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Sikorsky S-69

Experimental Compound Helicopter Prototype

Sikorsky S-69

Experimental Compound Helicopter Prototype


Two Model S-69 aircraft were built by Sikorsky for the United States Army and NASA to validate various components of a compound helicopter design.
National Flag Graphic
ORIGIN: United States
YEAR: 1973
STATUS: Retired, Out-of-Service
MANUFACTURER(S): Sikorsky Aircraft - USA
OPERATORS: United States (retired)

Unless otherwise noted the presented statistics below pertain to the Sikorsky S-69 model. Common measurements, and their respective conversions, are shown when possible.
LENGTH: 40.75 feet (12.42 meters)
WIDTH: 118.11 feet (36 meters)
HEIGHT: 42.98 feet (13.1 meters)
WEIGHT (MTOW): 12,566 pounds (5,700 kilograms)
ENGINE: 2 x Pratt & Whitney J60-P-3A turbojet engines developing 3,000lb of thrust each; 1 x Pratt & Whitney Canada PT6T-3 Turbo Twin-Pac turboshaft engine developing 1,826 horsepower driving 2 x Three-bladed main rotor units.
SPEED (MAX): 323 miles-per-hour (520 kilometers-per-hour; 281 knots)
CEILING: 14,993 feet (4,570 meters; 2.84 miles)
RATE-OF-CLIMB: 1,200 feet-per-minute (366 meters-per-minute)


Series Model Variants
• S-69 - Base Company Designation
• XH-59 - Military Designation (US Army)
• S-69A - Initial form flown; two prototypes completed - one lost to accident and rebuilt as a wind tunnel test article.
• S-69B - Proposed advanced form with GE T700 turboshaft engines, new main rotor blade assemblies, and ducted pusher propeller unit at tail.


Detailing the development and operational history of the Sikorsky S-69 Experimental Compound Helicopter Prototype.  Entry last updated on 8/7/2018. Authored by Staff Writer. Content ©
The road to the Sikorsky S-97 "Raider" compound helicopter program of today was through such developments as the experimentally-minded Model "S-69". For decades, rotary-wing engineers have attempted to exact every ounce of speed and performance from helicopter systems only to be limited by traditional engine and blade arrangements. The compound helicopter was born to provide the same systems with the benefits of a revised main blade arrangement or the addition of a tail thruster/propulsor unit to give the airframe jet-like performance while retaining the Vertical Take-Off and Landing (VTOL) capability inherent in helicopters. The modern-day S-97 embodies this as did the S-69 of the early-1970s.

The S-69 was financed by both the United States Army as well as NASA through the "Advancing Blade Concept" (or "ABC") program. Because of military involvement in the program, the Model S-69 was also recognized under the military designation of "XH-59" and two flyable specimens were ultimately built for the program with the first unit flying on July 26th, 1973.

The aircraft was given a twin-main-rotor mast arrangement in which one main rotor system sat above the other ("co-axial contra-rotating"). No anti-torque rotor was fitted at the tail as the two contra-rotating main blade units countered the naturally occurring torque force. The rotors, of rigid design, sat atop the slender fuselage with two outboard-positioned engine nacelles positioned at each fuselage side. The cockpit sat over the nose in the usual way and featured side-by-side seating for the flight crew of two. The tail unit incorporated split vertical fins set atop upward-cranked horizontal planes. The undercarriage was retractable.

Structural dimensions of the aircraft included an overall length of 40.8 feet, a diameter (with main rotor) of 36 feet, and a height of 13.2 feet. Loaded weight was 12,500lb.

Three total engines were installed in the S-69: 2 x Pratt & Whitney J60-P-3A turbojets of 3,000lb thrust each and 1 x Pratt and Whitney Canada (PWC) PT6T-3 "Turbo Twin-Pac" turboshaft engine of 1,825 horsepower output. Performance specs showcased a maximum speed of 322 miles-per-hour with cruising capable of near-125 mile-per-hour speeds. The service ceiling reached 15,000 feet and the rate-of-climb was 1,200 feet-per-minute.

The first prototype lasted airborne only until August 24th, 1973 when it crashed during a test flight. This example was rebuilt to serve in wind tunnel testing from 1979 onward. The second prototype followed into the air on July 21st, 1975 sans the outboard jet engines. Once successfully passing its early testing phase, the aircraft received its complete powerplant arrangement during March of 1977. This airframe recorded a maximum speed of 300+ miles-per-hour in a dive.

Active testing of the S-69 ran into 1981 by which point the XH-59 was retired from further work after accruing some 106 hours in the air. It was found to burn through fuel quite quickly and the airframe vibrated violently in certain flight envelopes. It was planned that the XH-59 prototype be converted with new GE T700 turboshaft engines, a ducted "pusher" propeller unit at the tail, and all-new main rotors as the "XH-59B" but Sikorsky was not interested in funding the venture, even partially. The work on the S-69 was not all for loss for the company's "X2", flying on August 27th, 2008, carried on the tradition of the Sikorsky experimental compound helicopter - which eventually led to the modern-day S-97 "Raider" concept under consideration by the United States Army.


Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.

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Relative Maximum Speed
Hi: 400mph
Lo: 200mph
This entry's maximum listed speed (323mph).

Graph average of 300 miles-per-hour.
Aviation Era
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Pie graph section
Pie graph section
Pie graph section
Pie graph section
Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production (2)
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units

  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.

Altitude Visualization
Small airplane graphic
Supported Roles
Ground Attack
Aerial Tanker
A2A=Air-to-Air; UAV=Unmanned; CAS=Close Support; ASW=Anti-Submarine; AEW=Airborne Early Warning; MEDEVAC=Medical Evac; EW=Electronic Warfare; SAR=Search-Rescue
Commitments / Honors
Military lapel ribbon for Operation Allied Force
Military lapel ribbon for the Arab-Israeli War
Military lapel ribbon for the Battle of Britain
Military lapel ribbon for the Battle of Midway
Military lapel ribbon for the Berlin Airlift
Military lapel ribbon for the Chaco War
Military lapel ribbon for the Cold War
Military lapel ribbon for the Cuban Missile Crisis
Military lapel ribbon for pioneering aircraft
Military lapel ribbon for the Falklands War
Military lapel ribbon for the French-Indochina War
Military lapel ribbon for the Golden Age of Flight
Military lapel ribbon for the 1991 Gulf War
Military lapel ribbon for the Indo-Pak Wars
Military lapel ribbon for the Iran-Iraq War
Military lapel ribbon for the Korean War
Military lapel ribbon for the 1982 Lebanon War
Military lapel ribbon for the Malayan Emergency
Military lapel ribbon representing modern aircraft
Military lapel ribbon for the attack on Pearl Harbor
Military lapel ribbon for the Six Day War
Military lapel ribbon for the Soviet-Afghan War
Military lapel ribbon for the Spanish Civil War
Military lapel ribbon for the Suez Crisis
Military lapel ribbon for the Vietnam War
Military lapel ribbon for Warsaw Pact of the Cold War-era
Military lapel ribbon for the WASP (WW2)
Military lapel ribbon for the World War 1
Military lapel ribbon for the World War 2
Military lapel ribbon for the Yom Kippur War
Military lapel ribbon for experimental x-plane aircraft
* Ribbons not necessarily indicative of actual historical campaign ribbons. Ribbons are clickable to their respective campaigns/operations.

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