Sikorsky S-67 Blackhawk

Template:Infobox Aircraft

The Sikorsky S-67 Blackhawk was a private-venture, prototype attack helicopter built in 1970 with Sikorsky Aircraft R&D funds. A tandem, two-seat aircraft designed around the dynamic drive and rotor systems of the Sikorsky S-61, it was designed to serve as an attack helicopter or to transport up to 8 troops into combat.

Development

When the Lockheed AH-56 Cheyenne failed to live up to expectations, Sikorsky offered an intermediate aircraft consisting of an armed version of its S-61 (which evolved into the Sea King helicopter). Sikorsky then designed a simplified AAFSS using the maximum number of components from the S-61.

The result was the Sikorsky S-67 Blackhawk , which featured a five-bladed main rotor and tail rotor. The main rotor shared many features with the parent S-61, but differed in its swept main rotor blade tips and a special "alpha-1" linkage which was added to the main rotor controls to increase collective pitch sensitivity and so extend the collective pitch range. These allowed the S-67 to achieve and maintain very high cruise speeds. To reduce drag at high speed, the main wheels were made fully retractable. It had speed brakes on the wing trailing edges that deployed as commanded by the pilot, or automatically at a set airspeed to improve dive speed control and reduce pilot targeting workload during firing runs.

The S-67 was fitted with a moving map display, a hands-on-collective radio tune control, night vision systems, a Tactical Armament Turret (TAT-140) with a 20 mm cannon, 16 130 mm TOWs, and 2.75 inch rockets or Sidewinder air-to-air missiles. The Blackhawk was powered by two General Electric T58-GE-5 1500 shp engines.

Operational history

The S-67 performed a series of aerobatic maneuvers during its various marketing tours, including rolls, split s, and loops. The S-67 was reputed to be very smooth and responsive, in spite of its size and speed.

Piloted by Sikorsky Test Pilots Kurt Cannon and Byron Graham, the S-67 established two E-1 class world speed records on December 14, 1970 by flying at 216.84 mph (188.4 knots) over a 1.86 mile (3 km) course, and 220.85 mph (191.9 knots)on a 15/25 kilometer course (reference 1). These records stood for 8 years. As part of internal Sikorsky R&D efforts, in 1974 the S-67 Blackhawk had a 3.5 foot diameter ducted fan fitted instead of its original conventional tail rotor. In this configuration it reached a speed of 230 mph (199.9 knots) in a test dive. The original tail rotor and vertical tail fin were re-installed in August of 1974.

The S-67 Blackhawk, along with a specially modified "King Cobra" from Bell helicopter, was put through a series of flight test evaluations in 1970 by the Army. Neither aircraft was selected to replace the AH-56 Cheyenne. The Army instead chose to create a new major attack helicopter program, powered by the new T-700 engine series. Called the Advanced Attack Helicopter (AAH), this new program produced the AH-64 Apache several years later.

Fatal crash

The lone S-67 prototype crashed while conducting a low-level aerobatic demonstration at the Farnborough Air Show in 1974, killing Sikorsky test pilots Kurt Cannon and Stu Craig.^{[citation needed]}

Keen observers will note that the aft fuselage and vertical tail design of the S-67 was used as a basis for the NASA S-72 Rotor Systems Research Aircraft (RSRA) which was the test bed for the X-Wing Stopped Rotor Program.

In 1976, Sikorsky aircraft lifted the trademark on the name "Blackhawk" and allowed the US Army to assign that name (as the "Black Hawk") to the UH-60 Utility Tactical Transport System.

Specifications (S-67 Blackhawk)

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

General characteristics

Crew: 2
Capacity: 15 troops

Performance

References

Derived from public ___domain text at http://tri.army.mil/LC/CS/csa/aahist3.htm
Any more data about S-67 at http://avia.russian.ee/helicopters_eng/sik_s-67-r.html

Reference 1 http://records.fai.org/rotorcraft/history.asp?id1=112&id2=28&id3=1&id4=2