From The Department of Redundancy Department
From Danger Room
The Speedhawk was funded by the Army to test the possibility of pushing existing helicopters to reach speeds up to 200 knots (360 kilometers per hour).
Anyone remember this? I mean besides me...
Specifications: Lockheed AH-56A Cheyenne
Length: 60.04ft (18.30m)
Width: 25.92ft (7.90m)
Height: 13.78ft (4.20m)
Max Speed: 245mph (395kmh; 213kts)
Max Range: 629miles (1,013km)
Climb Rate: 3,420 ft/min (1,042 m/min)
Ceiling: 25,997ft (7,924m; 4.9miles)
Empty Weight: 11,718lbs (5,315kg)
MTOW: 16,995lbs (7,709kg)
Engine(s): 1 x General Electric T64-GE-16 turbine engine generating 3,435hp.
From Military Factory.com
The Cheyenne was built in 1967 so maybe the dog ate the homework or something. There was also a Lockheed experimental compound helicopter known as the XH-51.
Lockheed began developing its rigid rotor concept with the CL-475 helicopter design in 1959. The choice of a rigid rotor meant that the helicopter was more agile than it would have been with a flapping rotor. The performance of the CL-475 encouraged Lockheed to seek further development. Lockheed submitted the CL-475 to the Army as a candidate to replace the OH-13 Sioux and OH-23 Raven helicopters. Lockheed also tested the commercial market waters without success. However, in February of 1962, Lockheed's Model 186, a new design based on the CL-475 rigid rotor, was selected as the winner for a joint Army-Navy program to evaluate the rigid rotor for high-speed flight capability.
Two four-seat, three-bladed XH-51As were ordered and built for the program. Powered by the 550 shp (410 kW) Pratt & Whitney Canada PT6B-9 turboshaft engine, XH-51A (serial number 61-51262) first flew on 2 November 1962. As flight testing progressed, the original three-bladed, rigid rotor system demonstrated instability at higher speed ranges. Lockheed engineers solved the problem by modifying the aircraft with a four-bladed rotor system. In 1963, the Army's Technology Research and Evaluation Command (TRECOM) contracted with Lockheed to modify one of the XH-51 aircraft into a compound helicopter.
The second XH-51A (serial number 61-51263) was subsequently converted by adding wings with a span of 16.1 ft (4.9 m), and a 2,500 hp (1,864 kW) Pratt & Whitney J60-2 turbojet engine mounted on the left wing to increase performance. The XH-51A Compound first flew without powering up the turbojet on 21 September 1964, while tests were conducted for balance and handling. The aircraft's first flight as a true compound helicopter took place on 10 April 1965. and on 29 November 1967 achieved a speed of 263 knots (302.6 mph, 486.9 km/h).
So I guess the real question would be what are we proving or are we re-inventing the wheel...again?