period of time due to a shortage of available aircraft. Some 57 S.A-2s and S.A-4s went to the Imperial Russian Air Service. During winter operations, Russian aircraft were fitted with skis instead of wheels. Although Russian crews also thought very little of the SPAD (not made any better by the acronym SPAD (СПАД) in Russian meaning "slump" or "plummet"), at least two crews achieved successes with it. On November 25, 1916, Russian pilot Karpov and his gunner, Bratolyubov Jurij Aleksandrovich, claimed a German aircraft near the village of Vulka. At least one example survived to be used briefly by the Soviet Union before they retired all obsolete types. Variants SPAD S.A-1 – initial production variant with 80 hp Le Rhône 9C engine and tapered tailplane – 11 built. SPAD S.A-2 – main production variant with constant chord tailplane and 110 hp Le Rhône 9J. – 35 built SPAD S.A-3 – dual-control trainer, with both pilot and observer being given flexible gun mounts – two built with 110 hp Le Rhône 9J. SPAD S.A-4 – an improved A.2 with a less powerful 80-hp Le Rhône 9C engine. – 59 built. SPAD S.D – slightly larger aircraft with an additional gunner position behind pilot, powered by a 220-hp Renault 8Fg engine – one built SPAD S.G – S.A with observer replaced by guns mounted in the nacelle – one built and one modified. SPAD S.H – unbuilt development without pulpit, precursor to SPAD S.V (5), which was SPAD S.VII prototype Operators French Air Force Imperial Russian Air Service Workers' and Peasants' Air Fleet Specifications (S.A-2) See also References Bibliography External links Essais du SPAD SAL (in French) 1910s French fighter aircraft A Aircraft first flown in 1915 Biplanes Single-engined tractor aircraft Rotary-engined aircraft