Airco DH.9A

The DH.9A was planned as an improved version of the existing Airco DH.9. The DH.9 was a disappointment owing to its under-performing and unreliable engines, and the DH.9A was to use a more powerful engine to resolve this. As the Rolls-Royce Eagle engine used in the successful DH.4 was unavailable in sufficient quantities, the new American Liberty engine was chosen instead. As Airco was busy developing the Airco DH.10 Amiens twin-engined bomber, detailed design was carried out by Westland Aircraft. The DH.9 was fitted with new, longer-span wings and a strengthened fuselage structure. The first prototype flew in March 1918, powered by a Rolls-Royce Eagle as no Liberty engines were yet available. The prototype proved successful, with the first Liberty-engined DH.9A flying on 19 April 1918, and deliveries to the Royal Air Force starting in June. By the end of the war, a total of 2,250 DH.9As had been ordered, with 885 being built by the end of the year. As it was decided that the DH.9A would be a standard type in the postwar RAF, the majority of outstanding orders were fulfilled, with 1,730 being built under the wartime contracts before production ceased in 1919. While the existing aircraft were subject to a programme of refurbishment, a number of small contracts were placed for new production of DH.9As in 1925–26. These contracts resulted in a further 268 DH.9As being built. The new production and refurbished aircraft included batches of dual control trainers, as well as six aircraft powered by Napier Lion engines, which were capable of a maximum speed of . Soviet versions The Soviet Union acquired a number of DH.9A’s during the Allied intervention in the Russian Civil War; they built large numbers of an unlicensed copy of the aircraft, supervised by N. N. Polikarpov and designated the Polikarpov R-1. After the production of 20 DH.4 copies, followed by about 200 copies of the DH.9 powered by the Mercedes D.IV engine (also designated R-1) and a further 130 powered by the Siddeley Puma (designated R-2), a copy of the DH.9A powered by the M-5 engine, a Soviet copy of the DH.9A's Liberty, entered production in 1924. Over 2,400 built from 1922 to 1932. The R-4 was a modification of the R-1, with the engine lowered and moved forward by to improve both the forward visibility and the C.G position. The nose shape was improved by fairing and by installing a retractable ventral radiator. Overall length was increased by . Landing legs were changed from wood to steel. Testing showed insufficient improvement over the R-1 to justify production but late R-1s incorporated some of the modifications. US version and pressurised flights The United States also planned to adopt the DH.9A as a replacement for the DH.4. Development work on the Americanization of the aircraft commenced at McCook Field in Dayton, Ohio. Plans called for Curtiss to build 4,000 modified aircraft, designated USD-9A. This order was cancelled with the end of the war and only nine were built by McCook Field and Dayton-Wright. ==Operational history==

First World War The DH.9A entered service in July 1918 with No. 110 Squadron RAF, moving to France on 31 August 1918 to serve with the RAF's Independent Air Force on strategic bombing missions. Its first mission was against a German airfield on 14 September 1918. Other squadrons flew coastal patrols from Great Yarmouth before the end of the year. The United States Marine Corps Northern Bombing Group received at least 53 DH-9As, and commenced operations in September 1918. Interwar RAF service While the squadrons in service at the end of the First World War quickly disbanded or re-equipped in the postwar dis-armament, the DH.9A continued in service as the RAF's standard light bomber, with 24 squadrons being equipped between 1920 and 1931, both at home and abroad. The first post war operations were in southern Russia during 1919, in support of the "White Army" against the Bolsheviks during the Russian Civil War. In September 1919, the RAF personnel were ordered to return home, leaving their aircraft behind. A squadron of DH.9As was deployed to Turkey in response to the Chanak Crisis in 1922, but did not engage in combat. The DH.9A was one of the key weapons used by Britain to manage the territories that were in its control following the collapse of the Ottoman Empire following the Great War. Five squadrons of DH.9As served in the Middle East, occasionally carrying out bombing raids against rebellious tribesmen and villages. An additional radiator was fitted under the fuselage to cope with the high temperatures, while additional water containers and spares (including spare wheels lashed to the fuselage) were carried in case the aircraft were forced down in the desert, the DH.9A's struggling under ever heavier loads. Despite this the aircraft served successfully, with the Liberty engine being picked out for particular praise for its reliability ("as good as any Rolls Royce") in such harsh conditions. Some DH.9A aircraft were also transported to India to supplement the British Indian Army. At home, the DH.9A continued on in regular RAF service until 1930, also forming the initial equipment of the Royal Auxiliary Air Force (RAuxAF). Soviet service The R-1 and R-2 were heavily used by the Soviet Air Forces through the 1920s as its standard light bomber and reconnaissance aircraft. The Soviets deployed them in support of the Chinese Kuomintang forces in the Northern Expedition against warlords in 1926–27, and against Chinese forces for control of the Chinese Eastern Railway in Manchuria in 1929. R-1s and R-2s were also used in support of operations during the Basmachi Revolt in central Asia. ==Variants==

