Airco DH.9

DH.9
275px
Airco D.H.9
Type	Bomber
Manufacturer	Airco
Designed by	Geoffrey de Havilland
Maiden flight	July 1917
Introduced	1917
Retired	1920
Primary users	Royal Air Force RNAS, RFC.
Number built	4091
Variants	Airco DH.9A Westland Walrus

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

Design and development

The DH.9 was designed by de Havilland for the Aircraft Manufacturing Company in 1916 as a successor to the DH.4. It used the wings and tail unit of the DH.4 but had a new fuselage. This enabled the pilot to sit closer to the gunner/observer and away from the engine and fuel tank. The other major change from the DH.4 was the choice of the promising new BHP/Galloway Adriatic 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 DH.9, and the similarity to the DH.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 DH.4) first flew at Hendon in July 1917. Unfortunately, the BHP engine proved unable to reliably deliver its expected power, 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 DH.4 it was supposed to replace. This meant that the DH.9 would have to fight its way through enemy fighters, which could easily catch the DH.9 where the DH.4 could avoid many of these attacks.

While attempts were made to provide the DH.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 DH.9A to transform the aircraft.

Operational history

File:Airco dh9.png

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

The DH.9's performance in action over the Western front was a disaster, with heavy losses 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 DH.9 was however more successful against the Turkish forces in the Middle East, where they faced less opposition, and it 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 DH.9 finally going out of service in 1920.

DH.9A

File:600 DH 9A.jpg

Three DH.9A in formation.

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

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

Civilian use

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

Variants

• DH.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 Belgium and Spain).
• DH.9A - Improved and re-engined version (2,300 built by ten different British companies).
• DH.9B - Conversions for civilian use as three-seaters (one pilot and two passengers)
• DH.9C - Conversions for civilian use as four-seaters (one pilot and three passengers)
• DH.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.
• DH.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.
• Handley Page HP.17 - A DH.9 experimentally fitted with slotted wings

Operators

Military Operators

File:World operators of the DH 9.png

DH.9 operators

• Template:Country data Afghanistan: 18 aircraft, including 16 built by Duks Aircraft Works, were acquired from 1924 by the Afghan Air Force.
• Template:AUS
• Template:BEL: 18 aircraft
• Template:Country data India British India (Part of Imperial Gift Scheme)
• Template:Country data Canada
• Template:Country data Greece
• Template:Country data Kingdom of Hejaz
• Template:IRL
• Template:LAT
• Template:NLD
• Template:NZL: Three Airco DH.9s were in service with the New Zealand Permanent Air Force from 1923 to 1929. The DH.9s were used by the NZPAF as advanced training aircraft.
• Template:PER
• Template:POL
• Template:Country data Romania
• Template:Country data Spain Kingdom of Spain
• Template:Country data South Africa (Locally modified with Jupiter engines and given the local name Mpala).
• Template:SUI
• Template:UK: Royal Flying Corps, Royal Naval Air Service, Royal Air Force
• Template:Country data United States: American Expeditionary Force, United States Marine Corps

Civil Operators

• Template:AUS: Qantas
• Template:BEL: Sabena
• Template:NLD: KLM
• Template:Country data Spain Kingdom of Spain: Cia Espanola del Trafico Aereo
• Template:UK: Aircraft Transport and Travel, Handley Page Transport Company

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

Data from The British Bomber since 1914

General characteristics

• Crew: 2
• Length: 30 ft 5 in (9.27 m)
• Wingspan: 42 ft 4⅝ in (19.92 m)
• Height: 11 ft 3½ in (3.44 m)
• Wing area: 434 ft² (40.3 m²)
• Empty weight: 2,360 lb (1,014 kg)
• Max takeoff weight: 3,790 lb (1,723 kg)
• Powerplant: 1× Armstrong Siddeley Puma piston engine, 230 hp (172 kW)

Performance

• Maximum speed: 98 knots (113 mph, 182 km/h)
• Service ceiling: 15,500 ft (4730 m)
• Endurance: 4½ hours

Armament

Forward firing Vickers machine gun

1 or 2 Rear Lewis guns on scarff ring

Up to 460 lb (209 kg) bombs

References

Bibliography

• Mason, Francis K. The British Bomber Since 1914. London: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.
• Winchester, Jim, ed. Bombers of the 20th Century. London: Airlife Publishing Ltd., 2003. ISBN 1-84037-386-5.

External links

• British Aircraft Directory Entry for Airco DH.9
• DH9 at Imperial War Museum, Duxford

See also

Wikimedia Commons has media related to:

Category:Airco DH.9

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Airco DH.9".