Lockheed YF-12
Encyclopedia
The Lockheed YF-12 was an American prototype
interceptor aircraft
, which the United States Air Force
evaluated as a development of the highly-secret Lockheed A-12 that also spawned the SR-71 Blackbird
.
(USAF) sought a replacement for the F-106 Delta Dart
. As part of the Long Range Interceptor Experimental (LRI,X) program, the North American XF-108 Rapier, a Mach 3 interceptor, was selected. However, the F-108 was canceled in September 1959. During this time Lockheed's Skunk Works was developing the A-12 spy plane
for the Central Intelligence Agency
(CIA) under the Oxcart program. Skunk Works' Kelly Johnson proposed a version of the A-12 called AF-12 by the company and the USAF ordered three AF-12s in mid-1960s.
The AF-12s would take the seventh through ninth slots on the A-12 production line and have them completed in the YF-12A interceptor configuration. The main changes involved modifying the aircraft's nose to accommodate the Hughes AN/ASG-18
fire-control radar originally developed for the XF-108, and the addition of a second cockpit for a crew member to operate the fire control radar. The nose modifications changed the aircraft's aerodynamics enough to require ventral fins to be mounted under the fuselage and engine nacelles to maintain stability. Finally, four bays previously used to house the A-12's reconnaissance equipment were converted to carry Hughes AIM-47 Falcon
(GAR-9) missiles. One bay was used for fire control equipment.
The first YF-12A flew on 7 August 1963. President Lyndon B. Johnson
announced the existence of the plane on 24 February 1964. The YF-12A was announced in part to continue hiding the A-12, its still-secret ancestor; any sightings of CIA/Air Force A-12s based at Area 51
in Nevada could be attributed to the well-publicized Air Force YF-12As based at Edwards Air Force Base
in California.
On 14 May 1965 the Air Force placed a production order for 93 F-12Bs for its Aerospace Defense Command
(ADC). However, Secretary of Defense Robert McNamara
would not release the funding for three consecutive years due to Vietnam War
costs. Updated intelligence placed a lower priority on defense of the continental US, so the F-12B was deemed as being no longer needed. Then in January 1968, the F-12B program was officially ended.
would go on to become a NASA astronaut and walk on the Moon.
The program was abandoned following the cancellation of the production F-12B, but the YF-12s continued flying for many years with the USAF and with NASA
as research aircraft.
. Air Force objectives included exploration of its use in a tactical environment, and how AWACS would control supersonic aircraft. The Air Force portion was budgeted at US$4 million. The NASA
tests would answer questions such as how engine inlet performance affected airframe and propulsion interaction, boundary layer noise, heat transfer under high Mach conditions, and altitude hold at supersonic speeds. The NASA budget for the 2.5-year program was US$14 million.
Of the three YF-12As, #60-6934 was damaged beyond repair by fire at Edwards during a landing mishap on 14 August 1966; its rear half was salvaged and combined with the front half of a Lockheed static test airframe to create the one and only SR-71C. That aircraft was nicknamed "The Bastard" by its pilots, as it did not fly quite straight. It is unique among SR-71s as it retained the ventral fins under its nacelles from its YF-12 lineage.
YF-12A #60-6936 was lost on 24 June 1971 due to an inflight fire caused by a failed fuel line; both pilots ejected safely just north of Edwards AFB. YF-12A #60-06935 is the only surviving YF-12A; it was recalled from storage in 1969 for a joint USAF/NASA investigation of supersonic cruise technology, and then flown to the National Museum of the United States Air Force
at Wright-Patterson Air Force Base
near Dayton
, Ohio on 17 November 1979.
A fourth YF-12 aircraft, the "YF-12C", was actually the second SR-71A (61–7951). This SR-71A was re-designated as a YF-12C and given a fictitious serial number 60-6937 from an A-12 to maintain SR-71 secrecy. The YF-12C was loaned to NASA for propulsion testing after the loss of YF-12A (60–6936) in 1971. The YF-12C was operated by NASA until September 1978, when it was returned to the Air Force.
