Tag Archives: Blackbird

29 February 1964

Lockheed YF-12A 60-6934, the first of three prototype Mach 3+ interceptors. (U.S. Air Force)
Lockheed YF-12A 60-6934, the first of three prototype Mach 3+ interceptors. (U.S. Air Force)

29 February 1964: President Lyndon B. Johnson publicly revealed the existence of the Top Secret Lockheed YF-12A, a Mach 3+ interceptor designed and built by Clarence L. “Kelly” Johnson’s “Skunk Works.” President Johnson referred to the interceptor as the “A-11.”

The following day, the Los Angeles Times ran two lengthy articles on its front page:

Johnson Discloses New Jet Secretly Developed by U.S.

Manned Aircraft Flies at 3 Times Speed of Sound; Military Potential Great


Times National Science Correspondent

     WASHINGTON—President Johnson disclosed Saturday the secret five-year development of an experimental jet aircraft whose performance “far exceeds that of any other aircraft in the world today.”

     Several of the craft, designated A-11, have been “tested in sustained flight” at speeds greater than 2,000 m.p.h. and at heights over 70,000 ft., he said.

     The craft has been made possible “by major advances in aircraft technology of great significance to both military and commercial application,” Mr. Johnson told a press conference.

     Tests are under way at Edwards AFB, Cal., to determine the capability of the airplanes as long-range interceptors of enemy bombers. The plane was developed by Lockheed Aircraft Corp. of Burbank as a special project.

     “Appropriate members of the Senate and the House have been kept fully informed on the program since its day of inception” in 1959, Mr. Johnson said.

     Costs of the A-11 were not revealed, and the President said detailed performance information on the aircraft “will remain strictly classified.” Personnel working on the project have been told to keep quiet, he added.

     Why the project has been wrapped in secrecy was not immediately clear. All that a White House spokesman would say, in answer to a question, was the A-11 represents “a new plateau in aircraft potential”—of such great potential that the military wanted to “explore it in secrecy.”

     The A-11’s development also will aid in building a supersonic transport for commercial airlines, Mr. Johnson said. Like A-11, the transport would fly about Mach 3, or three times the speed of sound.

     One of the most important technological achievements of the A-11 project, the President said, has been the mastery of the problem of using titanium metal on aircraft.

Great Heats

     The aluminum used in today’s airplanes wears out in sustained flight at speeds greater than about Mach 2.2. This is due to the great heats generated by friction as air rushes over the surfaces of the aircraft, particularly the leading edges of the wings.

     “The existence of this (A-11) program is being disclosed today to permit the orderly exploitation of this advanced technology in our military and commercial planes,” Mr. Johnson said.

     High performance aircraft like the controversial TFX multi-service airplane and the Navy’s Phantom fighter will have speeds up to about Mach 2.5—about 1,600 m.p.h. These high speeds are possible for relatively short duration, however.

     Funds for the A-11 were presumably buried in other appropriations, conceivably in part in Air Force appropriations for the B-70.

     Dimensions of the A-11 were not revealed although an in-flight picture of the side view of the plane was distributed. It suggests the A-11 is more than 100 ft. long, based on the size of the pilot’s head in the cockpit.

     The front half of the A-11 looks very similar to that of the X-15 rocket plane which has flown at speeds over 4,000 m.p.h. The characteristic tail surfaces of the X-15, extending both above and below the fuselage, also were obvious.

     The A-11’s engine, a J-58 from Pratt & Whitney, occupies the rear third of the vehicle.

     The experimental fire control and air-to-air missile system was developed by the Hughes Aircraft Co. The “A” in the aircraft’s designation suggests an “attack” function.

Number of Questions

     Announcement of the project raises a number of questions, some of which Presidential Press Secretary Pierre Salinger answered at a subsequent briefing.

     For example, why did the Pentagon object to the Boeing Aircraft Co.’s proposal to use titanium in the TFX if the A-11 had proved that the metal can be used?

     “The technical knowledge obtained in the A-11 program made it possible to evaluate Boeing’s proposal,” Mr. Salinger said, and the Pentagon concluded that the titanium in the TFX represented a “High development risk.”

Technical Justification

     This seemed to be further technical justification for the choice of General Dynamics over Boeing for the TFX, a choice which raised a political furor in Congress.

The economic meaning of the A-11 was another question put to Mr. Salinger. While the project makes a major contribution to Mach 3 flight, he replied, “It cannot be converted into a transport. A major independent development program is still necessary to produce a supersonic transport.”

