An attack helicopter is an armed helicopter with the primary role of an attack aircraft, with the offensive capability of engaging ground targets such as enemy infantry, military vehicles, and fortifications. Due to their heavy armament, they are sometimes called helicopter gunships.
Attack helicopters can use weapons including autocannons, machine guns, rockets, and anti-tank missiles such as the AGM-114 Hellfire. Some attack helicopters are also capable of carrying air-to-air missiles, though mostly for purposes of self-defense against other helicopters and low-flying light combat aircraft.
A modern attack helicopter has two primary roles: first, to provide direct and accurate close air support for ground troops; and second, the anti-tank role to destroy grouped enemy armored vehicles. Attack helicopters are also used as protective escort for transport helicopters, or to supplement lighter helicopters in the armed reconnaissance roles. In combat, an attack helicopter is projected to destroy targets worth around 17 times its own production cost before being destroyed.
Development Background Low-speed, fixed wing Allied aircraft like the Soviet Polikarpov Po-2 training and utility biplane had been used as early as 1942 to provide night harassment attack capability against the Wehrmacht Heer on the Eastern Front, most effectively in the Battle of the Caucasus as exemplified by the Night Witches all-female Soviet air unit. Following Operation Overlord in 1944, the military version of the similarly slow-flying Piper J-3 Cub high-wing civilian monoplane, the L-4 Grasshopper, begun to be used in a light anti-armor role by a few U.S. Army artillery spotter units over France; these aircraft were field-outfitted with either two or four bazooka rocket launchers attached to the lift struts,Francis, Devon E., Mr. Piper and His Cubs, Iowa State University Press, , 9780813812502 (1973), p. 117. against German armored fighting vehicles. During the summer of 1944, U.S. Army Major Charles Carpenter managed to successfully take on an anti-armor role with his rocket-armed Piper L-4. His L-4, bearing US Army serial number 43-30426 and named Rosie the Rocketer, armed with six bazookas, had notable success in an engagement during the Battle of Arracourt on September 20, 1944, employing top attack tactics in knocking out at least four German armored vehicles,Gantt, Marlene, Riding His Piper Cub Through The Skies Over France, Bazooka Charlie Fought A One-man War, World War II Magazine, September 1987 as a pioneering example of taking on heavy enemy armor from a slow-flying aircraft.Fountain, Paul, The Maytag Messerschmitts, Flying Magazine, March 1945, p. 90
The Germans were also engaged in such ad hoc low-speed light aircraft platforms for ground attack very late in the war, with one subtype of the Bücker Bestmann trainer—the Bü 181C-3—armed with four Panzerfaust 100 anti-tank grenade launchers, two under each of the low-winged monoplane's wing panels, for the concluding two months of the war in Europe.Christian Möller: Das letzte Aufgebot der deutschen Luftwaffe Helios Verlag 2010 This sort of role, being undertaken by low-speed fixed-wing light aircraft, was also likely to be achievable after World War II, from the increasing numbers of post-war military helicopter designs. The only American helicopter in use during the war years, the Sikorsky R-4, was used only for rescue and remained very much experimental.
In the early 1950s, various countries around the world began to make greater use of helicopters in transport and liaison roles. Later on, it was realized that these helicopters, successors to the World War II-era Sikorsky R-4, could be armed to provide them with limited combat capability. Early examples include armed Sikorsky H-34s in service with the US Air Force and armed Mil Mi-4 in service with the Soviet Air Forces. This "experimental" trend towards the development of dedicated attack helicopters continued into the 1960s with the deployment of armed Bell UH-1s and Mil Mi-8s during the Vietnam War, to this day the pair of most produced helicopter designs in aviation history. Bell Helicopter employee and Vietnam War veteran Billy "Bill" Frank Perkins, though less well known, was the first person ever to fly an attack helicopter; he possesses an official certificate to that effect. These helicopters proved to be moderately successful in these configurations. Still, due to a lack of armor protection and speed, they were ultimately ineffective platforms for mounting weapons in higher-threat ground combat environments.
Since the 1960s, countries around the world have begun designing and developing helicopters to provide heavily armed, protected aerial vehicles capable of performing a variety of combat roles, from reconnaissance to aerial assault. By the 1990s, the missile-armed attack helicopter evolved into a primary anti-tank weapon. Able to quickly move about the battlefield and launch fleeting "pop-up attacks", helicopters presented a major threat even with the presence of organic air defenses. The helicopter gunship became a major tool against tank warfare, and most attack helicopters were increasingly optimized for the anti-tank mission.Mazarella, Mark N. "Adequacy of U.S. Army Attack Helicopter Doctrine to Support the Scope of Attack Helicopter Operations in a Multi-Polar World" . Fort Leavenworth, Kansas: U.S. Army Command and General Staff College, 1994. Accessed on 12 December 2007.
United States
In the opening months of the Korean War, in August 1950, a joint US Navy and Marine Corps test used a newly acquired Bell HTL-4 helicopter to determine whether a bazooka could be fired from a helicopter in flight. One of the larger 3.5-inch (90mm caliber) bazooka models was chosen and mounted ahead and to the right of the helicopter to keep the door clear. The bazooka was successfully tested, although it was discovered that it would require shielding for the engine compartment, which was exposed in the model 47 and other early helicopters. The helicopter itself belonged to HMX-1, a Marine experimental helicopter squadron.Helicopter Gunships: Deadly Combat Weapon Systems, Wayne Mutza, pp. 13–14.
