Boulton Paul Overstrand
Overstrand | |
---|---|
Overstrand in flight | |
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 a twin-engine
First flown in 1933, the Overstrand was essentially an improved model of the Boulton Paul Sidestrand of the 1920s, thus early references to the type referred to it as the Sidestrand Mk IV instead. It demonstrated a higher maximum speed than its predecessor and was procured for the RAF in limited numbers. As such, the type entered service during the mid 1930s, but became increasingly overshadowed by the new generation of monoplane medium bombers, such as the Vickers Wellington and Armstrong Whitworth Whitley. Nevertheless, the Overstrand remained operational during the early years of the Second World War, albeit only being flown by training units. The few surviving aircraft were withdrawn from service during 1941, having been rendered surplus to requirements.
Design and development
Origins
The Overstrand was a development of the
The Overstrand's innovative turret was largely developed in-house by Bolton Paul's chief armament designer H. A. Hughes.
In addition to the turret, various other revisions and improvements were also incorporated. It was decided that the cockpit ought to also be fully enclosed within a canopy of anti-glare Perspex, complete with a sliding hood.[6] The airframe was strengthened considerably in many areas, which facilitated an increased bomb capacity of up to 1,500 lb (680 kg), up to two 500 lb (230 kg) bombs could be carried in the aircraft's recessed bomb cell in addition to two 250 lb (110 kg) bombs on external carriers. A new levered main undercarriage, complete with larger wheels, was also fitted, while the tailskid of the Sidestrand was replaced by a tailwheel.[7] The wing design was also revised, a noticeable sweepback was added to the outer sections in order to compensate for the aircraft's heavier nose section.[7]
Into flight
During 1933, the first Overstrand performed its maiden flight, at which point the type was still known as the Sidestrand Mk IV.[8] Shortly thereafter, it was decided to rename the aircraft after the village of Overstrand. On 22 February 1934, the prototype was delivered to RAF Andover for trials conducted by No. 101 Squadron.[8] Some criticisms of the aircraft were produced during this time, one early report by the Aeroplane and Armament Experimental Establishment (A&AEE) observed the powered turret to be somewhat cramped, while excessive engine vibration and issues with the longitudinal controls were also noted. Various positive attributes were also noted, such the addition of crew comfort features, as well as the aircraft's ability to attain speeds as high as 153 mph (246 km/h) at an altitude of 6,500 ft (2,000 m) without any negative impact upon its manoeuvrability.[8]
Modifications were made after the aircraft's return on 19 March to refine the design.[8] This led to a second Sidestrand being converted to the Overstrand configuration, incorporating these improvements, such as larger diameter turret, tweaks to the fins and elevators, and a simplification of the rear engine mount area. While the initial example had been powered by a pair of Bristol Pegasus IM.3 radial engines, each capable of generating up to 580 hp (430 kW), in comparison to the 460 hp (340 kW) provided by the Bristol Jupiters used upon the Sidestrand, the second aircraft was outfitted with the improved Bristol Pegasus II.M3 engine, capable of 580 hp (430 kW), instead.[3][9]
Continued flight testing revealed the vibration issues to be present still, but would be largely resolved upon later new-build Overstrands.[1] Having been encouraged by the demonstrated performance, which displayed a meaningful improvement over the Sidestrand, the Air Ministry authorised the modification of a further two Sidestrands into Overstrands. Shortly thereafter, the Ministry selected the type to fulfil Specification 23/34 and issued an initial order for 19 Overstrands.[1] A small follow-on order for five new-built Overstrands would lead to a total of 24 aircraft being built in addition to the four converted Sidestrands.[10]
At one stage, plans were drawn up for an improved variant of the aircraft to be developed, the principal difference being the adoption of a retractable undercarriage, designated the P.80 "Superstrand"; however, this project was ultimately abandoned due to alternative options involving rival monoplane designs proving to be more attractive in the eyes of military planners.[1][11]
Operational history
A total of 24 Overstrands would be procured for the RAF, a quantity that facilitated the complete replacement of the older Sidestrands flown by No. 101 Squadron, the only squadron equipped with the type, to commence in January 1935.[12] The type was also briefly adopted by No. 144 Squadron, although it was quickly replaced by the more modern Bristol Blenheim bomber during 1938. The Overstrand proved to be relatively popular with its crews, who often appreciated the attention paid to crew comfort as well as the ability of the newly developed powered turret.[13]
While
Due to the rapid advances made in bomber technology during the late 1930s, the Overstrand had been effectively rendered obsolete by 1938, the final example of the type being withdrawn from frontline duties during the summer of that same year.
Aircraft on display
A replica of an Overstrand nose section, marked as K4556, is on display at the Norfolk and Suffolk Aviation Museum. [17]
Operators
- Royal Air Force
- RAF Second line units[18]
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.[14]
- 22 April 1940: K8173 of 101 Squadron crashed off Chesil Beach, Dorset following an engine fire, three crew killed.[16]
Specifications
Data from The British Bomber since 1914.[19]
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: Five minutes and 24 seconds to 6,500 ft (2,000 m)
Armament
- Guns: Three .303 in (7.7 mm) Lewis guns in nose turret, dorsal and ventral gun positions
- Bombs: 1,500 lb (680 kg) bombs (two 500 lb/227 kg and two 250 lb/113 kg) and four 20 lb (9 kg) bombs could be carried on fuselage racks by the cockpit and dorsal gun position
See also
Related development
Aircraft of comparable role, configuration, and era
- Martin B-10, contemporary American all-metal monoplane bomber with nose turret
- Breguet 410
Related lists
References
Citations
- ^ a b c d Brew 1993, p. 231.
- ^ Winchester 2003, p. 11.
- ^ a b Lewis 1967, p. 238.
- ^ a b c Brew 1993, p. 227.
- ^ Brew 1993, pp. 227-228.
- ^ Brew 1993, pp. 228-229.
- ^ a b Brew 1993, p. 229.
- ^ a b c d Brew 1993, p. 230.
- ^ Brew 1993, pp. 230-231.
- ^ Brew 1993, pp. 231-232.
- ^ Lewis 1967, p. 240.
- ^ a b Brew 1993, p. 232.
- ^ a b Brew 1993, pp. 232-233.
- ^ a b Brew 1993, p. 233.
- ^ Halley 1976, p. 68.
- ^ a b Brew 1993, p. 234.
- ^ "Our Aircraft". www.aviationmuseum.net. Retrieved 30 May 2023.
- ^ March 2000, p. 34.
- ^ Mason 1994, p. 256.
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.