In 1916 British aircraft engineer Geoffrey de Havilland designed an airplane which was soon to be established in the history of aviation as the very best of its class. It was the famous De Havilland DH.4
The Airco D.H.4 was the Royal Flying Corps' first purpose-built day bomber, filling a role that until then had been carried out by aircraft that had been designed for other duties.
The D.H.4 was originally designed to use a 160hp Beardmore engine, but while it was under development a new engine appeared. This was the 200hp water-cooled, six-cylinder inline Beardmore-Halford-Pullinger or B.H.P. engine, designed by F. B. Halford with the support of William Beardmore and T. C. Pullinger, the head of Arrol-Johnston Ltd. of Dumfries. This new engine was roughly the same shape as the 160hp Beardmore, although it was 25cm longer, 20cm taller and 75lb heavier.
The new engine began bench tests in June 1916, at about the same time as the prototype D.H.4 was approaching completion. The aircraft was modified to take the new engine, and made its maiden flight in August 1916, with Geoffrey de Havilland at the controls.
The D.H.4 was later used to test many other engines including the 300hp Renault 12Fe, 400hp Sunbeam Matabele, 353hp Rolls-Royce G, Ricardo-Halford inverted supercharged engine and the 400hp Liberty 12.
The D.H.4 was conventional two-bay biplane, built around a fabric covered spruce and ash framework. As on a number of earlier de Havilland designs the front of the aircraft was reinforces with plywood, producing a light but strong structure. The pilot's cockpit was located under the centre section of the upper wing, below a transparent area of the wing. The D.H.4 had the same curved rudder shape as the D.H.3 and most later de Havilland aircraft.
Despite its impressive performance the original B.H.P. engine was not used in production D.H.4s. A second prototype was completed with a 250hp Rolls Royce engine, and most early Airco produced aircraft were powered by either the Rolls Royce Eagle III or Eagle IV, both providing 250hp.
Rolls Royce soon ran into production problems, and a number of alternative engines had to be used to keep up with D.H.4 production. A modified version of the B.H.P. engine was produced by J. D. Siddeley as the Siddeley Puma, but this engine also suffered from production delays and wasn't available in large numbers until 1918.
When it became clear that neither Rolls Royce nor Siddeley engines would be available Airco turned to the 200hp R.A.F.3a as an alternative. No.18 Squadron was the first to receive this version of the D.H.4, in June 1917, and it was not a great success, suffering from a series of technical problems and failures, as well as being the least powerful engine used with the D.H.4.
Yet another engine appeared later in 1917. Britain had agreed to provide 50 D.H.4s to the Russian government, to be powered by 260hp Fiat A-12 engines. When the German bombing offensive forced the British to plan for their own offensive over Germany Russia agreed to let the R.F.C. keep these aircraft on the understanding that they would be replaced in the spring of 1918.
Finally, in the summer of 1917, a suitable engine was found in the shape of the 375hp Rolls Royce Eagle VIII and by 1918 most D.H.4s in British service used this engine, which gave the aircraft a top speed of 143mph, 35mph better than Puma powered aircraft.
A total of 1,700 D.H.4s were ordered from Airco and six main sub-contractors, of which 1,449 were eventually delivered. The D.H.4 was also produced in very large numbers in the United States, where it was powered by the 400hp Liberty 12 engine.
The D.H.4 was a popular aircraft with its pilots, who appreciated its handling, its high speed and its high rate of climb, which made it very difficult for German fighters to catch it. It did have some limits – the two cockpits were too far apart, making it hard for the pilot and observer/ gunner to communicate, and the pressurised fuel system used until late in 1917 was very vulnerable to enemy fire. The risk of fire was reduced late in 1917 when a new system using two wind-driven pumps was installed.
Combat – R.F.C./ R.A.F.
No.55 was the first R.F.C. Squadron to receive the D.H.4 when its aircraft were flown out to France on 6 March 1917. The first operation came a month later, on 6 April 1917 at the start of the battle of Arras when the squadron attacked railway sidings at Valenciennes.
No.55 Squadron was one of the few R.F.C. squadrons not to suffer heavy losses during 'Bloody April', the costly aerial fighting that accompanied the battle of Arras. While most British aircraft were outclassed by the latest generation of German fighters the D.H.4 was able to use its superior speed and climb rate to escape from attack.
