The Grigorovich M-24 was a Soviet

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 biplane flying boat built during the 1920s.

Dmitri Grigorovich began developing the aircraft in April 1922, whilst he was flying the successful Grigorovich M-9

Grigorovich M-9

-Sources:Heinonen, Timo: Thulinista Hornetiin - Keski-Suomen ilmailumuseon julkaisuja 3, Keski-Suomen ilmailumuseo, 1992, ISBN 951-95688-2-4-See also:...

. Flight tests with the aircraft, which featured a 14 metre wingspan

Wingspan

The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...

 and a maximum speed of 160 km/h, began in 1923 and subsequently 40 aircraft were produced, which were delivered from April 1924. The flight performance was poor, however, and the pilots and maintenance personnel complained about the aircraft's many defects.

Following these complaints, Grigorovich began working on a revised version of the aircraft. One development he made was building a stronger engine, with 260 hp, as opposed to the original which produced 220 hp. Twenty of the new aircraft were built, and they were used, until 1926, by the Soviet Navy

Soviet Navy

The Soviet Navy was the naval arm of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy would have played an instrumental role in a Warsaw Pact war with NATO, where it would have attempted to prevent naval convoys from bringing reinforcements across the Atlantic Ocean...

for coastal reconnaissance.