Helicopter Weapons

Early in the Vietnam War, many helicopters were shot down by ground fire. The need for helicopter weaponry was clear, and the AH-1 Cobra “gunship” was developed in response. The Cobra, with a chin mounted cannon and ability to fire rockets, quickly proved its value in Vietnam. Since then, many military helicopters have been developed with cannon, rocket, missile and countermeasure capabilities. We’ll discuss each of these below.

• Cannons
• Rockets
• Missiles
• Countermeasures

Cannons

A cannon or autocannon is an automatic gun that fires larger caliber ammunition. Rounds may be armor-piercing, explosive or incendiary. Helicopter cannons are typically placed on a turret, where they can tilt/rotate to hit targets at various locations around the helicopter. Rarely, cannons may be fixed, firing in the direction the helicopter is facing.

Cannons may be operated by a gunner at an open door or, in the case of modern attack helicopters, controlled by a helmet-mounted sight (HMS) system—the turret essentially points the cannon in the direction the pilot sees a target. Both options are shown in the image below.

These cannons are capable of firing several rounds per second for extended times. For example, the AH-1Z is equipped with a three-barreled M197 rotary cannon capable of firing up to 1500 rounds per minute. While it’s typically fired in 40-round bursts, it’s capable of over 500-round bursts depending on the platform.

Examples of helicopter cannons follow.

• The XM140 on the UH-1B Iroquois.
• The M197 on the AH-1Z Viper.
• The M230 chain gun on the AH-64 Apache.
• The XM915 on the UH-60 Blackhawk.

Rockets

A rocket is typically an unguided munition that flies under the power of a rocket motor. Guided rocket-powered weapons may also be classified as rockets if they were derived from an unguided rocket (otherwise, the more appropriate term is missile).

Cylindrically-shaped rocket pods are often mounted on the stub wings of a helicopter, as shown below. Each pod houses 7 to 20 rockets and a helicopter may have up to four pods (two on each wing).

The Bell UH-1B Iroquois was able to fire grenades as well as Mk4 and Mk40 folding-fin rockets. Hydra 70 rockets have been used on many helicopters including Apaches, OH-58D, UH-1, AH-1 and UH-60 helicopters. Most of these employ 19-shot pods on each wing.

In 2012, a laser-guided variant of the Hydra 70 rocket went into service, called the Advanced Precision Kill Weapon System (APKWS). APKWS may be used on helicopters like the AH-1Z and allows for very precise strikes at low cost.

Missiles

A missile is a guided munition that flies under the power of a rocket motor or jet engine. Helicopters began incorporating missiles in the late 1960s. Variants of the UH-1B Iroquois could launch both AGM-22 and BGM-71 missiles.

Many modern military helicopters incorporate Hellfire missiles, often located in 4-round M299 missile launchers, as shown above on an Apache’s wingtips. There’s an assortment of Hellfire missiles today, using laser and/or radar guidance. These are used to strike various ground-based targets, including tanks and “high-value targets.” They’ve killed many high-ranking leaders of terrorist organizations in the Middle East.

Helicopters have even used missiles to strike targets in the air. In 2018, Hellfire missiles fired from an Israeli AH-64 reportedly destroyed an Iranian UAV. The Bell AH-1Z can fire AIM-9 Sidewinder air-to-air missiles to fight other aircraft. When used, these Sidewinders are located on the wing tips, as shown in the image below (the Sidewinder is blue).

Dispensable Countermeasures

Dispensable countermeasures protect helicopters from enemy fire. When a helicopter is at risk of being shot down, it may emit these items for protection. The two main dispensable countermeasures are chaff and flares.

Chaff consists of millions of small pieces of aluminum, or other radar-reflecting substance. When these are ejected from a helicopter they spread out, making enemy radars (and radar-guided missiles) see a large cloud, rather than a more focused picture of the helicopter only. This effectively distracted early radar-guided missiles from striking helicopters, but since then there’s been an “arms race” in which both radar guidance and chaff have iteratively improved to outsmart prior versions.

Flares consist of material that burns at temperatures near or above the helicopter’s engine. They are ignited and emitted from helicopters to distract heat-seeking (infrared) missiles, just as chaff is used to distract radar-guided missiles. As with chaff and radar-guided missiles, there’s been an arms race in which both flares and heat-seeking missiles have become increasingly more sophisticated to outsmart the prior generation. Flares are more effective if emitted before a missile approaches, otherwise modern missiles can reliably discriminate the flares and ignore them.