Military helicopter

A military helicopter is an aircraft designed or modified for use by armed forces. These machines are essential for modern land, sea, and air operations. While many helicopters are built specifically for combat, others are converted from civilian models. Their primary purpose is determined by their specific design or the equipment installed on them.

The most frequent mission is airlift, which involves moving personnel or supplies. However, specialized versions can perform complex tasks like combat search and rescue (CSAR) or medical evacuation (MEDEVAC).

Engineers use several methods to create different types of military helicopters. To minimize development costs, manufacturers often create basic airframes in various weight and size classes. These frames can be stretched or shortened to change their capacity. They can also be updated with new engines or advanced electronics. Sometimes, the mechanical and flight systems are moved to entirely new fuselages to create a different aircraft. For example, the Bell UH-1 Iroquois, known as the "Huey," led to the development of the Bell AH-1. Modern aircraft like the Augusta Westland AW101 "Merlin" use modular systems. This allows them to switch from anti-submarine warfare (ASW) to transport roles in just a few hours.

Attack helicopters are a distinct class built for anti-tank and close air support roles. The Bell AH-1 Cobra was the first modern attack helicopter of the Vietnam era. It introduced a classic design featuring a narrow fuselage where the pilot and weapons officer sit in tandem. These aircraft often use stub wings to mount rockets and missiles.

To identify targets, many modern attack helicopters use millimeter wave radar systems. These sensors allow the crew to find and track enemies effectively. Some models may also carry gun pods or air-to-air missiles for defense.

Transport helicopters focus on moving troops and cargo to support military operations. They provide a major advantage because they do not require a runway for takeoff or landing. Cargo can be carried inside the cabin or as a slung load suspended underneath the aircraft.

When the terrain is too rough for landing, crews use rescue hoists or rope lines to pick up personnel while hovering. This capability is vital for air assault strategies. In an air assault, helicopters transport a large number of troops to a landing zone (LZ) to overwhelm an objective. Unlike airborne assaults, helicopters can continually resupply the force during the operation.

Observation helicopters serve as the eyes of the military. Early reconnaissance relied on balloons or light airplanes, but helicopters became ideal due to their ability to hover.

While early models relied on the human eye through large windows, modern versions use advanced optical sensors. These include low light level television and forward looking infrared (FLIR) cameras. These sensors are often mounted on stabilized platforms with lasers for rangefinding. While their main tools are sensors and radios, they can also carry light weapons to fight other reconnaissance assets.

Maritime helicopters are specialized for operation from naval vessels like frigates and destroyers. These aircraft are "navalized," meaning they have extra protection against salt water corrosion. They are also designed to prevent water ingestion and to handle forced ditching at sea.

In the 1960s, the development of the turboshaft engine and transistor technology revolutionized this field. Turboshaft engines allowed smaller helicopters to operate from smaller ships. Transistors allowed aircraft like the Sikorsky SH-3 Sea King to carry integral equipment like dunking sonar and magnetic anomaly detection gear. Today, these helicopters can operate nearly autonomously to hunt submarines or protect the fleet.

Survivability is a major concern in helicopter design, leading to the use of heavy armor and redundancy. Armor is typically placed around the most critical parts, including the pilots, engines, and fuel tanks.

Some components, like fuel lines and tail rotor cables, may be protected by Kevlar. Redundancy means having backup systems to prevent a single failure from causing a crash. For instance, the Blackhawk family uses two engines and can often fly on just one. The engines are also placed strategically so that one can act as a shield for the transmission and the other engine during an attack.