The Boeing/Sikorsky RAH-66 Comanche was an advanced five-blade armed reconnaissance and attack helicopter designed for the United States Army. The RAH-66 program was canceled in 2004 after nearly $7 billion was spent on the program, before production started.
During the early 1980s, the U.S. Army began formulating a requirement for a replacement of its helicopters then in service, resulting in the Light Helicopter Experimental program. In 1991, the Boeing-Sikorsky team was chosen to produce prototypes. The Comanche would incorporate stealth technologies, featuring a number of designs previously untried. It was to employ advanced sensors in its reconnaissance role, and was intended to designate targets for the AH-64 Apache. The aircraft was also armed with missiles and rockets to destroy armored vehicles. The two RAH-66 prototypes were built and flight tested from 1996 to 2004; they were then placed into museums.
In 1982 the U.S. Army started the Light Helicopter Experimental (LHX) program to replace UH-1, AH-1, OH-6, and OH-58 helicopters. It took six years, until 1988, before the request for proposal (RFP) was issued, in which requirement was changed to a reconnaissance helicopter. In October that year, the Boeing-Sikorsky and Bell-McDonnell Douglas teams received contracts for their designs. The program's name was changed to Light Helicopter (LH) in 1990. In April 1991, the Boeing-Sikorsky team was selected as the contest winner and received a contract to build four prototypes for a demonstration and evaluation (Dem/Val) phase. Also that month the helicopter was designated RAH-66 Comanche by the Army.
The RAH-66 was the first stealth helicopter; as such it included a number of techniques were used to reduce its radar cross-section (RCS). Radar-absorbent material (RAM) was used on the Comanche, as well as having infrared-suppressant paint applied on its faceted surface; with these measures, the Comanche's RCS is 360 times smaller than the AH-64 Apache attack helicopter. The Comanche's noise signature is noticeably smaller than others in its class; this was partly achieved through the fitting of a special all-composite 5-blade main rotor, along with a special tail rotor assembly.
The Comanche's very sophisticated detection and navigation systems were intended to allow it to operate at night and in bad weather. Each of the two crew-members is equipped with two LCD multi-functional displays, as well as the Helmet-Integrated Display and Sight System (HIDSS). It has a digital fly-by-wire system. Its primary mission was to use its advanced sensors to find and designate targets for other attack helicopters, such as the AH-64. However, the RAH-66 is armed for destroying enemy tanks and ground vehicles. The aircraft has a three-barrel XM301 20 mm cannon under the nose, the Comanche can also carry six AGM-114 Hellfire and twelve FIM-92 Stinger missiles, split evenly between the two retractable weapons pylons. More armament can be accommodated at the expense of stealth.
The RAH-66 is powered by two LHTEC T800 turboshaft engines. Its fuselage is 43 feet (13 m) long and made of composite material. The F-22 Raptor-derived airframe was designed to fit more easily onto transport ships, enabling it to be deployed to hot spots quickly. If transport assets were not available, the Comanche's ferry range of 1,260 nmi (2,330 km) would allow it to fly to battlefields overseas on its own. The Comanche was specifically tailored to the role of armed scout, replacing the U.S. Army's current armed scout helicopter, the OH-58D Kiowa Warrior, which is an upgraded version of a Vietnam War-era observation helicopter. The Comanche is smaller and lighter than the AH-64.
In November 1993, the first prototype began assembly at Sikorsky's Stratford and Boeing's Philadelphia plants, before the sub-assemblies were transferred to the former location for final assembly. The following year the number of prototypes was cut to two. The first Comanche prototype was rolled out of the Sikorsky Aircraft's helicopter production facility on 25 May 1995, before being transferred to West Palm Beach, Florida, for flight testing. The prototype, piloted by Bob Gradle and Rus Stiles, made its 39-minute maiden flight on 4 January 1996. The flight was originally planned for August 1995, but was delayed by structural and software problems. The second prototype made its first flight on 30 March 1999. Through the early 2000s, the U.S. Army planned to purchase over 1,200 Comanches to fill the scout and light attack roles, with deliveries of operational RAH-66s scheduled to begin in 2006.
Length: 46.85 ft (14.28 m)
Rotor diameter: 39.04 ft (11.90 m)
Height: 11.06 ft (3.37 m)
Disc area: 1,197 ft² (111 m²)
Empty weight: 8,690 lb (3,942 kg)
Loaded weight: 10,597 lb (4,806 kg)
Max takeoff weight: 17,175 lb (7,790 kg)
Powerplant: 2 × LHTEC T800 turboshaft, 1,432 hp (1,068 kW) each
Fuselage length: 43.31 ft (13.20 m)
Rotor systems: 5 blades on main rotor
Maximum speed: 175 knots (201 mph, 324 km/h)
Cruise speed: 165 knots (190 mph, 306 km/h)
Range: 262 nmi (302 mi, 485 km) (internal fuel)
Ferry range: 1,260 nmi (1,450 mi, 2,330 km)
Service ceiling: 14,980 ft (4,566 m)
Rate of climb: 1,418 ft/min (7.20 m/s)
1× 20 mm XM301 three-barrel cannon mounted in a Turreted Gun System (500 round capacity)
Internal bays: 6 Hellfires or 6 Stingers (ATAS) or 24 Hydra 70 2.75 in (70 mm) air-to-ground rockets
Optional stub wings: 8 Hellfire, 16 Stinger or 56 x Hydra 70 air-to-ground rockets
Other model helicopters:Ka-58, RAH-66 Comanche, UH-60 Black Hawk, AH-64 Apache, Ka-52 Alligator, PAH-2 Eurocopter, Ka-50 Black Shark, AH-1W Super Cobra, Mi-24 Hint, Mi-8 Hip, AS-332 Super Puma, UH-1 Iroqoies, MD-500