The prototype Airco DH9 was a single-engine biplane designed by Geoffrey de Havilland during his time at the Aircraft Manufacturing Company (Airco). It was planned as a successor to the DH4 as a bomber for use during the First World War.
The prototype DH9 (A7559) was a modified Airco-built DH4 and first flew in July 1917 at Hendon in North London. It was powered by a six-cylinder in-line 230hp BHP Adriatic engine although throughout its life it was fitted with a multitude of differing engines.
The main external difference from the DH4 was a change in the cockpit arrangement to bring the pilot and observer closer together rather than being separated by the fuel tank. This improved communications enormously.
To aid the switch in production from the DH4 to the DH9, the design utilised the wings and tail assembly from the DH4, mounted onto a larger fuselage.
As previously mentioned, a number of different engines were tried and fitted to the DH9 including (most commonly) the 230 hp Siddeley Puma and the 230hp Fiat A-12. The 430hp Napier Lion was also fitted experimentally to a number of aircraft.
The Siddeley Puma power unit was a lighter weight version of the BHP engine which was modified for mass production by the Siddeley-Deasy Car Company.
Originally intended to deliver 300 hp, the Puma engine proved unreliable and so it was de-rated to 230 hp, resulting in a disappointing performance. Even at 230hp, the engine still proved unreliable which severely compromised performance, resulting in high operational loss rates.
The DH9 entered service in November 1917 but the type’s performance was soon regarded as being hugely inferior to that of the DH4, despite the forcast improved performance estimates to the contrary.
Based upon those estimates, a massive order had been placed for 4,630 aircraft even before the first flight. This saw existing contracts for DH4's also being converted to DH9's. The order had been largely based upon a prediction of only 'one months disruption to production' although by July 1917 it was evident that the choice of engine was causing 'serious manufacturing difficulties'.
The type’s poor operational performance on the Western Front soon resulted in it being transferred to operations in the Middle East and for coastal patrol duties in the UK, spotting U-Boats.
More than 1,300 DH9 were ordered directly from Airco with additional orders placed with Alliance; F.W. Berwick; Cubitt; Mann Egerton; National Aircraft Factory No.1 & No.2; Short Brothers; Waring & Gillow; G. & J. Weir; Westland Aircraft Works; and Whitehead Aircraft.
Despite its faillings in performance, huge numbers of DH9's actually went into service in virtually all theatres of conflict during the war. Eventually, a re-design produced the Liberty-powered DH9A (described separately) which resulted in an ultimately more successful aircraft.
A production total of 4,091 has been quoted from the 4,630 ordered and it is reported that around 800 aircraft were not fully completed, these being delivered directly to storage from late-1918 onward.
After the war, No's 47 & 221 Squadrons were deployed to Southern Russia during the Civil War, often called upon to operate in 'challenging conditions'.
The final combat mission for a DH9 was in support of 'Mad Mullah' (Mohammed Abdullah Hassan) in Somalia during 1920, where some aircaft operated as single-stretcher ambulances.
Surplus DH9s were modified for civilian use, resulting in a range of converted variants with several different engine types and various accommodation arrangements, typically for 2 (DH9B) or 3 (DH9C) passengers.
48 aircraft were purchased by the South African Air Force and saw service during the Rand Revolt in 1922.
AT&T operated a fleet of sixteen on routes from London to Amsterdam and Paris.
A number of DH9's were converted into floatplanes for use in India, Rhodesia and Bolivia whilst other were reconfigured as Trainers (and fitted with rubber undercarriages), the last of which was finally withdrawn and scrapped in 1936.
The newly formed De Havilland Aircraft Company converted a few DH9's and fitted and enclosed passenger cockpit for subsequent use in its aeroplane hire business.
These were known as the DH9B and they were initially flown with open cockpits, with later conversions having a 'cockpit enclosure' suitable for the two passengers.
The DH9C featured an enlarged enclosed cabin for three passengers, with the wings swept back to compensate for a more rearward centre of gravity. The type saw service with QANTAS in Australia where at least 15 examples of the type appeared on the civil register.
QANTAS created one unique adaptation in the form of a DH9C (G-AUFM) ‘Ion’ which featured a fuselage of DH9C dimensions with a forward three-seat cabin and an aft pilot’s cockpit (the same configuration as the DH50).
This fuselage was married to DH50 wings and was powered by a Siddeley Puma engine. It was first flown on 5th February 1927.
DH9 (G-EAQM) was the first single-engine aircraft to fly the full distance from England to Australia, leaving Hounslow on 8th January 1920 and landing at Port Darwin on 2nd August 1920. Piloted by Lt Ray 'Battling Ray' Parer, this aircraft is now preserved at the Australian National War Memorial, Canberra, Australia. The striking PD markings is in honour of the flights sponsor, whisky manufacturer Peter Dawson.
The DH9J was a version fitted, from 1926, with the Armstrong Siddeley Jaguar III radial engine.
Fourteen of these aircraft were converted and saw service with the De Havilland School of Flying, the Armstrong Whitworth Reserve School and Air Service Training until 1936.
|Powerplant||One 230 hp Siddeley Puma|
|Span||42 ft 4.6 in|
|Maximum Weight||3,790 lb (3.900 lb also quoted for civil machines)|
|Maximum Speed||113 mph|
|Capacity / armament||Pilot and gunner. Forward firing Vickers gun and observer’s Lewis gun. Two 230lb or four 112lb bombs carried under wings.|
|Range / Endurance||4.5 hr|
|4,091||From orders for 4,630; some not fully complete and delivered to store.|
|DH9||Revised version of the DH4, generally with 230hp Siddeley Puma engine|
|DH9A||Liberty engine and modified design - described separately|
|DH9B||Conversions for civilian use as three-seaters (one pilot and two passengers)|
|DH9C||Conversions for civilian use as four-seaters (one pilot and three passengers)|
|DH9J||Modernised and re-engined conversions using the AW Jaguar III radial engine. Used by the De Havilland School of Flying|
|Handley Page HP 17||Modified aircraft used to demonstrate and promote the Handley Page automatic slot system.|
|DH9J M'pala I||Re-engined conversions carried out by the SAAF. Powered by a 450hp Bristol Jupiter VI engine.|
|M'pala II||As above, with 480hp Bristol Jupiter VIII.|
|Mantis||As above, with 200hp Wolseley Viper engine|
Musée de l'Air et de l'Espace in Paris
The first single-engined aircraft to fly from the United Kingdom to Australia; Australian War Memorial at Canberra.
South African National Museum of Military History
Imperial War Museum, Duxford
(E-8894 / G-CDLI)
Recovered from India and under restoration to flying condition for Historic Aircraft Collection at Duxford