Handley Page Heyford Heavy Night-Bomber / Crew Trainer Aircraft

Specifications

Year: 1934
Status: Retired, Out-of-Service
Manufacturer(s): Handley Page Aircraft - UK
Production: 125
Capabilities: Ground Attack; Training;

Crew: 4
Length: 58.07 ft (17.7 m)
Width: 75.13 ft (22.9 m)
Height: 17.55 ft (5.35 m)
Weight (Empty): 9,215 lb (4,180 kg)
Weight (MTOW): 16,932 lb (7,680 kg)

Power: 2 x Rolls-Royce Kestrel II-S V12 liquid-cooled inline piston engines developing 525 horsepower each.

Speed: 143 mph (230 kph; 124 kts)
Ceiling: 20,997 feet (6,400 m; 3.98 miles)
Range: 920 miles (1,480 km; 799 nm)
Rate-of-Climb: 655 ft/min (200 m/min)

Operators: United Kingdom

In 1927 the British Air Ministry introduced Specification B.19/27 calling for a new twin-engined heavy night-bomber capable of speeds of 115 miles per hour with a 1,546lb war load out to 920 miles. The type was expected to replace the aging stock of Vickers Virginia and Handley Page Hinaidi biplane bombers then in service. While the Fairey Hendon was eventually selected as the winner, delays in that program forced the Air Ministry to also select the Handley Page Heyford. Submissions were also had from regular industry players in Avro, Bristol and Vickers.

Handley Page engineers fleshed out the "HP.38" which continued use of a biplane wing planform forming a two-bay arrangement with parallel struts. The fuselage incorporated aluminum in its construction and the internal structure of the wings were also of metal while being covered over in fabric. The HP.38 appeared somewhat unconventional for a biplane bomber as the fuselage was attached to the upper wing section. This forced designers to fit the bomb bay into the center section of the lower wing assembly. As a benefit, the fuselage was now cleared of the space-consuming bomb bay with more room for crew spaces and defensive machine gun positions - guns were fitted to a dorsal, nose and ventral position (7.7mm types). The tail unit incorporated a twin rudder configuration and the undercarriage was fixed and of a "tail dragger" arrangement which saw the main legs faired over (spatted). The operating crew numbered four and consisted of the pilot, the bombardier-navigator (who also doubled as a machine gunner), a dedicated radioman, and a machine gunner to manage both the dorsal and ventral emplacements. The bomb load was listed at 2,500lb of conventional drop stores.

With delays being encountered in the Hendon product by Fairey (the prototype had crashed) and the Handley Page offering proving sound in evaluations with the RAF, the HP.38 was pushed through under the revised designation of "HP.50". The "Heyford" name was derived from the bomber's first posting - this at RAF Upper Heyford (Oxfordshire) as part of No.99 Squadron RAF in November 1933. Production netted 125 bombers from the period spanning 1933 until 1936 with service introduction in 1934.

There were four major production variants of this bomber led by "Heyford Mk.I" which fitted 2 x Rolls-Royce Kestrel III series engines of 575 horsepower. Fifteen were built to this standard with the last serving as the prototype for the "Heyford Mk.IA". In this revised form, four-bladed propellers were installed as was a power-driven generator while modifications were made to the engine area. Twenty-three of this mark were completed. The "Heyford Mk.II" brought along use of 2 x Rolls-Royce Kestrel IV engines of 640 horsepower output and production totaled sixteen examples. "Heyford Mk.III" marked the last Heyford product but more or less the definitive form of the series - it fitted 2 x Rolls-Royce Kestrel VI supercharged engines (steam condenser-cooled) of 695 horsepower and some 70 aircraft were built to the standard.

The Heyford eventually stocked twelve RAF squadrons for its time in the air - though its service life was relatively short being an inter-war design and a biplane at that. The aircraft became the last biplane-configured heavy bomber in RAF service as monoplanes quickly became the road forward for modern air services. Nevertheless, the Heyford series was an important contributor (both on paper and in terms of keeping night-bomber crews sharp) in the RAF inventory during the middle portion of the 1930s as Europe geared up for another World War.

The Heyford was not exported and saw no formal combat service before its retirement came in 1939, at which point the design was wholly obsolete - the last forms flew as trainers into 1941. After introduction of Heyford I models in 1933, the Heyford IA took over in August of 1934. The Heyford III mark arrived in late-1936. Their replacement was as soon as 1937, giving way to Armstrong Whitworth Whitley and Vickers Wellesley bombers in turn.

The competing Fairey Hendon managed to enter service in 1936 but only fifteen of the type were completed. These were also pulled in 1939 and led quiet service lives - though they did mark the first all-metal low-wing monoplane bombers in RAF service.

Armament

STANDARD:
1 x 7.7mm Lewis Machine Gun in nose position.
1 x 7.7mm Lewis Machine Gun in dorsal position.
1 x 7.7mm Lewis Machine Gun in ventral position.

OPTIONAL:
Up to 2,500 lb of bombs carried.

Graphical image of an aircraft conventional drop bomb munition

Variants / Models

• Heyford - Base Series Name
• Heyford Mk.I - Initial production block; fitted with Rolls-Royce Kestrel III engines of 575 horsepower; fifteen examples.
• Heyford Mk.IA - Revised variant with four-bladed propeller units; twenty-three examples.
• Heyford Mk.II - Fitted with Kestrel IV series engines of 640 horsepower; sixteen completed.
• Heyford Mk.III - Fitted with Kestrel VI engines of 695 horsepower; 70 completed.