Grigorovich M-5 (Shch M-5, or Shchetinin M-5) was a successful Russian two-bay unequal-span biplane flying-boat with a single-step hull, designed by Grigorovich. It was the first mass-produced flying-boat built in Russia.
Designer Dmitry Pavlovich Grigorovich completed his first flying-boat (the model M-1) in late 1913 and produced a series of prototypes, gradually improving the design, until the M-5 appeared in the spring of 1915, which was to be his first to enter series production, with at least 100 being built, primarily as replacements for foreign built aircraft then in service, including Curtiss Model K and FBA flying boats.
The M-5 was of wooden construction, the hull being covered with a plywood skin and the wings and tailplane surfaces covered in fabric. Aft of the step the hull tapered sharply into little more than a boom, supporting a characteristic single fin and rudder, which was braced by struts and wires. The normal powerplantconsisted of a 100-hp Gnome Monosoupape engine mounted as a pusher between the wings, but some were fitted with 110-hp Le Rhône or 130-hp Clerget engines. The pilot and observer were accommodated side-by-side in a large cockpit forward of the wings; the observer being provided with a single 7.62-mm Vickers machine gun on a pivoted mount.
Most of the M-5s served in the Black Sea or in the Baltic, initially with the Imperial Russian navy air arm and later with both sides in the Russian Civil War. Some remained in service until the late 1920s as trainers, reconnaissance and utility aircraft.
One M-5 fell into Finnish hands when it was found drifting at Kuokkala in 1918. This aircraft was flown by the Finnish Air Force until 1919, when it was accidentally sunk.