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Aircraft Manufacturing Company Ltd / Airco DH 4 / O2B-1

Aeromarine DH-4B

 

dh4


The two-seat D.H.4 was designed as a fast day bomber, with a conven-tional two-bay biplane fuselage of wood and fabric structure incor-porating two open cockpits, its forward fuselage having plywood skins. The braced tail unit had an adjustable tail-plane, to enable the pilot to trim the aircraft in flight, and landing gear was of fixed tailwheel type.


During the period when design of the D.H.4 was being finalised, a new engine was designed and constructed. Designated B.H.P. and rated at 172kW (230 hp), the prototype engine was installed in the prototype D.H.4, and early flight testing began in August 1916. Fifty were ordered in the summer of 1916, before the prototype had flown.


Considerable delays occurred in getting the B.H.P. into production but an alternative powerplant, rated at 186 kW (250 hp), became available from Rolls-Royce. This engine was to become known as the Eagle. The 250-hp Rolls-Royce IIIs or IVs (later known as Eagles) were fitted to production aircraft.


Production aircraft included improvements introduced by the second prototype, including a ring mounting for the observer's Lewis gun in the rear cockpit; a forward-firing Vickers gun, with a Constantinesco synchronizing gear, was fitted in front for the pilot. Some RNAS D.H.4s had twin Vickers and an elevated Scariff ring for the Lewis. The maximum bombload was two 104-kg (230-lb), four 51-kg (112-lb) or an equivalent weight of smaller bombs.


When the 280-kW (375-hp) Eagle VIII became available, D.H.4s with this engine were superior in performance to most of the contemporary fighter aircraft.


Equipping initially the RFCs No. 55 Squadron in March 1917 (making its first operational sortie in France in April), the D.H.4 was operating 11 squadrons of the RFC or RNAS and 13 American squadrons by the late spring of 1918. The type also served with the Royal Naval Air Service (combined with the RFC to form the RAF on 1 April 1918) for coastal patrol, and was used to equip home defence squadrons.


Two were fitted out experimentally with extra fuel tanks, enough to give 14 hours' flying, and were intended to carry out a special photographic reconnaissance of shipping in the Kiel Canal. This mission never took place, but the two D.H.4s were later fitted instead with twin over-wing Lewis guns and used for night fighting.


The DH4 was withdrawn from RAF service soon after the Armistice, and in the early postwar years many were supplied to the air forces of Belgium (where SABCA also built a small number), Canada, Chile, Greece, Persia, New Zealand, South Africa and Spain. Some remained in service until the early 1930s, and others were converted for civil use in the 1920s.

 

Airco-DH4-01

 

Production in Britain totalled 1450, built by by Airco and under sub-contract by F.W. Berwick and Company, Glendower Aircraft Company, Palladium Autocars Ltd, The Vulcan Motor and Engineering Company, Waring & Gillow Ltd, and the Westland Aircraft Works. At the end of the First World War 548 were still in service.


Rolls-Royce engine production could not keep pace with this, resulting in several batches of D.H.4s being fitted with such alternative powerplants. Other than the Rolls-Royce III, IV or Eagle, these included the 149-kW (200-hp) R.A.F.3a, 172-kW (230-hp) Siddeley Puma, Adriatic (200-hp), and 194-kW (260-hp) Fiat A-12.

 

Experimental engine installations included a 224-kW (300-hp) Renault l2Fe, 239-kW (320-hp) Armstrong Siddeley Jaguar I, 263-kW (353-hp) Rolls-Royce ‘G’, 298-kW (400-hp; Sunbeam Matabele, and a Ricardo-Halford supercharged engine. lncreasing engine powers required larger diameter propellers, steadily reducing clearance between the propeller tip and the ground, and resulted in the main landing gear units being extended sufficiently to cater for future growth.


Highest performance was achieved with the Rolls-Royce Eagle VIII (375-hp), which gave the D.H.4 a top speed of 230 km/h (143 mph).


Armament of the standard D.H.4s consisted of a fixed forward-firing Vickers machine-gun that was synchronised by a Constantinesco interrupter gear; the observer/gunner had one or two Lewis guns mounted on a Scarff ring. Underfuselage and underwing bomb racks had a maximum capacity of 209 kg (4601b). Aircraft built by Westland Aircraft for the RNAS had twin Vickers machine-guns for the pilot, and the rear Lewis guns were on a pillar mounting. Two examples of the D.H.4 were modified to mount a Coventry Ordnance works (C.O.W.) quick-firing gun, which fired a 0.68-kg (1.5-lb) shell. Mounted to fire almost vertically upward, this gun as intended for attacks on German Zeppelins; but by the time they were ready for service, Zeppelin raids on Britain had ended.


The United States possessed no combat-worthy aircraft upon entry into World War I in 1917 and selected the DH-4 because of its comparatively simple construction and it was well-suited to the 400-horsepower Liberty V-12 engine.