F-12B : Production version of the YF-12A; canceled before production could begin.
YF-12C : Fictitious designation for a SR-71 provided to NASA for flight testing. The YF-12 designation to keep SR-71 information out of the public domain.
The sole remaining YF-12A is located at the National Museum of the United States Air Force
, at Wright-Patterson Air Force Base, near Dayton
, Ohio. This aircraft has small patches in its skin, on the starboard side below the cockpit. The patches cover holes caused by the "spurs" of a crewman who had to evacuate the plane after an emergency landing. The "YF-12C" (actually SR-71A, serial 61-7951) is on display at the Pima Air Museum in Tucson, AZ as of 2005.
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
interceptor aircraft
Interceptor aircraft
An interceptor aircraft is a type of fighter aircraft designed specifically to prevent missions of enemy aircraft, particularly bombers and reconnaissance aircraft. Interceptors generally rely on high speed and powerful armament in order to complete their mission as quickly as possible and set up...
, which the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
evaluated as a development of the highly-secret Lockheed A-12 that also spawned the SR-71 Blackbird
SR-71 Blackbird
The Lockheed SR-71 "Blackbird" was an advanced, long-range, Mach 3+ strategic reconnaissance aircraft. It was developed as a black project from the Lockheed A-12 reconnaissance aircraft in the 1960s by the Lockheed Skunk Works. Clarence "Kelly" Johnson was responsible for many of the...
.
Design and development
In the late 1950s the United States Air ForceUnited States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
(USAF) sought a replacement for the F-106 Delta Dart
F-106 Delta Dart
The Convair F-106 Delta Dart was the primary all-weather interceptor aircraft for the United States Air Force from the 1960s through the 1980s. Designed as the so-called "Ultimate Interceptor", it has proven to be the last dedicated interceptor in USAF service to date...
. As part of the Long Range Interceptor Experimental (LRI,X) program, the North American XF-108 Rapier, a Mach 3 interceptor, was selected. However, the F-108 was canceled in September 1959. During this time Lockheed's Skunk Works was developing the A-12 spy plane
Reconnaissance aircraft
A reconnaissance aircraft is a manned military aircraft designed, or adapted, to carry out aerial reconnaissance.-History:The majority of World War I aircraft were reconnaissance designs...
for the Central Intelligence Agency
Central Intelligence Agency
The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...
(CIA) under the Oxcart program. Skunk Works' Kelly Johnson proposed a version of the A-12 called AF-12 by the company and the USAF ordered three AF-12s in mid-1960s.
The AF-12s would take the seventh through ninth slots on the A-12 production line and have them completed in the YF-12A interceptor configuration. The main changes involved modifying the aircraft's nose to accommodate the Hughes AN/ASG-18
Hughes AN/ASG-18
The Hughes AN/ASG-18 was a prototype fire control system and radar, originally intended for the XF-108 Rapier interceptor aircraft, for the United States Air Force....
fire-control radar originally developed for the XF-108, and the addition of a second cockpit for a crew member to operate the fire control radar. The nose modifications changed the aircraft's aerodynamics enough to require ventral fins to be mounted under the fuselage and engine nacelles to maintain stability. Finally, four bays previously used to house the A-12's reconnaissance equipment were converted to carry Hughes AIM-47 Falcon
AIM-47 Falcon
The Hughes AIM-47 Falcon, originally GAR-9, was a very long-range high-performance air-to-air missile that shared the basic design of the earlier AIM-4 Falcon. It was developed in 1958 along with the new Hughes AN/ASG-18 radar fire-control system intended to arm the Mach 3 XF-108 Rapier interceptor...
(GAR-9) missiles. One bay was used for fire control equipment.
