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Airco DH.4
| Airco DH.4 | |
|---|---|
| An early production DH.4 | |
| Type | Biplane Light Bomber/General Purpose |
| Manufacturer | Airco |
| Maiden flight | August 1916 |
| Primary users | RFC (RAF) American Air Service RNAS |
| Number built | 1,449 in UK - at least 1,885 in USA |
| Variants | DH9, DH9A, Dayton-Wright Cabin Cruiser |
The Airco DH.4 was a British two-seat biplane day-bomber of the First World War. It was designed by Geoffrey de Havilland (hence "DH") for Airco, and was the first British two seat light day-bomber to have an effective defensive armament. It first flew in August 1916 and entered service with the Royal Flying Corps (RFC) in March 1917. The majority of DH.4s were actually built as general purpose two seaters in the USA, for service with the American forces in France.
The DH.4 was tried with several engines, of which the best was the 375 hp Rolls-Royce Eagle engine. 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 DH.4 entered service on 6 March 1917 with No. 55 Squadron in France.
Contents
Design and development
The DH.4 was designed by Geoffrey de Havilland as a two-seat day (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.4s, powered by 250 hp Eagle III engines was placed at the end of 1916.
As production continued, DH.4s were fitted with Eagle engines of increasing power, settling on the 375 hp Eagle VIII, which powered the majority of front line DH.4s by the end of 1917. Because of the chronic shortage of Rolls-Royce aero engines in general, and Eagles in particular, 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 there were simply not enough Eagles available.
In American production, the DH.4 proved suitable for the new Liberty engine - although this produced a slightly inferior performance to the Eagle it was also to eventually power the British DH.9A.
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 1,449 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 with the Liberty L-12 engine for the American air services. A total of 9,500 DH.4s were ordered from American builders, of which 1,885 actually reached France during the war.
After the war a number of firms, most significantly Boeing, were contracted by the US Army to re-manufacture surplus DH.4s to DH.4B standard. Known by Boeing as the Model 16, deliveries of 111 aircraft from this manufacturer took place between March and July 1920, with 50 of them returned for further refurbishments three years later.[1]
In 1923, the Army ordered a new DH.4 variant from Boeing, characterised by a fuselage of fabric-covered steel tube in place of the original plywood structure. These three prototypes were designated DH-4M-1 (M for modernized) and were ordered into production alongside the generally similar DH-4M-2 developed by Atlantic Aircraft. Twenty-two of the 163 DH-4M-1s were converted by the Army into dual-control trainers (DH-4M-1T) and a few more into target tugs (DH-4M-1K). Thirty of the aircraft ordered by the Army were diverted to the Navy for Marine Corps use, these designated 02B-1 for the base model, and O2B-2 for aircraft equipped for night and cross-country flying.[2]
Operational history
The D.H.4 entered service with the RFC in January 1917, first being used by No. 55 Squadron. More squadrons were equipped with the type to increase the bombing capacity of the RFC, 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 D.H.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 type proved highly popular with its crews. The Airco DH.4 was easy to fly, and especially when fitted with the Rolls-Royce Eagle engine, its speed and altitude performance gave it a good deal of invulnerability to German fighter interception, so that the D.H.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 between the crew members difficult. There was some controversy (especially in American service) that this placement of the fuel tank was inherently unsafe. In fact most contemporary aircraft were prone to catching fire in the air. In any case the arrangement of fuel tank and cockpits was rectified in the otherwise inferior D.H.9.
Despite its success, numbers in service with the RFC actually started to decline from spring 1918, mainly due to a shortage of motors, and production switched to the D.H.9, which turned out to be disappointing, being inferior to the D.H.4 in most respects. It was left to the further developed D.H.9A, with the American Liberty engine, to satisfactorily replace the D.H.4.
At the time of entry into the war the American Air Service lacked any aircraft suitable for front line war service. They therefore procured various aircraft from the British and French, one being the D.H.4. As the D.H.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 heavier engine reduced performance a little compared with the Rolls Royce powered version, but as the "Liberty Plane" it became the Americans' standard general purpose two seater, and on the whole was fairly popular with its crews. The type flew with 13 U.S. squadrons by the end of 1918.
