US Air Force SR-71 Blackbird Spy Plane

SR-71 Blackbird: The Fastest Jet Ever Built

The SR-71 Blackbird is the fastest jet in the world.¹The Blackbird was built in the early 1960s to be a high-speed, Mach 3+ spy plane to replace the aging fleet of U-2 high-altitude spy planes.²During the Cold War, a U-2 spy plane was shot down over the Soviet Union by a SAM (Surface-to-Air Missile), which signalled that the days were over for slow-speed reconnaissance.³With the ever-increasing threat of surface-to-air missile technology in the Soviet Union, it was clear that the U-2 would not be able to face the challenges posed by the modern air defence systems of the Soviet Union. Lockheed Martin began working on a high-speed, high-altitude spy plane that could fly above 80,000 ft and with a top speed of Mach 3.2 to gather intelligence over long ranges while evading SAMs (Surface-to-Air Missiles).

During the cold war, the reconnaissance was done with the help of slow, low flying aircrafts that were prone to Anti Aircraft Artillery.

Studies were already conducted to enhance the capabilities of U-2 to enable the aircraft to fly at higher altitude and make it less vulnerable while flying in the adversary airspace but little was achieved due to the design limitations of the aircraft.

In this article we will explore the marvelous SR-71 Blackbird’s history, capabilities and technology of the spy plane and top speed records set by the fastest jet of the world.

2. The Genesis of Speed: History and Development of the SR-71 Blackbird Spy Plane

On 1 May 1960, Francis Gary Powers U-2 was shot down over Soviet Union by a surface to air missile. It was clear that U-2 will not be able to survive in the ever-increasing threat of surface to air missiles so the need for an high speed, high altitude aircraft was felt which can fly over hostile airspace and gather intelligence, evade enemy missiles and air to air threats. Kelly Johnson and Skunkworks begin working on design of the aircraft in the late 1950s. The J58 engine flight tests were completed by 30 July 1962 and six aircraft were ordered on 28 December 1962. The first SR-71 prototype (#61-7950) was delivered on 29 October 1964. The first operational mission SR-71 (#61-7976) was flown from Kadena AB over Vietnam on 21 March 1968.

3. Need for Speed: Engine Technology and Design Features of the Fastest Jet

The SR-71 Blackbird was designed to be a high speed, high altitude, low radar cross section spy plane. Many technologies had to be developed to achieve the successful completion of the aircraft. To counter the heat generated at Mach 3+, titanium alloys were used so the SR-71 blackbird can withstand temperatures of 1050-1,600 °F with average temperature range of 462 to 622 °F.

Conventional engine design proved inadequate so ramjet engine with high bypass tubes which injected direct air to the afterburners of the aircraft was used. The J58 engine was developed by Pratt & Whitney that was able to deliver 32,500 lbs of thrust with afterburners. A nine-stage compressor was installed on the engine to achieve top speed of Mach 3+ at an altitude of 80,000 ft.

4. Eyes Over the Horizon: The Spy Capabilities and Surveillance Technology of the SR-71 Blackbird

For reconnaissance, the SR-71 blackbird was able to carry a wide range of high resolution cameras and different sensors to record real time data depending on the mission requirements.

The Operational Object Camera (OOC) were developed by ITEK with a focal length of 13 inches and 70mm wide film. Installed on each side under the aircraft, the cameras were able to scan from -5 degrees to 45 degrees vertically and horizontally.

The Optical Bar Camera (OBC) was able to capture an area of 100,000 square miles an hour while flying at a speed of mach 3+ from 80,000 ft altitude. OBC was able to capture an image 72 miles wide and and film length with 10,500 ft. The camera can be extended from 24 inch focal length to 30 inch, both the camera provided superior detail with very high resolution.

5. Pushing the Limits: World Records and Speed Achievements of the SR-71 Blackbird

The SR-71 Blackbirds holds record of the fastest and highest flying air breathing aircraft till today. Here is a list of some of the world records set by SR-71.

Absolute altitude record: On 28 July 1976, the SR-71 serial number 61-7962 set highest flying record when it flow at an altitude of 85,069 ft (25,929m) in sustained flight.

Absolute speed record: The same aircraft 61-7962 broke the world record of highest speed when it flew at a speed of mach 3.3 (1,905.81 knots; 2,193.2 mph; 3,529.6 km/h).
Brian Shul, the SR-71 pilot stated in a book “The Untouchables”, that he was able to accelerate the aircraft to mach 3.5 when evading a missile while flying over Libya on 15 April 1986.

4 new speed records were set during the final flights of SR-71 before the retirement in 1990.

A supersonic flight from Los Angeles, California, to Washington, D.C. (2,299.7 miles or 3,701.0 km) was completed in 64 minutes and 20 seconds, achieving an average speed of 2,144.8 mph (3,451.7 km/h).
A West Coast to East Coast flight (2,404 miles or 3,869 km) took 67 minutes and 54 seconds, with an average speed of 2,124.5 mph (3,419.1 km/h).
The journey from Kansas City, Missouri, to Washington, D.C. (942 miles or 1,516 km) was remarkably fast, taking only 25 minutes and 59 seconds and averaging 2,176 mph (3,502 km/h).
An even shorter flight from St. Louis, Missouri, to Cincinnati, Ohio (311.4 miles or 501.1 km), was completed in a mere 8 minutes and 32 seconds, with an average speed of 2,189.9 mph (3,524.3 km/h).

6. From Flight Line to Museum: Retirement and Current Status of the Fastest Jet

With evolution of Unmanned Aerial Vehicles (UAVs) and satellites that can photograph the earth from space with high resolution, the high maintenance costs of SR-71, it was decided to retire the SR-71 fleet in mid 1990.

Some aircraft were put on static displays at different aviation museums across the United States while a few were kept in storage.

Later in 1993, three SR-71 were reactivated under 9^th reconnaissance wing at Beale Air Force Base. Modifications were made at Edwards Air Force Base where the real time data link was installed to provide real time imagery to the ground sites. The final retirement was made and the aircraft (Serial No. 61-7980/NASA 844) flew for the last time on 9 October 1999.

7. The Future of Reconnaissance: Exploring Potential Successors to the SR-71 Spy Plane

While the satellites are considered to be the ideal choice for reconnaissance, there are certain limitations that affect the real time data collection a challenge. A satellite may need up to 24 hours to be put in the proper orbit to photograph the target or area of interest, this can significantly hamper the operational requirements where every minute counts.

So, Unmanned Aerial Vehicles (UAVs) or drones today play a vital role in reconnaissance missions replacing many manned systems, which posed risk to human life when flying over hostile territory.

Unlike satellites, which can photograph the target for a very short period of time as it orbits at high speed in lower earth orbit, a UAV can provide real time data to the ground stations. A UAV can take pictures and provide real time video surveillance of the target from 8-9 hours while flying high above the target.

A RQ-4 Global Hawk can remain over the target area for up to 30+ hours providing unmatched intelligence and situational awareness. Another Unmanned Aerial System (UAS),

MQ-9 Reaper drone can provide real time intelligence data and if required, can also attack the target with missiles showcasing tremendous capabilities of the unmanned aerial systems.

SR-71 Dimensions & Weights

Wingspan: 55 ft 7 in (16.94 m)
Length: 107 ft 5 in (32.74 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)