M551 Sheridan

   Development of the M551 Sheridan began in 1959. It's programme was known as the AR/AAV or Armored Reconnaissance / Airborne Assault Vehicle. First prototypes were built in 1962 and production commenced in 1966. Vehicle is named in honor to Civil War General Philip Sheridan. A total of 1 700 M551 Sheridan light tanks were built until 1970, when production ceased. The M551 Sheridan replaced the M41 tanks and M56 self-propelled guns in service with the US Army. Sheridans were gradually phased out of service since 1978, however last vehicles were decommissioned in 1996. Currently the US Army has no real replacement for this light tank.

   Sheridan can be airdropped, including low altitude drops. Low altitude drops are made using LAPES extraction system. A special pallet absorbs most of the landing impact during impact. This maneuver allows to deliver vehicle when landing is not possible and enemy has a strong air defense. In fact Sheridan was the only air-deployable tank in service with US Army.

   Hull of the M551 Sheridan is welded from aluminum alloys and turret is welded from steel. It was made in attempt to save weight. Front armor protects against 20-mm armor piercing rounds, while overall protection is against 14.5-mm bullets. Vehicle is fitted with NBC protection system.

   The M551 Sheridan light tank is armed with the same weapons as the M60A2 main battle tank. It is fitted with a rather unique fully-stabilized 152-mm gun-launcher capable of firing ordinary projectiles and MGM-51 Shillelagh anti-tank guided missiles. This gun allowed to deal with most contemporary main battle tanks at short ranges, but had low accuracy on longer ranges. It also had sufficient firepower for infantry support role. The Shillelagh missiles allowed to deal with MBTs at long ranges, however due to the complicated electronics and and guidance system this missile ended up almost never being fired, except for crew training purposes.

   Secondary armament consists of 7.62-mm coaxial machine gun and 12.7-mm anti-aircraft machine gun.

   Vehicle has a crew of four, including commander, gunner, loader and driver.

   The M551 Sheridan is powered by the Detroit Diesel 6V53T diesel engine, developing 300 hp. Vehicle is amphibious after a preparation lasting two minutes. On water this light tank is propelled by spinning it's tracks.

   Approximately 200 of the Sheridans were used during Vietnam War by the US Army. It's combat experience revealed a number of drawbacks. This light tank was very vulnerable to grenades and mines. It's gun-launcher had problems with cracks developing after repeated firing. The gun also had too much recoil for a light vehicle. Most field units were modified to help address the problems.

   The M551A1 Sheridan is an improved version of the base vehicle. It was developed in 1971 considering operational experience of the M551. It had improved suspension and had laser rangefinder fitted.

   It was a very innovative light tank design, however due to it's numerous faults the M551 Sheridans have been replaced in reconnaissance role with the M60A1 main battle tanks and later with the M3 Bradley armored reconnaissance vehicles.