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 passengers in glazed cabin behind pilot.
- DH-4A : Civil version. Built in the United States.
- DH-4B : Rebuilt version of Liberty powered DH-4 for United States Army. Pilot's cockpit relocated to behind fuel tank, adjacent to observer's cockpit.
- DH-4B-1 :
- DH-4BD :
- DH-4C :
- DH-4L :
- DH-4M : Rebuilt version of DH-4 with steel tube fuselage.
- DH-4Amb :
- DH.4R : Single seat racer - 450 hp Napier Lion engine.
- DH-4M-1 - postwar version by Boeing (Model 16) with new fuselage, designated O2B-1 by Navy
- DH-4M-1T - Dual control trainer conversion of DH-4M
- DH-4M-1K - target tug conversion
- O2B-2 - cross-country and night-flying conversion for Navy
- DH-4M-2 - postwar version by Atlantic
Operators
Civil operators
Military operators
- The New Zealand Permanent Air Force operated two aircraft from 1919 to 1929. It was used by the NZPAF as an advanced training aircraft. The DH.4 has the distinction of being the first aircraft to fly over Mount Cook on 8 September 1920. It also set a New Zealand altitude record of 21,000 ft (6,400 m) on 27 November 1919.
Specifications (DH.4 - Eagle VIII engine)
Data from The British Bomber since 1914[3]
General characteristics
- Crew: 2
- Length: 30 ft 8 in (9.35 m)
- Wingspan: 43 feet 4 in (13.21 m)
- Height: 11 ft (3.35 m)
- Wing area: 434 ft² (40 m²)
- Empty weight: 2,387 lb (1,085 kg)
- Loaded weight: 3,472 lb (1,578 kg)
- Powerplant: 1× Rolls-Royce Eagle VII inline liquid cooled piston, 375 hp (or 230 hp (171.5 kW) for BHP Puma) (289 kW)
Performance
- Maximum speed: 143 mph (106 mph for Puma) (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 10,000 ft: 9 min
Armament
See also
Related development
Airco DH.9 - Airco DH.9A
Lists relating to aviation | |
|---|---|
| General | Timeline of aviation · Aircraft · Aircraft manufacturers · Aircraft engines · Aircraft engine manufacturers · Airports · Airlines |
| Military | Air forces · Aircraft weapons · Missiles · Unmanned aerial vehicles (UAVs) · Experimental aircraft |
| Notable incidents and accidents | Military aviation · Airliners · General aviation · Famous aviation-related deaths |
| Records | Flight airspeed record · Flight distance record · Flight altitude record · Flight endurance record · Most produced aircraft |
References
Notes
Bibliography
- Bowers, Peter M. Boeing Aircraft since 1916. London: Putnam, Second edition, 1989. ISBN 0-85177-804-6.
- Mason, Francis K. The British Bomber since 1914. London: Putnam Aeronautical Books, 1994. ISBN 0-85177-861-5.
- Sturtivant, Ray and Page, Gordon. The D.H.4/D.H.9 File. Tunbridge Wells, Kent, UK: Air-Britain (Historians) Ltd., 2000. ISBN 0-85130-274-2.
External links
Template:USN observation aircraft Template:De Havilland aircraft Template:Boeing model numbers
Lists relating to aviation | |
|---|---|
| General | Timeline of aviation · Aircraft · Aircraft manufacturers · Aircraft engines · Aircraft engine manufacturers · Airports · Airlines |
| Military | Air forces · Aircraft weapons · Missiles · Unmanned aerial vehicles (UAVs) · Experimental aircraft |
| Notable incidents and accidents | Military aviation · Airliners · General aviation · Famous aviation-related deaths |
| Records | Flight airspeed record · Flight distance record · Flight altitude record · Flight endurance record · Most produced aircraft |
cs:Airco D.H.4 de:Airco D.H.4 es:Airco DH.4 fr:Airco DH.4 pl:Airco DH.4 pt:Airco DH.4
| This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Airco DH.4". |
