The DH9A was a single-engine light bomber designed and used towards the end of World War 1.
It was designed around the US built 400hp Liberty 12 engine to improve the performance of its underpowered predecessor, the Airco DH9 (which is described on its own web page).
The first prototype DH9A was a modification of a Westland-built DH9 (B7664), with a second Airco-converted prototype (C6350) assisting in the trials programme.
Both prototypes were powered by the Rolls-Royce Eagle VIII engine as deliveries of the Liberty 12 engines were still awaited. Colloquially, the aircraft was nicknamed the 'Ninak' (based on the phonetic alphabet Nine-A).
The prototype was first flown in March 1918 and this was quickly followed by the first Liberty-powered prototype (C6122) which flew at Yeovil in April 1918. With a greater span and wing area, and with a new wire braced fuselage, the DH9A was in effect, a new design, despite its generic resemblance to the DH9.
Westland Aircraft Works, who were familiar with DH4 and DH9 production, was selected to develop the DH9A as Airco were fully occupied in the production of the DH10.
The modifications to generate the DH9A were developed by the Westland Design Team with the assistance of Mr John Johnson, who was loaned to Westland by Airco for this purpose. Airco had received contracts for over 600 DH9A's and the degree of urgency was foremost.
Other companies in receipt of DH9A orders (or involved in their refurbishment) included F.W. Berwick; George Parnall & Co, Gloucestershire Aircraft, Handley Page, H.G. Hawker Engineering, Mann, Egerton & Co, Saunders-Roe, Vulcan Motor & Engineering and Whitehead Aircraft.
In addition, Westland's themselves built six aircraft powered by the 475 hp Napier Lion II engine, this version having a somewhat 'inelegant' appearance.
Production deliveries to the RAF began in June 1918 and some 2,250 DH9A's were ordered. Despite the Armistice and the end of hostilities in Europe, production continued well into 1919. 1,730 aircraft were finally built with a significant number being refurbished and a second further production batch of 267 aircraft being built in the mid-1920’s. With three prototypes and the combined wartime and peacetime production (1,997 aircraft) a grand total of over 2,000 DH9A's were built.
The Soviet Union produced an intitial batch of 20 unlicenced copies of the DH9A, known as the R-1 which was then followed by 200 further aircraft powered by the Mercedes D.IV engine. Another 130 aircraft (designated R-2) were later produced with the Siddeley Puma engine. Finally in 1924, the Soviets produced their own M-5 engine for the aircraft which was in essence a copy of the DH9A's Liberty engine.
The United States planned to order 4,000 DH9A's for local manufacture in a modified version (the USD-9) although in the end only four prototypes were constructed. These were followed by another four (USD-9A's) built by Dayton Wright as well as an additional five (USD-9A) which were built by the Engineering Division and were used for experimental purposes.
In service with the RAF, the DH9A was used on strategic bombing missions such as attacking German airfields whilst operating from bases in liderated France. Some aircraft were allocated to coastal patrols operating from various airfiields through out East Anglia.
The RAF made much use of the DH9A during the inter-war period, particularly for operations in the Middle East and India. Between 1920 and 1931, some 24 RAF squadrons were equipped with the DH9A which became its standard light day bomber.
Only 13 DH9A's came onto the British Civil Aircraft Register featuring a variety of engines including the Liberty 12, the Napier Lion and the Rolls-Royce Eagle.
Eleven DH9A reached the Canadian Civil Register mainly being used for forestry and other survey work.
The DH9R Racer (K-172 / G-EAHT) was a sesquiplane variant with a passing resemblance to the earlier and cruder DH4R. It was powered by the Napier Lion engine and achieved closed circuit speeds approaching 150 mph.
The DH9AJ Stag was the final DH9A version with a single example (J7028) being built. This aircraft was powered by a Bristol Jupiter engine and first flew on 15th July 1926 as an intended replacement for the DH9A.
The DH9A remained in RAF service until 1933.
|Powerplant||One 400hp Liberty 12|
|Span||45 ft 11.4 in|
|Maximum Weight / Capacity||4,645 lb|
|Maximum Speed||123 mph at sea level, 114.5 mph at 10,000ft|
|Cruising speed||96 mph|
|Capacity & Armament||Pilot and observer and 460 lb of bombs, forward firing Vickers machine gun and single or twin Lewis guns for self-defence.|
|Range / Endurance||5.25 hrs|
Variants and Numbers built
|DH9A||Three prototypes and 1,997 production aircraft|
|DH9R||One-off racing aircraft K-172 / G-EAHT using DH9A components|
|DH9AJ Stag||One-off Jupiter-powered J7028 built intended replacement for the DH9A|
|USD-9, USD-9A||Four USD-9 prototypes followed by four USD-9A by Dayton Wright and five USD-9A by the US Army's Engineering Division|
Airco DH9A (F1010)
Displayed in the RAF Museum, Hendon