Skyfire77 last edited by
A CIA A-12, with USAF markings to disguise its ownership. Note the unpainted rudders, which was normal for OXCARTs even after the rest of the planes were painted with Iron Ball radar-masking paint. | Photo: USAF
In the beginning, there was Project GUSTO, a plan to replace the U-2 spyplane with a faster, higher plane hoped to be immune to Soviet SAMs. Lockheed's Skunk Works, which produced the U-2 under the internal name "Angel", began researching new ideas under the name "Archangel". Beginning with Archangel 1, the group refined the ideas being incorporated into the new plane, including ramjets, zip fuels, new materials and radical ideas for wing and fuselage shaping. Competition came from within Lockheed, as the company had also proposed SUNTAN, a scaled-up F-104 powered by hydrogen, as well as from Convair, which advanced their FISH (First Invisible Super Hustler) parasite design.
SUNTAN would have been fast, but the range was an issue. | Illustration: Lockheed Aircraft Corp.
The FISH would have been launched from an enlarged variant of the Hustler, the B-58B. | Illustration: Convair
Basically none of the eventual OXCART is recognizable in the A-1 | Illustration: Lockheed Aircraft Corp.
A number of revisions followed, with Lockheed dropping the CL400 entirely, and evolving from the A-1 to the A-2, and so on up to the A-11. The plane was massive for a two-seater, nearly 120' long, with gross take-off weight of 92,000lbs. The plane was powered by two J58 engines, and would hit an estimated Mach 3.2 burning a mix of zip fuel and JP-150. The Convair FISH had similarly been refined into the KINGFISH, now a single aircraft of somewhat more modest proportions than the A-11. The KINGFISH would also have been powered by J58s, with a cruise speed of Mach 3.2. The Convair design had an additional advantage of being shaped to lower its radar cross-section (RCS), which was expected to also help hide the plane from Soviet radars.
The KINGFISH was larger than the original FISH, though it was still a twin-tailed delta wing. | Illustration: Convair
Archangel design #11 is still pretty far from the final A-12, though the forward fuselage is close, only missing the eventual chines. | Illustration: Lockheed Aircraft Corp.
Lockheed further refined the A-11 to also lower its RCS, with the single large fin replaced by two smaller fins, each canted inwards, mounted over the engines, which were now housed in nacelles 2/3rds of the way out on the wings. Chines were also added to the fuselage forwards of the wing to remove right angles. The A-12 was also composed of titanium and heat-resistant composites, the first time either was used on such a large scale.
Lockheed's Burbank plant began work on the A-12s, which presented a number of challenges. Titanium had only been used in limited quantities until this point, and the largest supplier of the metal was in the USSR. The CIA set up a number of shell corporations to acquire enough to construct the OXCARTs. Titanium's strength makes it difficult to machine and form into curves given the available techniques. This limited the ability to form the metal into the wing leading edges, for example. Lockheed's solution was to machine small "fillets" of the material with the required shape and then glue them onto the underlying framework, which was more linear. This construction method is most apparent on the wings; the underlying framework of spars and stringers formed a grid, leaving triangular notches along the leading edge that were filled with fillets. As part of the Skunk Works' efforts to reduce the RCS of the A-12, fillets were made with new radar-absorbing composite materials made from iron ferrite and silicon laminate, both combined with asbestos to absorb radar returns and make the aircraft more stealthy. This is evident on early flights, when the titanium was unpainted, but the composite filets were colored black.
Composite fillets prior to installation. | Photo: Lockheed Aircraft Corp./Nevada Aerospace Collection
A-12s on the Lockheed factory floor. | Photo: Lockheed Aircraft Corp./Nevada Aerospace Collection
Once the A-12s were completed, the next problem was transporting them to the Groom Lake testing grounds. Lockheed contracted with Roadrunners Internationale to build special containers to protect and disguise the OXCARTs, then had them trucked out to Nevada.
