Engineering:Boulton & Paul Overstrand

Overstrand
Role	Bomber
Manufacturer	Boulton Paul
Designer	H.A. Hughes
First flight	1933
Introduction	1934
Retired	1941
Primary user	Royal Air Force
Number built	28 (four converted Sidestrands)
Developed from	Boulton Paul Sidestrand

The Boulton Paul P.75 Overstrand was the last of the twin-engine biplane medium bombers of the Royal Air Force , a series that had begun during the First World War with the likes of the Vickers Vimy and Handley Page Type O. The Overstrand saw brief service in the late 1930s but by the Second World War only a few surviving aircraft remained in operation with training units.

Design and development

The Overstrand was a development of the Boulton Paul Sidestrand, which had first flown in 1928 and like the Sidestrand was named for a village in Norfolk, home also of Boulton Paul's Norwich factory. The Sidestrand was similar to its First World War predecessors, in that it had open cockpits and hand-operated machine-guns. Unlike its predecessors, the Sidestrand could fly at 140 mph (230 km/h) making operating the guns in exposed positions difficult, particularly in the nose. The Overstrand was fitted with an enclosed and powered nose turret with a Lewis gun, the first RAF aircraft to have a power-operated turret. Traverse of the turret was driven by pneumatic motors, elevation and depression of the gun by hydraulic rams. The cockpit was also enclosed but the dorsal and ventral gun positions remained open, though shielded.

Operational history

The first Overstrand flew in 1933 as the Sidestrand Mk IV, powered by two 580 hp (430 kW) Bristol Pegasus IM.3 engines, instead of the 460 hp (340 kW) Bristol Jupiters in the Sidestrand and was capable of 153 mph (246 km/h). The bomb load was also increased to 1,500 lb (680 kg). The conversion was a success and three more Sidestrands were modified using the 580 hp (430 kW) Bristol Pegasus II.M3. 24 Overstrands were produced and in 1936 began replacing the Sidestrand in No. 101 Squadron RAF, the only Sidestrand squadron) and briefly in No. 144 Squadron RAF, being replaced by Bristol Blenheims in 1938. At the outbreak of the Second World War, eleven Overstrands remained in service and six were used for gunnery training. They remained in operation until May 1941, though flying was limited following the mid-air breakup of Overstrand K8173 on 22 April 1940. Plans were made to develop a version with retractable undercarriage as the P.80 "Superstrand" but the project was abandoned.

Operators

United Kingdom

• Royal Air Force
  • No. 101 Squadron RAF
  • No. 144 Squadron RAF
• RAF Second line units
  • No. 2 Air Observer School RAF
  • No. 10 Bombing and Gunnery School RAF
  • Balloon Development Unit RAF
  • Army Co-operation Development Unit RAF

Accidents and incidents

A number of Overstrands were destroyed or beyond economic repair in accidents, the type had only two fatal accidents

• 11 January 1937 K4564 of 101 Squadron flew into ground in fog at Swanbourne, Buckinghamshire, three crew killed.
• 22 April 1940 K8173 of 101 Squadron crashed off Chesil Beach, Dorset following an engine fire, three crew killed.

Specifications

Data from The British Bomber since 1914

General characteristics

• Crew: five
• Length: 46 ft 0 in (14.02 m)
• Wingspan: 72 ft 0 in (21.95 m)
• Height: 15 ft 6 in (4.72 m)
• Wing area: 980 sq ft (91 m²)
• Empty weight: 7,936 lb (3,600 kg)
• Gross weight: 11,932 lb (5,412 kg)
• Powerplant: 2 × Bristol Pegasus IIM.3 nine-cylinder radial engines, 580 hp (430 kW) each

Performance

• Maximum speed: 148 mph (238 km/h, 129 kn) at 6,500 ft (2,000 m)
• Range: 545 mi (877 km, 474 nmi)
• Service ceiling: 21,300 ft (6,500 m)
• Time to altitude: 5 min 24 s to 6,500 ft (2,000 m)

Armament

• Guns: 3 × .303 in (7.7 mm) Lewis guns in nose turret, dorsal and ventral gun positions
• Bombs: 1,500 lb (680 kg) bombs (2 × 500 lb/227 kg and 2 × 250 lb/113 kg) and 4 × 20 lb (9 kg) bombs could be carried on fuselage racks by the cockpit and dorsal gun position

See also

Related development

• Boulton Paul Sidestrand

Aircraft of comparable role, configuration and era

• Martin B-10, contemporaneous American all-metal monoplane bomber with nose turret
• Breguet 410

Related lists

• List of bomber aircraft

References

Bibliography

• Brew, Alec. Boulton Paul Aircraft since 1915. London: Putnam, 1993. ISBN:0-85177-860-7.
• Halley, James J. Royal Air Force Aircraft: K1000 to K9999. Tonbridge, Kent, UK: Air-Britain (Historians) Ltd., 1976. ISBN:0-85130-048-0.
• Lewis, Peter. The British Bomber since 1914: Fifty Years of Design and Development. London: Putnam & Company Ltd./Fallbrook, California: Aero Publishers Inc., 1967.
• March, Daniel J. British Warplanes of World War II. Rochester, Kent, UK: Grange Books, 2000. ISBN:1-84013-391-0.
• Mason, Francis K. The British Bomber since 1912. London: Putnam, 1994. ISBN:0-85177-861-5.
• Taylor, John W.R. "Boulton and Paul Overstrand". Combat Aircraft of the World from 1909 to the Present. New York: G.P. Putnam's Sons, 1969. ISBN:0-425-03633-2.
• Taylor, Michael J.H., ed. "Boulton Paul Overstrand".Jane's Encyclopedia of Aviation, Vol. 2. Danbury, Connecticut: Grolier Educational Corporation, 1980. ISBN:0-7106-0710-5.
• Winchester, Jim. Bombers of the 20th Century. London: Airlife Publishing Ltd., 2003. ISBN:1-84037-386-5.