 |
The M75 was an automatic grenade launcher used primarily as an aircraft-mounted weapon.
History[]
Development of the M75 began in late 1950s by the Philco-Ford Corporation (later known as Ford Aerospace). While the 40×46mm grenades were developed for use by infantry, the M75 was to be an aircraft weapon using the 40×53mm grenade, which had a higher velocity for greater range. While the XM13 aircraft gun pod was developed for it, the M75 would see greater usage as a helicopter weapon, mainly during the Vietnam War. The most notable helicopter armament subsystems that the M75 was part of were the M5 of the UH-1 Iroquois and the AH-1 Cobra's M28 turret system. It was quickly replaced by the improved M129.
Design Details[]
The M75 is an air-cooled, electrically-powered automatic grenade launcher. All parts of the firing cycle, being powered in this fashion, requires an external power source. Other important features include a reciprocating barrel and a cam assembly which drives the other components of the system. All phases of the firing cycle are positively controlled by the drum cam assembly, in which a planetary gear train is enclosed, responsible for reducing the 5/8 hp 28V DC motor's high speed to the desired cyclic rate for the gun. The motor is mounted on the turret bracket and drives the drum cam through a flexible shaft in order to isolate it from the weapon's recoil. The M75 is belt-fed, and ammunition was fed from rotary drum magazines in the case of the M5 and M28 subsystems, and from box magazines in the case of the XM9 system. The M5 could also use box magazines.
Drawback(s)[]
The positioning of the cam assembly and the barrel meant that excessive torque occurs during firing. In addition, a 1964 report on Army aircraft armament deemed the weapon inherently unsafe in its basic design, which allowed for live rounds to be left in the breech after firing had ceased. The weapon's mechanism allowed for it to "run away" under certain circumstances as well, functioning without any user input.
Trivia[]
- The M75 was one of the first weapons to fire the 40×53mm grenade.
Gallery[]
