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Airco DH.9

From Alfawiki
Airco
IndustryAircraft manufacturing
Founded1912
FounderGeoffrey de Havilland
Headquarters
London
,
United Kingdom


The Airco DH.9—later known post-1920 as the de Havilland DH.9—is a British single-engine biplane bomber that was developed and utilized during the First World War.

Derived from the earlier successful DH.4 model by Airco, the DH.9 incorporated numerous shared parts but featured a completely redesigned fuselage combined with the new Beardmore Halford Pullinger 230 hp (170 kW) powerplant, which was expected to offer enhanced capabilities. Anticipating its operational value, the aircraft was ordered in substantial quantities for service with the Royal Flying Corps (RFC) of Britain.

However, once deployed, the DH.9's performance proved disappointing. The BHP engine suffered from reliability issues and did not deliver the anticipated power output, resulting in inferior performance compared to the aircraft it was intended to replace. This shortfall contributed significantly to the heavy casualties experienced on the Western Front. To address these deficiencies, the updated DH.9A variant was introduced, equipped with a more robust and dependable American Liberty L-12 engine, effectively resolving the original model’s limitations.

Origins

In June 1917, following German bombing raids on London, the War Office recommended nearly doubling the size of the Royal Flying Corps (RFC) to 200 squadrons. This proposal was approved by the British Cabinet in early July 1917, with plans for most new units to operate bomber aircraft.[1] Although an order for 700 DH.4s had been placed on 28 June 1917, by 23 July 1917, the Air Board received designs for a modified DH.4 featuring extended range under a new designation, DH.9.[2]

The DH.9 was conceived by de Havilland at the Aircraft Manufacturing Company in 1916 as a successor to the DH.4. It retained the wings and tail assembly of its predecessor but introduced a revised fuselage that repositioned the pilot closer to the gunner/observer, distancing them from both the engine and fuel tank—this arrangement improved communication and created a more effective combat setup.[3] Another significant modification was adopting the promising new B.H.P engine, anticipated to generate 300 hp (220 kW) and provide performance competitive with enemy fighters.[4]

Given optimistic performance projections for the DH.9—which were initially expected to exceed those of the DH.4—and its similarity facilitating straightforward production transition, an extensive order totaling 4,630 units was placed before any prototype had flown.[2] Existing contracts for DH.4s were also converted to DH.9 production. The Air Board had been assured that initial manufacturing delays would not exceed one month. Aviation historian J.M Bruce notes that this decision "appears to have been made with optimism or blind faith," especially since in July 1917, serious production problems were affecting the chosen engine.[5]

Into flight

The prototype, which was a modified DH.4, completed its first flight in July 1917 at Hendon Aerodrome, located in Colindale, London.[4] The aircraft underwent extensive testing, including numerous trials conducted at RAF Martlesham Heath.[2] Unfortunately, the BHP engine failed to consistently produce the anticipated power, leading to its output being reduced to 230 hp (170 kW) in an effort to enhance dependability. This power shortfall significantly impaired the aircraft's capabilities, particularly at higher altitudes, rendering it less effective than the DH.4 it was intended to replace.[2]

Due to the aircraft's inadequate performance, the DH.9 was forced to confront enemy fighters directly, unlike the DH.4 which could evade many such threats. By November 1917, figures like General Hugh Trenchard had voiced strong criticisms regarding the aircraft’s underwhelming operational results; nevertheless, President of the Air Council Sir William Weir responded by stating that "the choice was between having the DH.9 powered by the B.H.P. engine or having no aircraft at all."[2] Additionally, by this stage, production of the DH.9 was already progressing rapidly.[2]

The BHP engines were manufactured by Siddeley-Deasy (under the designation Puma) and Galloway Engineering (marketed as the Adriatic). Within British military service, engines from both manufacturers were referred to as the 230 hp BHP despite differing dimensions and limited interchangeability of parts.[6][7] The majority of BHP engines in operation were produced by Siddeley-Deasy.[6]

File:Record du monde (d')altitude, capitaine Lang, lieutenant Blowes - btv1b532384931.jpg
Captain Lang and Lieutenant Blowes alongside their Napier Lion-powered DH.9 that set a World Altitude Record.

