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The Airco DH.4 is a British two-seat
biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...
day bomber of the
First World War World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
. It was designed by
Geoffrey de Havilland Captain (British Army and Royal Marines), Captain Sir Geoffrey de Havilland, (27 July 1882 – 21 May 1965) was an English aviation pioneer and aerospace engineer. De Havilland, The aircraft company he founded produced the de Havilland Mosquit ...
(hence "DH") for Airco, and was the first British two-seat light day-bomber capable of defending itself. It was designed and developed specifically as a bomber, as well as
aerial reconnaissance Aerial reconnaissance is reconnaissance for a military or Strategy, strategic purpose that is conducted using reconnaissance aircraft. The role of reconnaissance can fulfil a variety of requirements including Artillery observer, artillery spott ...
missions. The DH.4 was to have been powered by the new Beardmore Halford Pullinger (BHP) engine, but problems with that resulted in numerous other engines being used, perhaps the best of which was the Rolls-Royce Eagle engine. The DH.4 first flew in August 1916 and it entered operational service in France on 6 March 1917 less than a year later. The majority were manufactured as general purpose two-seaters in the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
for the American expeditionary forces in France, becoming the only American made plane to see combat in WW1. Following the Armistice of 11 November 1918, many DH.4s were sold to civil operators where it was found to be particularly useful as a mailplane. Early commercial passenger airplane service in Europe was initiated with modified variants of the DH-4. War-surplus DH-4s became key aircraft in newly emerging air forces throughout the world. The U.S. Army later had several companies re-manufacture its remaining DH.4s to DH.4B standard and they operated the type into the early 1930s.


Development


Origins

The DH.4 was designed by Geoffrey de Havilland as a light two-seat combat aircraft, intended to perform both day bomber and
aerial reconnaissance Aerial reconnaissance is reconnaissance for a military or Strategy, strategic purpose that is conducted using reconnaissance aircraft. The role of reconnaissance can fulfil a variety of requirements including Artillery observer, artillery spott ...
missions. The intention was for it to be powered by the newly developed Beardmore Halford Pullinger (BHP) engine. The DH.4 was developed in parallel to the rival Bristol Fighter.Bruce, 1966, p.3 During August 1916, the prototype DH.4 made its first flight, powered by a prototype BHP engine.Jackson, 1987, p.53 Initial flight tests revealed it to have favourable handling and performance. The Central Flying School (CFS) conducted early evaluation flights using the prototype, leading to it producing a favourable report on the aircraft, observing good stability in flight, light flying controls and its relatively comfortable crew positions. During its flights with the CFS, it was able to attain previously unheard-of time-to-altitude figures, unmatched by any of its predecessors. While flying trials with the prototype had been producing promising results, it soon became clear that the BHP engine would require a major redesign prior to entering production.Bruce, 1966, p.4 Even by the time of flying trials with the first prototype, there had been no finalised plans for quantity production of the BHP engine. Coincidentally, another suitable and promising aeroengine, the water-cooled Rolls-Royce Eagle in-line engine, was approaching the end of its development process. According to Bruce, the Eagle shared the same basic configuration as the BHP engine, which greatly aided in its adoption by de Havilland, as did the engine's endorsement by William Beardmore. During the summer of 1916, a second prototype, equipped with the Rolls-Royce engine, conducted its first flight. In response to its favourable performance, the
Royal Flying Corps The Royal Flying Corps (RFC) was the air arm of the British Army before and during the First World War until it merged with the Royal Naval Air Service on 1 April 1918 to form the Royal Air Force. During the early part of the war, the RFC sup ...
(RFC) decided to place an initial order for the type during late 1916. Separately to the RFC's interactions with the DH.4, it had received substantial interest from the
Royal Navy The Royal Navy (RN) is the naval warfare force of the United Kingdom. It is a component of His Majesty's Naval Service, and its officers hold their commissions from the King of the United Kingdom, King. Although warships were used by Kingdom ...
as well. The Admiralty decided to order a further pair of prototypes, configured to suit the service's own requirements, for evaluation purposes; however, according to Bruce, it is unlikely that the second of these was ever constructed. Following trials with the first of these prototypes, orders were placed for the production of DH.4s to equip the
Royal Naval Air Service The Royal Naval Air Service (RNAS) was the air arm of the Royal Navy, under the direction of the Admiralty (United Kingdom), Admiralty's Air Department, and existed formally from 1 July 1914 to 1 April 1918, when it was merged with the British ...
.Bruce, 1966, p.5