Los Angeles Times, Vol. LXXXIII, Sunday, 1 March 1964, Page 1, Columns 7–8, and Page 6, Columns 3–4

The second Times article identifies the designer as Clarence L. (“Kelly”) Johnson:



Times Aerospace Editor

     President Johnson’s announcement of a new triple-sonic interceptor Saturday disclosed on of the best kept secrets in military annals, a security feat comparable in many ways to that achieved with the atomic bomb.

     Apparently even the House Armed Services Committee didn’t know of the project for it recommended $40 million for an improved manned interceptor, a fund approved by the full House just 10 days ago.

     The Senate, however, must have had more information, for it made no provision for the new interceptor studies in approving aircraft funding last Thursday, including $52 million for an advanced bomber.

     The secret of Lockheed’s new A-11 interceptor was kept far better than that of the same company’s U-2 reconnaissance plane that was eventually shot down on a sky-spy flight over Russia.

     Dozens of reports on the mysterious U-2 from various sections of the world had filtered into the news before the international incident over Russia.

     The Times learned the new A-11 was spurred by the same aircraft genius who headed development of the U-2 and Lockheed’s famed F-104 Starfighter interceptor, Clarence (Kelly) Johnson, vice president for advanced development projects.

     Johnson and his crew work in a carefully-guarded area at the Lockheed Burbank factory known as the “Skunk Works.”

     Pierre Salinger, White House press officer, told newsmen the A-11 was funded and managed by the Air Force in the normal manner for a classified project.

     Inasmuch as the new plane was started in 1959, this gave rise to speculation as to why a similar plane, the F-108, was canceled in that year.

     The F-108 was a North American Aviation project in the same time era that the company’s triple-sonic B-70 bomber was started.

     Like the A-11, it was to have had a speed of Mach 3 (about 2,000 m.p.h.) with a range of about 2,000 miles, plus combat time.

     Reason for canceling the F-108 was largely budgetary, according to reports in 1959, with the Defense Department declaring that of the two North American projects, the B-70 bomber was a more urgent program than the F-108.

     Some estimates of the A-11 can be drawn from the F-108. The North American plane was to have been powered by two engines, and one considered was the Pratt & Whitney J-58, the engine that will power the A-11.

     This indicates the new Lockheed interceptor will have two engines also. The J-58 has never been used, either militarily or commercially, as far as The Times could determine. It has a thrust of about 30,000 lb.

     Another indication from the F-108 relates to the armament of the A-11. The canceled North American interceptor was to have been armed with Hughes GAR-9 nuclear-tipped rockets.

     The A-11 has a Hughes fire control system and its armament could well be the same guided, air-to-air rocket or an advancement of it.

     The new interceptor will answer fears expressed by many military experts that Russia’s bomber fleet poses a greater threat to North America than her intercontinental missiles.

     The A-11 will have the speed to intercept high speed bombers and shoot them down at ranges that would precluded their launching air-to-ground missiles against U.S. targets.

     In appearance, the A-11 looks something like the X-15 rocket plane, a long, slim craft with sharp pointed nose section similar to that of the F-104 Starfighter.

     It has both ventral and dorsal fins and appears to be about 90 ft. long over-all.

Los Angeles Times, Vol. LXXXIII, Sunday, 1 March 1964, Page 1, Columns 7–8 and Page 6, Column 5–6

The YF-12A first flew 7 August 1963.

Clarence L. (“Kelly”) Johnson, Director of Lockheed’s Advanced Development Projects (“the Skunk Works”) with the first YF-12A interceptor, 60-6934. (Lockheed Martin)

Intended as a replacement for Convair’s F-106 Delta Dart, three pre-production YF-12As were built for testing. On 1 May 1965, a YF-12A set a speed record of 2,070.103 miles per hour (3,331.507 kilometers per hour) and reached an altitude of 80,259 ft (24,463 meters).

The reason for President Johnson’s announcement of the existence of the YF-12A prototypes was to conceal the existence of the Central Intelligence Agency’s fleet of Lockheed A-12 Oxcart reconnaissance aircraft based at Groom Lake, Nevada. Any sightings of these aircraft could be attributed to test flights of the YF-12As based at Edwards Air Force Base, 160 miles (258 kilometers) to the southwest.