The first YF-12A flew on 7 August 1963. President Lyndon B. Johnson
Lyndon B. Johnson
Lyndon Baines Johnson , often referred to as LBJ, was the 36th President of the United States after his service as the 37th Vice President of the United States...
announced the existence of the plane on 24 February 1964. The YF-12A was announced in part to continue hiding the A-12, its still-secret ancestor; any sightings of CIA/Air Force A-12s based at Area 51
Area 51
Area 51 is a military base, and a remote detachment of Edwards Air Force Base. It is located in the southern portion of Nevada in the western United States, 83 miles north-northwest of downtown Las Vegas. Situated at its center, on the southern shore of Groom Lake, is a large military airfield...
in Nevada could be attributed to the well-publicized Air Force YF-12As based at Edwards Air Force Base
Edwards Air Force Base
Edwards Air Force Base is a United States Air Force base located on the border of Kern County, Los Angeles County, and San Bernardino County, California, in the Antelope Valley. It is southwest of the central business district of North Edwards, California and due east of Rosamond.It is named in...
in California.
On 14 May 1965 the Air Force placed a production order for 93 F-12Bs for its Aerospace Defense Command
Aerospace Defense Command
Aerospace Defense Command is an inactive United States Air Force Major Command. Established in 1946 under the United States Army Air Forces, its mission was to organize and administer the integrated air defense system of the Continental United States , exercise direct control of all active...
(ADC). However, Secretary of Defense Robert McNamara
Robert McNamara
Robert Strange McNamara was an American business executive and the eighth Secretary of Defense, serving under Presidents John F. Kennedy and Lyndon B. Johnson from 1961 to 1968, during which time he played a large role in escalating the United States involvement in the Vietnam War...
would not release the funding for three consecutive years due to Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
costs. Updated intelligence placed a lower priority on defense of the continental US, so the F-12B was deemed as being no longer needed. Then in January 1968, the F-12B program was officially ended.
USAF testing
During flight tests the YF-12As set a speed record of 2,070.101 mph (3,331.505 km/h) and altitude record of 80,257.86 ft (24,462.6 m), both on 1 May 1965, and demonstrated promising results with their unique weapon system. Six successful firings of the AIM-47 missiles were completed. The last one launched from the YF-12 at Mach 3.2 at an altitude of 74,000 ft (22,677 m) to a JQB-47E target drone 500 ft (152 m) off the ground. One of the Air Force test pilots, Jim IrwinJames Irwin
James Benson Irwin was an American astronaut and engineer. He served as Lunar Module pilot for Apollo 15, the fourth human lunar landing; he was the eighth person to walk on the Moon.-Early life:...
would go on to become a NASA astronaut and walk on the Moon.
The program was abandoned following the cancellation of the production F-12B, but the YF-12s continued flying for many years with the USAF and with NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
as research aircraft.
NASA testing
The initial phase of this program included test objectives aimed at answering some questions about implementation of the B-1B-1 Lancer
The Rockwell B-1 LancerThe name "Lancer" is only applied to the B-1B version, after the program was revived. is a four-engine variable-sweep wing strategic bomber used by the United States Air Force...
. Air Force objectives included exploration of its use in a tactical environment, and how AWACS would control supersonic aircraft. The Air Force portion was budgeted at US$4 million. The NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
tests would answer questions such as how engine inlet performance affected airframe and propulsion interaction, boundary layer noise, heat transfer under high Mach conditions, and altitude hold at supersonic speeds. The NASA budget for the 2.5-year program was US$14 million.
Of the three YF-12As, #60-6934 was damaged beyond repair by fire at Edwards during a landing mishap on 14 August 1966; its rear half was salvaged and combined with the front half of a Lockheed static test airframe to create the one and only SR-71C. That aircraft was nicknamed "The Bastard" by its pilots, as it did not fly quite straight. It is unique among SR-71s as it retained the ventral fins under its nacelles from its YF-12 lineage.
