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The A-12/SR-71 is the fastest, highest flying, air-breathing aircraft in the world. It flies at mach 3.5 and above 80,000 feet. The SR-71 is affectionately called HABU  (for a poisonous snake in Okinawa) [the A-12 aircraft was first deployed there] by the pilots who fly her. This is her story.

Kelly Johnson started working on a mach three design in early 1957, and called the design Archangel. The design was for a mach 3 aircraft that flew between 90,000 and 95,000 feet. A development contract for an aircraft called A-12 was let to the Lockheed Skunk Works on August 29, 1959. The propulsion system dominated the design the engine nacelles were larger in diameter than the fuselage. The propulsion system consisted of three main components; the modified Pratt and Whitney J-58 engine; inlet and control system and self-actuating airframe mounted ejector nozzle. One of the stickiest problems of design was to try and build an aircraft with as small a radar cross section (RCS) as possible to prevent radar detection. The A-12 structure was comprised of 85% titanium and 15% composite materials. Never before had anyone anywhere tried to build an aircraft structure from titanium. Titanium parts are 30% lighter than the equivalent strength steel part, great strength properties at high temperatures, scratches easily, extremely hard to machine, and very costly due to world wide scarcity. Many other hurdles had to be breached during development. Some outstanding problems were a fuel that would be stable at temperatures above 350(F, lubricating oil that would operate at 600(F and still be liquid at 40(F, and hydraulic O-rings and seals that would operate between 40(F and 600(F and retain their elasticity. The vertical stabilizers were built of high temperature composites, probably a first for major aircraft subassemblies. The first flight of the A-12 took place on April 30, 1962 eight months after the scheduled date, much to the chagrin of the customer (CIA). So many major problems occurred during production of this truly beyond state-of -the-art aircraft, even the Skunk Works couldn't pull it off. Pratt Whitney had many severe engine development problems that were not anticipated that the A-12 was equipped with available J-75 engines for the first flight. The first flight with both J-58 engines mounted in the aircraft was on January 15, 1963. The A-12 broke the mach 3.0 barrier on July 20, 1963.

After being briefed on the A-12 program President Johnson decided to partially lift the veil of secrecy of the project. He saw that this was a perfect way to tell other American companies the technology existed to manufacture major aircraft subassemblies out of titanium. At this time the worldwide competition to build a commercial supersonic transport (SST) was underway, and American companies needed an edge. Since the A-12 program was funded with taxpayers money all the technology belonged to the government. This allowed the government to release non-classified information on methods of working titanium to Lockheed and Boeing the two American competitors for the SST.  The Skunk Works was a very special part of Lockheed and so the information never escaped into the commercial aircraft part of Lockheed, until then. So on February 29, 1964 President Johnson announced the development of the A-11 aircraft. Kelly had worked on a draft of the president's speech and suggested that the aircraft be called A-11 in the speech as no A-11 hardware existed but was one of the non-anti-radar versions. Two of the AF-12 interceptor versions, recently re-identified by the Air Force as YF-12s, were flown to Edwards Air Force base from their secret test facility to show the media. The president announced that the aircraft flew in excess of 2,000 miles per hour in sustained flight and at altitudes above 70,000 feet.

 

A-12 and the CIA.

The first operational mission for the A-12 over hostile territory occurred on November 10, 1964 when an A-12 over-flew Cuba during the Cuban missile crisis. The second operational mission for the A-12 was flown from Kadena air base on the island of Okinawa on May 31, 1967 over North Vietnam looking for SA-2 surface to air missile sites. The mission was a success, there was no radar activity detected by the aircraft, meaning the Vietnamese were totally unaware of the over-flight. The span of more than 30 months between operations was fraught with administration false starts. Originally the CIA wanted to over-fly Mainland China and then when the Vietnamese war heated up tried to get the president to authorize the use of the A-12s over North Vietnam. There was a great deal of disagreement in the upper echelons of the United States government over the use of the A-12 as an intelligence gather. The naysayer were afraid that if one went down that a great deal of exotic technology would be compromised. Because of the tremendous speed of the A-12 a one-pass mission over North Vietnam only lasted 12-1/2 minutes. A two-pass mission put the aircraft over North Vietnamese territory for only 21-1/2 minutes. With a turning radius greater than 85 miles, on some missions it would invade Mainland China airspace during the turns. A typical mission profile would be to launch from Kadena top off the fuel tanks by in-flight refueling blast over the target, refuel again over Thailand and then motor back to Kadena and land. Once the aircraft landed, the exposed film was removed and sent on special aircraft to the laboratory in Japan for developing. Within 24 hours the information was in the American commanders hands.  The North Vietnamese tried unsuccessfully to track and shoot down the A-12s using their SA-2s. The last operational mission for the A-12s was over North Korea on May 8, 1968. Just thirteen days after the last over-flight of North Korea the President mothballed the A-12 fleet as a budgetary measure. The U. S. could not operate the A-12 and the new SR-71s that were now serviceable.  The A-12 program lasted just over ten years from its inception in 1957 to mothballing in 1968. There were fifteen A-12s produced and three YF-12A. Five A-12s and two YF-12s were lost along with two pilots during the program, none due to hostile action.

