Airco DH.4

From Wikipedia, the free encyclopedia

The Airco DH.4 was a British two-seat biplane day-bomber of the First World War. It was a design by Geoffrey de Havilland (hence "DH") for Airco, and was the first British aircraft to be designed for a specific combat role of day-bomber. It first flew in August 1916 and entered service in early 1917.

The DH.4 was tried out with a wide variety of engines before the 375 hp Rolls-Royce Eagle engine was selected as the power plant. Armament and ordnance for the aircraft consisted of one 0.303 in Vickers machine gun for the pilot and one 0.303 in. Lewis machine gun on a Scarff ring mounting for the Observer. Two 230 lb bombs or four 112 lb bombs could be carried. The design entered service on 6 March 1917 with No. 55 Squadron RFC in France.

Contents 1 Development 2 Service 3 Production 4 Variants 5 Civil operators 6 Military operators 7 Specifications (DH.4 - Eagle VIII engine) 8 References 9 Related content

[edit] Development

The DH.4 was designed by Geoffrey de Havilland as a two seat light bomber powered by the new BHP engine. The prototype first flying in August 1916, powered by a prototype BHP engine rated at 230 hp. While the DH.4 trials were promising, the BHP engine required major redesign before entering production. It was therefore decided to fit the DH.4 with the Rolls-Royce Eagle engine, the first order for 50 DH.9s, powered by 250 hp Eagle III engines was placed at the end of 1916.

As production continued, DH.9s were fitted with Eagle engines of increasing power, settling on the 375 hp Eagle VIII, which powered the majority of front line DH.9s by the end of 1917. Alternative engines were also investigated, with the BHP (230 hp), the Royal Aircraft Factory RAF3A (200 hp), the Siddeley Puma (230 hp) and the 260 hp Fiat, all being used in production aircraft. None of these engines could match the Rolls-Royce Eagle, however.

[edit] Service

The DH.4 entered service with the RFC in January 1917, first being used by No. 55 Squadron. More squadrons were rushed into service to try and replace the heavy losses that the RFC received during Bloody April 1917, with two squadrons re-equipping in may, and a total of six squadrons by the end of the year. As well as the RFC, the RNAS also used the DH.4, both over France and over Italy and the Aegean front.

The DH.4 proved a huge success and was considered the best single-engined bomber of the First World War. With its reliability and impressive performance -even when fully loaded with bombs- the variant proved highly popular with its crews. The Airco DH.4 was easy to fly, could fly at over 100 mph and had a ceiling of 17 to 23,000 feet. German fighters were ineffective in reaching these heights and thus the DH.4 often did not require a fighter escort on missions. One design drawback was the distance between pilot and observer, caused by the fuel tank placed between the pilot and observer, making communication difficult. This mid-placed fuel tank meant that if hit by enemy fire both crew were in danger of being burnt to death. This was rectified in the otherwise inferior De Havilland DH.9.

Despite its success, numbers in service with the RFC actually started to decline from spring 1918, as production started to be switched to the DH.9, which was expected to give greater performance, but turned out to be disappointing, being inferior to the DH.4. It was left to the further developed DH.9A, with the American Liberty engine to finally replace the DH.4.

[edit] Production

Production was by Airco, F.W. Berwick and Co, Glendower Aircraft Company, Palladium Autocars, Vulcan Motor and Engineering, and the Westland Aircraft Works in the UK. SABCA of Belgium made fifteen. A total of 1449 aircraft were made in the UK for the RFC and RNAS.

In the United States, the Boeing Airplane Corporation, Dayton-Wright Aeroplane Company, The Fisher Body Corporation, and the Standard Aircraft Corporation produced the DH.4

At the time of entry into the war the American Air Service lacked any aircraft suitable for service. They therefore procured various aircraft from the British and French, one being the DH.4. As the DH.4a, it was manufactured mostly by Dayton-Wright and Fisher Body for service with the United States from 1918. The powerplant was a Liberty L-12 of 400 hp and it was fitted with two .30 inch Marlin machine guns in the nose and two .30 inch Lewis machine guns in the rear and could carry 322 pounds of bombs. The larger engine gave a better ceiling (19,600 feet) and top speed (128 mph).

[edit] Variants

• DH.4 : Two-seat day bomber biplane.
• DH-4 : Two-seat day bomber biplane. Built in the United States.
• DH.4A : Civil version. Built in the United Kingdom. Two pasengers in glazard cabin behind pilot.
• DH-4A : Civil version. Built in the United States.
• DH-4B :
• DH-4B-1 :
• DH-4BD :
• DH-4C :
• DH-4L :
• DH-4M :
• DH-4Amb :
• DH.4R : Single seat racer - 450 hp Napier Lion engine.

[edit] Civil operators

• Aircraft Transport and Travel Company
• Handley Page Transport
• Imperial Airways
• Instone Air Line Ltd
• SNETA

[edit] Military operators

• Belgium
• Canada
• Chile
• Cuba
• Greece
• New Zealand
  • New Zealand Permanent Air Force
• Persia (Iran)
• South Africa
  • South African Air Force
• Spain
• United Kingdom
  • Royal Flying Corps
  • Royal Air Force
  • Royal Naval Air Service
• United States
  • Air Service
  • U.S. Navy
  • U.S. Marine Corps

[edit] Specifications (DH.4 - Eagle VIII engine)

Data from The British Bomber since 1914^[1]

General characteristics

• Crew: 2
• Length: 30 ft 8 in (9.35 metres)
• Wingspan: 43 feet 4 inches (13.21 m)
• Height: 11 ft 0 in (3.35 m)
• Wing area: 434 ft² (40 m²)
• Empty weight: 2,387 lb (1085 kg)
• Loaded weight: 3,472 lb (1,578 kg)
• Powerplant: 1× BHP Puma or Rolls-Royce Eagle VII , 230 hp, or 375 hp (171.5 kW or 289 kW)

Performance

• Maximum speed: 143 mph (171 km/h) at sea level
• Range: 470 miles (770 km)
• Service ceiling: 22,000 ft (6,700 m)
• Rate of climb: 1,000 ft/min (305 m/min)
• Wing loading: 8 lb/ft² (39.5 kg/m²)
• Power/mass: 0.108 hp/lb (0.266 kW/kg)
• Endurance 3¾ hr
  
• Climb to 10000 ft, 9 min

Armament

• Forward firing Vickers machine gun and rear Lewis gun on Scarff ring.
  
• 460 lb (209 kg) bombs.

[edit] References

1. ^ Mason, Francis K (1994). The British Bomber since 1914. Putnam Aeronautical Books. ISBN 0 85177 861 5. 

[edit] Related content

Related development

Airco DH.9
Airco DH.9A

 

Designation sequence

• Airco DH.2 - Airco DH.4 - Airco DH.9 - Airco DH.9A - Airco DH.10