64-462: DH4 may refer to: Airco DH.4 , British World War I two-seat biplane de Lackner HZ-1 Aerocycle , also known as the YHO-2 and DH-4 Heli-Vector (1950s) Bombardier Dash 8 Q400, turboprop passenger airliner (since 1996, called DH4 by various airlines) [REDACTED] Topics referred to by the same term This disambiguation page lists articles associated with
128-553: A Handley Page O/100 bomber in December 1915, the first flight of a Rolls-Royce aero engine. The Eagle was developed further during 1916 and 1917, with power being progressively increased from 225 hp (168 kW) to 266 hp (198 kW), followed by 284 hp (212 kW), and then 322 hp (240 kW), and finally 360 hp (270 kW) by February 1918 by which time eight Eagle variants had been produced. Throughout World War I Rolls-Royce struggled to build Eagles in
192-697: 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. After the war, a number of firms, most significant of these being Boeing , 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. During 1923,
256-457: A coast-to-coast, transcontinental airmail service, between San Francisco and New York, a distance of 2,680 mi (4,310 km), 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. War-surplus DH-4s were available cheaply in sufficient quantities to stimulate
320-516: 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 . 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
384-479: A group of four RNAS DH.4s were jointly credited with the sinking of the German U-boat UB 12 on 19 August 1918. 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
448-688: A second prototype, equipped with the Rolls-Royce engine, conducted its first flight. In response to its favourable performance, the Royal Flying Corps (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 as well. The Admiralty decided to order a further pair of prototypes, configured to suit
512-575: Is 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 capable of defending itself. It was designed and developed specifically as a bomber , as well as aerial reconnaissance missions. The DH.4 was to have been powered by the new 160 hp (120 kW) Beardmore Halford Pullinger (BHP) engine, but problems with that resulted in numerous other engines being used, perhaps
576-592: 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
640-549: The Australian airline QANTAS , flying its first airmail service in 1922. Twelve DH.4s forming part of the Imperial Gift to Canada 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. The U.S. Post Office also adopted the DH-4 to carry air mail. The Service acquired 100 of them from
704-610: 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. 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
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#1732894143260768-648: 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 (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 type flew with 13 U.S. squadrons by
832-504: 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 . 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
896-775: 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 , Royal Aircraft Factory RAF3A , the Siddeley Puma and the Fiat . Regardless of the engine used, it drove a four-bladed propeller 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
960-473: The Royal Flying Corps (RFC) and the Royal Naval Air Service (RNAS). Overseas, SABCA of Belgium produced a further 15 DH.4s during 1926. 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 375 hp (280 kW) Eagle VIII, which powered
1024-463: The Royal Naval Air Service (RNAS) played a key role in the success of the engine by directing the car designer W.O. Bentley , who had enlisted in the Royal Navy , to place his expertise in the design of aluminium pistons at the service of Rolls-Royce. This gave significant weight saving to the Eagle and contributed to its excellent performance. On 3 January 1915 the Admiralty ordered twenty-five of
1088-734: The United States Army Air Corps , successor to the United States Army Air Service, until 1932. A large number of DH-4s were also used by the United States Navy 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. They remained in service with
1152-564: The transatlantic flight of Alcock and Brown in June 1919. At the outbreak of World War I in August 1914, the Royal Aircraft Factory asked Rolls-Royce to develop a new 200 hp (150 kW) air-cooled engine. Despite initial reluctance, they agreed, on condition that it be cooled by water rather than by air, which was the company's area of expertise. Development of the new 20 litre engine
1216-638: The "Billion Dollar Bonfire". 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. 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
1280-476: The 40/50. The engine was also run faster, and an epicyclic reduction gear was designed to keep the propeller speed below 1,100 rpm. To reduce inertia and improve performance the valvetrain design was changed from sidevalves to a SOHC design, closely following the original "side-slot" rocker arm design philosophy used on the contemporary German Mercedes D.I , Mercedes D.II and Mercedes D.III straight-six aviation powerplants. The engineering department of
1344-444: 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. 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
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#17328941432601408-402: 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,
1472-543: 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 newspaper and a load of newspapers and other freight. They were used by Aircraft Transport and Travel until it shut down in 1920, while Handley Page Transport and SNETA continued operating
1536-659: 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. Several different manufacturers, including the Boeing Airplane Corporation , Dayton-Wright Company ,
1600-466: 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. Even by the time of flying trials with the first prototype, there had been no finalised plans for quantity production of
1664-580: 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 , 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
1728-485: The DH.4 until 1921. One aircraft was used by Instone Air Lines until its merger into Imperial Airways in 1924. 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
1792-594: 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 (230 hp (170 kW), the Royal Aircraft Factory RAF3A (200 hp (150 kW)), the Siddeley Puma (230 hp (170 kW)) and the 260 hp (190 kW) Fiat , all of which were used to power production aircraft, with varying degrees of success. None of these engines proved to be capable of matching
1856-634: The Marine Corps until 1929, being used against rebel factions in Nicaragua 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. 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 , Handley Page Transport and
1920-598: The Ministry of Munitions took over coordination of aircraft production in 1917, Sir William Weir declined to intervene in the company's commercial strategy, even though success of the engine owed much to the technology transfer directed by the RNAS. He preferred to support untested engines using cast aluminium components like the Siddeley Puma and the Sunbeam Arab , believing them to be better suited to mass production, in comparison to
1984-728: The RAF, and a further nine for civil use. 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. The powerplant
DH4 - Misplaced Pages Continue
2048-677: 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 and over Italy , 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 L70 on 5 August 1918. In another incident,