Production

During late 1916, the first order for 50 DH.4s, powered by Eagle III engines, was received from the RFC. According to Bruce, it was not a surprise to most observers that the Eagle had been selected to power the first batch of production DH.4s. The initial production aircraft were largely identical to the second prototype, the main difference being the adoption of armament, which included a single synchronised Vickers machine gun for the pilot, while the observer was provided with a Lewis gun mounted upon a Scarff ring.Bruce, 1966, pp.4–5 Production of the DH.4 was performed by a variety of companies beyond Airco themselves; these included F.W. Berwick and Co, Glendower Aircraft Company, Palladium Autocars, Vulcan Motor and Engineering, and the Westland Aircraft Works. By the end of production, a total of 1,449 aircraft (from orders for 1,700 aircraft) were constructed in Britain for the
Royal Flying Corps The Royal Flying Corps (RFC) was the air arm of the British Army before and during the First World War until it merged with the Royal Naval Air Service on 1 April 1918 to form the Royal Air Force. During the early part of the war, the RFC sup ...
(RFC) and the
Royal Naval Air Service The Royal Naval Air Service (RNAS) was the air arm of the Royal Navy, under the direction of the Admiralty (United Kingdom), Admiralty's Air Department, and existed formally from 1 July 1914 to 1 April 1918, when it was merged with the British ...
(RNAS).Jackson, 1987, p.54 Overseas, SABCA of
Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...
produced a further 15 DH.4s during 1926.Jackson, 1987, p.60 As production progressed, various changes and improvements to the design were introduced upon the DH.4. As time went on, production DH.4s were fitted with Eagle engines of increasing power, ending with the Eagle VIII, which powered the majority of frontline DH.4s by the end of 1917. However, this transition was greatly hindered as by January 1917, it had become clear that there was a chronic shortage of Rolls-Royce aero engines, and of the Eagle in particular; it has been claimed by Bruce that this shortfall was partially the result of protracted decision-making on the part of the Air Board. In response to the limited availability of the Eagle, extensive investigations into the use of alternative engines for the DH.4 were conducted. This resulted in aircraft being outfitted with a diverse range of engines; these included the BHP (, the Royal Aircraft Factory RAF3A (), the Siddeley Puma () and the
Fiat Fiat Automobiles S.p.A., commonly known as simply Fiat ( , ; ), is an Italian automobile manufacturer. It became a part of Fiat Chrysler Automobiles in 2014 and, in 2021, became a subsidiary of Stellantis through its Italian division, Stellant ...
, all of which were used to power production aircraft, with varying degrees of success. None of these engines proved to be capable of matching the performance of the Eagle engine, which remained the preferred options despite the persistent supply constraints.Bruce, 1966, pp.5–8


American versions

At the time of entry of the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
into the First World War on 6 April 1917, the aviation section of the U.S. Signal Corps was unprepared, not being equipped with any aircraft suitable for combat. However, considerable optimism and energy was put into addressing this identified need, leading to the mobilization of American industry to set about the production of contemporary combat aircraft. As there were no suitable aircraft domestically, a technical commission, known as the Bolling Commission, was dispatched to Europe to seek out the best available combat aircraft and to make arrangements to enable their production to be established in the United States.Bowers, 1966, p.3 As a result of the efforts of the Bolling Commission, the DH.4, along with the Bristol F.2 Fighter, the Royal Aircraft Factory S.E.5, and French SPAD S.XIII were selected. On 27 July 1917, a single DH.4 was sent to the United States as a pattern aircraft. It was not until 1918 that the first American-built DH.4s came off the production line.Bowers, 1966, pp.3, 10 Several different manufacturers, including the Boeing Airplane Corporation, Dayton-Wright Company, the Fisher Body Corporation, and the Standard Aircraft Corporation produced this Americanized variant of the DH.4, featuring over 1,000 modifications from the original British design, to equip the American air services.Bowers, 1966, pp.3–4 A total of 9,500 DH.4s were ordered from American manufacturers, of which 1,885 actually reached France during the war. In American production, the new Liberty engine, which had proved suitable as a DH.4 power plant, was adopted. The Liberty was also eventually adopted by the British to power the DH.9A variant of the type.Jackson, 1987, p.58Bowers, 1966, pp.6–7 After the war, a number of firms, most significant of these being
Boeing The Boeing Company, or simply Boeing (), is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, and missiles worldwide. The company also provides leasing and product support s ...
, were contracted by the U.S. Army to remanufacture surplus DH.4s to the improved DH.4B standard. Internally referred to by Boeing as the Model 16, deliveries of 111 aircraft from this manufacturer took place between March and July 1920; reportedly, roughly 50 of these were returned for further refurbishments three years later.Bowers, 1989, p.67Bowers, 1966, pp.7–8 During 1923, the Army placed an order for a new DH.4 variant from Boeing, distinguished by a fuselage of fabric-covered steel tube in place of the original plywood structure.Bowers, 1966, p.9 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. A total of 22 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 O2B-1 for the base model, and O2B-2 for aircraft equipped for night and cross-country flying.Bowers, 1989, p.70


