The Lockheed YF-12 is the older brother to the more famous SR-71. Whilst both were used by both the USAF and NASA, they were both used for completely different things!
However, whilst the SR-71 prospered, the YF-12 gained traction before slowly fading away. So why did the Lockheed YF-12 fail when all other Blackbird family members prospered?
Pre-YF-12
The late 1950’s had seen not only the Korean War, but also the beginning of the Vietnam War. Whilst the conflict itself was the US’s first real failure of the Cold War, it did yield a lot in terms of new aircraft requirements.
Prior to this, the newly-formed USAF had been utilizing some of the first generation jet aircraft. These aircraft served in several different roles, as fighters, interceptors, fighter-bombers, bombers etc.
The USAF’s primary interceptor aircraft was the Convair F-106 Delta Dart. However, a new generation of jet aircraft were not only faster, but also more maneuverable, making the F-106 all but outdated.
As such, the USAF began looking for an alternative, launching the Long Range Interceptor Experimental (LRI-X) program. This yielded several aircraft, including the North American XF-108 Rapier.
Initially, the USAF settled for the XF-108, stating that it would enter service as the F-108 Rapier. However, delays and cost overruns caused the DoD to cancel the project in September 1959.
However, they still needed an F-106 replacement, so they continued to evaluate other options. This is where Kelly Johnson’s A-12 came in to the picture, but you may know its more famous descendant, the SR-71.
SR-71 and A-12
Kelly Johnson had been working with the CIA to develop a high altitude reconnaissance aircraft to replace the U-2, which wasn’t as invulnerable as the CIA and US military had first believed. This aircraft was later known as the A-12.
On top of this, the USAF had seen the development of the A-12 and saw the strategic value a similar aircraft would have. This aircraft was developed from the A-12 and was designated as SR-71, sacrificing speed for range.
Up until this point, the USAF hadn’t considered the Blackbird family for any other role than as a reconnaissance aircraft. However, Lockheed executives, backed by Kelly Johnson, convinced the USAF of another use for the Blackbird.
This was as a high speed, high altitude, missile-armed armed interceptor unlike anything the Soviets have ever seen. Compared to Soviet aircraft or the era, even those under development, no aircraft could compete with its speed or altitude.
As such, the USAF very very keen, giving Lockheed almost unlimited financial resources to develop a longer range, Mach 3+, missile-equipped variant of the Lockheed A-12.
Very soon, Lockheed had began designing this variant, designating this as the AF-12. Once it entered USAF service, it was redesignated as the YF-12 whilst it was in the prototype phase (to be redesignated as the F-12 when it entered service).
Development
As Kelly Johnson had led the design team for the A-12 (and eventually the SR-71), he once again led the AF-12 program (eventually the YF-12 program). Johnson used the A-12 as a base, whilst redesigning several key elements of the aircraft.
Johnson brought in Lockheed’s engine inlet expert, Ben Rich, to help with the YF-12’s new engines. These engines made the YF-12 as fast as the A-12, however, gave it a superior range.
As a part of the previous Long Range Interceptor Experimental (LRI-X) program, the USAF had contracted Hughes Aircraft Company to develop the Hughes AN/ASG-18Â radar.
In order to try to save on costs, and not waste cutting-edge technology, Lockheed was ordered to make the YF-12 accommodate the AN/ASG-18. This saw almost a complete redesign of the YF-12’s nose section.
Due to the YF-12’s intended role, much of the fuselage was hollowed out. Instead of containing cameras and other spy gear, the YF-12 had a completely new, state-of-the-art bomb bay designed, to carry a series of air-to-air missiles.
On top of this, the YF-12 had to have a lengthened cockpit installed. This was so that the YF-12 could have both a pilot and someone to be both a navigator and, primarily, a fire control officer (FCO).
Operational History
Despite never properly entering service as both Lockheed and the USAF had hoped, it never stopped the YF-12 from having a very detailed service life. This operated for two different branches of the government: the USAF and NASA.
USAF
In August 1963, the USAF took possession of three YF-12s for testing purposes. These flights would be carried out by a series of Lockheed and USAF test pilots.
These tests aimed to push the YF-12 to its limits, placing it in almost every situation it was likely to come across. Part of these tests included intercepting “Russian” bombers and fighter jets.
