In 1968 the Army Limited War Laboratory developed a weapon system for troop-carrying UH-1D/H helicopters for close suppressive fire during take-off and landing in combat operations. It consisted of four modules mounted under the nose, each containing 306 barrels for firing .22 caliber rounds, arranged to spread forward of the aircraft similar in principle to a shotgun.
It seems only four of these prototype systems were built by 1971, when the project was cancelled.
I imagine it would only be effective at relatively close range because of the rotorwash. :P
Except for two major problems, one of them being rotor downwash and other wind conditions effecting the small caliber rounds as Leela already pointed out. The other is that the system was meant to be operated like a directional mine. The gunner could not fire each barrel separately and instead had to fire the entire payload of each unit - Four shots and they had to count, get as many targets as you could. It was more efficient to use traditional means of airborne defense (door guns, outrigged mounts, undernose grenade launchers, etc.)
Though the points raised make sense, I think the name suggests that these were mainly to keep the enemy at bay rather than to actually hit anything with extreme accuracy. Nevertheless, a modern weapon system in a hot LZ with only four shots is pretty useless.
hillberg wrote:rotor wash will do nothing from the nose you have only a few feet
rotor wash will do nothing from the nose you have only a few feet
Operators of the early M75 in noe/take-off/landing situations would disagree. Wind conditions from above and reflecting off the ground (in ground effect) will affect any small projectile, especially .22 rounds.