modern aircraft meant that a number of Heyfords were retained as gunnery and bombing trainers until the middle of 1940, by which time the Heyford was too slow for useful bombing practise and her open gun positions not in use on any modern aircraft.
Perhaps the Heyford’s most important contribution to history was its use in early radar tests in 1936-7, when it was used to test very early airborne radar systems. Its unobstructed fuselage made it ideal for early experiments with bulky radar equipment. In 1937 a Heyford became the first aircraft to carry a working air to air radar set.
Engine: Rolls Royce Kestrel IIIS or IIIS
Horsepower: 575 hp and 2,700 rpm at 11,500 ft
Span: 75 ft
Length: 58 ft
Max Speed: 142 mph at 12,500 ft
Ceiling: 21,000 ft
Range: 920 miles at 115 mph at 10,000 ft with 1,598 lb of bombs, 400 miles with 3,143 lb of bombs.
Armament: Three .303in Lewis machine guns, one in nose, one in mid-upper position, one in ventral turret
Bombload: The central bomb rack could carry ten bombs, from 112lb to 500lb in weight (with a maximum of four 500lb bombs in the central bays on the rack). Each wing could carry four 20lb bombs and three 120lb bombs.
10 x 250 lb and 8 x 20 lb (2660 lb)
or 4 x 500 lb and 8 x 20 lb (2160 lb)
or 16 x 112 lb and 8 x 20 lb (1952 lb)
or 6 x 250 lb and 8 x 20 lb (1660 lb)