Two of the A-12s under construction, with a container behind them. | Photo: Lockheed Aircraft Corp./Roadrunners Internationale
The boxes were actually skeletal frames covered by cloth. | Photo: Lockheed Aircraft Corp./Roadrunners Internationale
A route was scouted ahead of time, since the boxes were rather large, and major roadways were to be avoided for security's sake.
Map of the route taken by the OXCART convoy. | Map: Nevada Aerospace Collection
Photo: Roadrunners Internationale
Photo: Roadrunners Internationale
The convoy had to travel the wrong way on several stretches to clear tight underpasses. | Photo: Roadrunners Internationale
Photo: Roadrunners Internationale
The OXCARTs were eventually delivered to Groom Lake, where they were reassembled and prepped for the first flight. Ongoing production issues with the J58 meant that the first A-12s were fitted with less powerful J75 engines. A-12 number 60-6924 first flew on 26 April 1962, during a high-speed taxi test. Pilot Lou Schalk recalls:
"It was determined that we would make a high-speed taxi test going down our 8000-foot concrete runway towards the Groom Lake bed which had probably 4-5 miles of lake bed suitable for landing beyond the end of the runway, so that seemed like a safe direction to go. The idea was that as I reached takeoff speed was to lift it off the ground and set it back down to see how it felt.
"Well, when we went down the runway and hit takeoff speed and lifted off, it was immediately out of control. It was oscillating longitudinally and laterally. It was obvious the airplane was very unstable. We did not have the damper systems on; no one ever turned the damper systems on on the first flight because you didn't trust them!
"Finally I got hold of it, set it back down on the ground, and was probably a mile or so out on the lakebed at that point in time. Immediately disappeared into a cloud of dust. The tower called to see if I was all right. I replied 'I'm fine, I'm rolling out to slow down and turn around and taxi back.' The tower couldn't hear me because the antenna for my UHF transmitter was on the bottom of the fuselage and was blanked out for the direction of the tower's line of sight. So no one knew what was happening and in the dust kept waiting for the burst of flames as I ran into the mountains. After I turned the corner, if Kelly Johnson hadn't already had a heart attack, he probably breathed a sigh of relief. I taxied back in, and we talked about it that night...I said, 'Why don't we turn the dampers on before we try this again?' We all agreed that was a very good idea!"
I still didn't know what had gone wrong, but I did know we had 12 to 15 thousand pounds of fuel on board for the taxi test. Flying an F-104, that's an awful lot of fuel, that's more that it carries, but we carried 76,000 pounds of fuel so we hardly had anything at all. It was all in the back end. The airplane was statically unstable, which meant that anytime you move the controls or if the airplane had any movement, you had to make a correctional movement with the controls to stop it, otherwise it would keep right on going; where if the airplane is stable, that means it will tend to return to its normal position, say if it hits some rough air or something like that. This is because of the center of gravity and its location to the center of pressure, which is usually about the midpoint of the wing.
"We had so much fuel in the back end of the airplane that the center of gravity was about 3 percent beyond the aft limit, and we were terrifically unstable. On the actual flight where we got airborne and stayed there, we were probably 3 percent forward of where our normal fuel loading would be. The reason that happened was that the ground crew and most of the people who were getting the airplane ready for this taxi test didn't know that we had decided to lift off the airplane and set it back down again that night except for Kelly, myself and the flight test engineer...no one told them!"
This first hop had the fortuitous side-effect of uncovering an issue with the epoxy used to affix the titanium fillets (foreshadowing troubles that would haunt the A-12s and SR-71s for their entire service lives), which the plane shed down the length of the runway. The pieces were hurriedly retrieved (which had to have been fun) and reattached in time for the plane’s official first flight on April 30th.
924 takes off on her official maiden flight, flown by Lou Schalk. | Photo: Lockheed Aircraft Corp.
The A-12 broke the speed of sound just a few days later, achieving Mach 1.1 on 4 May. The J75-equipped A-12s were limited to just Mach 2.0, but by early 1963 the more powerful J58s were being fitted to the fleet, which could now reach the official top speed of Mach 3.35.