• Airco DH.9A: Original version. • de Havilland DH.9AJ: Single prototype with Bristol Jupiter engine. • de Havilland DH.9R: Racing aircraft with sesquiplane wings and powered with a Napier Lion engine – (one built). • Airco DH.15 Gazelle: DH.9A fitted with a Galloway Atlantic inline engine, one conversion • Airco DH.16: Civil transport with widened fuselage seating four passengers in a glazed cabin behind the pilot, who sat in an open cabin, nine built. Rolls Royce Eagle or Napier Lion Engine. • de Havilland DH-49 – proposed modernised version with Eagle IX engine (not built) • Engineering Division USD-9A: United States built version, 9 built. One modified with a pressurised cockpit. • Engineering Division USD-9B: USD-9A fitted with more powerful Liberty engine and greater area wings. • Polikarpov R-1 BMW: R-1 fitted a BMW IVa engine, 20 built. • Polikarpov MR-1: Twin-float seaplane version, 124 built. • Polikarpov PM-2: Prototype floatplane fitted with metal floats. • Polikarpov R-4: R-1 with better forward view and CG position, forward profile cleaned up with fairings and a retractable ventral radiator. Stronger landing gear. No production but changes incorporated into late R-1s. ==Operators==

; • Afghan Air Force – Airco DH.9As and Polikarpov R-1s ; • Royal Australian Air Force: 30 received as an imperial gift in 1920 plus one attrition replacement purchased in 1921. It was the first aircraft from the imperial gift to enter Australian service. The aircraft were in service from 1920 to 1930, and were replaced by the Westland Wapiti. • No. 1 Flying Training School RAAF (22 aircraft: A1-1/2/5/7-11/13-21/23/24/26/29/30) • No. 1 Squadron RAAF (12 aircraft: A1-4/5/7/9/12/14/20-22/25/26/28) • No. 3 Squadron RAAF (8 aircraft: A1-3/6/8/10/24/25/27/28) • Central Flying School RAAF (4 aircraft: A1-16/17/26, E8616) ; • Canadian Air Force (1918–1920) • No. 2 Squadron CAF • Canadian Air Force (1920–1924) • Royal Canadian Air Force ; • Imperial Iranian Air Force ; • Latvian Air Force ; • Mongolian People's Air Force : Polikarpov R-1s and R-2s ; • Portuguese Air Force ; • Swiss Air Force : One aircraft only. ; • Royal Air Force • No. 3 Squadron RAF • No. 8 Squadron RAF • No. 11 Squadron RAF • No. 14 Squadron RAF • No. 15 Squadron RAF • No. 18 Squadron RAF • No. 22 Squadron RAF • No. 24 Squadron RAF • No. 25 Squadron RAF • No. 30 Squadron RAF • No. 39 Squadron RAF • No. 45 Squadron RAF • No. 47 Squadron RAF • No. 55 Squadron RAF • No. 60 Squadron RAF • No. 84 Squadron RAF • No. 99 Squadron RAF • No. 100 Squadron RAF • No. 110 Squadron RAF • No. 205 Squadron RAF • No. 207 Squadron RAF • No. 207 Squadron RAF • No. 221 Squadron RAF • No. 273 Squadron RAF • No. 501 Squadron RAF • No. 600 Squadron RAF • No. 601 Squadron RAF • No. 602 Squadron RAF • No. 603 Squadron RAF • No. 604 Squadron RAF • No. 605 Squadron RAF ; • United States Navy • United States Marine Corps ; • Soviet Air Force : Polikarpov R-1s and R-2s ==Surviving aircraft==

A single example, serial number F1010, survives and is on display at the Royal Air Force Museum London. The aircraft was completed by Westland Aircraft in June 1918 and was one of 18 DH.9A's assigned to No. 110 Squadron RAF. It was the thirteenth aircraft, but was given the number "12A" because thirteen was thought unlucky. The squadron began flying bombing missions in September 1918, and on the 25th, the crew of F1010 claimed the destruction of a German Fokker D.VII fighter. The aircraft's fourth and final combat mission was on 5 October when either flak damage or engine trouble forced a landing behind German lines. The aircraft was undamaged by the landing and the crew were taken prisoner. ==Specifications (DH.9A)==