Lockheed A-12 Oxcarts and YF-12As at Groom Lake, Nevada. (Central Intelligence Agency)
Lockheed A-12 Oxcarts and YF-12As at Groom Lake, Nevada. (Central Intelligence Agency)

The YF-12A interceptor is very similar to its A-12 Oxcart and SR-71A Blackbird stablemates. It is a large twin-engine delta wing aircraft, flown by a pilot and weapons system operator. Because of the altitudes that the F-12 operates, the crew wears S901F full-pressure suits produced by the David Clark Company. The A-12 is 101.6 feet (30.97 meters) long with a wingspan of 55.62 feet (16.953 meters) and overall height of 18.45 feet (5.624 meters). It has a zero fuel weight of 54,600 pounds (24,766 kilograms) and a maximum ramp weight of 124,600 pounds (56,518 kilograms). ¹

Lockheed YF-12A three-view illustration. (NASA)

The YF-12A is powered by two Pratt & Whitney J58 (JT11D-20A) engines. These are single rotor bleed-bypass turbojets with a 9-stage compressor section and 2-stage turbine. They have a static thrust rating of 31,500 pounds (140.118 kilonewtons), each, at Sea Level with afterburning. The J58s use a unique JP-7 fuel.

Pratt & Whitney J58 test. (Central Intelligence Agency)
Pratt & Whitney J58 test. (Central Intelligence Agency)

The YF-12A has a maximum speed of Mach 3.35 (2,232 miles per hour/3,342 kilometers per hour) at 80,000 feet (24,384 meters). The A-12 has a normal operating cruise speed of Mach 3.1. Its maximum operating altitude is 85,000 feet (25,908 meters) and it has a range of 3,000 miles (4,828 kilometers). Unlike most fighters, the A-12 has a maximum load factor of 2.5 gs. Its maximum bank angle when above Mach 2.5 is 30°.

The United States Air Force ordered 93 production F-12B aircraft, which would have been armed with three Hughes AIM-47A Falcon air-to-air missiles in enclosed bays in the bottom of the fuselage. However, Secretary of Defense Robert S. McNamara refused to release the funds for the purchase for three consecutive years and eventually the project was cancelled.

AIM-47A missile ready for loading into the weapons bay of a Lockheed YF-12A. (U.S. Air Force)
Hughes AIM-47A guided missile ready for loading into the weapons bay of a Lockheed YF-12A. (U.S. Air Force)

The first YF-12A, 60-6934, seen in the top photograph, was extensively damaged by a brake system fire on landing at Edwards AFB, 14 August 1966. It was salvaged and rebuilt as SR-71C 61-7981. The third YF-12A, shown in the photograph below, was lost due to an inflight fire 24 June 1971. The crew safely ejected.

The only existing YF-12A, 60-6935, is in the collection of the National Museum of the United States Air Force at Wright-Patterson Air Force Base, Ohio.

Lockheed YF-12A 60-6936, holder of three World Absolute Speed Records and the World Absolute Altitude Record. (U.S. Air Force)
Lockheed YF-12A 60-6936, holder of three World Absolute Speed Records and the World Absolute Altitude Record, at Edwards Air Force Base, California. (U.S. Air Force)

¹ The Lockheed SR-71A has a length of 107.4 feet (32.74 meters). Wingspan and height are the same. Its zero fuel weight varied from 56,500–60,000+ pounds (25,628–27,216+ kilograms) and the gross weight had a range of approximately 135,000–140,000+ pounds (61,235–63,503+ kilograms).

© 2023, Bryan R. Swopes

22 December 1964

 Lockheed M-21 with D-21 in position for takeoff. (Central Intelligence Agency)
Lockheed M-21 with D-21 in position for takeoff. (Central Intelligence Agency)

22 December 1964: At Groom Lake, Nevada, a Lockheed M-21, a special two-place variant of the Central Intelligence Agency’s A-12 Oxcart Mach 3 reconnaissance aircraft, took off for the first time while carrying a D-21 drone. The pilot was William C. Park, Jr., Lockheed’s Chief Engineering Test Pilot.

Lockheed M-21 60-6940 in flight, carrying a D-21 drone. (The Museum of Flight)
Lockheed M-21 60-6940 in flight, carrying a D-21 drone. (The Museum of Flight)

Two M-21s were built, Article 134, 60-6940, and Article 135, 60-6941. Article 135 was struck by its drone during an air launch off the coast of California, 30 July 1966, and both aircraft were destroyed. Bill Park escaped, but the Launch Control Officer, Ray Torick, was killed.

Lockheed M-21 60-6940 is on display at The Museum of Flight, Seattle, Washington.

