Hispano Cannon

ArmourWorm · November 20, 2017

Hispano Cannon - as Hispano-Suiza HS 404 20 mm auto-cannon is commonly know - was one of the most common aircraft weapons (along .50 cal Browning) of WWII. Used by every allied nation and few Axis as well and in service with US Navy and Israeli Defense Forces among others well into 1970's, Hispano was and is one of the most popular auto-cannons ever built (still in production, or at least was few years back in South America).

In different incarnations it was mounted on planes starting from D.501 and ending with to F9F in game and was base for extremely capable Israeli TCM-20 AA mount IRL, which was derived from Maxon (of .50 cal Quad fame) mount with licensed twin Hispano cannons.

Hispano - Suiza HS 404 was designed by Mark Birkigt in 1933 and defining aircraft version was first produced in 1938 after which French seem to have mounted it on everything with wings. Weapon was different from most earlier designs by the fact it was gas operated - like modern assault rifles - which made it capable of firing more powerful 110 mm long round with faster muzzle velocity and rate of fire when compared to similar blowback operated models like those from Oerlikon or Bofors (Oerlikon did have 110 mm round version, but with slower RoF than Hispano and MG 151/20 was capable of same RoF, but had slower muzzle velocity). Licensed by British in 1939 and by US in 1941, it was those who developed the design as France (where Hispano - Suiza had its HQ at the time) fell in 1940.

Licensed major versions of British; Hispano Mk I, Hispano Mk II, Hispano Mk V

US versions; 20 mm Autocannon M1, AN/M2, AN/M3, T31, M24, Colt Mk-12.

Major innovation for the gun was done by the British in fall of 1940, when they found that even in roomy Beaufighter night-fighter with second crewman it was impossible to reload the cannons' drums while in the air. Not wanting to waste time to re-design entire gun, British invented a piece of kit known as "Mechanism, Belt Feed Mk I" to fit onto the drum port of the Hispano. This took belt of 20 mm ammo, stripped the rounds from links and the just inserted the rounds themselves into the gun like it was still drum fed. This worked extremely well and most aircraft mounted Hispanos were in fact belt fed (note that NO French pre-war/early war aircraft mounted this, so for the early French A/C 60 round drum is only option).