DH-4 De Havillands
Two-seat Biplanes for the AEF, 1918
When America entered the war, the most common aircraft type at the front was the two-seat biplane used for observation and light bomber work. Germany confronted the Allies with 1,557 two-seaters at the front on April 30, 1917, compared to 686 single-seat fighters and 71 twin-engine bombers.
Missions of these two-seaters included observation of enemy activities behind the front-lines, the direction of artillery fire, photographic reconnaissance, and daytime light bombing. Such close support aircraft had the first priority for army leaders, and the Bolling Commission chose Britain’s De Havilland 4 as the best type for production
Since the first American two-seater squadrons arrived at the front before their DH-4s, French types were used. The 1st Aero Squadron made its first mission on April 11, 1918, with Spad llA2s, and on May 8, this squadron was joined to the 12th (A.R.l) and 88th (French-built Sopwith 1A2) Aero Squadrons to become the I Corps Observation Group.
These aircraft were considered obsolete, and would be replaced in June by the Salmson 2A2. Fortunately, the Group sector was quiet, without enemy fighters, and there was no air combat in the first weeks. Corps observation missions were short-range, with each squadron assigned to support an infantry division on the ground. From dawn to dusk, single planes would fly along the trench lines, watching for enemy activity. Occasionally, the observer in the rear cockpit would take photos, or signal in Morse code to adjust the shots of divisional artillery batteries.
Observation squadrons directly attached to 1st Army headquarters were expected to make deep penetrations for photographs. The first such American squadron was the 91st, whose Salmsons made their first sorties on June 7, 1918. In September the 1st Army Observation Group was formed with the 91st and 24th Observation Squadrons, and 9th Night Observation Squadron.
A Salmson pilot sat ahead of the wings behind a radial engine water-cooled by a circular radiator; future American-made radials would all be air-cooled. Armament consisted of a Vickers gun for the pilot and a pair of Lewis flexible guns for the observer behind the wings.
The AEF in France received 705 Salmsons, which were used in combat by ten squadrons. These Salmsons had to do a lot of hard fighting to bring their information back home, usually flying in formations of three or four planes for protection against enemy fighters. During the Argonne drive, observation squadrons were credited with destroying 26 enemy planes, 17 of these being downed by the 91st Squadron’s Salmsons. Unlike later concepts of reconnaissance by single unarmed fast aircraft, 1918 missions usually expected to fight their way.
The first American bombing mission was flown by the 96th Aero Squadron against a railroad yard on June l2, 1918. They used the standard French light bomber, the Breguet 14B2 powered by the 300-hp Renault 12F with a prominent exhaust stack pointing upwards. The lower wing had full-span trailing edge flaps for landing, and the racks for 32 16-pound bombs, or their 520-pound equivalent in larger bombs.
Defensive armament comprised one fixed Vickers and two flexible Lewis guns. Forty-seven Breguet 14B2 bombers were sold to the AEF in 1918, along with 229 14A2 and 100 14E2 models mostly used for training. The Breguet 14A2 was equipped for observation work with a camera and wireless transmitter, but fewer bombs.
A second AEF Breguet squadron, the 9th with 14A2 models, was assigned to the front on August 26 for night observation work, while the 96th continued to be the only American bomber outfit until it joined with the new DH-4s of the 11th and 20th Squadrons on September 10, to form the First Day Bombardment Group. Their first mission would be bombing the German army transportation system during the St. Mihiel offensive.
The long-heralded DH-4 was the only American-built Army plane to be flown in combat in World War I, and became the most widely used American warplane of its decade. Typical of the period, it had two open cockpits, a big flat nose radiator for its water-cooled engine, wooden frame construction, and fabric-covered wings held together with four pairs of struts and numerous bracing wires. Cotton cloth replaced the scarce linen used in Britain and was made taut and waterproof by varnish called “dope” – so called because the mixtures gave off strong fumes that seemed to make workers dopey.
The DH-4 had first flown in Britain in August 1916, used a 250-hp Rolls-Royce engine when the first squadron began operations at the front in March 1917, and its performance was highly recommended to the Americans. A sample airframe, without engine or equipment, arrived in the United States on July 18, 1917, and was sent to the Aviation Section’s Technical Staff at McCook Field, Dayton, Ohio by August 15.
The Dayton-Wright Airplane Company, a new Ohio firm formed three days after war was declared, was chosen on August 14 to produce an American version. Although Orville Wright’s name as “Consulting Engineer“ was invoked, company executives were automobile industry leaders who planned to achieve rapid mass production, bypass the small aircraft manufacturers, and thereby win the major share of government aviation spending. Much publicity was given to their promises, but production of wooden airplanes requiring thousands of engineering changes had little resemblance to automobile production.
A pre-production prototype, quickly hand-built using the new 12-cylinder Liberty engine, was first flown on October 29, 1917, by Howard M. Rinehardt. While the Dayton company had been awarded a production contract on October 8, 1917, the DH-4 structural details had to be redesigned to fit American manufacturing methods and the heavier engine. No less than 10,000 DH-4s would be ordered from three companies in 1917.
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