 

YF-12A INTERCEPTORS:

During the development of the A-12 the Air Force asked if the Skunk Works could modify several of the A-12s into a high altitude interceptor. Kelly said yes, that was not a problem that A-12 aircraft would be modified by installing the Hughes AN/ASG-18 fire control radar, design weapons bays to carry two Hughes GAR-9/AIM-47 missiles internally and space for a second seat for the fire control system operator. A ventral fin was attached under each nacelle and a folding ventral fin was mounted under the fuselage for added stability due to flight characteristics impacted by the revised nose and cockpit area to house the massive radar. This version was labeled AF-12 and later re-identified by the Air Force as YF-12. During flight testing there were several missile launches at drone targets. The most impressive launch was at mach 3.2 and at an altitude of 75,000 feet at a target 36 miles away and at 1,500 feet with a direct hit on the Boeing B-47 drone. The missiles were moved out of the weapons bays and into the air-stream on a device called a trapeze, and then fired. The Air Force never issued a production contract for the YF-12. It was the opinion of many in the Johnson administration including Secretary of Defense Robert McNamara that there would never be a need for a high altitude intercept capable aircraft. That is, until the soviet Backfire bomber showed up-too late for the YF-12. In one of Kelly Johnson's speeches I was fortunate enough to hear him lament, "every day a high altitude penetration of U.S. airspace occurs and we do not have an aircraft with the ability to fly up and eyeball the threat, including F-14 and F-15 fighters, and this aircraft carries women and children-the Concord SST". 

During flight testing several A-12s were lost, but the testing continued on both the YF-12 and the A-12 aircraft. Mach 3.0 was routinely broken and many speed records held by soviet aircraft fell. However, these records could not be made public due to the secrecy of the program. The Department of Defense decided to take back the records from the soviets. On May 1, 1965 two YF-12 aircraft set the absolute altitude record of 80,258 feet, and a speed of 2,070 miles per hour on a closed course. During continued flight testing an A-12 exceeded mach 3.28 at 90,000 feet altitude. On December 21, 1966 an A-12 piloted by Lockheed test pilot Bill Park covered 10,198 statute miles in six hours.

 

The SR-71:

The SR-71 was the Air Force answer to the CIA's A-12 program. The Air Force had been chafing ever since President Eisenhower had given the U-2 program to the CIA. They wanted a reconnaissance platform to operate in the arena that they believed was always theirs. During the A-12 program the Air Force started talks with the Skunk Works about a true reconnaissance variant of the A-12.  They gave the Skunk Works a go ahead on February 18, 1963 for production of six SR-71 aircraft, with a promise of an additional order for 25 more by July of that year. The CIA was already getting into more exotic methods of obtaining over-flight data (codename Corona) using satellites so they did not fight the Air Force demands that airborne recognizance become their domain once more. The Air Force did indeed order 31 SR-71 aircraft.

The SR-71 was based on the A-12 design, in fact it was called the RS12 (R for reconnaissance and S for strike) at the Skunk Works.  The original A-12 design was stretched for another fuel tank and the Q-bay was converted to a second cockpit for the system reconnaissance officer (SRO). Several other modifications including sensor placement were also made. Once again President Johnson revealed the existence of the aircraft in a speech on July 24, 1964, calling it the SR-71 for strategic reconnaissance. The first flight of the aircraft took place on December 22, 1964 at Palmdale California piloted by Bob Gilliland.