M-21 60-6940 (Article 134) in flight, carrying a D-21 reconnaissance drone. (Central Intelligence Agency)
Lockheed M-21 60-6940 (Article 134) in flight, carrying a D-21 reconnaissance drone. (Central Intelligence Agency)

Bill Park has the distinction of having bailed out of four Lockheed aircraft and living to tell about it:  the first XF-104 prototype, 56-7786, when its tail came off at 12,500 feet (3,810 meters), 11 July 1957; an A-12, 60-6939, when the flight controls locked on approach to Groom Lake at only 200 feet (61 meters), 9 July 1964; the M-21; and the first Have Blue stealth technology demonstrator, 1001, at 10,000 feet (3,048 meters), 4 May 1978.

A Lockheed M-21 with a D-21 drone. (Central Intelligence Agency)

© 2016, Bryan R. Swopes

22 December 1964

The first Lockheed SR-71A, 61-7950, takes off for the first time at Air Force Plant 42, Palmdale, California. An F-104 Starfighter follows as chase. (Lockheed Martin)

22 December 1964: Lockheed test pilot Robert J. “Bob” Gilliland made a solo first flight of the first SR-71A, 61-7950, at Air Force Plant 42, Palmdale, California. The “Blackbird” flew higher than 45,000 feet (13,716 meters) and more than 1,000 miles per hour (1,609 kilometers per hour) before landing at Edwards Air Force Base, 22 miles (35 kilometers) northeast, to begin the flight test program.

Bob Gilliland made the first flight of many of the Lockheed SR-71s. It is reported that he has logged more flight time in excess of Mach 3 than any other pilot.

Robert J. Gillilan (Lockheed)
Blackbird test pilot Robert J. Gilliland, with a Lockheed SR-71A. Gilliland is wearing an S901J full-pressure suit made by “Northeast Manufacturing” (the David Clark Co.) (Lockheed Martin)

The SR-71A Blackbird is a Mach 3+ strategic reconnaissance aircraft designed and built by Lockheed’s famous (but Top Secret) “Skunk Works” for the United States Air Force. It was developed from the Central Intelligence Agency’s A-12 Oxcart program.

The SR-71A is a two-place aircraft, operated by a Pilot and a Reconnaissance Systems Officer (“RSO”). It uses electronic and optical sensors. The fuselage has a somewhat flattened aspect with chines leading forward from the wings to the nose. The wings are a modified delta, with integral engine nacelles. Two vertical stabilizers are mounted at the aft end of the engine nacelles and cant inward toward the aircraft centerline.

The SR-71A is 107 feet, 5 inches (32.741 meters) long with a wingspan of 55 feet, 7 inches (16.942 meters), and overall height of 18 feet, 6 inches (5.639 meters). Its empty weight is 67,500 pounds (30,620 kilograms) and maximum takeoff weight is 172,000 pounds (78,020 kilograms).

Lockheed SR-71A 61-7950 in flight. (U.S. Air Force)
Lockheed SR-71A 61-7950 in flight. (U.S. Air Force)

The Blackbird is powered by two Pratt & Whitney JT11D-20 (J58-P-4) turbo-ramjet engines, rated at 25,000 pounds of thrust (111.21 kilonewtons) and 34,000 pounds of thrust (151.24 kilonewtons) with afterburner. The exhaust gas temperature is approximately 3,400 °F. (1,870 °C.). The J58 is a single-spool, axial-flow engine which uses a 9-stage compressor section and 2-stage turbine. The J58 is 17 feet, 10 inches (7.436 meters) long and 4 feet, 9 inches (1.448 meters) in diameter. It weighs approximately 6,000 pounds (2,722 kilograms).

The SR-71A has a maximum speed of Mach 3.3 at 80,000 feet (24,384 meters)—2,199 miles per hour (3,539 kilometers per hour). Its maximum rate of climb is 11,810 feet per minute (60 meters per second), and the service ceiling is 85,000 feet (25,908 meters). The Blackbird’s maximum unrefueled range is 3,680 miles (5,925 kilometers).

Lockheed built 32 SR-71As. They entered service with the 4200th Strategic Reconnaissance Wing (later redesignated the 9th SRW) in 1966 and were initially retired in 1989. Several were reactivated in 1995, but finally retired in 1999.

Lockheed SR-71A-LO 61-7950 was lost to fire during a brake system test at Edwards AFB, 10 January 1967.
Lockheed SR-71A-LO 61-7950 was lost to fire during a brake system test at Edwards AFB, 10 January 1967. (Lockheed Martin via habu.org)

© 2016, Bryan R. Swopes

18 December 1969

Lockheed SR-71A 69-7953. (U.S. Air Force)
Lockheed SR-71A 61-7953. (U.S. Air Force)
Colonel Joseph W. Rogers with a Lockheed SR-71A. (U.S. Air Force)
Colonel Joseph W. Rogers with a Lockheed “Blackbird.” (U.S. Air Force)

18 December 1969: Colonel Joseph William Rogers and Major Gary Heidelbaugh were flying  Lockheed SR-71A 61-7953 to test a new system installation followed by a training mission. The functional test had gone well and the Blackbird rendezvoused with a KC-135 tanker before proceeding with the mission.