2112-402: 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 0.303 in (7.7 mm) Vickers machine gun for the pilot, while the observer
2176-567: The Rolls-Royce Eagle engine, its speed and altitude performance gave it a good deal of invulnerability to German fighter interception, so that the DH.4 often did not require a fighter escort on missions, a concept furthered by de Havilland in the later Mosquito 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
2240-535: 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 Harold Ernest Goettler and Second Lieutenant Erwin R. Bleckley received posthumous awards after being killed on 12 October 1918 attempting to drop supplies to
2304-516: 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 400 lb (180 kg) watertight mail compartment replacing the forward cockpit. The airmail DH-4B were later modified with revised landing gear and an enlarged rudder . DH-4s were used to establish
2368-555: The best of which was the 375 hp (280 kW) 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 for the American expeditionary forces in France, becoming the only American made plane to see combat in WW1. Following
2432-423: The crew members difficult, especially in combat with enemy fighters. There was also 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. 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
2496-427: The development of "utility aviation": surveying, commercial photography, law enforcement, agricultural applications and other practical applications. DH-4: DH-4B: DH-4M-1 DH-4M-2A Data from The British Bomber since 1914 , The de Havilland DH.4 General characteristics Performance Armament Related development Related lists Rolls-Royce Eagle The Rolls-Royce Eagle
2560-457: The end of 1918. 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
2624-523: The end of the Great War. One of the more elaborate modifications of the DH.4 was the adaption 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
DH4 - Misplaced Pages Continue
2688-521: 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 situation, where the speaking tube that linked the two cockpits was of only limited use. 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
2752-497: The intricate machining required to build the Eagle and its smaller cousin the Falcon . After the War, a Mark IX version of the Eagle was developed for civilian use. Production continued until 1928, and in total 4,681 Eagle engines were built. Time between overhaul (TBO) for later Eagles was around 100–180 hours. Note: Examples of the Rolls-Royce Eagle are on display at the: One of
2816-500: The leader's command and with the massed defensive fire of the formation deterring attacks by enemy fighters. 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. After the Armistice , the RAF formed No. 2 Communication Squadron , equipped with DH.4s to carry important passengers to and from
2880-464: 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
2944-399: 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. As a result of the efforts of
3008-502: The new engines. The Eagle first ran on a test bed at Rolls-Royce's Derby works in February 1915, producing 225 hp (168 kW) at 1,600 rpm. This was quickly increased to 1,800, then in August 1915 to 2,000 rpm where it produced 300 hp (220 kW). After further testing, it was decided to approve the engine for production at 1,800 rpm and 225 hp (168 kW); 1,900 rpm was allowed for short periods. The engine first flew on
3072-427: The performance of the Eagle engine, which remained the preferred options despite the persistent supply constraints. At the time of entry of the United States 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
3136-453: The pilot's safety in the event of a crash, as well as allowing for better communication with the observer. The DH.4 was armed with a single forward-firing synchronised Vickers machine gun along with either one or two .303 in (7.7 mm) Lewis guns fitted on a Scarff ring fired by the observer. In terms of bomb load, it accommodate a maximum payload of 460 lb (210 kg), which could be mounted upon external racks. Throughout
3200-464: The prototype DH.4 made its first flight, powered by a prototype 230 hp (170 kW) BHP engine. 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
3264-516: The quantities required by the War Office , but the company resisted pressure to license other manufacturers to produce it. The fears of Rolls-Royce that the engine's much admired quality would be compromised by other manufacturers is often given as an explanation for this resistance, but the commercial terms sought by Rolls-Royce for licence production were so restrictive that other manufacturers - apart from Brazil Straker - refused to accept them. When
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#17328941432603328-463: The role, a number of DH.4 seaplanes were produced for trial purposes at Felixstowe and were successfully flown. 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. During late 1917,
3392-513: The same title formed as a letter–number combination. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=DH4&oldid=818347234 " Category : Letter–number combination disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Airco DH.4 The Airco DH.4
3456-412: 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 . During late 1916, the first order for 50 DH.4s, powered by 250 hp (190 kW) Eagle III engines, was received from
3520-413: The type into the early 1930s. 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 missions. The intention was for it to be powered by the newly developed 160 hp (120 kW) Beardmore Halford Pullinger (BHP) engine. The DH.4 was developed in parallel to the rival Bristol Fighter . During August 1916,
3584-508: 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
3648-500: 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
3712-452: 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 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
3776-561: 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 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. As well as
3840-583: Was a 400 hp (300 kW) Liberty L-12 and it was fitted with two forward-firing .30 in (7.62 mm) synchronized Marlin-Rockwell M1917 (a development of the Colt-Browning ) machine guns in the nose and two .30 in (7.62 mm) Lewis guns in the rear and could carry 322 lb (146 kg) 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
3904-488: Was led by Henry Royce from his home in Kent . Based initially on the 7.4 litre 40/50 Rolls-Royce Silver Ghost engine, and drawing also on the design of a 7.2 litre Daimler DF80 aero engine used in a 1913 Grand Prix Mercedes that had been acquired, the power was increased by doubling the number of cylinders to twelve and increasing their stroke to 6.5 inches (170 mm), although their bore remained at 4.5 inches (110 mm) of
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#17328941432603968-441: Was not initially adopted by American-built aircraft. 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
4032-562: Was provided with a 0.303 in (7.7 mm) Lewis gun mounted upon a Scarff ring . 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
4096-462: Was the first aircraft engine to be developed by Rolls-Royce Limited . Introduced in 1915 to meet British military requirements during World War I , it was used to power the Handley Page Type O bombers and a number of other military aircraft. The Eagle was the first engine to make a non-stop trans-Atlantic crossing by aeroplane when two Eagles powered the converted Vickers Vimy bomber on
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