Airco DH.10 Amiens

Airco

Industry	Aerospace
Founded	1912
Fate	Acquired by BSA group after World War I
Headquarters	United Kingdom
Products	Aircraft manufacturing

The Airco DH.10 Amiens was a British twin-engine heavy bomber developed and manufactured by Airco. Notably, it was involved in the world's inaugural nighttime air mail operation on the night of 14-15 May 1919.

Conceived during the closing phase of the First World War, the DH.10 was created to fulfill the newly established Royal Air Force (RAF)'s demand for enhanced offensive bombing capabilities. Its design drew heavily from the earlier Airco DH.3, a bomber that had not advanced due to limited interest in heavy bombers at that time. The initial prototype took to the skies on 4 March 1918; however, its underwhelming performance prompted a redesign featuring more powerful engines arranged in a tractor configuration, which received better approval. At one point, orders exceeded 1,200 units.

Only a small number of DH.10s were delivered before the Armistice of 11 November 1918 ended hostilities, with just a single combat mission flown. Subsequently, the reduced necessity for bombers led to significant cuts in production and order cancellations. Despite this, over 250 examples were completed and remained in service during the interwar period, participating in conflicts such as the Third Anglo-Afghan war and supporting various air mail routes. By the early 1920s, they were superseded by more advanced bomber aircraft.

Background

The inception of the DH.10 traces back to April 1917 when the Air Board issued Specification A.2.b, which called for a new day bomber powered by either one or two engines. The specification required the aircraft to carry up to 500 lb of bombs, be armed with at least two guns accompanied by 150 lb of ammunition, and achieve a minimum speed of 110 mph at an altitude of 15,000 feet when fully loaded. Additionally, effective crew communication and the capability to remain afloat for three hours after ditching in water were mandated. In late 1917, Airco embarked on developing a response to Specification A.2.b under the leadership of aeronautical engineer Geoffrey de Havilland. The design was heavily influenced by Airco's earlier 320 hp (240 kW) DH.3A bomber from 1916, which had been rejected primarily due to inadequate engine power resulting in a slow climb rate—taking nearly an hour to reach just over 6,000 feet—rendering it unsuitable for strategic bombing missions; its competitor, the Royal Aircraft Factory F.E.4, performed even less effectively.

Compared with the DH.3, the DH.10 retained a similar overall layout but was marginally larger. It featured twin more powerful Siddeley Puma engines delivering up to 230 hp (170 kW) each arranged in a pusher configuration. Designed as a three-seat aircraft—despite the official specification calling for two crew members—this arrangement was accepted by authorities. Impressed by this design, Airco received Contract No. AS.31576 to build four prototypes.

Into flight

The initial prototype, designated C8858, completed its maiden flight on 4 March 1918. Although the inaugural flight was originally scheduled for January 1918, delays in component deliveries and labor difficulties postponed its completion. During the evaluation phase at Martlesham Heath a month later, this prototype's performance fell short of expectations, achieving only 90 mph (140 km/h) at 15,000 ft (4,600 m) while carrying the specified bomb load, compared to the required 110 mph (180 km/h). Due to these unsatisfactory results, the DH.10 underwent redesigning to incorporate more powerful engines arranged in a tractor configuration.

The second prototype, C8959, known as the Amiens Mark.II, featured two 360 hp (270 kW) Rolls-Royce Eagle VIII engines. It first flew on 20 April 1918 and underwent approximately two months of testing by Airco. Demonstrating enhanced performance, it outpaced the single-engine Airco DH.9A while carrying double the bomb load, leading the company to adopt the tractor engine layout for subsequent models. Although production of the Amiens Mark.II was hindered by Eagle engine shortages, it validated the design concept for the final aircraft. The third iteration, Amiens Mark III, represented by prototypes C8860 and C4283, was powered by the more readily accessible 395 hp (295 kW) Liberty 12 engine from the United States, similar to that used in the DH.9A.

Testing of the third prototype began in June 1918; despite sustaining damage in a crash at Martlesham Heath during that summer, it was repaired. The fourth prototype closely resembled the production model and commenced official trials in August 1918. Aviation historian J.M. Bruce notes that confidence among officials regarding the DH.10 was relatively strong at this stage. Following successful evaluations, substantial orders were placed, reaching a total of 1,291 aircraft at one point.

Production

By 22 March 1918, contracts for manufacturing had been awarded to five different firms for a combined total of 800 aircraft, even before the first prototype's evaluation was finalized. Additional contracts were issued in June and July for 475 more units from Airco, Alliance, and Mann Egerton. Production rates of the Liberty engine were lower than expected, which limited DH.10 manufacturing output and renewed interest in utilizing Rolls-Royce Eagle engines.

By late 1918, Daimler was producing DH.10s at a rate of 80 per month. Daimler was part of the BSA group, which acquired Airco after World War I and established both charter and scheduled airline services under Daimler Air Hire and Daimler Airway. Aside from Aircraft Manufacturing Company's order for 420 units, several companies received subcontracts to manufacture DH.10s; however, due to the war's end, not all contracted aircraft were completed:

• The Birmingham Carriage Company – 100
• Daimler Limited – 150
• National Aircraft Factory No.2 (Heaton Chapel) – 200
• The Siddeley-Deasy Car Company – 150
• The Alliance Aero Company – 200
• Mann, Egerton & Company – 75

By June 1920, surplus DH.10 aircraft were being offered for sale both domestically and internationally to interested buyers.