After coming off the tanker, Colonel Rogers (call sign “Dutch 68”) radioed the regional air traffic control center for permission to climb through all flight levels to 60,000 feet (18,288 meters), or Flight Level Six Zero Zero.

A short transcript of the radio and intercom transmissions follows:

(Pilot, Colonel Joseph W. Rogers; RSO, Major Gary Heidelbaugh; L.A. Center: Los Angeles Center, the Federal Aviation Administration Air Traffic Control Center at Palmdale, California. Times listed are UTC.)

Pilot’s station of a Lockheed SR-71A. (NASM)

Pilot: “Los Angeles Center, Dutch 68.” [2106:45]

L.A. Center: “Dutch 68, rog, loud and clear. How me?”

Pilot: “Roger, you’re loud and clear. I’m in a left turn flight level two six zero, requesting climb above six zero zero Route Aqua.”

L.A. Center: “Rog, your routing is approved. Climb and maintain above 600 and squawk 4400.”

Pilot: “Four four squawking.” [2107:13]

L.A. Center: “Dutch 68, Rog. Have you radar contact. Report 310 climbing.” [2107:27]

Pilot: “Roger.”

Pilot: “Okay, I’m going to light them off, Gary.” [est 2107:30]

RSO: “Rog.”

RSO: “That’s our heading.”

Pilot: “Roger.”

RSO: “What caused all that?” [est 2108:00]

Pilot: “I don’t know.”

RSO: “. . . Climbing.”

Pilot: “Let’s go.” [est 2108:15] CREW EJECTS

L.A. Center: “Dutch 68. Say your altitude.” [2110:30]

L.A. Center: “Dutch 68. Say your altitude.” [2110:50]

L.A. Center: “Dutch 68, Dutch 68, Los Angeles.” [2111:12]

L.A. Center: “Dutch 68, Dutch 68, Los Angeles.” [2111:28]

When Colonel Rogers advanced the SR-71’s throttles to go into afterburner for the climb, the compressor sections of both engines stalled. (Compressor stall is a condition that occurs when airflow through the engine intake is disrupted. Normal flow ceases, the engine stops producing thrust, and there can be violent oscillations and uncontained failure of the compressor section.) The SR-71A slowed abruptly and then violently pitched upward. Rogers said, “Let’s go,” and both men ejected from the out-of-control airplane.

Rogers and Heidelbaugh safely parachuted to the ground. 61-7953 crashed near Shoshone, California, and was totally destroyed by the crash and fire that followed.

The accident investigation determined that a small roll of 2″-wide (5.08 centimeters) duct tape was lodged inside one of the tubes of the airplane’s pitot-static system. When the new system had been installed, it required that the pitot-static tubing be modified and rerouted. A technician apparently placed the rolled duct tape inside an open section of tubing to prevent entry of dirt or foreign objects. When the tubing was reassembled, this makeshift plug was not removed. Post crash testing showed that the plug did not totally close off airflow, but that it decreased it, causing the altimeter to read too high and the airspeed indicator too fast. The normal test of the pitot-static system following the modification did not reveal the problem.

A Lockheed SR-71 Pratt & Whitney J58 turbo ramjet engine running on a test stand, in full afterburner.

When Joe Rogers advanced the throttles, he was at approximately 27,000 feet (8,230 meters) rather than the indicated 25,000 feet (7,620 meters). He was also about 30 miles per hour (48 kilometers per hour) slower than indicated.  The sudden demand for increased airflow as the throttles advanced could not be met by the thinner, slower air, and the compressors stalled.

Joe Rogers was a fighter pilot in World War II, the Korean War and the Vietnam War. He was a highly experienced test pilot with considerable experience in Mach 2+, high-altitude aircraft. He had been the commanding officer of the F-12/SR-71 Test Force at Edwards Air Force Base. Ten years and three days before this accident, he had set a World Speed Record while flying a Convair F-106A Delta Dart. (See TDiA post for 15 December 1959)

The wreck of Lockheed SR-71A 61-7953 burning near Shoshone, California, 18 December 1969.
The wreck of Lockheed SR-71A 61-7953 burning near Shoshone, California, 18 December 1969. (Check-Six.com)

© 2016, Bryan R. Swopes