The Sikorsky S-16 (named after its designer) or RBVZ S-XVI (named after its manufacturer) was a Russian equi-span single-bay two-seat biplane designed by Igor Sikorsky in 1914-15. Conceived in response to demand for an escort fighter for the Ilya Muromets bombers, it was noteworthy in that it was one of the first aircraft to possess synchronisation gear for its 7.7mm machine gun.