In the summer of 1917 a pattern aircraft had been fitted with a 400-hp Liberty 12 engine and the US government ordered more than 12,000 'Liberty Planes', although 7502 were cancelled after the Armistice. A total of 4846 were completed by Dayton-Wright (3106), Fisher Body Division of General Motors (1600) and Standard Aircraft Corporation (140) before production ceased at the war’s end in 1918.


By war's end, 13 Army Air Service squadrons, five of them bomber squadrons, were equipped with them (from August 1918). In addition, four combined Navy-Marine squadrons of the US Naval Northern Bombing Group were flying DH-4s along the Belgian coast. Of the 4,346 DH-4s built in the United States, 1,213 were delivered to France, but of those only 696 reached the Zone of Advance. In the postwar period, the DH-4 was the principal aircraft used by the U.S. Government when airmail service began in 1918.

 

Airco-DH4a
DH.4a, 1919

 

The Americans designated the initial version the DH4A, but it was obsolescent by the time it entered US service, having had to be reworked to suit it to US production techniques, and the improved DH-4B was ready too late (October 1918) to take its place on the Western Front. American-built DH-4As were armed with two Marlin or Browning machine-guns in the front and two Lewis guns in the rear cockpit, and could carry up to 150 kg (332 lb) of bombs. After the war, 283 of the Army's DH-4As were transferred to the US Navy or Marine Corps as observation or transport planes until 1932.

 

dh4b
DH.4B

After the war a building and conversion programme (of more than 1500 DH4As) kept the DH4B, DH-4M (for Modernized) and other later variants in US service until 1932.
 
Airco-DH4B
DH4B

 

The DH4B rectified a fault of the original D.H.4 by relocating the main fuel tank (previously between the two cockpits) in front of the pilot's cockpit. Boeing built 150 DH4Ms for the US Army and 30 O2B-1s for the Marines; Fokker Atlantic Aircraft built 135 DH-4Ms.

 

Aeromarine converted 125 DH-4B under contract for de Havilland, first flown in 1917. One Aeromarine DH-4B conversion example was specially tested at Wright Field. Possibly same as Whitbeck Special.

 

 Aerom-DH4
Aeromarine DH-4B


The NASM collection has the prototype American-built DH-4, manufactured by the Dayton-Wright Airplane Company. This airplane was used in more than 2,600 experiments until its retirement in April 1919. It was also the airplane in which Orville Wright made his last flight as a pilot in 1918.


The career of the D.H.4 was to continue long After the Armistice of 1918, war surplus examples went to the Belgian, Greek, Japanese, and Spanish air forces, with American-built machines continuing to serve with the United States Army Air Corps and with many Latin American countries. In 1924 the Mexican government procured a number of US-built D.H.4B bombers. Large num-bers of varants appeared in the USA during the early post-war years, these being conversions of ex-military aircraft, and many pioneering flights were made wth them. Two USAAC DH-4Bs were used in the first successfu experiments of inflight refuelling.

 

The D.H.4 was not limited to military applications in these early years of peace, and in the UK it was the earliest type to be used as a civil transport by Holt Thomas’ Aircraft Transport & Travel Ltd for the first cross-Channel service between London and Paris. For peace celebrations in Paris, special flights were made between London and Paris during Jul. In August the regular service opened when Lt. E.H.Lawford left Hounslow carrying one passenger, a package of newspapers, a supply of leather, several brace of grouse, and some jars of Devonshire cream.
 
Lt. Lawford landed at Le Bourget, Paris, and set out for the return flight to Hounslow one hour later. The 216 miles between London and Paris were covered by the DH.4a in two hours 30 minutes on the outward journey and two hours five minutes on the return. The fare for a single journey was twenty guineas. A.T.&T. advertised one flight in each direction each day. In the first month, only two of the fifty-six flights were cancelled.
 
It was also used by Handley Page Transport Ltd and the Belgian airline SNETA. In the USA, a number, acquired by the US Post Office Department in 1919 and converted as mailplanes, remained in use until 1927. Canada, which received 12 of the aircraft as an ‘Imperial Gift’ from Britain, used them for spotting forest fires.

 

airco-dh9-2
 
 
 

Variants:
Airco D.H.4A
Designation of British post-war civil conversions with an enclosed two-seat passenger cabin formed from the aft cockpit

DH-4A
Designation of US-built version with revised and increased capacity fuel system.

DH-4B/-4C/-4L/-4M/-4Amb/-4Ard
Blanket desgnation covering a large numner of US post-aver variants; for example, DH-4B varianns included DH-4B, DH 4B-1, DH-4BD etc., to the extent of some 60 versions, many of them experimental.

