Canon d'Infanterie de 37 modèle 1916 TRP

The Canon d'Infanterie de 37 modèle 1916 TRP was a French infantry support gun, first used during World War I. TRP stands for tir rapide, Puteaux. The tactical purpose of this gun was the destruction of machine gun nests.
It was also used on aircraft such as the Beardmore W.B.V and the Salmson-Moineau. Fighter ace René Fonck was one pilot known to have used the SPAD S.XII, which was designed around a variant of the 37mm Puteaux gun firing though the propeller spinner.

Service history

During the First World War, the guns saw widespread use with both French and United States forces and were designated the
37mm M1916 in U.S. service. In combat they were found to be wanting, and it was found their intended task of destroying gun emplacements was better done by mortars. As well as infantry use, the guns were also fitted to the M1917 light tank, the first mass-produced U.S. tank. These tanks entered service too late for World War I, and none ever saw action.
During the interwar years the U.S. Army organized its infantry regiments with "howitzer companies," armed, with among other heavy infantry weapons for want of actual infantry support howitzers, 37 mm M1916 guns. The Regular Army could not afford to maintain full companies, but the National Guard could. The Army adopted a .22 caliber sub-caliber device as an economic measure that allowed training with the guns on indoor ranges. By 1941, the howitzer companies of regiments were disbanded and converted to antitank platoons; the Army put most of the M1916 guns into storage, scrapped them, or converted their mechanisms for use as sub-caliber training devices for heavy guns. Some were used in the Philippines campaign in 1941-42 as antitank weapons due to shortages of the 37 mm gun M3. The Japanese Type 11 37 mm infantry gun was based on this design.
The French Army still had the cannon in service in 1940 as a substitute for the 25 mm Hotchkiss anti-tank gun, which was in short supply. After the defeat of France by Germany, the Wehrmacht began using the TRP under the designation 3.7 cm IG 152.
Some were used by the Việt Minh at the beginning of the First Indochina War.
File:Hispano-Suiza 8C.JPG|thumb|A geared-output shaft HS.8C engine for a SPAD S.XII, showing the elevated intake manifold to clear the 37mm cannon mounted in the "vee" between the cylinder banks

Aircraft use

The gun was fitted on some aircraft, firing through the propeller's spinner to avoid hitting the blades. It was used in combat on the 1917 French SPAD S.XII. The prototype 1917 British Beardmore W.B.V shipborne fighter was fitted with a 37mm for use against airships, but the gun was considered dangerous and removed.