Airco DH-9
The Airco DH.9 was a British light bomber developed during the First World War. It was designed by Geoffrey de Havilland for the Aircraft Manufacturing Company, better known as Airco. The DH.9 was intended as an improvement on the earlier DH.4, with its primary design change being the relocation of the pilot's cockpit closer to the observer’s position to improve communication during flight. The fuselage was also revised, but many structural elements such as the wings and tailplane remained the same. While the design changes aimed to improve operational effectiveness, they also introduced new issues, most notably in performance.
The DH.9 was powered by the Siddeley Puma engine, a derivative of the BHP engine, which had been expected to deliver 300 horsepower. However, due to reliability concerns, it was derated to around 230 horsepower. This resulted in significant underperformance, making the DH.9 slower and more vulnerable than its predecessor. Despite these shortcomings, the urgency of wartime needs led to the aircraft being pushed into large-scale production.
Aircraft were manufactured not only by Airco but also by a range of subcontractors, including Alliance, Short Brothers, and others. Orders for the DH.9 totaled around 4,630 units, with about 4,091 completed by the end of the war. Another estimate places the number delivered by the end of 1918 at 3,204. Due to the aircraft’s limited performance, some of the airframes remained incomplete or were delivered in a non-operational state.
In terms of armament, the DH.9 carried both offensive and defensive weapons. For forward-firing capability, the pilot operated a fixed .303 Vickers machine gun synchronized to fire through the propeller. In the rear cockpit, the observer operated one or two .303 Lewis guns mounted on a Scarff ring, giving flexible coverage against attacking fighters. The aircraft was also capable of carrying a bomb load of up to 460 pounds, typically consisting of four 112 lb bombs or a mix of smaller bombs such as eight 65 lb or up to twenty 20 lb bombs, depending on the mission requirements. This made it suitable for both tactical and strategic bombing roles, although the underwhelming engine performance often limited its operational effectiveness when fully loaded.
In combat, the DH.9 served with several squadrons on the Western Front beginning in early 1918. Unfortunately, its performance in this theater was marred by severe losses. Slow speeds and mechanical unreliability made it easy prey for German fighters. Between May and November 1918, No. 99 and No. 104 Squadrons lost 54 DH.9s to enemy action and another 94 to crashes and mechanical failures. It was not uncommon for fewer than half of a bombing formation to reach its target.
Despite this, the DH.9 did see moments of success and bravery. On 23 August 1918, Lt. Rowe Spurling and Sgt. Bell managed to shoot down five Fokker D.VII fighters during a single mission. Other crews also scored multiple aerial victories under difficult circumstances. However, as it became clear that the DH.9 was not suited for the Western Front, it was gradually reassigned to secondary theaters of war.
The aircraft saw more effective service in regions with less intense aerial opposition, such as the Middle East and Turkey. It also flew patrols along the British coastline, guarding against submarine threats. Armed with bombs and machine guns, the DH.9 was used in anti-submarine roles and coastal patrols, where it faced fewer threats from enemy aircraft.
After the Armistice, many surplus DH.9s found new roles in colonial policing. One of the most famous postwar operations took place in British Somaliland in 1920, where a small number of DH.9s carried out a bombing campaign against insurgent forces, marking one of the first uses of airpower in a policing role. The campaign was completed in a matter of days and was hailed in Britain as a highly cost-effective use of military force.
The DH.9 was also distributed to Commonwealth and allied air forces through the Imperial Gift programme. Aircraft were sent to countries such as Australia, Canada, South Africa, and New Zealand, and some were sold or donated to emerging air forces in Europe, Asia, and Latin America. In South Africa, the aircraft was modified with a more reliable Bristol Jupiter radial engine and served under the name "M’pala," with some units remaining in service until 1937.
Though the RAF began phasing out the DH.9 in 1920, the aircraft's wide export and postwar utility gave it a surprisingly long service life. While its reputation during the war was poor due to its performance issues, the DH.9 played a significant role in transitioning military aviation from the frantic experimentation of World War I to the more stable interwar years.