Airco D.H.4R
Designation of a singe racing version converted by clipping the lower wings and installing a 336 kW (450-hp) Naper Lion inline piston engine

Specifications:

Airco D.H.4
Engine: BHP, 200 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2197 lb / 996 kg
Loaded weight: 3386 lb / 1535 kg
Max speed: 108 mph / 173 kph
Ceiling: 17,500 ft / 5334 m
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
Airco D.H.4
Engine: Siddeley Puma, 230 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2230 lb / 1011 kg
Loaded weight: 3344 lb / 1516 kg
Max speed: 106 mph / 171 kph
Ceiling: 17,400 ft / 5324m
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
Airco D.H.4
Engine: Galloway Adriatic, 230 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2209 lb / 1002 kg
Loaded weight: 3641 lb / 1651 kg
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
Airco D.H.4
Engine: RAF 3A, 200 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2304 lb / 1044 kg
Loaded weight: 3340 lb / 1515 kg
Max speed: 122 mph / 196 kph
Ceiling: 18,500 ft / 5638 m
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
Airco D.H.4
Engine: Fiat A.12, 260 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2306 lb / 1045 kg
Loaded weight: 3360 lb / 1524 kg
Max speed: 114 mph / 183 kph
Ceiling: 17, 000 ft / 5181 m
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
D.H.4
Engine: Liberty 12
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2391 lb / 1084 kg
Loaded weight: 3297 lb / 1949 kg
Max speed: 124 mph / 199 kph
Ceiling: 17,500 ft / 5334 m
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
Airco D.H.4
Engine: Rolls-Royce Mk. I, II, II, 250 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
Airco D.H.4
Engine: Rolls-Royce Mk. I, II, 275 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2303 lb / 1044 kg
Loaded weight: 3313 lb / 1502 kg
Max speed: 119 mph / 191 kph
Endurance: 3 – 4.5 hr
Armament: 2 x .303 Lewis mg
Bombload: 2 x 230 lb or 4 x 112 lb
 
DH.4
Engine: Rolls Royce Eagle III, 250 hp
Length: 30.7 ft / 9.23 m
Wing span: 42.3ft / 12.9m
Weight empty: 2,303 lb / 1,044 kg
Gross weight: 1503 kg / 3313 lb
Max speed: 119 mph / 190 kph
Ceiling: 16,000 ft / 4,900 m
Seats: 2
Armament (Standard version): One fixed machine gun firing forward
One or two free guns in the rear cockpit.
Armament (R.N.A.S. aircraft): Two fixed machine guns firing forward
One or two free guns in the rear cockpit
Max. bomb; load 460 lb / 210 kg
 
DH.4
Engine: 1 x 250hp Rolls-Royce Eagle VI inline engine
Wingspan: 12.92 m / 42 ft 5 in
Length: 9.35 m / 30 ft 8 in
Height: 3.35 m / 10 ft 11 in
Empty Weight: 2,392lbs (1,085kg)
Max take-off weight: 1575 kg / 3472 lb
Max. speed: 230 km/h / 143 mph / 124kt
Maximum Range: 478miles / 770km
Rate-of-Climb: 1,000ft/min (305m/min)
Ceiling: 6705 m / 22000 ft
Crew: 2
Armament: 2 x 7.62mm Vickers machine-guns, 209kg of bombs
Maximum External Bomb Load: 460 lbs
 
Airco D.H.4
Engine: Rolls-Royce Eagle VIII, 280 kW / 375 hp
Wingspan: 42 ft 4.5 in / 12.9 m
Wing area: 40.32 m / 434 sq.ft
Length: 30 ft 8 in / 9.3 m
Height: 10 ft 1 in / 3.0 m
Empty weight: 2387 lb / 1082 kg
Loaded weight: 3472 lb / 1574 kg
Max speed: 143 mph / 230 kph
Service ceiling: 6705 m / 22,000 ft
Climb to 1830m / 6,000 ft: 4 minutes 50 sec
Endurance: 3 hours 45 min
Armament: one (RFC) or two (RNAS) fixed forward-frng 7.7 mm (0.303-in) Vickers machine-guns and one or two 7.7-mm 1(.303-in) Lewis gone in aft cockpit.
Bombload: 2 x 230 lb or 4 x 112 lb
 
Airco D.H.4R
Engine: Naper Lion 336 kW / 450-hp
Maximum level speed: 241 km/h / 150 mph
Empty weight: 1129 kg / 2490 lb
Maximum take off weight: 1447 kg / 3,191 lb
Length: 8.36 m / 27 ft 5in
De Havilland DH-4B
Manufacturer: Dayton-Wright Airplane Co.
Engine: Liberty V-12 water-cooled, 400-hp
Wingspan: 13.0 m / 42 ft 8 in
Length: 9.3 m / 30 ft 5 in
Height: 3.2 m / 10 ft 6 in
Empty weight: 1,087 kg / 2,391 lb
Gross weight: 1,953 kg / 4,297 lb
Seats: 2
Armament: two 7.62 mm (0.3 in) Marlin forward firing machine-guns
Airframe: Wood
Covering: Fabric

 

dh-4-ld

 


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