Curtiss-Wright X-100 Tilt-Prop VTOL
The Curtiss-Wright X-100 was a company-funded, experimental proof-of-concept demonstrator for a tilting propeller (tilt-prop) vertical takeoff and landing (VTOL) aircraft. It utilized a novel propeller design that was able to produce a lifting force when the propeller was rotated above the horizontal to a vertical position. This concept was known as the “radial force” principle and was also utilized by the follow-on Curtiss-Wright X-200/X-19 Tri-Service quad tilt-prop VTOL aircraft prototype.
The X-100 was a two-seat, metal and fabric-covered aircraft with fixed landing gear: two main landing wheels, a tailwheel and a nosewheel that was added later. It was powered by a single Lycoming YT-53-L-1 turboshaft that produced 825 shp (615 kW). The laterally displaced tilt-props were mounted on a very small span, narrow-chord wing in streamlined tilting nacelles. Yaw and pitch control in hover and low speeds was achieved by vectoring pressurized engine exhaust ducted a “Jetivator” vented nozzle.
By February 1958, Curtiss-Wright started construction of the prototype and with the aircraft nearly completed, a roll-out ceremony was held on Dec. 22, 1958 at the Curtiss-Wright airport, Fairfield, New Jersey. “Tethered” hover testing commenced on April 20, 1959 and the aircraft completed its first free hover flight on Sept. 12, 1959. On March 29, 1960, test pilot Bill Furlich made the first rolling takeoff. The X-100 completed its one and only transition on April 13, 1960 with the tilting nacelles rotation limited to 12 deg. above horizontal.
Flight testing revealed the high velocity propeller downwash, combined with limited effectiveness of the “Jetivator” nozzle, made operations in ground effect very challenging. By August 1960, Curtiss-Wright testing was completed and the aircraft was transferred to NASA’s Langley Research Center for further, limited hover testing. A total of 14 hours of flight time was achieved for the X-100 tilt-prop VTOL and in 1969 Curtiss-Wright donated the aircraft to the Smithsonian Institution and it now resides in storage.
Characteristics:
- Propeller diameter: 10 ft (3.05 m)
- Length: 28 ft 4 in (8.64 m)
- Height: 10 ft 9 in (3.28 m)
- Empty weight: 3,265 lb (1,481 kg)
- Gross weight: 3,729 lb (1,691 kg)
References:
- https://airandspace.si.edu/collection-objects/curtiss-wright-x-100, R.D. Connor
- “The Curtiss-Wright X-19 Experimental Aircraft – Lessons Learned,” H. Borst, AIAA 90-3206
- Thrust Control of VTOL Aircraft – Part Deux, Daniel C. Dugan, Fifth Decennial AHS Aeromechanics Specialists’ Conference, San Francisco, CA, January 22-24, 2014
Text by Ken Bartie
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