Airco DH.9

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The Airco D.H.9 (from de Havilland 9) also known after 1920 as the de Havilland D.H.9 was a British bomber used in the First World War. It was subsequently developed into the D.H.9A with a more powerful and reliable engine.

Development

The D.H.9 was designed by de Havilland for the Aircraft Manufacturing Company in 1916 as a successor to the D.H.4. It used the wings and tail unit of the DH.4 but had a new fuselage. This enabled the pilot to sit closer the gunner/observer and away from the engine and fuel tank. The other major change from the D.H.4 was the choice of the promising new Galloway-Adriatic (or BHP) engine, which was predicted to produce 300 hp and so give the new aircraft an adequate performance to match enemy fighters.

By this time, as a result of attacks by German bombers on London, the decision was made to almost double the size of the Royal Flying Corps, with most of the new squadrons planned to be equipped with bombers. Based on the performance estimates for the D.H.9, and the similarity to the D.H.4, which meant that it would be easy to convert production over to the new aircraft, massive orders (4,630 aircraft) were placed.

The prototype (a converted D.H.4) first flew at Hendon in July 1917. Unfortunately, the BHP engine proved unable to reliably deliver the power expected of it, with the engine being de-rated to 230 hp in order to improve reliability. This had a drastic effect on the aircraft's performance, especially at high altitude, with it being inferior to that of the D.H.4 it was supposed to replace. This meant that the D.H.9 would have to fight its way through enemy fighters, which could easily catch the D.H.9s where the D.H.4 could avoid many of these attacks.

While attempts were made to provide the D.H.9 with an adequate engine, with aircraft being fitted with the Siddeley Puma, a lightened and supposedly more powerful version of the BHP, with the Fiat A12 engine and with a 430 hp Napier Lion engine, these were generally unsuccessful and it required redesign into the D.H.9A to transform the aircraft.

Operational Service

The first deliveries were made in November 1917 to 108 Squadron RFC, with several more squadrons being formed or converted to the D.H.9 over the next few months, and with nine squadrons operational over the Western Front by June 1918.

The D.H.9's performance in action over the Western front was a disaster, with heavy losses being incurred, both due to its low performance, and engine failures (despite the prior de-rating of its engine). For example, between May and November 1918, two squadrons on the Western Front (Nos. 99 and 104) lost 54 shot down, and another 94 written off in accidents. The D.H.9 was however more successful against the Turkish forces in the Middle East, where they faced less heavy opposition, and was also used extensively for coastal patrols, to try and deter the operations of U-boats.

Surprisingly, production was allowed to continue after the end of the war into 1919, with the D.H.9 finally going out of service in 1920.

D.H.9A

Main article: Airco DH.9A
File:600 DH 9A.jpg
Three DH.9A in formation.

The D.H.9A (also referred to as the Nine-Ack) was designed for Airco by Westland Aircraft to take advantage of the American Liberty 12 400 hp (298 kW) engine. Apart from the new engine and slightly larger wings it was identical to the D.H.9.

Initially it was hoped to quickly replace the D.H.9 with the new version - however a shortage of Liberty engines available to the RAF curtailed the new type's service in World War I - and it is best known as a standard type in the post-war RAF - serving as a general purpose aircraft for several years.

Civil Use

Because of the large number of surplus D.H.9s available after the war many were used by air transport companies. They provided a useful load carrying capablity and were cheap. Early air services between London, Paris and Amsterdam were operated by D.H.9s owned by Aircraft Transport and Travel.

Variants

  • D.H.9 - Revised version of the DH.4 with the pilot and observer/gunner placed closer together (3,024 production aircraft built with others built in Belgian and Spain.
  • D.H.9A - Improved and re-engined version (2,300 built by 10 different British companies).
  • D.H.9B - Conversions for civilian use as three-seaters (one pilot and two passengers)
  • D.H.9C - Conversions for civilian use as four-seaters (one pilot and three passengers)
  • D.H.9J - Modernised and re-engined conversions using the 385-hp (287-kW) Armstrong Siddeley Jaguar III radial piston engine. Used by the De Havilland School of Flying.
  • D.H.9J M'pala I - Re-engined conversions carried out by the South African Air Force. Powered by a 450-hp (336-kW) Bristol Jupiter VI radial piston engine.
  • M'pala II - Re-engined conversions carried out by the South African Air Force. Powered by a 480-hp (358-kW) Bristol Jupiter VIII radial piston engine.
  • Mantis - Re-engined conversions carried out by the South African Air Force. Powered by a 200-hp (149-kW) Wolseley Viper piston engine.

Operators

Military Operators

DH.9 operators

Civil Operators

Specifications (D.H.9 (Puma Engine))

Data from The British Bomber since 1914[1]

General characteristics

  • Crew: 2

Performance

  • Endurance: 4½ hours

Armament

References

  1. ^ Mason, Francis K (1994). The British Bomber since 1914. Putnam Aeronautical Books. ISBN 0 85177 861 5. {{cite book}}: Cite has empty unknown parameter: |1= (help)
  • Winchester, Jim. Bombers of the 20th Century. United Kingdom: Airlife Publishing LTD. p. 7. ISBN 1-84037-386-5.

External links

Related content

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