Design

The Airco DH.4 was a conventional tractor two bay biplane of all-wooden construction. It was entirely built of traditional materials. The forward fuselage section and the underside of the tail area was covered by a 3mm plywood skin; this construction led to the fuselage being both strong and lightweight, heavily contributing to cross-bracing only being used for the four bays directly behind the rear cockpit. The nose of the aircraft was considerably longer than necessary, the cowling having been originally designed to accommodate the Beardmore Halford Pullinger (BHP) engine, rather than the Rolls-Royce Eagle that was adopted for production instead. The DH.4 was powered by a variety of engines, including the Eagle, the BHP, the American
Liberty Liberty is the state of being free within society from oppressive restrictions imposed by authority on one's way of life, behavior, or political views. The concept of liberty can vary depending on perspective and context. In the Constitutional ...
, Royal Aircraft Factory RAF3A, the Siddeley Puma and the
Fiat Fiat Automobiles S.p.A., commonly known as simply Fiat ( , ; ), is an Italian automobile manufacturer. It became a part of Fiat Chrysler Automobiles in 2014 and, in 2021, became a subsidiary of Stellantis through its Italian division, Stellant ...
. Regardless of the engine used, it drove a four-bladed
propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...
mounted upon the nose. Cooling for the engine was provided via an oval-shaped radiator, while a port-mounted exhaust manifold discarded waste emissions above the upper wing. An unusual modification featuring on a small proportion of production DH.4s was the inversion of the engine, a design change that had been implemented in order to better accommodate the relatively-tall Ricardo-Halford-Armstrong (RHA)
supercharged In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. It is a form of forced induction that is mechanically powered (usually by ...
engine, which would otherwise unduly obstruct the pilot's forward field of view. The DH.4 was operated by a crew of two, who were accommodated in widely spaced cockpits, between which the fuel tank was positioned. While the crew arrangement provided good fields of view for both the pilot and observer; however, it had the noticeable downside of causing communication problems between the two crew members, particularly during combat situations, where the speaking tube that linked the two cockpits was of only limited use.Bruce, 1952, p.507Bruce, 1966, pp.3–4 On the majority of American-built aircraft, the pilot's seating and fuel tank arrangement were switched around; aviation author Peter M Bowers credits this change with improving the pilot's safety in the event of a crash, as well as allowing for better communication with the observer.Bowers, 1966, p.7 The DH.4 was armed with a single forward-firing synchronised Vickers machine gun along with either one or two Lewis guns fitted on a Scarff ring fired by the observer. In terms of bomb load, it accommodate a maximum payload of , which could be mounted upon external racks. Throughout the type's production life, a number of alterations to the armaments, such as the ergonomics of the observer's Lewis gun and the installation of an additional Vickers gun, were implemented. A pair of DH.4s were outfitted with COW 37 mm guns for experimental purposes, but the war came to a close prior to firing trials being conducted. All armaments would typically be removed from those DH.4s that were used by civil operators, including ex-military aircraft that were sold on in great numbers following the end of the Great War. One of the more elaborate modifications of the DH.4 was the adaptation of the type as a seaplane. It was furnished with large floats, which were allegedly based upon the design of those used upon the German Hansa-Brandenburg W.29 seaplane. According to Bruce, while no such aircraft entered into operational service as a result of competition from other aircraft to perform the role, a number of DH.4 seaplanes were produced for trial purposes at
Felixstowe Felixstowe ( ) is a port town and civil parish in the East Suffolk District, East Suffolk district, in the county of Suffolk, England. The estimated population in 2017 was 24,521. The Port of Felixstowe is the largest Containerization, containe ...
and were successfully flown.Bruce, 1966, p.10