YF-12A #60-6936 was lost on 24 June 1971 due to an inflight fire caused by a failed fuel line; both pilots ejected safely just north of Edwards AFB. YF-12A #60-06935 is the only surviving YF-12A; it was recalled from storage in 1969 for a joint USAF/NASA investigation of supersonic cruise technology, and then flown to the National Museum of the United States Air Force
National Museum of the United States Air Force
The National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
at Wright-Patterson Air Force Base
Wright-Patterson Air Force Base
Wright-Patterson Air Force Base is a United States Air Force base in Greene and Montgomery counties in the state of Ohio. It includes both Wright and Patterson Fields, which were originally Wilbur Wright Field and Fairfield Aviation General Supply Depot. Patterson Field is located approximately...
near Dayton
Dayton, Ohio
Dayton is the 6th largest city in the U.S. state of Ohio and the county seat of Montgomery County, the fifth most populous county in the state. The population was 141,527 at the 2010 census. The Dayton Metropolitan Statistical Area had a population of 841,502 in the 2010 census...
, Ohio on 17 November 1979.
A fourth YF-12 aircraft, the "YF-12C", was actually the second SR-71A (61–7951). This SR-71A was re-designated as a YF-12C and given a fictitious serial number 60-6937 from an A-12 to maintain SR-71 secrecy. The YF-12C was loaned to NASA for propulsion testing after the loss of YF-12A (60–6936) in 1971. The YF-12C was operated by NASA until September 1978, when it was returned to the Air Force.
Variants
YF-12A : Pre-production version. Three were built.F-12B : Production version of the YF-12A; canceled before production could begin.
YF-12C : Fictitious designation for a SR-71 provided to NASA for flight testing. The YF-12 designation to keep SR-71 information out of the public domain.
Specifications (YF-12A)
Aircraft disposition
| Serial number | Model | Location or fate |
|---|---|---|
| 60-6934 | YF-12A | Transformed into SR-71C 61-7981 after fire damage in 1966, on display at Hill Aerospace Museum Hill Aerospace Museum Hill Aerospace Museum, located near Ogden, Utah, is a U.S. Air Force museum that is part of the United States Air Force Heritage Program.The museum, founded in 1981 and moved to its current location in 1991, displays over 90 aircraft from around the world, in addition to a variety of munitions,... , Hill AFB, UT |
| 60-6935 | YF-12A | National Museum of the U.S. Air Force, Wright-Patterson AFB, OH |
| 60-6936 | YF-12A | Lost, 24 June 1971 |
The sole remaining YF-12A is located at the National Museum of the United States Air Force
National Museum of the United States Air Force
The National Museum of the United States Air Force is the official museum of the United States Air Force located at Wright-Patterson Air Force Base northeast of Dayton, Ohio. The NMUSAF is the world's largest and oldest military aviation museum with more than 360 aircraft and missiles on display...
, at Wright-Patterson Air Force Base, near Dayton
Dayton, Ohio
Dayton is the 6th largest city in the U.S. state of Ohio and the county seat of Montgomery County, the fifth most populous county in the state. The population was 141,527 at the 2010 census. The Dayton Metropolitan Statistical Area had a population of 841,502 in the 2010 census...
, Ohio. This aircraft has small patches in its skin, on the starboard side below the cockpit. The patches cover holes caused by the "spurs" of a crewman who had to evacuate the plane after an emergency landing. The "YF-12C" (actually SR-71A, serial 61-7951) is on display at the Pima Air Museum in Tucson, AZ as of 2005.
See also
External links
- Mach 3+: NASA/USAF YF-12 Flight Research, 1969–1979 by Peter W. Merlin (PDF book)
- YF-12A Flight Manual and YF-12A #60-6935 Photos on SR-71.org
- YF-12 fact sheet on USAF Museum site
- Blackbird Spotting maps the location of every existing Blackbird, with aerial photos from Google Maps
- USAF Aircraft Serial Numbers for 1960, including all A-12s, YF-12As, and M-21s