Sikorsky S-67 Blackhawk
| S-67 Blackhawk | |
|---|---|
| |
| S-67 Blackhawk in 1972 | |
| Role | Attack/assault helicopter |
| Manufacturer | Sikorsky Aircraft |
| First flight | 20 August 1970 |
| Status | Destroyed (1974 crash) |
| Number built | 1 |
| Developed from | Sikorsky SH-3 Sea King |
The Sikorsky S-67 Blackhawk was a private-venture, prototype attack helicopter built in 1970 with Sikorsky Aircraft research and development (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 eight troops into combat.
Design and development
AAFSS and S-66 bid
The
The U.S. Army awarded Lockheed and Sikorsky contracts for further study on 19 February 1965.[1] On 3 November 1965, the Army announced Lockheed as the winner of the AAFSS program selection. The Army perceived Lockheed's design as less expensive, able to be available earlier, and that it would have less technical risk than Sikorsky's Rotorprop.[1]
S-67 development
Lockheed's design soon ran into development problems and cost and timelines began to grow. Sensing an opportunity, Sikorsky offered an armed
The S-67 featured a five-bladed
The S-67 was fitted with a moving map display, a hands-on-collective radio tune control, and
Operational history
Evaluation and records
The S-67 Blackhawk, along with the Bell 309 KingCobra, was put through a series of flight test evaluations in 1972 by the U.S. Army.[10] Neither aircraft was selected to replace the AH-56 Cheyenne. Instead, the Army chose to create the new Advanced Attack Helicopter program, which would lead to the AH-64 Apache several years later.
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 14 December 1970 by flying at 348.97 km/h (217 mph) over a 3 km (1.9 mi) course,[11] and 355.48 km/h (221 mph) on 15 to 25 km (9.3 to 16 mi) course on 19 December 1970.[12] These records stood for eight years.
As part of internal Sikorsky R&D efforts, in 1974, the S-67 had a 3.5-foot-diameter (1.1 m) ducted fan fitted instead of its original conventional tail rotor.[3] The S-67 with fan was tested over 29 flight hours to compare to the conventional tail.[13] In this configuration it reached a speed of 230 mph (370 km/h) in a test dive.[3] The original tail rotor and vertical tail fin were re-installed in August 1974.
Fatal crash and aftermath
The lone S-67 prototype crashed while conducting a low-level aerobatic demonstration at the Farnborough Airshow on 1 September 1974. The crew misjudged their pitch in a low-level roll maneuver causing the nose to drop below the horizon: they attempted to recover from their inverted position by performing a Split S maneuver, but they were too close to the ground. The aircraft struck the ground in a level attitude and immediately burst into flames. Sikorsky test pilot Stu Craig died on impact, and test pilot Kurt Cannon died nine days later from his injuries.[14] Development work on the S-67 ceased after the accident.[9]
The U.S. Army later assigned the name Black Hawk to the Sikorsky UH-60 Black Hawk helicopter.
Specifications (S-67 Blackhawk)
Data from Jane's all the World's Aircraft 1973–74[15] Illustrated Encyclopedia of Helicopters,[3] Attack Helicopter Evaluation[16]
General characteristics
- Crew: 2
- Capacity: (in a modified cabin up to 15 troops)
- Length: 74 ft 4 in (22.66 m) overall ; 64 ft 9 in (19.74 m) fuselage only
- Wingspan: 27 ft 4 in (8.33 m)
- Height: 15 ft 0 in (4.57 m) to top of rotor hub ; 18 ft 0 in (5.49 m) with rotors turning
- Aspect ratio: 8:1
- Airfoil: root: NACA 4415; tip: NACA 4412
- Empty weight: 12,514 lb (5,676 kg)
- Gross weight: 14,000 lb (6,350 kg)
- Max takeoff weight: 22,050 lb (10,002 kg)
- Fuel capacity: 400 US gal (330 imp gal; 1,500 L) in two internal tanks plus optional 2x 200 US gal (170 imp gal; 760 L) / 2x 300 US gal (250 imp gal; 1,100 L) / 2x 400 US gal (330 imp gal; 1,500 L) underwing drop tanks
- Powerplant: 2 × General Electric T58-GE-5 turboshaftengines, 1,500 shp (1,100 kW) each
- Main rotor diameter: 62 ft 0 in (18.90 m)
- Main rotor area: 3,020 sq ft (281 m2) 5-blade main rotor, NACA 0012 section.