Operational history


British military service

The DH.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.Bruce, 1966, p.9 During late 1917, the uptake of the type by the RFC was accelerated due to a desire to launch retaliatory bombing raids upon Germany following such attacks having been conducted against the British mainland. While
Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
had been an early customer for the DH.4, having ordered 50 of the type in September 1917, the Russian and British governments subsequently agreed to delay the former's deliveries, instead diverting those aircraft to RFC squadrons in France.Bruce, 1966, pp.7–8 As well as the RFC, the RNAS also used the DH.4. During the spring of 1917, No. 2 Squadron became the first unit of the service to receive examples of the type. The RNAS flew their DH.4s over both
France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
and over
Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...
, specifically the Aegean front in the latter case. The DH.4 was typically used to conduct coastal patrols by the RNAS. One such flight, crewed by the pilot Major Egbert Cadbury and Captain Robert Leckie (later Air Vice-Marshal) as gunner, shot down
Zeppelin A Zeppelin is a type of rigid airship named after the German inventor Ferdinand von Zeppelin () who pioneered rigid airship development at the beginning of the 20th century. Zeppelin's notions were first formulated in 1874Eckener 1938, pp. 155� ...
''L70'' on 5 August 1918.Thetford 1978, p.86 In another incident, a group of four RNAS DH.4s were jointly credited with the sinking of the German
U-boat U-boats are Submarine#Military, naval submarines operated by Germany, including during the World War I, First and Second World Wars. The term is an Anglicization#Loanwords, anglicized form of the German word , a shortening of (), though the G ...
''UB 12'' on 19 August 1918.Bruce, 1966, pp.9–10 The DH.4 proved a huge success and was often considered the best single-engined bomber of World War I. Even when fully loaded with bombs, with its reliability and impressive performance, 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,Jackson, 1987, pp.54–56 so that the DH.4 often did not require a fighter escort on missions, a concept furthered by
de Havilland The de Havilland Aircraft Company Limited (pronounced , ) was a British aviation manufacturer established in late 1920 by Geoffrey de Havilland at Stag Lane Aerodrome Edgware on the outskirts of North London. Operations were later moved to ...
in the later
Mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...
of the Second World War. A drawback of the design was the distance between pilot and observer, as they were separated by the large main fuel tank. This made communication between the crew members difficult, especially in combat with enemy fighters.Jackson, 1987, p.56 There was also some controversy (especially in American service) that this placement of the fuel tank was inherently unsafe.Maurer, 1979, pp.12, 87, 120, 132Bowers, 1966, pp.5–6 In fact, most contemporary aircraft were prone to catching fire in the air. The fire hazard was reduced, however, when the pressurised fuel system was replaced by one using wind-driven fuel pumps late in 1917, although this was not initially adopted by American-built aircraft.Maurer, 1979, p.551 The otherwise inferior DH.9 brought the pilot and observer closer together by placing the fuel tank in the usual place, between the pilot and the engine. Despite its success, numbers in service with the RFC actually started to decline from spring 1918, mainly due to a shortage of engines, and production switched to the DH.9, which turned out to be disappointing, being inferior to the DH.4 in most respects. It was left to the further developed DH.9A, with the American Liberty engine, to satisfactorily replace the DH.4. When the Independent Air Force was set up in June 1918 to carry out strategic bombing of targets in
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
, the DH.4s of 55 Squadron formed part of it, being used for daylight attacks. 55 Squadron developed tactics of flying in wedge formations, bombing on the leader's command and with the massed defensive fire of the formation deterring attacks by enemy fighters.Williams, 1999, p.84 Despite heavy losses, 55 Squadron continued in operation, the only one of the day bombing squadrons in the Independent Force which did not have to temporarily stand down owing to aircrew losses.Williams, 1999, p.195 After the
Armistice An armistice is a formal agreement of warring parties to stop fighting. It is not necessarily the end of a war, as it may constitute only a cessation of hostilities while an attempt is made to negotiate a lasting peace. It is derived from t ...
, the RAF formed No. 2 Communication Squadron, equipped with DH.4s to carry important passengers to and from the Paris Peace Conference. Several of the DH.4s used for this purpose were modified with an enclosed cabin for two passengers at the request of
Bonar Law Andrew Bonar Law (; 16 September 1858 – 30 October 1923) was a British statesman and politician who was Prime Minister of the United Kingdom from October 1922 to May 1923. Law was born in the British colony of New Brunswick (now a Canadi ...
.Jackson, 1987, p.77 One of these planes was extensively used by Prime Minister David Lloyd George and was sometimes called ''Lloyd George's airplane'' - probably the first aeroplane widely used by a political leader. Modified aircraft were designated DH.4A, with at least seven being converted for the RAF, and a further nine for civil use.Jackson, 1987, p.81


