Lockheed YF-12
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| Lockheed YF-12A | ||
|---|---|---|
| Image:YF-12A.jpg | ||
| Description | ||
| Role | Prototype interceptor | |
| Crew | two, pilot and WSO | |
| First Flight | August 7 1963 | |
| Manufacturer | Lockheed | |
| Dimensions | ||
| Length | 101 ft 7 in | 30.97 m |
| Wingspan | 55 ft 7 in | 16.95 m |
| Height | 18 ft 6 in | 5.64 m |
| Wing area | 1,795 ft² | 167 m² |
| Weights | ||
| Empty | 60,730 lb | 27,604 kg |
| Loaded | lb | kg |
| Maximum takeoff | 127,000 lb | 57,727 kg |
| Powerplant | ||
| Engines | 2x Pratt & Whitney J58 | |
| Thrust | 65,000 lbf | 290 kN |
| Performance | ||
| Maximum speed | 2,110 mph | 3,376 km/h |
| Mach 3.2 | ||
| Unrefuelled range | 2,500 miles | 4,000 km |
| Service ceiling | 85,000 ft | 25,914 m |
| Rate of climb | ft/min | m/min |
| Wing loading | lb/ft² | kg/m² |
| Thrust/weight | ||
| Avionics | ||
| Fire control radar | Hughes AN/ASG-18 | |
| Armament | ||
| Missiles | 3x Hughes AIM-47B | |
The Lockheed YF-12 was a prototype interceptor aircraft, one of several variants of the the CIA's highly-secret A-12 OXCART that also spawned the now-famous USAF SR-71 Blackbird.
The YF-12 program was a development of the A-12 OXCART spy plane designed for the CIA and first flown in 1962. Lockheed was able to interest the United States Air Force in the project after the USAF had been forced to cancel the XF-108 Rapier, a Mach 3-capable interceptor intended to replace the F-106 Delta Dart in service. It was pointed out that an aircraft based on the A-12 would provide a less costly alternative to the XF-108, since much of the design and development work on the YF-12 had already been done and paid for. In 1960 the USAF agreed to take the 11th through 13th 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 F-108, and the addition of a second cockpit for a crewmember 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, bays previously used to house the A-12's reconnaissance equipment were converted to carry missiles.
Tests were very impressive: The YF-12As set a number of new speed and altitude records, 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 74,400 feet (22,677 meters) to a target drone B-47 500 feet (152 m) off the ground. In 1965 the Air Force placed an order for 93 YF-12Bs, but this was cancelled due to budget cuts by Secretary of Defense Robert McNamara. The program was abandoned at that point, but the YF-12s continued flying for many years with the United States Air Force, and with NASA as research aircraft.
Of the three YF-12As, #06934 was damaged beyond repair by fire at Edwards AFB during a landing mishap on August 14, 1966; its rear half was salvaged and combined with the front half of a Lockheed static test airframe to create the one and only SR71C. That aircraft (nicknamed "The Bastard" by its pilots, as it did not fly quite straight, and required the pilot to hold some rudder pressure at cruise) today is on display at a museum at Hill AFB, UT. It is unique among all SR-71's as it still carries the ventral fins under its nacelles--an artifact of its YF-12 lineage which does not exist on any other SR-71. YF-12A #06936 was lost June 24, 1971 due to in in-flight fire caused by a failed fuel line; both pilots ejected safely just north of Edwards AFB. YF-12A #06935 is the only surviving YF-12A; it is on display at the National Museum of the United States Air Force at Wright-Patterson Air Force Base near Dayton, Ohio.
A fourth YF-12-series aircraft, the YF-12C, was actually not a YF-12 at all; it was an Air Force SR-71A (#417951) loaned to NASA a month after the loss of YF-12A #06936 for the purposes of allowing NASA to complete propulsion tests originally slated for the lost YF-12. The SR-71A was re-designated as a YF-12C and given a fictional serial number, #06937. (That serial number actually belongs to the 11th A-12; it, like the rest of the OXCART fleet, had been retired in 1968 and was in storage at Palmdale.) 951 was operated (as 937) by NASA until September of 1978, when it was returned to the Air Force. This aircraft is today on display at the Pima Air Museum in Tucson, AZ.
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Image gallery
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Specifications (YF-12A)
Image:Lockheed YF-12A 3view.png {{airtemp |plane or copter?=plane |jet or prop?=jet
|ref=Lockheed's SR-71 'Blackbird' Family; Goodall, James, and Miller, Jay; Midland Publishing, Hincley, England, 2002. |crew=2 |capacity= |length main= 101 ft 8 in |length alt= m |span main= 55 ft 7 in |span alt= m |height main= 18 ft 6 in |height alt= m |area main= 1795 ft² |area alt= m² |airfoil= |empty weight main= lb |empty weight alt= kg |loaded weight main= lb |loaded weight alt= kg |useful load main= lb |useful load alt= kg |max takeoff weight main= 124,000 lb |max takeoff weight alt= kg |more general=
|engine (jet)=Pratt & Whitney J58 (JT11D-20A) |type of jet=high bypass-ratio turbojet with afterburner |number of jets=2 |thrust main= 20,500 lbf |thrust alt= kN |thrust original= |afterburning thrust main= 31,500 lbf |afterburning thrust alt= kN |engine (prop)= |type of prop= |number of props= |power main= hp |power alt= kW |power original=
|max speed main= 2110 mph |max speed alt=above 75,000 ft. |cruise speed main= Mach 3.0 |cruise speed alt= 75,000 to 90,000 ft. |never exceed speed main= mph |never exceed speed alt= km/h |stall speed main= mph |stall speed alt= km/h |range main= 3000 mi |range alt= 4800 km |ceiling main= 90,000 ft
|climb rate main= ft/min |climb rate alt= m/s |loading main= lb/ft² |loading alt= kg/m² |thrust/weight= |thrust/weight main= lbf/lb |thrust/weight alt= N/kg |power/mass main= hp/lb |power/mass alt= kW/kg |more performance=
|armament= 3 x Hughes GAR-9/AIM-47A air-to-air, radar-guided, Mach 4.0 |guns=none |rockets={nubmer of rockets}× {type of rockets} |missiles= |bombs= none
|avionics=Hughes AN/ASG-18 look-down/shoot-down fire control radar
}}
External links
- USAF Museum: YF-12
- SR-71 Online - YF-12A #60-6935 Photos
- Blackbird Spotting maps the location of every existing Blackbird, with aerial photos from Google Maps