SR-71 Blackbird at March Air Field Museum

12/29/2004
Updated July 25, 2008

Stealth: The ability to avoid detection by radar

Stealth Design

Designed by Clarence "Kelly" Johnson of Lockheed, the SR-71 Blackbird was a high-speed high-altitude spy plane that pioneered stealth technology when it was built in 1962. The sharp edges, made of radar-absorbing composite materials, and tail fins that leaned toward each other were part of the stealth design. The structure was coated in radar-absorbing black paint that dissipated heat. The Blackbird had a 100-times smaller radar return than the F14, which was half the size and designed ten years after the Blackbird. At the timeit was built, aircraft the same size as the Blackbird showed up on radar the size of a flying house, while the Blackbird appeared the size of the front door of a house. The Blackbird preceded the Stealth Fighter by 25 years.

When first built in the early 1960s, the SR-71 Blackbird could fly higher and faster than any jet aircraft in production. That still holds true today.

The Blackbird frame was made out of titanium and titanium alloys because they were light and strong enough to withstand Mach 3 temperatures. It was the first plane to be comprised of titanium, so Lockheed had to create the tools needed to work with the material. After the planes were built, all dies and molds were destroyed to prevent theft of the design by other countries.

The Blackbird was also nicknamed SR, Sled, Lady in Red, and Habu, after a deadly snake native to Japan.

Facts & Figures

Commissioned by the CIA, it was designed as a replacement to the U2 (also designed by Johnson) after one was shot down over the USSR. The first version was a single seat model called the A12. It flew until 1968 when the twin-seat version designed for the Air Force and called the SR-71 took over reconnaissance duties. Nearly identical, both versions could fly faster than Mach 3 at heights above 85,000 feet.

The plane was about 110 feet long and could carry 20 tons of JP7 jet fuel in the fuselage and wing tanks. In its first flight the Blackbird flew for one hour up to speeds over 1000 miles per hour. When the SR-71 hit Mach 3, there was a triple sonic boom followed by temperatures radiating from the skin in excess of 1100 degrees. The surface was designed to expand during flight from the heat and when sitting on the ground would actually leak fuel. The expansion caused the aircraft to grow a couple inches in length and after landing the plane would be so hot that crews couldn't go near it for over 30 minutes.

Two crew members manned the SR-71. One piloted and the second was the Reconnaissance Systems Officer in charge of the optic equipment and radar-scrambling equipment. The 6 cameras were able to photograph 100,000 square miles in one hour, at such high resolutions that license plates on cars could be read. The pilots wore specially designed suits to withstand the temperatures and pressure. Before flights, pilots ate high protein meals of steak and eggs.

On September 13, 1974, an SR-71 flew from London to Los Angeles in 3 hours, 47 minutes, and 39 seconds. A pilot recalled watching it on the radar screen: "The 747s went 'blip...blip...blip' while the SR-71 went more like 'bpbpbpbpbpbpb.'" Also in 1974, a Blackbird flew from New York to London in a record 1 hour, 54 minutes and 56 seconds. Charles Lindbergh made approximately the same flight in 33 hours. In 1976, the SR-71 set a world speed record of 2193.167 miles per hour and an altitude record of 85,068 feet, records that stand to this day.

The Blackbird served under 6 presidents and was the only operational plane in Air Force history in which no crew member was killed. Blackbirds were shot at over 9000 times but not one was ever lost to enemy fire. Despite this impeccable record, the Blackbird fleet was mothballed in 1990 because its costs of operation weren't sustainable and satellites were claimed to do the job better.

Inspiration?

Designer Kelly Johnson had two verified encounters with UFOs and filed reports about both. In 1951 in Agoura, California, Johnson witnessed a flying object with a swept-back wing shape.

In 1953 in the same area he saw an elliptical shape hovering in the sky. It suddenly accelerated at a vast speed. Johnson took detailed notes and made a sketch of the craft. He estimated it to be 200 feet wide and flying at an altitude of 15,000 feet. His sketch resembled the modern stealth bomber, a flying-wing shape. The second sighting was also reported at the same time by 2 Lockheed test pilots near Long Beach, CA. They reported seeing the same shape and size as Johnson.

The show UFO Hunters proposes that Johnson was inspired by his UFO sightings. Johnson founded Lockheed's Skunk Works program, which designed planes including the XP-80, F-104 Starfighter, F-117A, and the JSF/X-35B. Kelly Johnson died in 1990 without explaining the source of his inspiration.

Information gathered from "Modern Marvels: Blackbird Stealth," "Modern Marvels: Extreme Aircraft" and UFO Hunters: Reverse Engineering" on the History Channel, and supplemented with information from the March Air Field Museum's web site.