Numerous efforts were made to equip the DH.9 with more reliable powerplants.[5] In August 1917, an order for 2,000 Fiat A.12 engines was placed with deliveries scheduled between January and June 1918; some production batches of the D.H9 utilized these engines but delivery performance was unsatisfactory.[3]

Another engine option was the 430 hp (320 kW) Napier Lion, which powered an aircraft flown by Captain Lang and observer Lieutenant Blowes that established a World Altitude Record of 30,500 ft (9,300 m) within 66 minutes on January 2, 1919.[8] At an altitude of 21,000 ft, Lieutenant Blowes’ oxygen supply malfunctioned causing unconsciousness until descent to about 10,000 feet. Unaware of his observer’s condition, Captain Lang could not surpass the altitude of 30,500 feet due to failure of their oil heater and fuel pumps caused by insufficient air pressure. Both crew members required hospitalization afterward because of frostbite affecting their faces, hands, and feet.[9]

Despite these alternatives being explored,[3] none fully met expectations; consequently, a redesign led to the development of the DH.9A model which incorporated an American V-12 Liberty engine. Bruce noted that aside from engine complications: "Certainly, there was little wrong with the aircraft itself".[3]

Design

The Airco DH.9 was a British single-engine bomber aircraft that bore many resemblances to its predecessor, the DH.4. While the primary flight control surfaces remained largely unchanged, the aircraft featured a significantly redesigned fuselage layout, including relocating the pilot's cockpit further aft. The fuselage construction closely mirrored that of the earlier model; the forward section was covered with plywood without internal bracing, whereas the rear section behind the cockpits utilized a traditional wire-braced box girder framework. The aircraft included internal compartments capable of carrying either two 230-pound bombs or four 112-pound bombs, although operational use of this bomb load capacity was limited.

Though considered suitable for daylight bombing missions, the DH.9 was found to be ineffective for nocturnal operations due to restricted pilot visibility and an unsuitable bombsight arrangement. Moving the cockpit rearwards brought the pilot and observer into closer proximity, which the Royal Air Force regarded as a tactical advantage during aerial engagements; however, this adjustment compromised the pilot’s ability to conduct ground reconnaissance effectively. The aircraft could be equipped with both radio equipment and cameras. Its fuel tanks were covered with doped fabric designed to allow fuel to drain safely if punctured by enemy fire. Test pilots reported that the DH.9 was highly maneuverable and relatively straightforward to land, despite limited visibility during final approach.

A range of enhancements and additional gear were experimented with and occasionally incorporated into the design. Various engine types, radiators, silencers, and parachutes underwent testing to assess their suitability, though few modifications were ultimately implemented. Throughout the war, ground crews frequently introduced squadron-specific adaptations aimed at mitigating persistent engine reliability problems. After hostilities ceased, many DH.9 bombers were sold off and often converted for alternative functions such as passenger and freight transport, pilot training, and air ambulance duties.

First World War service

To accelerate production rates, orders for the DH.9 were also placed with manufacturers including Alliance, G & J.Weir, Short Brothers, Vulcan, Waring & Gillow, as well as National Aircraft Factories No. 1 and No. 2. Deliveries began in November 1917 with No. 108 Squadron of the Royal Flying Corps receiving the initial aircraft; by year-end five DH.9s had been delivered and passed inspections. The type’s combat debut occurred in March 1918 over France with No. 6 Squadron of the Royal Naval Air Service operating it in action. By July 1918, nine operational squadrons on the Western Front had integrated the DH.9 into their forces.

The aircraft’s performance on the Western Front was generally regarded as poor; it suffered heavy losses attributed to both underwhelming performance and frequent engine failures despite efforts to reduce engine stress through derating. Between May and November 1918 alone, Nos. 99 and 104 Squadrons lost 54 DH.9s to enemy fire and another 94 were written off due to accidents. Often fewer than half of a bomber flight would successfully reach their targets; according to accounts, successful missions owed much to "the courage and determination of the pilots and observers." To improve reliability and performance, individual squadrons frequently implemented their own modifications such as enlarged carburetor air intakes and altered fuel mixture controls.

Despite its shortcomings, there were notable instances of effectiveness: on 23 August 1918, Lieutenant Arthur Rowe Spurling of 49 Squadron and his observer Sergeant Frank Bell engaged thirty Fokker D.VII fighters alone and shot down five enemy aircraft. On 9 August that same year, Lieutenant E.A. Simpson of 49 Squadron defended his formation during a bombing raid on bridges at Falvy and Bethencourt by downing four hostile fighters amid repeated attacks. Captain John Stevenson Stubbs also achieved eleven aerial victories flying a DH.9, including rare balloon-busting missions.

