<p>A product of the Royal Aircraft Factory at Farnborough, Hampshire, England, the S.E.5 single-seat fighter was designed by H. P. Folland. The first production aircraft were delivered to the Royal Flying Corp's No. 56 Squadron on 13 March 1917 and, less than a month later, on 7 April, the squadron had moved to France. Of what was then typical biplane configuration with tailskid-type landing gear, the S.E.5 was powered by a new 150-hp (112-kW) Hispano-Suiza V-8 piston engine. The improved S.E.5a which followed soon after had detail airframe revisions and a more powerful version of the Hispano-Suiza engine driving a four-bladed propeller. From June 1917 they began to replace the S.E.5s with No. 56 Squadron. Unfortunately, it took some time for both the engine and the Constantinesco interrupter gear to settle down to a reasonable standard of reliability, a state not achieved until the early months of 1918. Even before that time, however, the S.E.5a had begun to gain an enviable reputation for its capability as a dogfighter in the hands of such well known aces as Major Edward ('Mick') Mannock and Captain J. T. B. McCudden.
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<p>With the arrival in France on 5 June 1917 of the US Army's First Aeronautic Detachment, the process began of procuring from the Allies suitable combat aircraft to equip what was to become a growing American force. The capability of the S.E.5a ensured that this aircraft was numbered among procurement plans, although only 38 were acquired from the British government for service in France (with units that included Nos 17, 25 and 148 Aero Squadrons). The S.E.5a was chosen by the Bolling Commission for mass production in the United States, and the Curtiss Aeroplane and Motor Company was contracted to produce 1,000. Only one of these was built (serial no. 43153) before the Armistice brought cancellation of the remainder. Subsequently, Curtiss modified and assembled 57 S.E.5a airframes received from the UK. These, plus the surviving S.E.5a aircraft that the AEF squadrons brought back to the USA after the Armistice, provided the nation's first-line pursuit force until indigenous fighters became available at the beginning of the 1920s. In 1923, 50 of these aircraft were rebuilt by the Eberhart Aeroplane & Motor Company to become redesignated SE-5E. In the process they acquired a plywood-covered fuselage structure and more power in the form of a Wright E engine, which was a licence-built version of the 180-hp (134-kW) Hispano-Suiza.
<item><hi format=bold>Powerplant:</hi> one 200-hp (149-kW) Hispano-Suiza V-8 piston engine
<item><hi format=bold>Performance:</hi> maximum speed 138 mph (222 km/h) at sea level; service ceiling 19,500 ft (5,945 m); endurance 3 hours
<item><hi format=bold>Weights:</hi> empty 1,400 lb (635 kg); maximum take-off 1,955 lb (887 kg)
<item><hi format=bold>Dimensions:</hi> span 26 ft 7.5 in (8.12 m); length 20 ft 11 in (6.38 m); height 9 ft 6 in (2.9 m); wing area 244 sq ft (22.67 m<su>2</su>)
<item><hi format=bold>Armament:</hi> one fixed forward-firing Vickers 0.303-in (7.7-mm) synchronized machine gun on the port upper forward fuselage, and one 0.303-in (7.7-mm) Lewis gun on a Foster mounting above the upper wing center-section