Part of these tests also included dogfights. Whilst the YF-12 wasn’t designed for such a feat, it was nevertheless placed in that situation, to see how it handled. During this, several tactics were developed, but were never used.
Throughout its entire testing, the YF-12 continued to break both speed and altitude records. On May 1 1965, a YF-12 test flight resulted in the aircraft setting two records, one for speed and one for altitude.
These were: 2,070.101 miles per hour (3,331.505 km/h) and 80,257.86 feet in altitude. The former makes the Lockheed YF-12, even by modern standards, among the fastest aircraft in the world!
Even after the YF-12 project was cancelled, the USAF continued to use the YF-12 aircraft. These were mostly training flights for the SR-71, however, were also to throw off Soviet spies, as the YF-12 resembled the SR-71 and A-12.
NASA
Following its USAF service, NASA became quite interested in the YF-12, as it would eventually do for the A-12-derived SR-71 as well. Much of the NASA YF-12 research was done in tandem with the USAF.
Much of the work that NASA did was to do with the YF-12’s control issues. This was down to the same issue YF-12 pilots faced were the same as Apollo pilots faced. As such, NASA hoped to diminish or get rid of this issue on the YF-12.
They believed that if they could do it for the YF-12, they could eventually take that research and apply it to the space shuttle too. Eventually, both goals were accomplished.
Whilst attempting to do this, NASA developed the Cooperative Airframe-Propulsion Control System (CAPCS) for the Lockheed YF-12. This would essentially regulated pitch and direction in order to control airframe temperature.
This would later be added to several NASA aircraft. These would include the NASA X-43, as well as the subsequent space shuttles. This decreased the latter’s risk of exploding on takeoff.
A few Lockheed YF-12 test flights concerned altitude. As the YF-12 was the highest flying aircraft of its time, beat only by the SR-71’s 90,000 ft, NASA wanted to study how the airframe deteriorated over time, in order to better design their space shuttles.
Why Did The YF-12 Fail?
Initially, the USAF were extremely impressed with the YF-12. They believed that this aircraft would frighten the Soviets so much, that they would no longer test US airspace, nor would they want to continue Cold War-era proxy wars.
As such, they placed an order for 96 Lockheed YF-12s near the beginning of the YF-12’s testing. The USAF and Lockheed had agreed a price of $18 million per unit in 1965 (today worth almost $150 million).
However, this sale was blocked by Secretary of Defense, Robert McNamara. Instead, this money was funneled into the failed F-106X program (a modernized F-106 variant).
Ironically, it was the success of the A-12’s other descendant, the Lockheed SR-71 Blackbird that killed the Lockheed YF-12 so to speak. The intelligence that the SR-71 gathered revealed a change in the Soviet’s plans.
This in turn revealed that the Lockheed YF-12 interceptor was no longer needed. As such, the F-12 (YF-12) program was cancelled, with all YF-12s remaining in USAF service.
On top of this, the rising cost of titanium made the YF-12 extremely difficult to manufacture. The Soviets had been supplying the US with titanium (through several front companies) which were then being built into SR-71s.
The Soviets caught onto this trick through their spy rings, and ceased supplying the US with more titanium. Their other sources of titanium began to dry up too, driving the price through the roof.
Specifications
Although only three YF-12s were actually built and used, Lockheed designed three separate variants. These three variants (one pre-production) were designed for various different roles.
However, the DoD has only ever made the specifications for the pre-production YF-12 available to the public. This is perhaps due to the project still being highly classified, even almost 60 years on!
| Specifications | YF-12 |
|---|---|
| Length | 101 ft 8 in (31 m) |
| Wingspan | 55 ft 7 in (17 m) |
| Height | 18 ft 6 in (5.64 m) |
| Crew | 2 (Pilot and FCO) |
| Aspect Ratio | 1.7 |
| Max Speed | Mach 3.35 (2,570 mph; 4,137 kmh; 2,234 kn) |
| Combat Range | 3,000 mi (4,800 km, 2,600 nmi) |
| Service Ceiling | 90,000 ft (27,400 m) |
| MTOW | 140,000 lb (63,504 kg) |
| Armament | 3× Hughes AIM-47A air-to-air missiles located in internal bays |
What Was it Like to Fly the YF-12?