Although generally underperforming compared to expectations, the DH.9 was deployed extensively across nearly all theatres before the Armistice in November 1918 concluded hostilities. It reportedly experienced greater success against Turkish forces in the Middle East due to lighter aerial opposition there. Additionally, based at coastal airfields throughout Britain, DH.9s conducted numerous maritime patrol operations aimed at countering enemy U-boat activities along the coastline.

Post-war operations

After the conclusion of the First World War, several DH.9 aircraft operated by 47 Squadron and 221 Squadron were deployed to southern Russia in 1919 to assist the White Russian forces under General Denikin during the Russian Civil War.[10] Within this conflict zone, these planes frequently faced demanding operational environments.[11]

The RAF's final combat deployment of the DH.9 occurred during the closing campaign against Diiriye Guure[12] in Somalia during January and February 1920.[10] Among these aircraft operating in Somalia, one DH.9 was adapted to serve as an air ambulance, capable of carrying a single stretcher mounted on the upper longerons immediately behind the pilot’s cockpit.[13] Additional conversions for medical evacuation were undertaken, including several utilized by the Royal Netherlands Air Force.[14]

Production of the DH.9 continued into 1919 despite the war’s end. By 1920, the RAF officially retired the type from active service.[15] Beyond British manufacturing efforts, other nations initiated production as well; notably, the Airco DH.9A, equipped with the American V-12 Liberty engine, was produced in large quantities even though manufacturing was limited due to the Armistice that ended World War I.[11] Both Belgium and Spain also produced DH.9s—the latter manufactured hundreds powered by a 300 hp (220 kW) Hispano-Suiza engine; some remained operational as late as 1940.[14]

Following hostilities, a substantial surplus of DH.9s became available at low cost and were widely exported. This included aircraft gifted to various Dominions and India through the Imperial Gift initiative.[16][8][14] The South African Air Force (SAAF) acquired a total of 48 DH.9s which were extensively employed—including actions during the Rand Revolt in 1922. A number of these South African aircraft were later re-engined with Bristol Jupiter radial engines and redesignated as M′pala; these modified versions remained in service until 1937.[17][14]

The last known combat use of the DH.9 by any operator likely occurred in late 1922 amid the Turkish War of Independence.[18] Greek forces deployed several DH.9s against nationalist Kemalists, who opposed the British-backed Greek invasion of remaining Ottoman territories following the 1918 Armistice of Mudros and subsequent rejection of the Sevres Treaty. One Greek DH.9 made a forced landing behind Turkish lines near Muğla during July 1921’s Battle of Sakarya. This aircraft was quickly repaired and flown to Ankara in August by pilot Vecihi Hürkuş.[19] Renamed "Ismet," it served as Turkey’s sole operational aircraft during later stages of Sakarya, completing approximately twenty-three sorties primarily piloted by Vecihi.[20] This plane continued operations throughout Turkey’s War of Independence until late 1922. Additionally, three more Greek DH.9s were discovered intact with ample spare parts near İzmir after Greek forces hastily withdrew following defeat by Kemalist forces in August 1922. These four aircraft served within the fledgling Turkish Air Force until about 1925.[20]

The newly established Irish Free State acquired six surplus DH.9s from the Aircraft Disposal Company, delivered between January and February 1923. These aircraft were employed for reconnaissance missions, army support roles, and railway protection during the final months of the Irish Civil War. The DH.9 remained part of Irish military aviation into the early 1930s.[21]

Civilian service

File:G-AUED.jpg
DH-9 G-AUED adapted with an enclosed cabin for use as a passenger aircraft

Following the conclusion of the war, a substantial number of surplus DH.9 aircraft became available, as their original military users considered them redundant. Consequently, many were sold to civilian operators, including emerging commercial aviation companies. Numerous units underwent modifications to enhance their suitability for transport roles, such as installing cabins configured for passenger carriage.[14] In this capacity, the DH.9 offered a practical payload capability and was cost-effective to acquire. As a result, it found extensive application across various civil aviation configurations.[14]

Early commercial air routes connecting London, Paris, and Amsterdam were serviced by a fleet of DH.9s operated by Aircraft Transport and Travel. Several DH.9s were converted into floatplane variants and operated in regions including India, Bolivia, and Rhodesia.[22] Additionally, some aircraft were modified to fulfill the role of trainer aircraft, equipped with Armstrong Siddeley Jaguar radial engines and fitted with rubber-sprung landing gear; these models were designated DH.9Js, with the final examples retired and dismantled by 1936.[23]

