When Britain committed to World War 1 (1914-1918) it held a stable of just 113 aircraft and six airships. This undoubtedly grew as the war quickly progressed and, by the end of it all, a myriad of designs had appeared and production of these units collectively totaled in the tens of thousands - such was the impact of the war on the local aero-industry.
Martinsyde, founded in 1908 by H.P. Martin and George Handasyde, made a name for itself in both aviation and motorcycle fields - the latter following only after the war in 1919. Early aircraft developments included a racer (the No.3) and a single-seat scout platform (the S.1). In the fall of 1915, as the war raged on, the Martinsyde G.100 was flown for the first time with an Austro-Daimler 120 horsepower engine. It was adopted by the Royal Flying Corps (RFC) of Britain and the Australian Flying Corps (AFC) thereafter.
The G.100 was developed along the lines of single-seat fighter / escort aircraft. A biplane wing configuration, with parallel struts and twin bays, was used. The undercarriage was fixed and wheeled in the traditional way for the period and the pilot sat in an open-air cockpit under and aft of the upper wing assembly. The tail was conventional and featured a single vertical fin with mid-set horizontal planes. The engine, mounted in the nose, drove a two-bladed wooden propeller.
The G.100 initial production forms were fitted a Beardmore 6-cylinder engine of 120 horsepower. Armament was 1 x 0.303 Lewis Gun machine gun installed on the upper wing unit to clear the spinning propeller blades and the bombload totaled 260lb of externally-held stores. Total production of the mark was 100 aircraft. A second Lewis Gun was added only later and this set behind the cockpit along the portside fuselage (behind the pilot's left shoulder) - intended to fire rearwards as trailing, intercepting enemy aircraft. Performance included a maximum speed of 95 miles per hour, a range out to 450 miles and a service ceiling of 14,000 feet.
The G.100 began arriving in number for the summer of 1916 - it was named the "Elephant" by its operators because of its large size and lack of agility for a single-seat platform. This led to the RFC re-categorizing it as a light daytime bomber when the aircraft's limited usefulness as a fighter was realized. The deficiencies in the G.100 design led Martinsyde to develop the G.102 fitted with Beardmore engines of 160 horsepower. These, too, were taken into service with 171 delivered.
Despite not succeeding in its original fighter / escort role, the G-series did find some success as a light bomber owing to its good inherent operational range. It saw service into late-1917 before being overcome by more capable types. Squadron No.1 of the AFC operated the G-series in Egypt and Palestine while some fifteen RFC squadrons were formed with the type.