To this day, the idea of high-speed helicopters begins to gain attention, and some of them have been inspired by the AH-56’s unique rotor designs, and perfected it.

Introduce

In the first half of the 1960s, the US military began to realize the superior strike capabilities of helicopters, so they held a competition to build high-speed, fire-support helicopters for quick maneuvering on the battlefield.

Several companies entered the competition, and Lockheed’s AH-56 Cheyenne as the star of the entire project. The AH-56 Cheyenne was a perfect combination of a light helicopter and an attack aircraft. It was armed with powerful firepower, allowing it to escort large cargo helicopter, to assist in ground attack and independent combat.

Design

At the time of its birth, the AH-56 had a completely different and unique appearance compared to any previous aircraft. The two-seat cockpit was positioned tandem, with the pilot in the rear and the gunner in the forward position, featuring an advanced navigation and fire control suite. The pilot had a helmet mounted sight system for aiming weapons. The Cheyenne was one of the first aircraft to be fitted with an integrated avionics system consisting of a communications, navigation and weapons suite.

Lockheed’s helicopter was slender in shape and highly contoured to bring out the most aerodynamic qualities of the design. Cheyenne had a top rigid main rotor, low-mounted wings and a tail rotor, but it also added a pusher propeller. This gave it a respectable speed. The engine was fitted behind the cockpit and fed by small intakes to either side of the main rotor mast and the single exhaust system facing aft.

Powerplant

Cheyenne was powered by a General Electric T64 propeller shaft motor, producing 3,925 horsepower (2,927 kW).

AH-56 could reach a top speed of 400 km/h (244 mph), cruise speed 361 km/h (224 mph), a range of 1,969 km (1,223 mi), service ceiling was 6,100 m (20,000 ft) and Rate of climb was 15 m/s (3,000 ft/min).

Armament

Weapon turrets were mounted at the nose and the middle of aircraft underbelly. It could mount either a 40 mm grenade launcher, or a 7.62 mm minigun. The belly turret included a 30 mm automatic cannon with 360° of rotation.

Six external hardpoints were located along the bottom of the helicopter, with two under each wing and two on the fuselage under the sponsons. The two inner wing hardpoints could carry pods of three BGM-71 TOW anti-tank missiles. 2.75-inch (70 mm) rockets in 7-rocket or 19-rocket launchers could be carried on the four wing hardpoints. The two fuselage mounts were dedicated to carrying external fuel tanks. The wing hardpoints were also plumbed to allow the carriage of additional fuel tanks if required.

Specifications

(Source: Wikipedia)

General characteristics

Crew: 2 (pilot in the rear, gunner/co-pilot to the front)

Length: 54 ft 8 in (16.66 m)

Height: 13 ft 8.5 in (4.178 m)

Empty weight: 12,215 lb (5,541 kg)

Gross weight: 18,300 lb (8,301 kg)

Max takeoff weight: 25,880 lb (11,739 kg)

Powerplant: 1 × General Electric T64-GE-16 turboshaft engine, 3,925 shp (2,927 kW)

Main rotor diameter: 51 ft 3 in (15.62 m)

Main rotor area: 2,063.2 sq ft (191.68 m2)

Blade section: Root: NACA (4.6)3012 mod; Tip: NACA (0.6)3006 mod

Rotor systems: 4-bladed main rotor, 4-bladed tail rotor

Propellers: 3-bladed constant-speed pusher propeller

Performance

Maximum speed: 212 kn (244 mph, 393 km/h)

Cruise speed: 195 kn (224 mph, 361 km/h)

Range: 1,063 nmi (1,223 mi, 1,969 km)

Service ceiling: 20,000 ft (6,100 m)

Rate of climb: 3,000 ft/min (15 m/s)

Armament

Guns:

1 × nose turret with either a 40 mm (1.575 in) M129 grenade launcher grenade launcher or a 7.62 mm × 51 mm (0.300 in × 2.008 in) XM196 minigun plus 1 × belly turret with an XM140 30 mm (1.181 in) cannon

Hardpoints:

6 with provisions to carry combinations of:

Rockets: 2.75 in (70 mm) FFA rockets Missiles: BGM-71 TOW missiles

Video: AH-56 Cheyenne – A Superior Attack Helicopter, but was still Defeated by Money