Various civil conversion programs for the DH.9 were undertaken by Airco, its successor the de Havilland Aircraft Company, and other firms such as the Aircraft Disposal Company.[24] Some radial-engine DH.9J variants remained in civilian service until 1936.[25] One DH.9 was shipped to Japan during the Sempill Mission.[26] Furthermore, according to the Aircraft Disposal Company, numerous DH.9s were apparently exported to China.[27]

Variants

  • DH.9 – An improved iteration of the DH.4 featuring closer positioning of pilot and observer/gunner stations (3,024 built in total along with additional units produced in Belgium and Spain).
  • DH.9A – Also known as the Nine-Ack, this model was developed by Westland Aircraft for Airco to incorporate the 400 hp (300 kW) American Liberty L-12 engine. Aside from the upgraded powerplant and slightly enlarged wingspan, it closely resembled the original DH.9. Although intended to rapidly replace the DH.9 during World War I, limited availability of Liberty engines curtailed its wartime deployment; it later became a standard postwar RAF general-purpose aircraft with production totaling approximately 2,300 units across ten British manufacturers.
  • DH.9B – Modified civil versions configured as three-seaters (one pilot plus two passengers).
  • DH.9C – Civilian conversions arranged as four-seaters (one pilot plus three passengers).
  • DH.9J – Upgraded models featuring 385 hp (287 kW) Armstrong Siddeley Jaguar III radial engines; utilized by the De Havilland School of Flying.
File:HP 17.png
Handley Page H.P. 17 displaying slotted wing design
  • DH.9J M'pala I – South African Air Force conversions re-engined with a 450 hp (340 kW) Bristol Jupiter VI radial piston engine.
  • M'pala II – Further South African Air Force re-engined variants powered by a 480 hp (360 kW) Bristol Jupiter VIII radial piston engine.
  • Mantis – South African Air Force conversions fitted with 200 hp (150 kW) Wolseley Viper piston engines.
  • Handley Page HP.17 – A DH.9 experimentally adapted with slotted wings, tested during 1920–1921.[28]
  • USD-9/9A – DH.9s produced in the United States by the US Army's Engineering Division and Dayton-Wright Airplane Company (1,415 ordered but only four completed).[29]

Military operators

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(Part of Imperial Gift)

File:Greek aircraft during the Greco-Turkish War.jpg
Greek DH-9
File:Flag of Greece (1822-1978).svg Greece
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  • Hejaz Air Force – Between 1921 and 1924, the Kingdom of Hejaz obtained nine DH.9s and two DH.9Cs. By 1932, five remained, though none were operational.[33]
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Spain Kingdom of Spain
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File:De Havilland D.H.9 Ganimet.jpg
Turkish DH-9
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File:Flag of the United States (1912-1959).svg United States
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Civil operators

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Spain Kingdom of Spain
  • Cia Espanola del Trafico Aereo
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File:Flag of Bikaner.svg Bikaner State

Surviving aircraft

File:DH.9 F1258 LeB 05.07R.jpg
DH.9 F1258 exhibited at the Musée de l'Air et de l'Espace, Paris Le Bourget

Among the numerous DH.9 units produced, only a limited number remain preserved today:

  • The aircraft F1258 can be found on display at the Musée de l'Air et de l'Espace located in Paris.
  • An original DH.9, lacking a visible serial number, is exhibited at the South African National Museum of Military History. This particular DH.9 served with the South African Air Force following World War I and later operated as a civilian plane under the registration ZS-AOI before returning to military service with the SAAF.
  • The G-EAQM (initially RAF serial F1278), notable as the first single-engine airplane to complete a flight from the United Kingdom to Australia, is preserved at the Australian War Memorial in Canberra.

In 2000, wreckage from three DH.9 aircraft was uncovered in India; two of these were transported back to the United Kingdom for restoration. Specifically:

  • The D5649 was fully restored and is now on view at the Imperial War Museum, Duxford.
  • The E8894/G-CDLI underwent restoration to flying condition and is currently operated as a warbird by the Historic Aircraft Company based in England.
  • The third example remained in India, where it was restored with some deviations from its original state and is displayed at Junagarh Fort in Bikaner, Rajasthan.