In the mid-1960s, the U.S. Army concluded that a purpose-built attack helicopter with more speed and firepower than current armed helicopters was required in the face of increasingly intense ground fire (often using heavy machine guns and anti-tank rockets) from Viet Cong and NVA troops. Based on this realization and the growing involvement in Vietnam, the U.S. Army developed requirements for a dedicated attack helicopter, the Advanced Aerial Fire Support System (AAFSS). The aircraft design selected for this program in 1965, was Lockheed's AH-56 Cheyenne.
As the Army began acquiring a dedicated attack helicopter, it sought options to improve performance compared with the continued use of improvised interim aircraft (such as the UH-1B/C). In late 1965, a panel of high-level officers was selected to evaluate several prototype armed attack helicopters to determine which offered the greatest increase in capability over the UH-1B. The three highest-ranked aircraft, the Sikorsky S-61, Kaman H-2 "Tomahawk", and the Bell AH-1 Cobra, were selected to compete in flight trials conducted by the Army's Aviation Test Activity. Upon completion of the flight evaluations, the Test Activity recommended Bell's Huey Cobra to be an interim armed helicopter until the Cheyenne was fielded. On 13 April 1966, the U.S. Army awarded Bell Helicopter Company a production contract for 110 AH-1G Cobras. The Cobra had a tandem cockpit seating arrangement (vs UH-1 side-by-side) to make the aircraft a smaller frontal target, increased armor protection, and greater speed.
In 1967, the first AH-1Gs were deployed to Vietnam, around the same time that the Cheyenne completed its first flight and initial flight evaluations. And while the Cheyenne program suffered setbacks over the next few years due to technical problems, the Cobra was establishing itself as an effective aerial weapons platform, despite its performance shortcomings compared to the AH-56 and its own design issues. The cost estimates of the AH-56 increased substantially. By 1972, when the Cheyenne program was eventually cancelled to make way for the Advanced Attack Helicopter (AAH), the interim AH-1 "Snake" had built a solid reputation as an attack helicopter. In June 1972, the USMC began deploying AH-1J SeaCobra Attack Helicopters for combat operations in South Vietnam.
In the late 1970s, the U.S. Army recognized the need for greater sophistication in the attack helicopter corps to enable them to operate in all weather conditions.Advanced Attack Helicopter Operations in Adverse Envoriments - Official US Army video at Real Military Flix Although AH-1Gs served well, they proved vulnerable even in a mid-intensity environment. With that the Advanced Attack Helicopter (AAH) program started, aiming for a more durable, more advanced, longer range, stronger close air support helicopter, capable of destroying armored formations. It would be capable of carrying the new AGM-114 Hellfire and night fighting capabilities. From this program the Hughes YAH-64 came out as the winner. The prototype YAH-64 was first flown on 30 September 1975. The U.S. Army selected the YAH-64 over the Bell YAH-63 in 1976, and later approved full production in 1982. After purchasing Hughes Helicopters in 1984, McDonnell Douglas continued to produce and develop the AH-64 Apache. The helicopter was introduced to U.S. Army service in April 1986.
Today, the US attack helicopter has been further refined, and the AH-64D Apache Longbow demonstrates many of the advanced technologies being considered for deployment on future gunships. The US Marine Corps also continued to employ attack helicopters in a direct fire-support role, specifically the AH-1 Super Cobra. While helicopters were effective tank-killers in the Middle East, attack helicopters are being seen more in a multipurpose role. Tactics such as tank plinking demonstrated that fixed-wing aircraft could be effective against tanks, but helicopters retained a unique low-altitude, low-speed capability for close air support. Other purpose-built helicopters were developed for special operations missions, including the MH-6 for extremely close support.
Soviet Union and its successor states
During the early 1960s, Soviet engineers began experimenting with various designs to produce an aerial vehicle capable of providing battlefield mobility for infantry and fire support to ground forces. The first of these concepts was a mock-up unveiled in 1966 in the experimental shop of the Ministry of Aircraft's factory number 329, where Mikhail Leont'yevich Mil was head designer. The mock-up, designated V-24, was based on another project, the V-22 utility helicopter, which never entered production. The V-24 had an infantry transport compartment that could hold eight troops sitting back to back, and a set of small wings positioned to the top rear of the passenger cabin, capable of holding up to six missiles or rocket pods, along with a twin-barrel GSh-23L cannon fixed to the landing skid.
Mil proposed these designs to the Soviet armed forces. While he had the support of several strategists, he was opposed by several more senior members of the armed forces who believed that conventional weapons were a better use of resources. Despite opposition, Mil managed to persuade the defense minister's first deputy, Marshal Andrey A. Grechko, to convene an expert panel to investigate the matter. While the panel's opinions were mixed, supporters of the project eventually held sway, and a request for design proposals for a battlefield support helicopter was issued.