The SR-71 program had its share of flight testing mishaps, lost aircraft and production foul-ups. The first accident occurred above 77,000 feet in a 15( Right Bank. The right inlet suffered an unstart condition and the aircraft bank angle went from 35( to 65( immediately, then the aircraft started a pitch up maneuver until all the pilot could see was 'blue sky" then the nose broke off. The pilot Bill Weaver got out but the back seater did not and perished with the aircraft. Another aircraft was written off during a wet landing/braking exercise. The drag chute failed and the right hand wheels were ground off flat. Going off the end of the runway the right main gear broke off and then all the others went. The pilot escaped, but the aircraft burned completely. The Air Force showed great restraint with Lockheed during the flight-testing program, realizing that the SR-71 was a major modification of the A-12 and in many cases an entirely different aircraft. The first operational SR-71A was delivered to Beale Air Force near Sacramento, California on April 4, 1966. Previously the first SR-71B trainer was delivered to the Air Force on January 6, 1966. Fuel leaks, plumbing problems and electrical problems slowed the production line to a stand still at the Palmdale Site 2 facility. Finally in May things got better and the Skunk Works started delivering aircraft.

The SR-71 was deployed to such sites as Kadena and RAF Mindenhall in England. From here it performed its missions regularly. From Kadena it flew more than 600 missions over Vietnam from 1968 through 1973. During the 1970s and 1980s the aircraft deployed regularly to Kadena and RAF Mindenhall. Temporary deployment of the aircraft to other locations around the world occurred as political needs arose. During the course of it's distinguished carrier the aircraft over-flew every major political and militarily significant hot spot in the world gathering that most precious commodity intelligence. With in-flight refueling from special KC-135Q tankers their wasn't anywhere it could not go. One mission was over 14,000 miles long. The Israelis used SR-71 data collected by an aircraft stationed on the East Coast during the Yom Kippur War.

 

SR-71 Performance:

On April 26, 1971 a non-stop record of 15,000 miles in 10-1/2 hours was set. On July 27, 1976 the SR-71 eclipsed the records by its older brother the A-12. The aircraft achieved a sustained horizontal altitude of 85,069 feet and a straight-line speed of 2, 193.17 miles per hour (MPH). During a non-stop flight from Beale Air Force base in Sacramento, California to RAE Farnborough, England during September 1976, the New York to London leg (3,490 miles) was completed in 1 hour 55 minutes and 42 seconds. The London to Los Angeles leg of the return trip (5, 645 miles) took only 3 hours 45 minutes and 39 seconds with in-flight refueling. Average speed of the return trip was 1,487 (MPH). On it's final flight from Beale Air Force base to the Smithsonian Institution's National Air & Space Museum in Washington D.C. the record setting SR-71 set 4 world class records. Records set were U.S. coast-to-coast in 67 minutes 54 seconds with an average speed of 2, 124.5 MPH, Los Angeles, CA to Washington D.C. in 64 minutes and 2 seconds with an average speed of 2,144.8 MPH, Kansas City, KS to Washington D.C. in 25 minutes and 59 seconds with an average speed of 2,176.1 MPH and St. Louis, MO to Cincinnati, OH in 8 minutes 32 seconds at an average speed of 2,189.9 MPH.

 

Goodbye SR-71:

The changing world situation and other spending priorities eliminated the SR-71 from the 1990 fiscal budget and so the aircraft was retired officially in a ceremony at Beale Air Force base in January 1991. Many people who were involved with the A-12 through SR-71 program was there to say a fond farewell to the most significant military aircraft design of the twentieth century. The record setting SR-71A was donated to the Smithsonian Institution's National Air & Space Museum. Between January 1991 and April 26, 1995 the only flights the SR-71 made was under the control of NASA. Used as a high altitude, high speed platform for many experiments.

The United States Congress approved $100,000,000 to reactivate 3 SR-71 aircraft in the 1995 budget. The first flight of the refurbished SR-71 occurred on April 26, 1995. The SRs are now equipped with a real time data link allowing the Advanced Synthetic Aperture Radar (ASARS) data to be viewed at real time. This solved one of the detractors of the aircraft complaints, that the data they received from the SR-71 was not real time. During Desert Shield it took the intelligence community with all their assets (U-2s, RPVs and satellites) 6 months to collect enough data to ensure the success of Desert Storm. The SR-71, had it been available, could have gathered the data in 6 hours. But the powers to be retired her.

 

Goodbye Again Old Friend:

In 1997 President Clinton, vetoed the appropriations bill to continue funding the SR-71 program. Saying that by doing this ``he was saving the American people $35 million dollars for a weapons system that was not needed". Of course what was not said was to terminate the program the government would have to pay Lockheed-Martin $151 million dollars as per contract. Later in the year once again Iraq was rattling the sabers again and threatening to shoot down the U-2 over-flights. Had the SR-71 program been up and viable we would have had a penetrator that could have thumbed its nose at Saddam and collected the data anyway.