SR-71 Blackbird

The Lockheed SR-71 is an advanced, long range, Mach 3+ strategic reconnaissance aircraft developed from the Lockheed A-12 and YF-12A aircraft by theLockheed Skunk Works as a Black project. The SR-71 was unofficially named the Blackbird, and called the Habu by its crews, referring to an Okinawan species of pit viper. Clarence "Kelly" Johnson was responsible for many of the design's innovative concepts. A defensive feature of the aircraft was its high speed and operating altitude, whereby, if a surface-to-air missile launch were detected, standard evasive action was simply to accelerate. The SR-71 line was in service from 1964 to 1998, with 12 of the 32 aircraft being destroyed in accidents, though none were lost to enemy action. Since 1976, it has held the world record for the fastest air breathing manned aircraft, a record previously held by the YF-12.

The SR-71 was the first operational aircraft designed around a stealthy shape and materials. There were a number of features in the SR-71 that were designed to reduce its radar signature. The first studies in radarstealth technology seemed to indicate that a shape with flattened, tapering sides would avoid reflecting most radar energy toward the radar beams' place of origin. To this end, the radar engineers suggested adding chines to the design and canting the vertical control surfaces inward. The aircraft also used special radar-absorbing materials which were incorporated into sawtooth shaped sections of the skin of the aircraft, as well as cesium-based fuel additives to reduce the exhaust plumes' visibility on radar. Despite these efforts, the SR-71 was still easily detected on radar while travelling at speed due to its large exhaust stream and air heated by the body (large thermal gradients in the atmosphere are detectable with radar). The SR-71's radar cross section (RCS) was much greater than the later F-117's RCS, which is on the order of a small ball bearing.

The overall effectiveness of these designs is still debated; Ben Rich's team could show that the radar return was, in fact, reduced, but Kelly Johnson later conceded that Russian radar technology was advancing faster than the "anti-radar" technology Lockheed was using to counter it. The SR-71 made its debut years before Pyotr Ya. Ufimtsev's ground-breaking research made possible today's stealth technologies, and, despite Lockheed's best efforts, the SR-71 was still easy to track by radar and had a huge infrared signature when cruising at Mach 3.2 or more. It was visible on air traffic control radar for hundreds of miles, even when not using its transponder. SR-71s were evidently detected by radar, as missiles were often fired at them.

Although equipped with defensive electronic countermeasures, the SR-71's greatest protection was its high top speed, which made it almost invulnerable to the attack technologies of the time; over the course of its service life, not one was shot down, despite over 4,000 attempts to do so. All the pilot had to do when a SAM was fired was to accelerate.

Specifications (SR-71A)

General characteristics

• Crew: 2
• Payload: 3,500 lb (1,600 kg) of sensors
• Length: 107 ft 5 in (32.74 m)
• Wingspan: 55 ft 7 in (16.94 m)
• Height: 18 ft 6 in (5.64 m)
• Wing area: 1,800 ft² (170 m²)
• Empty weight: 67,500 lb (30,600 kg)
• Loaded weight: 170,000 lb (77,000 kg)
• Max takeoff weight: 172,000 lb (78,000 kg)
• Powerplant: 2× Pratt & Whitney J58-1 continuous-bleed afterburning turbojets, 32,500 lbf (145 kN) each
• Wheel track: 16 ft 8 in (5.08 m)
• Wheel base: 37 ft 10 in (11.53 m)
• Aspect ratio: 1.7

Performance

• Maximum speed: Mach 3.2+ (2,200+ mph, 3,530+ km/h, 1,900+ knots) at 80,000 ft (24,000 m)
• Range: 2,900 nmi (5,400 km)
• Ferry range: 3,200 nmi (5,925 km)
• Service ceiling: 85,000 ft (25,900 m)
• Rate of climb: 11,810 ft/min (60 m/s)
• Wing loading: 94 lb/ft² (460 kg/m²)
• Thrust/weight: 0.382