Originally conceived as a two-seater the prototype M-11 was built in 1916 at the Shchetinin factory in Petrograd. The M-11 was a biplane with a 100 hp (75 kW)
Gnome Monosoupape rotary engine with a pusher propeller strut mounted below the upper wing. The small number of two-seaters had a poor performance and were only used as trainers, Grigorovich developed a single-seat version powered by a 110 hp (82 kW) Le Rhône engine and fitted with a forward firing machine gun in front of the cockpit. Originally 100 single-seat M-11s had been ordered but this was reduced to 60 as the aircraft had poor handling when landing or alighting on water. The M-11 was operated from snow and ice with twin skis fitted under the forward
fuselage and a single ski under the tailplane. To improve the water handling an improved variant was developed as the
M-12 which had a re-designed hull and reduced loaded weight. Although the climb to height was improved the forward speed was 5 mph (8 km/h) less than the M-11 consequentially only a few M-12s were built. ==Variants==