Operational history

During the initial phases of the DH.10's development, plans envisioned equipping eight squadrons of the Independent Air Force (IAF) by 1919. However, by 31 October 1918—just days before the conclusion of the war—only eight units had been delivered to the Royal Air Force, including those assigned to the IAF.

No. 104 Squadron, part of the 41st Wing within VIII Brigade, conducted a single bombing sortie on 10 November 1918, shortly before the Armistice that ended World War I took effect. In September 1918, the IAF requested increased flight endurance, prompting a swift design and installation of a 40-gallon auxiliary fuel tank by the following month. Early DH.10 operations were frequently hampered by its unconventional fuel system, which was implicated in numerous takeoff accidents; according to Bruce, fuel starvation incidents persisted as late as May 1920.

Post-war utilization of the DH.10 was somewhat limited. Several aircraft equipped No. 120 Squadron, which employed them to facilitate an air mail route supporting the British Army of Occupation on the Rhine. Notably, one DH.10 from this squadron became the first-ever aircraft to operate a nighttime air service, flying between Hawkinge and Cologne on June 14-15, 1919.

The aircraft also served with No. 97 Squadron (later redesignated as No. 60 Squadron) during its deployment in India starting in 1919. In this role, it supported military operations on the North-West Frontier, engaging in combat missions including bombing raids during the Third Anglo-Afghan war. Specifically, DH.10s carried out retaliatory strikes at locations such as Datta Khel and Abdur Rahman Khel, among other sorties. Due to high temperatures affecting performance, larger radiators were commonly installed.

Additionally, No. 216 Squadron operated DH.10s in Egypt, providing a scheduled air mail service between Cairo and Baghdad beginning on June 23, 1921; this service was discontinued in 1923. The last operational DH.10 was retained for experimental testing purposes at the Royal Aircraft Establishment (RAE) located at Farnborough Airfield, including a series of trials involving single-engine flights.

Variants

Amiens Mk.I

Prototype equipped with two Puma engines configured as pushers.

Amiens Mk.II

Prototype featuring two Rolls-Royce Eagle engines arranged in tractor configuration.

Amiens Mk.III

Primary production model powered by Liberty L-12 engines mounted centrally between wings; total of 221 constructed.

Amiens Mk.IIIA (DH.10A)

An updated Mk III with engines affixed directly to lower wings and fitted with larger wheels measuring 1.2 m (3 ft 11 in) in diameter; production count was 32.

Amiens Mk.IIIC (DH.10C)

Variant of Mk IIIA powered by Rolls-Royce Eagle engines developed due to Liberty engine shortages. Five units were built.Template:Fix/category

There was a DH.10B designation whose exact reference remains unclear; Bruce proposes it might have been a Mk III fitted with Eagle engines replacing Libertys but retaining their original mid-wing mounting. Modifications were made to one DH.10 and one DH.10C to accommodate the installation of a 37mm Coventry Ordnance Works (COW) gun, involving an extended fuselage nose and addition of nosewheels; these aircraft underwent evaluation at the armament experimental facility at Orfordness.

Military Users

Template:UK

• Royal Air Force
  • No. 24 Squadron – operated a single DH.10 for communication missions during 1920.
  • No. 27 Squadron – deployed two DH.10 aircraft for operations over the North-West Frontier in December 1922.
  • No. 51 Squadron – tested one DH.10 as a home defence fighter in 1918.
  • No. 60 Squadron – active with the type from April 1920 until April 1923.
  • No. 97 Squadron – utilized from March 1919 to April 1920.
  • No. 104 Squadron – operated between November 1918 and June 1919.
  • No. 120 Squadron – employed a single DH.10 for night air mail experiments in May 1919.
  • No. 216 Squadron – used from August 1920 through June 1922.

Civil Users

Template:UK

• Aircraft Transport and Travel Ltd was the sole operator of the DH.10 registered on the British Civil Register. The aircraft, registered as G-EAJO, conducted scheduled airmail services between Hendon and Renfrew amid the railway strike of October 1919 before being lost in an accident in April 1920.

Template:USA

• A minimum of one DH.10 was employed by the US Post Office for air mail routes spanning New York City, Cleveland, and Omaha during the year 1920.

References

Bibliography

• Jackson, A. J. British Civil Aircraft Since 1919, Volume Two. London: Putnam, Second Edition, 1973.
• Jackson A. J. De Havilland Aircraft since 1909. London: Putnam,1987.
• Jarrett, Philip. "By Day and By Night – Part Four". Aeroplane Monthly, September 1992, Vol.20 No.9, pp.13–20.
• Mason, Francis K. The British Bomber since 1914. London: Putnam Aeronautical Books,1994.
• Thetford, Owen. Aircraft of the Royal Air Force 1918–57, First Edition, London: Putnam,1957.
• Thetford, Owen."By Day and By Night – Part Five". Aeroplane Monthly, October1992, Vol.20 No.10, pp.6–11.