United States military service

At the time of its entry into the war, the United States Army Air Service lacked any aircraft suitable for front line combat. It therefore procured various aircraft from the British and French, one being the DH.4. As the DH-4, it was manufactured mostly by Dayton-Wright and Fisher Body for service with the United States from 1918, the first American built DH-4 being delivered to France in May 1918, with combat operations commencing in August 1918."Fact Sheets: De Havilland DH-4."
''National Museum of the USAF''. Retrieved: 19 April 2008.
Bowers, 1966, p.6 The powerplant was a Liberty L-12 and it was fitted with two forward-firing synchronized Marlin-Rockwell M1917 (a development of the Colt-Browning) machine guns in the nose and two Lewis guns in the rear and could carry of bombs. it could also be equipped with various radios like the SCR-68 for artillery spotting missions. The heavier engine reduced performance compared with the Rolls-Royce powered version, but as the "Liberty Plane" it became the US Army Air Service standard general purpose two-seater, and on the whole was fairly popular with its crews. Aircrew operating the DH-4 were awarded four of the six Medals of Honor awarded to American aviators.
First Lieutenant First lieutenant is a commissioned officer military rank in many armed forces; in some forces, it is an appointment. The rank of lieutenant has different meanings in different military formations, but in most forces it is sub-divided into a se ...
Harold Ernest Goettler and Second Lieutenant Erwin R. Bleckley received posthumous awards after being killed on 12 October 1918 attempting to drop supplies to the Lost Battalion of the 77th Division, cut off by German troops during the Meuse-Argonne Offensive; while Second Lieutenant Ralph Talbot and Gunnery Sergeant Robert G. Robinson of the
United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines or simply the Marines, is the maritime land force service branch of the United States Department of Defense. It is responsible for conducting expeditionar ...
(USMC) were awarded the Medal of Honor for beating off attacks from 12 German fighters during a bombing raid over Belgium on 8 October 1918."The De Havilland DH-4, Workhorse of the Army Air Service."
''Air & Space Power Journal'', Winter 2002. Retrieved: 9 May 2008.
The type flew with 13 U.S. squadrons by the end of 1918.Angelucci, 1981, p.79 Following the end of the First World War, America had a large surplus of DH-4s, with the improved DH-4B becoming available, although none had been shipped to France. It was therefore decided that there was no point in returning aircraft across the Atlantic, so those remaining in France, together with other obsolete observation and trainer aircraft, were burned in what became known as the "Billion Dollar Bonfire".Swanborough and Bowers, 1963, p.198 With limited funds available to develop and purchase replacements, the remaining DH-4s formed a major part of American air strength for several years, used for many roles, with as many as 60 variants produced.Bruce, 1952, p.510 DH-4s were also widely used for experimental flying, being used as engine testbeds and fitted with new wings. They were used for the first trials of air-to-air refueling on 27 June 1923, and one carried out an endurance flight of 37 hours, 15 minutes on 27–28 August, being refueled 16 times and setting 16 new world records for distance, speed and duration. The DH-4 remained in service with the
United States Army Air Corps The United States Army Air Corps (USAAC) was the aerial warfare service component of the United States Army between 1926 and 1941. After World War I, as early aviation became an increasingly important part of modern warfare, a philosophical ri ...
, successor to the United States Army Air Service, until 1932.Swanborough and Bowers, 1963, p.199 A large number of DH-4s were also used by the
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
and United States Marine Corps, both during the First World War and postwar. The Navy and Marine Corps received a total of 51 DH-4s during wartime, followed by 172 DH-4B and DH-4B-1 aircraft postwar and 30 DH-4M-1s with welded steel-tube fuselages (redesignated O2B) in 1925.Swanborough and Bowers, 1976, p.156 They remained in service with the Marine Corps until 1929, being used against rebel factions in
Nicaragua Nicaragua, officially the Republic of Nicaragua, is the geographically largest Sovereign state, country in Central America, comprising . With a population of 7,142,529 as of 2024, it is the third-most populous country in Central America aft ...
in 1927, carrying out the first dive-bombing attacks made by U.S. military forces. The U.S. Navy converted some DH-4M-1s into primitive air ambulances that could carry one stretcher casualty in an enclosed area behind the pilot.


