Sikorsky S-72

S-72 RSRA
The S-72 in flight without a main rotor in 1984
Role	Experimental helicopter
Manufacturer	Sikorsky Aircraft
First flight	12 October 1976
Number built	2

The Sikorsky S-72 was an experimental hybrid helicopter/fixed-wing aircraft developed by helicopter manufacturer Sikorsky Aircraft.

Design and development

RSRA

The Rotor Systems Research Aircraft (RSRA) was developed by Sikorsky for NASA and the Army. Configured with rotor, wings and auxiliary jets, the RSRA allows testing of new rotor concepts at speeds up to 300 knots (560 km/h). It could fly like a helicopter with a wing and jets, or as a fixed-wing aircraft without a rotor.

The RSRA was a unique pure research aircraft developed to fill the void between design analysis, wind tunnel testing, and flight results of rotor aircraft. The joint NASA/Army project began in December 1970, first flight on October 12, 1976 with the first of two aircraft arriving from Sikorsky to NASA on February 11, 1979.

The X-Wing

Sikorsky S-72 modified as the X-Wing testbed

Rotor Systems Research Aircraft / X-Wing aircraft during a 1987 high speed taxi test.

The Sikorsky X-Wing was developed between 1983 and 1988 by helicopter manufacturer Sikorsky with NASA and DARPA funding. Intended to take off vertically like a helicopter, the craft's rigid rotors could be stopped in mid-flight to act as X-shaped wings to provide additional lift during forward flight, as well as having more conventional wings.

Instead of controlling lift by twisting its blades as more conventional helicopters do, the craft used compressed air fed from the engines and expelled from its blades to generate a virtual wing surface, similar to blown flaps on a conventional platform. Computerized valves made sure the compressed air came from the correct edge of the rotor, the correct edge changing as the rotor rotated.^{[citation needed]}

Specifications (S-72)

This aircraft article is missing some (or all) of its specifications. If you have a source, you can help Wikipedia by adding them.

Data from Aviastar.org^[1]

General characteristics

• Crew: 2-3
• Length: ft in (21.50 m)
• Wingspan: ft in (18.90 m)
• Height: ft in (4.42 m)
• Empty weight: lb (9,480 kg)
• Max takeoff weight: lb (11,815 kg)
• Powerplant:
  • 2× General Electric TF34-GE-400A turbofans, lbf (4180 kN) each
  • 2× General Electric T58-GE-5 turboshaft, shp (1,045 kW) each
• * Take-off weight without auxiliary jets: 8,300 kg
• Empty weight without auxiliary jets: 6,535 kg

Performance

• Maximum speed: 200 knots (230 mph, 370 km/h
• Max speed without auxiliary jets: 296 km/h)
• Cruise speed: 140 knots (160 mph, 258 km/h
• Cruising speed without auxiliary jets: 258 km/h)
• Rate of climb: 600 394 ft/min (3,050 m/s)

See also

Related development

• Sikorsky S-61
  

Comparable aircraft

• Sikorsky S-69
• Boeing X-50
  

Related lists

• List of helicopters
  

References

External links

Wikimedia Commons has media related to: Sikorsky S-72

• X-Wing Research Vehicle on NASA.gov
• S-72 on helis.com
• Sikorsky S-72 RSRA on aviastar.org