Despite the YF-12 not flying for over 40 years, the project us still incredibly classified. Unlike many other experimental aircraft of recent times, such as the X-32, there have been no public interviews with Lockheed YF-12 pilots.
Many interviews with former YF-12 pilots have skirted around the aircraft, likely due to the aircraft still being highly classified. Instead, these interviews often focus on other aircraft and achievements, rather than the YF-12.
However, there have been several interviews with A-12 and SR-71 pilots, who have hinted that the handling of the YF-12 is very similar to that of the A-12 or the SR-71. However, we can’t be sure.
Among USAF pilots interviewed by us for this article, with a mixture of currently serving and past pilots, most had a positive view of the Blackbird family as a whole, with a focus on the SR-71 and YF-12.
Avgeeks
Among avgeeks, the YF-12 is incredibly popular. For many of them, they see the speed of the A-12 and the range of the SR-71 combined to create a formidable combination!
Whilst some avgeeks dislike the SR-71 for various reasons, most avgeeks seem to love the YF-12. For those who dislike the SR-71, it has the parts that they don’t mind about the SR-71, minus the things they despise!
Because of its failure, many have wondered what a Lockheed F-12 would’ve looked like. More importantly, they have wondered how it would’ve altered the outcome of the Cold War.
Some believe that the Lockheed F-12 would’ve created a supersonic arms race, similar to the space race and/or the nuclear weapons race. This would’ve then prolonged the Cold War several more years, or ignited WWIII.
Others believe that the Soviets wouldn’t have come up with an equivalent aircraft, and would’ve feared US military intervention and domination. As such, they’d have sought to end the Cold War all together.
Legacy
Despite never entering “proper” service, the Lockheed YF-12 left a large impact on the aviation industry as a whole!
Lockheed
Despite the USAF cancelling the F-12 project, the USAF was still interested in the Blackbird family. Prior to the YF-12, the USAF and Lockheed had been discussing a longer range aircraft developed from the A-12.
Following the YF-12’s cancellation, Lockheed and the USAF began working on a spyplane similar to the A-12, which could fly over the USSR without being shot down or intercepted. Today, that aircraft is known as the SR-71.
The Blackbird family, and indeed the YF-12 in particular helped to put Lockheed firmly on the map. Prior to this, they had just been another military and civilian aircraft manufacturer.
However, the Lockheed YF-12 caused the aviation community to stop and marvel at it. Even today, Lockheed’s successor company, Lockheed Martin, is revered for its ability to produce breathtaking aircraft!
Lockheed YF-12
The YF-12 was finally retired from service in September 1978, after being stored and recalled from storage several times. Although two of the three Lockheed YF-12s were lost during service, one/two still remain.
Of these two remaining aircraft, one was a production YF-12, being the only one of the three to survive. The other one was actually the second SR-71 ever built, given the fictional YF-12C designation.
This was in order to keep up appearances for the secretly scrapped YF-12 project.
Both aircraft are currently preserved in two different locations in the US. The first aircraft, the production YF-12, is on display at the Wright-Patterson Air Force Base Museum in Dayton, Ohio.
The other YF-12, one of the three production YF-12s (one of the two which crashed), is on partial display at the Hill Aerospace Museum, Hill Air Force Base, Utah.
Future Aircraft
It wasn’t just the SR-71 that was influenced by the YF-12. Whilst the Lockheed D-21 was primarily based on the Lockheed A-12, a lot of its technology was incorporated from or based on the YF-12’s systems.
On top of this, many of the YF-12’s technologies were also incorporated on later Lockheed military aircraft. Some of these systems were significantly downgraded and had most if their military backgrounds erased to be use don the Lockheed L-1011.
Thanks to its service with NASA, both the designs of the B-1 and the E-3 Sentry were altered. The B-1 was altered to be more aerodynamic, this also helped to give it an air of stealth, which made it harder to track.
Whereas, the E-3 was altered to have a better radar that could detected supersonic aircraft easier. Many of these designs would be incorporated on most subsequent American-built AEW&C aircraft.
What do you think of the Lockheed YF-12? Should it have entered service regardless? Tell me in the comments!