Four A-12s were lost during the test program: Article 123 (60-6926) was lost on May 24th 1963 due to an instrument failure. The pilot was able to safely eject. Article 133 (60-6939) crashed in July of 1964 as a result of a failed pitch-control servo. The pilot ejected at an altitude of 200 feet and survived. Article 126 (60-6929) crashed due to the Stability Augmentation System being wired backwards. The pilot successfully ejected at 200 feet up. Article 125 (60-6928) crashed in January of 1967 after running out of fuel due to a faulty gauge. The pilot ejected but was unable to free himself from the seat and was killed when it hit the ground.
The A-12s, TA-12 and YF-12s, in the early scheme of unpainted titanium and black, lined up for a group photo. | Photo: Lockheed Aircraft Corp.
Despite being designed to overfly the USSR, the A-12 never undertook such a mission. In response to the 1960 shoot-down of Gary Powers, President Eisenhower banned all manned overflights of Russia (not to mention that the success of CORONA and other satellites made such flights unnecessary), and the U-2s had proved themselves capable of flying over Cuba. A-12s were then deployed to Okinawa in 1967 and began Operation BLACK SHIELD: mapping SAM sites in North Vietnam. Flights over North Vietnam continued into 1968, along with several flights over North Korea in response to the seizure of the USS Pueblo. Vietnamese forces fired SA-2 SAMs at A-12s on numerous occasions, but while one was found to have propelled a piece of shrapnel into the wing of one plane, no aircraft was ever brought down
Article 128, 60-6931 operating out of Okinawa. OXCARTs participating in BLACK SHIELD were often flown without national insignia, or with USAF markings, and painted with false tail numbers to hide how many A-12s were operating. | Photo: Lockheed Aircr
The A-12 program had actually been canceled in 1966, a victim of reduced budgets and advancing technology. The A-12 was overtaken by the USAF’s rival SR-71 Blackbird, which while slower and lower-flying, was more capable (boasting a pilot and sensor operator instead of the A-12's single pilot) and with a more varied fit of equipment. In June of 1968, the last A-12 loss occurred when Article 129 (60-6932) disappeared flying from Okinawa back to Palmdale. Approximately 20 minutes after refueling from a KC-135Q the automated telemetry system reported that exhaust gas temperature for the right engine had exceeded 860 degrees C. Several seconds later the fuel flow for that engine was reported at less than 7500 pounds per hour, and the system repeated the EGT error. Eight seconds after that, the system reported the same two issues, as well as the plane passing below 68,500 feet. There were no further transmissions, and the pilot did not respond to repeated attempts to communicate. No debris was ever located, and the plane and pilot were declared missing and presumed lost.
The surviving A-12s, TA-12 trainer, and M-21 were painted all black, given false USAF markings, and placed into storage for the next 20 years before being being dispersed across the country to various museums.
The A-12s, painted with false USAF markings, and with the J58 engines removed, sit in storage. | Photo: Lockheed Aircraft Corp.
The TA-12 trainer, the "Titanium Goose", is visible in the back, unpainted and with one nacelle open. | Photo: Lockheed Aircraft Corp.
The A-12 did not receive a formal nickname, partially because of the clandestine nature of its operation. Lockheed workers preferred calling it Cygnus, following Lockheed tradition of naming their planes after celestial bodies. It has also been referred to as Oxcart, the program name at the CIA, and Blackbird, though that name was applied to the SR-71 first. Civilians around the Kadena airbase on Okinawa referred to it as ‘habu’, a local venomous snake. The name was taken up by flight crews, and when the SR-71 arrived at Kadena they too were called Habu.
Chariotoflove last edited by
Bravo, nice write up. I especially like reading pilot memories.
sn4cktimes last edited by
So much info.
RamblinRover last edited by
It's instructive how the Kingfish actually has some design features later seen on the F117. The angled inlets in top of the wings and the like.
pyroholtz last edited by pyroholtz
Great stuff my friend, I'm a sucker for all things Oxcart and the like. I had no idea that the shipment "containers" used to transport from Burbank to Paradise Ranch, were cloth sided. Makes total sense to save weight.