The Rockwell XFV-12 was a prototype supersonic

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

fighter which was built in 1977. The XFV-12 design attempted to combine the Mach 2 speed and

AIM-7 Sparrow The AIM-7 Sparrow (Air Intercept Missile) is an American, medium-range semi-active radar homing air-to-air missile operated by the United States Air Force, United States Navy, and United States Marine Corps, as well as other various air forces ...

armament of the

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in a

VTOL A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...

(vertical takeoff and landing) fighter for the small

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which was under study at the time. On paper, it looked superior to the subsonic

Hawker Siddeley Harrier The Hawker Siddeley Harrier is a British military aircraft. It was the first of the Harrier series of aircraft and was developed in the 1960s as the first operational ground attack and reconnaissance aircraft with vertical/short takeoff and ...

attack fighter. However it was unable to demonstrate an untethered vertical takeoff and its inability to meet performance requirements terminated the program.

Design and development

In 1972, the Navy issued a request for proposals for a next generation supersonic V/STOL fighter/attack aircraft. Rockwell's design with the XFV-12 won against

Convair Convair, previously Consolidated Vultee, was an American aircraft manufacturing company that later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Consolidated Aircraft and Vultee Aircraft. In 1953, it ...

's proposal with the

Convair Model 200 The Convair Model 200 was a design for a supersonic vertical takeoff and landing (VTOL) fighter requirement for the United States Navy Sea Control Ship. Further versions were planned for conventional catapult launches and landing using the arre ...

. The XFV-12A, despite its concept being considered risky compared to that of the Harrier, was selected for development. To reduce costs, the nose from a

Douglas A-4 Skyhawk The Douglas A-4 Skyhawk is a single-seat subsonic carrier-capable light attack aircraft developed for the United States Navy and United States Marine Corps in the early 1950s. The delta-winged, single turbojet engined Skyhawk was designed a ...

and intakes from the F-4 were used. Engine rig testing began in 1974. Free-flight model tests conducted at the

NASA Langley The Langley Research Center (LaRC or NASA Langley), located in Hampton, Virginia, United States of America, is the oldest of NASA's field centers. It directly borders Langley Air Force Base and the Back River on the Chesapeake Bay. LaRC has foc ...

full-scale wind tunnel showed the projected thrust augmentation levels were highly optimistic, and that the aircraft would most likely be incapable of vertical flight on the thrust available, while the design remained suitable for conventional flight. The XFV-12 used a thrust augmented wing concept in which exhaust would be directed through spaces in a wing opened up like

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to increase available lift, somewhat like Lockheed's unsuccessful

XV-4 Hummingbird The Lockheed XV-4 Hummingbird (originally designated VZ-10) was a U.S. Army project to demonstrate the feasibility of using VTOL for a surveillance aircraft carrying target-acquisition and sensory equipment.canards were extremely large, with almost 50% of the area of the wings, making it effectively a

tandem wing QAC Quickie Q2 A tandem wing is a wing configuration in which a flying craft or animal has two or more sets of wings set one behind another. All the wings contribute to lift. The tandem wing is distinct from the biplane in which the wings are ...

. The 30,000 lbf (130 kN)-class afterburning

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engine had enough thrust to lift the weight of the 20,000 lb (9,072 kg) aircraft. It was modified to further increase thrust for vertical lift. The rear engine exhaust was closed and the gases redirected through ducts to ejector nozzles in the wings and canards for vertical lift.

Operational history

Ground testing of the XFV-12A began in July 1977, and the aircraft was officially rolled out at the Rockwell International facility in

Columbus, Ohio Columbus () is the state capital and the most populous city in the U.S. state of Ohio. With a 2020 census population of 905,748, it is the 14th-most populous city in the U.S., the second-most populous city in the Midwest, after Chicago, and t ...

on 26 August. Due to increasing costs, construction of the second prototype was abandoned. Tethered hover tests were conducted in 1978. Over the course of six months, it was determined that the XFV-12A design suffered from major deficiencies with regard to vertical flight, especially a lack of sufficient vertical thrust. Lab tests showed 55% thrust augmentation should be expected; however, differences in the scaled-up system dropped augmentation levels to 19% for the wing and a mere 6% in the canard. While the augmenters did work as expected, the extensive ducting of the propulsion system degraded thrust, and in the end the

power-to-weight ratio Power-to-weight ratio (PWR, also called specific power, or power-to-mass ratio) is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measuremen ...

was such that the engine was capable of vertically lifting only 75% of the weight of the aircraft in which it was mounted. Following the tests, and with the program suffering from cost overruns, the Navy decided the XFV-12A was not worth further development, and cancelled the project in 1981. The October 6, 1975 issue of ''

Aviation Week ''Aviation Week & Space Technology'', often abbreviated ''Aviation Week'' or ''AW&ST'', is the flagship magazine of the Aviation Week Network. The weekly magazine is available in print and online, reporting on the aerospace, defense and aviati ...

'' published an article about the Rockwell NA-382 which was an even more ambitious proposal to the Marine Corps to fit a similar wing to the

Lockheed C-130 Hercules The Lockheed C-130 Hercules is an American four-engine turboprop military transport aircraft designed and built by Lockheed (now Lockheed Martin). Capable of using unprepared runways for takeoffs and landings, the C-130 was originally design ...

, but the plan never made it off the drawing board. Of the two prototypes built, only one was completed, while the second prototype was cancelled. The

United States Marine Corps The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through combi ...

eventually adopted the subsonic British-designed Harrier, the only truly successful

V/STOL A vertical and/or short take-off and landing (V/STOL) aircraft is an airplane able to take-off or land vertically or on short runways. Vertical takeoff and landing (VTOL) aircraft are a subset of V/STOL craft that do not require runways at al ...

design of the 1960s. Its replacement, the

Lockheed Martin F-35 Lightning II The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, all-weather stealth multirole combat aircraft that is intended to perform both air superiority and strike missions. It is also able to provide ele ...

, uses a shaft-driven fan and a swivelling rear nozzle to achieve vertical landing. It is designed for supersonic and vertical flight with performance just over Mach 1.5 with weapons and range comparable to the older F-4 and F-18.

Surviving aircraft

Following program cancellation, the aircraft was disassembled and the cockpit section of the fuselage was stored at NASA's

Plum Brook Station NASA John H. Glenn Research Center at Lewis Field is a NASA center within the cities of Brook Park and Cleveland between Cleveland Hopkins International Airport and the Rocky River Reservation of Cleveland Metroparks, with a subsidiary facilit ...

in Sandusky, Ohio. As of May 2012, a group of high school students at the

EHOVE Career Center EHOVE Career Center is a public vocational school in Milan, Ohio. EHOVE is an acronym that stands for Erie Huron Ottawa Vocational Education. While Erie, Huron and Ottawa counties are the primary covered counties in the district, the school also ...

, with guidance from NASA contractor personnel, were to restore the fuselage for use as a museum display.

Specifications

References

;Notes ;Bibliography *Buttler, Tony. ''American Secret Projects, Fighters & Interceptors 1945-1978''. Hinckley, UK: Midland Publishing. 2007. . * * *

External links