Specifications (DH.9 with Puma Engine)

File:Airco de Havilland DH.9 dwg.jpg
Technical drawing of the Airco DH.9

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See also

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Notes

  1. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Bruce pt I p387
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Bruce 1965, p. 3.
  3. ↑ 3.0 3.1 3.2 3.3 Bruce 1965, p. 4.
  4. ↑ 4.0 4.1 Jackson 1987, p. 97.
  5. ↑ 5.0 5.1 Cite error: Invalid <ref> tag; no text was provided for refs named bruce 65 3 4
  6. ↑ 6.0 6.1 Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  7. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  8. ↑ 8.0 8.1 8.2 Jackson 1987, p. 100.
  9. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  10. ↑ 10.0 10.1 Bruce 13 April 1956, p. 424.
  11. ↑ 11.0 11.1 Bruce 1965, p. 8.
  12. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  13. ↑ Bruce 1965, pp. 8-9.
  14. ↑ 14.0 14.1 14.2 14.3 14.4 14.5 Bruce 1965, p. 9.
  15. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named masonp86
  16. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  17. ↑ Jackson 1987, p. 102.
  18. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  19. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  20. ↑ 20.0 20.1 Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  21. ↑ London 2015, p. 37
  22. ↑ Bruce 1965, pp. 9-10.
  23. ↑ Bruce 1965, p. 10.
  24. ↑ Jackson 1973, pp. 50-52.
  25. ↑ Jackson 1973, p. 56.
  26. ↑ Sturtivant 1999, p. 265.
  27. ↑ Sturtivant 1999, p. 261.
  28. ↑ Barnes 1976, pp. 211–213.
  29. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  30. ↑ Bruce 13 April 1956, p. 423.
  31. ↑ Gerdessen 1982, p. 76.
  32. ↑ 32.0 32.1 Bruce 13 April 1956, p. 425.
  33. ↑ Andersson Air Enthusiast July–August 2004, pp. 39–42.
  34. ↑ Kopański, Tomasz Jan. Samoloty brytyjskie w lotnictwie polskim 1918–1930 (British aircraft in the Polish air force 1918–1930). Bellona, Warsaw. 2001, ISBN 83-11-09315-6, pp. 55–62. (in Polish)

Bibliography

  • Andersson, Lennart. Wings Over the Desert: Aviation on the Arabian Peninsula: Part One Saudi Arabia. Air Enthusiast, no. 112, July–August 2004, pp. 39–43.
  • Barnes, C. H. Handley Page Aircraft since 1907. London, UK: Putnam, 1976. ISBN 0-370-00030-7.
  • Bruce, J. M. Aircraft Profile No. 62: The de Havilland D.H.9. Profile Publications Ltd, 1965.
  • Bruce, J. M. "The De Havilland D.H.9: Historic Military Aircraft: No. 12, Part I." Flight International, vol. 69, no. 2463, 6 April 1956, pp. 385–388, 392.
  • Bruce, J. M. "The De Havilland D.H.9: Historic Military Aircraft: No. 12, Part II." Flight International, vol. 69, no. 2464, 13 April 1956, pp. 422–426.
  • Cooksley, Peter. "Erratic Their Course." Air Enthusiast, no. 53, Spring 1994, pp. 53–59.
  • Gerdessen, Frederik. "Estonian Air Power 1918 – 1945." Air Enthusiast, no. 18, April–July 1982, pp. 61–76.
  • Jackson, A. J. British Civil Aircraft since 1919 Volume 2. Second edition, London, UK: Putnam, 1973. ISBN 0-370-10010-7.
  • Jackson, A. J. De Havilland Aircraft since 1909. Third edition, London, UK: Putnam, 1987. ISBN 0-85177-802-X.
  • London, Pete. "Air War Over Ireland." Aeroplane, vol. 43, no.10, October 2015, pp.32–37.
  • Klaauw, Bart van der. "Unexpected Windfalls: Accidentally or Deliberately, More than 100 Aircraft 'arrived' in Dutch Territory During the Great War." Air Enthusiast, no.80, March–April 1999, pp.54–59.
  • Mason, Francis K. The British Bomber Since 1914. London, UK: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.
  • Sturtivant, R., and G. Page.The DH.4/DH.9 File. Kent, UK: Air-Britain (Historians) Ltd.,1999.ISBN0-85130-274-2.
  • Thomas, Andrew."In the Footsteps of Daedulus: Early Greek Naval Aviation." Air Enthusiast,no94 July–August2001 pp8–9.
  • Wauthy Jean-Luc and Florian de Neve."Les aéronefs de la Force Aérienne Belge,deuxième partie1919–1935" (Aircraft of the Belgian Air Force). Le Fana de l'Aviation,no305 June1995 pp28–33 (French).
  • Winchester,Jim (ed.).Bombers of the 20th Century. London UK:Airlife Publishing Ltd.,2003.ISBN1-84037-386-5.

External links

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