Performance
- Maximum speed: 168 kn (193 mph, 311 km/h) at 18,000 lb (8,200 kg) AUW at sea level, ISA, clean
- Cruise speed: 120 kn (140 mph, 220 km/h) economical
- 162 kn (186 mph; 300 km/h) maximum cruise
- Never exceed speed: 200 kn (230 mph, 370 km/h)3 hours with 1,500 lb (680 kg) payload
- Service ceiling: 17,000 ft (5,200 m)
- Service ceiling one engine: 4,500 ft (1,400 m)
- Rate of climb: 2,350 ft/min (11.9 m/s)
Armament
- Guns: 1x 30 mm (1.181 in) XM188 / 1x 20 mm (0.787 in) XM197 / 1x 20 mm (0.787 in) M61A2 Vulcan cannon in a TAT-140 turret under the fuselage
- Hardpoints: 4
- Rockets: 70 mm (2.8 in) Hydra rocketlaunchers
- Missiles: 16x TOW missiles
See also
Related development
Aircraft of comparable role, configuration, and era
Related lists
References
Notes
- ^ a b c d Office of the Assistant Vice Chief of Staff of the Army (OAVCSA). An Abridged History of the Army Attack Helicopter Program, pp. 4–5, 9. Washington, DC: Department of the Army. 1973.
- ^ Landis and Jenkins 2000, pp. 25, 85–87.
- ^ a b c d e f g Apostolo 1984, p. 89.
- ^ Landis and Jenkins 2000, p. 21.
- ^ ISBN 978-1-56347-918-2.
- ^ Yamakawa, et al. 1972, p. 1.
- ^ US Patent: Blade for High Speed Helicopter
- ^ Yamakawa, et al. 1972, p. 49.
- ^ a b Donald 1998. p. 845.
- ISBN 0-85045-934-6.
- ^ "Speed over a straight 3 km course at restricted altitude : km/h". Fédération Aéronautique Internationale. Archived from the original on 2007-09-27. Retrieved 2007-08-05.
- ^ "Speed over a straight 15/25 km course : 355.48 km/h". Fédération Aéronautique Internationale. Archived from the original on 2007-10-11. Retrieved 2007-08-05.
- ^ Cocke, Karl E. Department of the Army Historical Summary: FY 1974, Chapter XI Archived 2017-07-10 at the Wayback Machine. U.S. Army Center of Military History, 1978.
- ^ Great Britain 1976.
- ISBN 978-0070320215.
- ^ Yamakawa, et al. 1972, pp. 49–51.
Bibliography
- Derived from text at Historic U.S. Army Helicopters - Modern era helicopters
- Apostolo, Giorgio. The Illustrated Encyclopedia of Helicopters. New York: Bonanza Books. 1984. ISBN 978-0-517-43935-7.
- Donald, David. "Sikorsky S-67, S-69 and S-72".The Complete Encyclopedia of World Aircraft. New York: Barnes & Noble Books, 1998. ISBN 978-0-7607-0592-6.
- Great Britain. Sikorsky S-67 Blackhawk N671SA: Report on the Accident at Farnborough, Hampshire, England on 1 September 1974. Aircraft accident report, 1/76. London: H.M.S.O., 1976. ISBN 0-11-511433-5.
- Landis, Tony and Dennis R. Jenkins. Lockheed AH-56A Cheyenne. Warbird tech series, v. 27. North Branch, MN: Specialty Press Publishers and Wholesalers, 2000. ISBN 1-58007-027-2.
- Yamakawa, George M., Albert L. Winn, Raymon B. Smith, Roy J. Anderson, Jr., and Warren E. Griffith, II. Attack Helicopter Evaluation, Blackhawk S-67 Helicopter. Ft. Belvoir: Defense Technical Information Center, July 1972. Retrieved on 22 December 2010.
External links
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