Civil use

Following the end of the First World War, large numbers of DH.4s and DH.4As were used to operate scheduled passenger services in Europe by such airlines as
Aircraft Transport and Travel Aircraft Transport and Travel Limited, also known as AT&T was a British airline formed during the First World War, a subsidiary of Airco. It was the first airline to operate a regular international flight (between London and Paris). It is the ...
, Handley Page Transport and the Belgium airline SNETA. ''G-EAJC'' of Aircraft Transport and Travel flew the first British commercial passenger service from Hounslow Heath Aerodrome to Paris Le Bourget on 25 August 1919, carrying a reporter from the ''
Evening Standard The ''London Standard'', formerly the ''Evening Standard'' (1904–2024) and originally ''The Standard'' (1827–1904), is a long-established regional newspaper published weekly and distributed free newspaper, free of charge in London, Engl ...
'' newspaper and a load of newspapers and other freight.Jackson, 1973, p.41Jackson, 1987, p.79 They were used by Aircraft Transport and Travel until it shut down in 1920, while Handley Page Transport and SNETA continued operating the DH.4 until 1921. One aircraft was used by Instone Air Lines until its merger into Imperial Airways in 1924.Jackson, 1973, p.43 On September 4, 1922, Jimmy Doolittle made the first cross-country flight, flying a de Havilland DH-4 – which was equipped with early navigational instruments – from Pablo Beach (now Jacksonville Beach), Florida, to Rockwell Field, San Diego, California, in 21 hours and 19 minutes, making only one refueling stop at Kelly Field. The DH.4 were also used by the
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
n airline
QANTAS Qantas ( ), formally Qantas Airways Limited, is the flag carrier of Australia, and the largest airline by fleet size, international flights, and international destinations in Australia and List of largest airlines in Oceania, Oceania. A foundi ...
, flying its first airmail service in 1922.Jackson, 1973, p.40 Twelve DH.4s forming part of the Imperial Gift to
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
were used for forestry patrol and survey work, spotting hundreds of forest fires and helping to save millions of dollars worth of timber, with the last example finally being withdrawn in 1927.Jackson, 1973, pp.70–71 The U.S. Post Office also adopted the DH-4 to carry air mail.Bowers, 1966, pp.9–10 The Service acquired 100 of them from the army in 1918, and retrofitted them to make them safer, denominating them as the DH.4B. In 1919, the DH-4B was standardised by the US Post Office, being modified to be flown from the rear cockpit with a watertight mail compartment replacing the forward cockpit. The airmail DH-4B were later modified with revised landing gear and an enlarged
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...
.Swanborough and Bowers, 1963, p.201 DH-4s were used to establish a coast-to-coast, transcontinental airmail service, between San Francisco and New York, a distance of , involving night flight, the first services starting on 21 August 1924. The DH-4 continued in Post Office service until 1927, when the last airmail routes were passed to private contractors.Bowers, 1966, p.10 War-surplus DH-4s were available cheaply in sufficient quantities to stimulate the development of "utility aviation": surveying, commercial photography, law enforcement, agricultural applications and other practical applications."General Aviation,"
in "History of Flight", ''Britannica'', retrieved May 29, 2021


Variants


UK variants

* DH.4 : Two-seat day bomber biplane. * DH.4A : Transport version. Built in the United Kingdom. Two passengers in glazed cabin behind pilot. * DH.4R : Single seat racer –
Napier Lion The Napier Lion is a 12-cylinder, petrol-fueled 'broad arrow' W12 engine, W12 configuration aircraft engine built by D. Napier & Son from 1917 until the 1930s. A number of advanced features made it the most powerful engine of its day and kept ...
engine.


Soviet variants

* copy of DH.4 manufactured by Polikarpov in the former Dux Factory in the 1920s


United States variants

Jackson, 1987, p.67 * DH-4 : Two-seat day bomber biplane, built in the United States. * DH-4A : Civil version, built in the United States. * DH-4B : Rebuilt version of Liberty powered DH-4 for U.S. Air Service. Pilot's cockpit relocated to behind fuel tank, adjacent to observer's cockpit. *** DH-4B-1 : Increased fuel capacity (). *** DH-4B-2 : Trainer version. *** DH-4B-3 : Fitted with fuel tank *** DH-4B-4 : Civil version *** DH-4B-5 : Experimental civil conversion with enclosed cabin. ** DH-4BD :Cropdusting version of DH-4B ** DH-4BG : Fitted with smokescreen generators ** DH-4BK : Night flying version ** DH-4BM: Single seat version for communications *** DH-4BM-1 : Dual control version of BM *** DH-4BM-2 : Dual control version of BM ** DH-4-BP : Experimental photo reconnaissance version *** DH-4-BP-1 : BP converted for survey work ** DH-4BS : Testbed for supercharged Liberty ** DH-4BT : Dual control trainer ** DH-4BW : Testbed for Wright H engine * DH-4C : Packard engine * DH-4L : Civil version * DH-4M : Rebuilt version of DH-4 with steel tube fuselage. * DH-4Amb : Ambulance. * 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 * L.W.F. J-2 – Twin-engine long range development of DH-4 (also known as Twin DH), powered by two Hall-Scott- Liberty L-6 engines and with wingspan of ; 20 built for U.S. Post Office, 10 for U.S. Army.Swanborough and Bowers, 1963, pp.202–203 ; XCO-7 : (Boeing Model 42) Two-seat observation version with Boeing designed wings, enlarged tailplane and divided landing gear. ;XCO-8 :Was a designation of one Atlantic DH.4M-2 fitted with Loening COA-1 wings and powered by a Liberty 12A engine.


