The Sopwith LCT (Land Clerget Tractor), better known as the 1½ Strutter, was a British biwing multi-role aircraft of the Great War. It was notable as the first British version of a two-seater tractor fighter and the first aircraft to be produced with a Vickers-Challenger synchronizing gear as standard equipment. Sopwith had designed a two-seat biplane, with the performance, equivalent to that of most fighter aircraft of the day. It was very effectively armed with machine-guns fore and aft and was the first true two-seat fighter to see service. As well as serving with 8 RFC Squadrons and 2 RNAS Wings and later the RAF, it also saw extremely widespread service with 13 Escadrilles of the French Aéronautique Militaire, and some use with 3 Squadrons of the USAAS, and 3 Squadrons of the Aviation Militaire Belge.