Two more squadrons, Nos.18 and 57, were equipped with the D.H.4 in May, No.25 Squadron got it in June and by the end of 1917 six R.F.C. squadrons were operating the D.H.4.
Production of the D.H.4 was scaled down rather prematurely. Major-General Hugh Trenchard and other supporters of the bomber offensive believed that it was obsolete by the end of 1917, and expected it to be replaced by the D.H.9. If a powerful enough engine had been available then this would have been true, but the D.H.9 was badly underpowered and when it entered service early in 1918 the D.H.9 proved to be less capable aircraft than the D.H.4. Only when it was given the American Liberty 12 engine did the new aircraft, as the D.H.9A, finally come into its own.
As a result of this by the middle of 1918 the RAF only had nine D.H.4 Squadrons available in France, of which four were former R.N.A.S. units. Another eight squadrons were based in Britain, where they were used for home defence and training.
The only significant British variant of the D.H.4 was the D.H.4A transport aircraft. This was created during the post-war Peace Conference to allow a Minister and his secretary to talk during the flight, and contained a two-man passenger cabin.
The D.H.4 was unusual in that both the R.F.C. and R.N.A.S. acquired the aircraft at about the same time. Ninety aircraft were built by Westland to Admiralty specifications, and another sixteen were transferred to the Navy from War Office orders. The purpose built Naval aircraft differed from the standard D.H.4 in having two forward firing Vickers guns and a higher mounting for the rear Scarff ring.
No.2 (Naval) Squadron at St Pol was the first to receive the D.H.4, in March-April 1917. This was a reconnaissance squadron that operated in support of naval monitors bombarding German coastal positions. On 1 April 1918 it became No.202 Squadron, R.A.F., and in this new role played an important role in the preparation for the raid on Zeebrugge of 22-23 April 1918, taking a complete set of photographs of the port.
No.5 (Naval) Squadron was next, receiving its D.H.4s at Coudekerque in late April. This squadron operated as a conventional day bomber squadron, attacking German naval targets and air fields in Belgium.
Eventually five R.N.A.S. squadrons operated the D.H.4 in Belgium and three from British Coastal Air Stations. On 5 August 1918 a D.H.4 from RNAS Coastal Station Great Yarmouth attacked and shot down a Zeppelin, variously identified as L.44 or L.70.
The Navy also operated the D.H.4 in the Aegean (four squadrons) and Italy (three squadrons) where they operated over the Balkans, as well as attacking the German cruiser Goeben.
The D.H.4 didn't remain in service for very long after the First World War. A large number of the improved D.H.9A were built towards the end of the war, and these superseded the older bomber in the post-war RAF, while the earlier D.H.9 was more popular with overseas governments. A small number of D.H.4s were distributed as Imperial Gifts, with Canada receiving twelve, New Zealand two, and South Africa and Australia both getting small amounts. The D.H.4 was also used by Belgium, Chile, Greece, Iran and Spain in small numbers, with some remaining in service until the early 1930s.
Cite: Rickard, J (31 March 2009), Airco D.H.4/4A , http://www.historyofwar.org/articles/weapons_airco_DH4.html
On August 25, 1919 an AT&T DH.4A made the first commercial flight from London to Paris. Its commercial load was only one passenger, a heap of Evening Standard newspapers, a box of Devonshire cream and some grouse. In this exotic fashion began the history of the aircraft company which nowadays is the leading name in world air travel, British Airways.
Soon such trips became regular: the DH.4A flew away from Hunslow Heath aerodrome near London, and in two and a half hours landed at Le Bourget near Paris. So began the history of commercial aviation in the skies of Europe and this very type, the DH.4A, was its foundation stone.
Commercial air transport was quite unusual for that sedate epoch, however, an awareness of the fact that speedy connections between distant centres of population would be essential in the near future, increasingly persuaded society of the need to develop commercial aviation.
In 1922 a DH.4A proved its technical quality once more, and that it possessed one of the best performances of the time it reached 124 miles an hour in the King's Cup air race and won.
With the growth of volume in air transport it became obvious, that commercial companies required newer, more comfortable airplanes, carrying more passengers and greater loads. Already in 1919 AT&T took delivery of the DH.16, a version of the DH.9, designed to carry four passengers. With its arrival the DH.4A was transferred to lesser duties and was soon was struck off as obsolete. However, this particular airplane deserves its place in aviation history as the first successful attempt to employ a winged machine to fulfil not military but entirely civil tasks.
