How could such a forward-thinking piece of machinery end up in a museum?
On March 6th 1990, pilot Colonel Ed Yielding and reconnaissance systems officer (RSO) Colonel Joseph Vida departed Palmdale in California flying U. S. Air Force SR-71A (serial number 61-17972). This was not just another Senior Crown SR-71 flight. Yielding and Vida landed one hour, four minutes, and 20 seconds later at Dulles International Airport outside Washington DC. The last operational flight of the SR-71 set a new Los Angeles to Washington speed record averaging a scorching 2,124 miles per hour (3,420 kilometers per hour), along with three other records. 972 was then delivered to the National Air and Space Museum for display.
Derived from the Lockheed A-12, the development of which is worthy of its own story, the 32 SR-71s built served with the US Air Force from 1964 until 1990. 12 of them were lost in operational accidents. Not a single SR-71 was lost to enemy action. The “Blackbird” was the most common nickname used to refer to the all-black monster, but “Habu” (Japanese venomous snake- a name bestowed while the SR-71 operated from Okinawa) was a moniker as well. Between the original A-12 and SR-71, these Lockheed “Skunk Works” products were the fastest air-breathing (jet-powered) aircraft inhabiting this planet from inception of the A-12 until the final retirement of the SR-71 by the National Aeronautics and Space Administration (NASA) in 1998.
The SR-71’s airframe was 85% titanium. Lockheed was forced to pioneer new tooling and fabrication methods just to build the aircraft. Due to the chlorine in tap water, even washing the welded titanium in the airframe components required distilled water. Tools had to be specially manufactured because they too could cause corrosion. Tools wore out quickly during the fabrication process too. Building the SR-71 was one engineering challenge after another.
Flying at Mach 3 or more generated friction. Lots of friction. And lots of friction equals lots and lots of heat. For that reason, major portions of the skin of the wings were corrugated. The intense heat would have caused smooth skin (even titanium) to deform and potentially curl up or even split. Conversely, corrugated skin could expand both vertically and horizontally and actually increased longitudinal strength.
The SR-71s fuselage panels were specially manufactured so they had gaps between them. When the aircraft encountered the heat from in-flight friction the panels would expand and fit properly. It was said that the Blackbird leaked more fuel on the ground than it used in the air. An obvious exaggeration, but the sight of a Blackbird sitting on the tarmac surrounded by dripped puddles of special high-flashpoint JP-7 fuel was a contradiction indeed. If you see a picture of an SR-71 in flight (most of which were captured at low altitude and low speed), chances are you’ll also see fuel streaming back from the as-yet unsealed joints as well.
Stealth technology has become a buzzword associated with the latest generation of military aircraft, but the SR-71 pioneered that tech way back in the 1960s. The very shape of the aircraft reduced its radar cross section. Inward canted vertical stabilizers, chines along the fuselage forward of the wing roots, and radar-absorbent materials also contributed to the Blackbird’s low radar cross-section (RCS). The chines along the forward fuselage also generated lift and actually improved the aircraft’s performance and made it easier to handle.
The inlet spikes in the engine inlets for the massive Pratt & Whitney J58 engines actually moved forward and backward dynamically to maintain the most efficient airflow to the engines. A part of the distinctive shape of the SR-71, those spikes made it possible for the Blackbird to fly at sustained Mach 3 speeds.
SR-71s usually took off with a partial fuel load and refueled once safely off the ground. Special KC-135Q tankers were required to refuel the SR-71. Equipped with a modified high-speed boom which allowed refueling of the Blackbird while the tanker flew close to its maximum airspeed (with the Blackbird just loafing along behind and below it), the Q also had special fuel pumping systems for moving the JP-4 fuel used by the Q tanker and the JP-7 fuel for the Blackbird between the different onboard fuel tanks.
SR-71 crews could not survive using standard flight survival equipment of any kind when flying at 80,000 feet (24,000 meters). Pressurized suits and helmets were required and made the crew look more like astronauts than pilots. In a very real sense they were astronauts considering the altitudes at which they regularly flew their missions. If forced to eject from their aircraft, the crew’s “space” suits would support them even in the 450 degree temperatures they would encounter in that scenario.
The SR-71 first flew on December 22nd 1964 from Air Force Plant 42 in Palmdale California. In January 1966 the first SR-71 to enter service was delivered to the 4200th Strategic Reconnaissance Wing at Beale Air Force Base in California.
Due to the extreme stresses on the airframe during prolonged flight at three times the speed of sound or more, each SR-71 could normally average only one flight per week- mostly because it took that long to fix everything that broke during a standard mission. Blackbirds would often recover missing parts and components that would need to be repaired or replaced. The SR-71 was never intended to be, and never was, a quick-turn aircraft.
Even though SR-71s flew hundreds of sorties over North Vietnam, and the North Vietnamese lobbed more than 800 surface-to-air missiles (SAMs) at them, no SAM ever touched a SR-71.
The Lockheed Blackbird family of aircraft flew 17,300 sorties totaling 53,493 flight hours and 11,674 hours flying at Mach 3 or higher overall. Actual mission statistics are 3,552 missions totaling 11,007 hours flown with 2,753 hours of Mach 3 or more flight time. Used to capture reconnaissance over scores of targets in high-threat environments like North Vietnam, Libya, and Korea, the Blackbird was the quintessential untouchable asset.
By October of 1989, many thought the SR-71 had come to the end of its useful life. Unmanned aerial vehicles (UAVs) were going to be the future of aerial reconnaissance. While the SR-71 relied on speed and stealth to compile an unparalleled record and served the nation during its most turbulent times, UAVs drone along at medium altitudes and rely on stealthy materials and shapes to deliver real-time reconnaissance, and in some cases deliver ordnance on target on-demand.
The 1st Strategic Reconnaissance Squadron remained ready and flew a limited number of operational reconnaissance missions through the end of 1989 and into 1990. The squadron’s SR-71s were finally deactivated in mid-1990 with the remaining aircraft either sent to be statically displayed or stored in reserve. There was talk of reactivating some of the Blackbirds but the Air Force never got back into the Blackbird business.
NASA operated the two last airworthy Blackbirds until 1999. All of the other SR-71s have been moved to museums except for the two SR-71s at the NASA Dryden Flight Research Center, part of the Edwards Air Force Base complex in California.