Blackburn Botha

The Blackburn B.26 Botha was a British four-seat reconnaissance and torpedo bomber. It was built by Blackburn Aircraft at its factories at Brough and Dumbarton, as a competitor to the Bristol Beaufort, entering service with the RAF in 1939. The design was underpowered and it was quickly withdrawn from operations.

B.26 Botha
Blackburn B.26 Botha
Role Torpedo bomber
Manufacturer Blackburn Aircraft
First flight 28 December 1938
Introduction 12 December 1939
Retired September 1944
Primary user Royal Air Force
Number built 580

Development and design

In September 1935, the British Air Ministry issued specification M.15/35, for a three-seat twin-engined reconnaissance/torpedo bomber. Two submissions that met this requirement were accepted, from Blackburn for the Botha and the Type 152 (later known as the Beaufort) from Bristol. Both were intended to use the 850 hp (634 kW) Bristol Perseus engine. The Air Ministry later revised the specification to M.10/36, which required a crew of four. The weight increase meant that both designs required more power. The 1,130 hp (840 kW) Taurus was provided for the Beaufort but the Botha received only the Perseus X of 880 hp (660 kW).[1]

The Air Ministry ordered 442 Bothas in 1936, while also placing orders for the Beaufort. The first flight took place on 28 December 1938.[2] The aircraft was built at Blackburn's factory at Brough and at a new factory at Dumbarton, Scotland. Brough built 380 aircraft and Dumbarton 200, a total of 580.[3][4]

Operational history

Service testing of the Botha showed that the aircraft had serious problems. It was considered to have poor lateral stability, while the view to the side or rearward was virtually nonexistent owing to the location of the aircraft's engines, the poor view making the aircraft "useless as a GR [General Reconnaissance] aircraft" and the Botha was underpowered.[5] Although the Botha passed torpedo and mine-dropping tests, the aircraft's poor performance resulted in the decision in April 1940 to issue the Botha only to four general reconnaissance squadrons equipped with the Avro Anson, rather than the torpedo bomber squadrons previously planned.[6]

The Botha entered squadron service in June 1940 with No. 608 Squadron RAF, the only squadron that used the Botha operationally, on convoy escort duties starting in August that year.[7] Typical bomb load on these patrols was three 100 lb (50 kg) anti-submarine bombs and two 250 lb (110 kg) general-purpose bombs.[8]

The Botha proved to be severely underpowered and unstable; there were a number of fatal crashes in 1940. The airframe and engines were subject to further development work but it was decided to withdraw the type from frontline service. The Air Staff decided to transfer the surviving aircraft to training units, which inevitably resulted in further casualties. Some Bothas were converted to target tugs as TT Mk.I. The type was retired in September 1944. In total, 580 aircraft were built.

Variants
  • Botha Mk I : Four-seat reconnaissance, torpedo bomber aircraft.
  • Botha TT Mk I : Target tug aircraft.

Operators

 Poland

 United Kingdom

Specifications (Botha Mk.I - Perseus XA)
Orthographic projection of the Botha, with inset detail showing the asymmetrical nose glazing.

Data from Blackburn aircraft since 1909,[9] The Hamlyn Concise Guide to British Aircraft of World War II [3]

General characteristics

  • Crew: 4
  • Length: 51 ft 0.5 in (15.558 m)
  • Wingspan: 59 ft 0 in (17.98 m)
  • Height: 14 ft 7.5 in (4.458 m)
  • Wing area: 518 sq ft (48.1 m2)
  • Empty weight: 12,036 lb (5,459 kg)
  • Gross weight: 18,450 lb (8,369 kg)
  • Fuel capacity: 435.75 imp gal (523 US gal; 1,981 l) normal fuel in 3 wing tanks and a distributor/collector tank, with 565.75 imp gal (679 US gal; 2,572 l) available for special operations.
  • Powerplant: 2 × Bristol Perseus XA 9-cylinder air-cooled radial piston engines, 930 hp (690 kW) each
  • Propellers: 3-bladed de Havilland Hydromatic Type 5/11 constant-speed propellers

Performance

  • Maximum speed: 209 mph (336 km/h, 182 kn) at sea level
220 mph (191 kn; 354 km/h) at 15,000 ft (4,572 m)
  • Cruise speed: 212 mph (341 km/h, 184 kn)
  • Stall speed: 75 mph (121 km/h, 65 kn) with flaps and undercarriage down[10]
  • Range: 1,270 mi (2,040 km, 1,100 nmi)
  • Service ceiling: 18,400 ft (5,600 m)
  • Absolute ceiling: 19,700 ft (6,005 m)
  • Rate of climb: 985 ft/min (5.00 m/s) initial
355 ft/min (1.80 m/s) at 15,000 ft (4,572 m)

Armament

  • Guns: 3 × 0.303 in (7.7 mm) machine guns (one fixed forward-firing, two in dorsal turret)
  • Bombs: internal torpedo, depth charges or bombs up to 2,000 lb (907 kg)

See also

Aircraft of comparable role, configuration, and era

Related lists

References

Notes

  1. Jackson 1968, p. 421.
  2. Mason 1994, p. 320.
  3. Mondey 1994, p. 38.
  4. Jackson 1968, pp. 423–424, 429
  5. Haywood Aeroplane Monthly February 2013, pp. 77–78.
  6. Haywood Aeroplane Monthly February 2013, pp. 79–80.
  7. Haywood Aeroplane Monthly February 2013, p. 80.
  8. Haywood Aeroplane Monthly February 2013, p. 84.
  9. Jackson, A.J. (1 April 1989). Blackburn aircraft since 1909. Naval Institute Press. pp. 421–438. ISBN 978-0870210242.
  10. "Botha I". Air Transport Auxiliary Ferry Pilots Notes.

Bibliography

  • Air Transport Auxiliary Ferry Pilots Notes (repr. ed.). Yorkshire Air Museum. 1996. ISBN 0-9512379-8-5.
  • Hayward, Roger (February 2013). "Database: Blackburn Botha". Aeroplane. Vol. 41 no. 2. pp. 69–85. ISSN 0143-7240.
  • Jackson, A.J. (1968). Blackburn Aircraft since 1909. London: Putnam. ISBN 0-370-00053-6.
  • Mason, Francis K. (1994). The British Bomber since 1914. London: Putnam. ISBN 0-85177-861-5.
  • Mondey, David (1994). The Hamlyn Concise Guide to British Aircraft of World War II. London: Aerospace Publishing. ISBN 1-85152-668-4.
  • Wixey, Ken (1997). Forgotten Bombers of the Royal Air Force. Arms & Armour Press. ISBN 1-85409-306-1.
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