The de Havilland DH-4 in the Smithsonian National Air and Space Museum collection was the first American-built version of Geoffrey de Havilland's famous British World War I bomber. Although the museum's specimen did not see action during the war, it was a test aircraft for what was to become America's first bomber and the only American-built aircraft to serve with the U.S. Army Air Service in the First World War.
When the United States entered the conflict on April 6, 1917, the Aviation Section of the Signal Corps did not possess any combat-worthy aircraft. So that a viable air arm could be created in the shortest possible time, a commission was established under the direction of Colonel R.C. Bolling to study current Allied aircraft designs being used at the front and to arrange for their manufacture in America.
Several European aircraft were considered, including the French Spad XIII, the Italian Caproni bomber, and the British SE-5, Bristol Fighter, and DH-4. The DH-4 was selected because of its comparatively simple construction and its apparent adaptability to mass production. It was also well-suited to the new American 400-horsepower Liberty V-12 engine. Still, considerable engineering changes from the original British design were required to apply U.S. mass production methods.
In 1916 British aircraft engineer Geoffrey de Havilland designed an airplane which was soon to be established in the history of aviation as the very best of its class. It was the famous De Havilland DH.4, a two-seat light bomber, able to execute bombing missions but also much more. During the WWI period the DH.4 was produced in large numbers by many firms and not only in Great Britain, but also in the United States of America. The DH.4 was also used as a night interceptor of Zeppelins, an artillery spotter, and some machines were modified for special high altitude long range reconnaissance.
On November 11, 1918 was signed the Armistice Treaty between the countries of the Entente and the Kaiser's Germany. The Great War was over; however, its official end would take place later, after the signing of the agreement concerning the almost complete disarmament of Germany, and the payment of reparations to the victors for their losses. This Peace Conference took place in January, 1919 in Paris and at its conclusion the League of Nations was proclaimed. The first delegation from Great Britain arrived in Paris headed by the Prime Minister, Lloyd George, and the British arrived in some style: the members of the delegation were carried in airplane.
These airplanes were DH.4A's from No. 2 Communication Squadron, a specially formed unit, equipped with this new version of the DH.4. For this purpose the Aircraft Manufacturing Co. rebuilt the DH.4 as a kind of limousine the gunner's position behind the cockpit was dismantled, and in its place in the fuselage was constructed a relatively luxurious cabin for two passengers, hidden under a special canopy. It goes without saying, that nobody thought much about the comfort of the journey; the main consideration was the speed with which passengers could be carried to their destination.
In this way the AMC engineers began to formulate the appearance of a commercial airplane. No. 2 Communication Squadron for the meanwhile conducted special missions for important public figures, and at the same time the newly created airline Aircraft Transport and Travel Limited turned their attention to the DH.4. On August 25, 1919 an AT&T DH.4A made the first commercial flight from London to Paris. Its commercial load was only one passenger, a heap of Evening Standard newspapers, a box of Devonshire cream and some grouse. In this exotic fashion began the history of the aircraft company which nowadays is the leading name in world air travel, British Airways.
Soon such trips became regular: the DH.4A flew away from Hunslow Heath aerodrome near London, and in two and a half hours landed at Le Bourget near Paris. So began the history of commercial aviation in the skies of Europe and this very type, the DH.4A, was its foundation stone. Commercial air transport was quite unusual for that sedate epoch, however, an awareness of the fact that speedy connections between distant centers of population would be essential in the near future, increasingly persuaded society of the need to develop commercial aviation. In 1922 a DH.4A proved its technical quality once more, and that it possessed one of the best performances of the time it reached 124 miles an hour in the King's Cup air race and won.
With the growth of volume in air transport it became obvious, that commercial companies required newer, more comfortable airplanes, carrying more passengers and greater loads. Already in 1919 AT&T took delivery of the DH.16, a version of the DH.9, designed to carry four passengers. With its arrival the DH.4A was transferred to lesser duties and was soon was struck off as obsolete. However, this particular airplane deserves its place in aviation history as the first successful attempt to employ a winged machine to fulfill not military but entirely civil tasks.