Operators


Civil operators

; * The River Plate Aviation Co. Ltd. ; *
QANTAS Qantas ( ), formally Qantas Airways Limited, is the flag carrier of Australia, and the largest airline by fleet size, international flights, and international destinations in Australia and List of largest airlines in Oceania, Oceania. A foundi ...
; * SNETA ;: * Aircraft Transport and Travel Limited * Handley Page Transport * Imperial Airways * Instone Air Line ; * U.S. Post Office


Military operators

; * Aviation Militaire Belge ; * Canadian Air Force (1918–1920) * Royal Canadian Air Force ; *
Chilean Air Force The Chilean Air Force () is the air force of Chile and branch of the Chilean military. History The first step towards the current FACh is taken by Lieutenant Colonel, Teniente Coronel training as a pilot in France. Although a local academy was c ...
; * Cuban Air Force – American built DH-4s ; * Hellenic Air Force * Hellenic Navy ; * Imperial Iranian Air Force ; * Fuerza Aérea Mexicana ; * Nicaraguan Air Force – The Nicaragua Air Force received seven DH-4Bs. ; *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 on 27 November 1919. ; *
South African Air Force The South African Air Force (SAAF) is the air warfare branch of South African National Defence Force, with its headquarters in Pretoria. The South African Air Force was established on 1 February 1920. The Air Force saw service in World War II a ...
; * Soviet Air Force ;
Kingdom of Spain Spain, or the Kingdom of Spain, is a country in Southern Europe, Southern and Western Europe with territories in North Africa. Featuring the Punta de Tarifa, southernmost point of continental Europe, it is the largest country in Southern Eur ...
* Spanish Air Force ; * Turkish Air Force ; *
Royal Flying Corps The Royal Flying Corps (RFC) was the air arm of the British Army before and during the First World War until it merged with the Royal Naval Air Service on 1 April 1918 to form the Royal Air Force. During the early part of the war, the RFC sup ...
*
Royal Air Force The Royal Air Force (RAF) is the Air force, air and space force of the United Kingdom, British Overseas Territories and Crown Dependencies. It was formed towards the end of the World War I, First World War on 1 April 1918, on the merger of t ...
*
Royal Naval Air Service The Royal Naval Air Service (RNAS) was the air arm of the Royal Navy, under the direction of the Admiralty (United Kingdom), Admiralty's Air Department, and existed formally from 1 July 1914 to 1 April 1918, when it was merged with the British ...
; * United States Army Air Service ** 8th Aero Squadron ** 11th Aero Squadron ** 20th Aero Squadron ** 50th Aero Squadron ** 85th Aero Squadron ** 91st Aero Squadron ** 104th Aero Squadron ** 135th Aero Squadron ** 163rd Aero Squadron ** 166th Aero Squadron ** 168th Aero Squadron ** 278th Aero Squadron ** 354th Aero Squadron *
United States Navy The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...
*
United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines or simply the Marines, is the maritime land force service branch of the United States Department of Defense. It is responsible for conducting expeditionar ...


Surviving aircraft

DH-4: * 21959 – The prototype American-built DH-4 is on display at the National Air and Space Museum in Washington D.C. * Unknown ID – A DH-4 is on display at the National Museum of the Marine Corps in Triangle, Virginia. It was restored by Century Aviation. * 32517 - A DH-4 is currently being reconstructed so it can be permanently displayed at the Wichita Dwight D. Eisenhower National Airport in
Wichita, Kansas Wichita ( ) is the List of cities in Kansas, most populous city in the U.S. state of Kansas and the county seat of Sedgwick County, Kansas, Sedgwick County. As of the 2020 United States census, 2020 census, the population of the city was 397, ...
. It will commemorate
United States Army The United States Army (USA) is the primary Land warfare, land service branch of the United States Department of Defense. It is designated as the Army of the United States in the United States Constitution.Article II, section 2, clause 1 of th ...
aviator An aircraft pilot or aviator is a person who controls the flight of an aircraft by operating its directional flight controls. Some other aircrew members, such as navigators or flight engineers, are also considered aviators because they a ...
Erwin R. Bleckley, who was
killed in action Killed in action (KIA) is a casualty classification generally used by militaries to describe the deaths of their personnel at the hands of enemy or hostile forces at the moment of action. The United States Department of Defense, for example, ...
during
World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
while flying a DH-4 near the "lost battalion" in France. * Unknown ID – A DH-4 is on display at the Omaka Aviation Heritage Centre in Blenheim, New Zealand. This aircraft was previously on display at the Crawford Auto-Aviation Museum in
Cleveland, Ohio Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County, Ohio, Cuyahoga County. Located along the southern shore of Lake Erie, it is situated across the Canada–United States border, Canada–U.S. maritime border ...
and was at one point loaned to the United States Air Force Museum. * Replica – A DH.4 is airworthy with The Vintage Aviator Limited in Masterton, New Zealand. It was built by Century Aviation and is powered by a rebuilt Liberty V-12. * Replica – A DH-4 is on display at the Museo del Aire in
Madrid, Spain Madrid ( ; ) is the capital and List of largest cities in Spain, most populous municipality of Spain. It has almost 3.5 million inhabitants and a Madrid metropolitan area, metropolitan area population of approximately 7 million. It i ...
. DH-4B: * Unknown ID – A DH-4B is on display in the main atrium of the National Postal Museum in Washington, D.C. * Unknown ID – A DH-4B at the Pearson Air Museum in
Vancouver, Washington Vancouver ( ) is a city on the north bank of the Columbia River in the U.S. state of Washington (state), Washington, located in Clark County, Washington, Clark County. Founded in 1825 and incorporated in 1857, Vancouver had a population of 190, ...
. It was restored by Century Aviation. * Unknown ID – A DH-4B is on display at the National Museum of the United States Air Force in
Dayton, Ohio Dayton () is a city in Montgomery County, Ohio, United States, and its county seat. It is the List of cities in Ohio, sixth-most populous city in Ohio, with a population of 137,644 at the 2020 United States census, 2020 census. The Dayton metro ...
. It was restored by Century Aviation. * Unknown ID – A DH-4B is on display at Fantasy of Flight in Polk City, Florida. It was restored by Century Aviation. * Unknown ID – A DH-4B is under restoration by Century Aviation for Fantasy of Flight in Polk City, Florida. It will be powered by a rebuilt Liberty V-12. DH-4M-1 * Unknown ID – A DH-4M-1 is on display at the Evergreen Aviation and Space Museum in
McMinnville, Oregon McMinnville is the county seat of and the most populous city in Yamhill County, Oregon, Yamhill County, Oregon, United States at the base of the Oregon Coast Range. The city is named after McMinnville, Tennessee. As of the 2020 United States cens ...
. This aircraft was previously owned by Paul Mantz. DH-4M-2A * Unknown ID – A DH-4M-2A is airworthy at the Historic Aircraft Restoration Museum in Maryland Heights, Missouri.


Specifications (DH.4 – Eagle VIII engine)


See also


References


Notes


Citations


Bibliography

*Angelucci, Enzo, ed. ''World Encyclopedia of Military Aircraft''. London: Jane's, 1991. . *Bruce, J.M
"The De Havilland D.H.4."
''Flight'', 17 October 1952, pp. 506–510. *Bruce, J.M. ''The de Havilland D.H.4. (Aircraft in Profile number 26)''. London: Profile Publications, 1966. No ISBN. *Bowers, Peter M. ''Boeing Aircraft since 1916''. London: Putnam, Second edition, 1989. . *Bowers, Peter M. ''The American DH.4 (Aircraft in Profile number 97)''. London: Profile Publications, 1966. No ISBN. *Jackson, A.J. ''British Civil Aircraft since 1919: Volume 2''. London: Putnam, Second edition, 1973. . *Jackson, A.J. ''De Havilland Aircraft since 1909''. London: Putnam, Third edition, 1987. . * *Mason, Francis K. ''The British Bomber since 1914''. London: Putnam Aeronautical Books, 1994. . *Maurer, Maurer, ed. ''The U.S. Air Service in World War I: Volume IV Postwar Review''. Washington, D.C.: The Office of Air Force History Headquarters USAF, 1979. * *Sturtivant, Ray and Gordon Page. ''The D.H.4/D.H.9 File''. Tonbridge, Kent, UK: Air-Britain (Historians) Ltd., 2000. . *Swanborough, F.G. and Peter M. Bowers. ''United States Military Aircraft since 1909''. London: Putnam, 1963. *Swanborough Gordon and Peter M. Bowers. ''United States Naval Aircraft since 1911''. London: Putnam, Second edition, 1976. . *Thetford, Owen. ''British Naval Aircraft since 1912''. London: Putnam, Fourth edition, 1978. . *Thomas, Andrew. "In the Footsteps of Daedulus: Early Greek Naval Aviation". ''Air Enthusiast'', No. 94, July–August 2001, pp. 8–9. *''United States Air Force Museum Guidebook''. Wright-Patterson AFB, Ohio: Air Force Museum Foundation, 1975. * * Williams, George K. ''Biplanes and Bombsights: British Bombing in World War I''. Maxwell Air Force Base, Alabama: Air University Press, 1999. .


External links


"Pilot Report, The deHavilland DH4: A Trip Back In Time,"
by Addison Pemberton

in ''Eight Great Aircraft,'' by Richard Harris. {{DEFAULTSORT:Airco DH.004 DH.004 1910s British bomber aircraft Single-engined tractor aircraft Biplanes Boeing aircraft Atlantic Aircraft aircraft Aircraft first flown in 1916 L-W-F aircraft Aircraft with fixed conventional landing gear Single-engined piston aircraft