Fastest Stealth Plane: SR-72, America’s Next-Gen Hypersonic Aircraft Takes Shape

Hypersonic speed refers to a velocity more than five times the speed of sound, or Mach 5. Typically, speeds slightly beyond Mach 5 are referred to as hypersonic. This is due to the difficulty in accurately measuring Mach 5 due to air friction, ions, and extreme heat. Since the 1990s, this technology has been applied to fighter jets and missiles. Now, its use is expanding to aircraft as well. Currently, only four countries in the world possess hypersonic missiles: the United States, Russia, China, and North Korea.

Not many countries own hypersonic military aircraft. The United States and Russia are among the few. The first military aircraft to be operated was a reconnaissance aircraft. The SR-71 Blackbird, developed by Lockheed Martin, is a strategic reconnaissance aircraft developed by Lockheed Martin’s Skunk Works. It is nicknamed Blackbird due to its black color.

SR-71, Mach 3.3 Speed, 41,632 Miles Range

It is the fastest human-crewed aircraft in the world, capable of Mach 3. If it were to race a bullet from a typical rifle, which travels at Mach 2 (1,522 mph), it would easily overtake the bullet. It can fly at Mach 3.3 (2,509 mph) in the stratosphere, about 78,740 feet (24 kilometers) above the ground, and can cover a maximum distance of 67,344 kilometers (41,632 miles). It can photograph an area of 260,000 square kilometers (100,000 square miles) per hour.

The predecessor, the A-11, began development in 1959. After the spy plane ‘U-2’ was shot down by a Soviet missile on May 1, 1960, the development of the SR-71 accelerated. Some of the SR-71 was unveiled in July 1964 and was deployed to the Strategic Air Force as a successor to the U-2 from 1965. The cruising time is 1.5 hours, and one pilot and reconnaissance officer operate it.

Due to the friction heat generated by high-speed flight, the exterior temperature of the aircraft can rise to several hundred degrees Celsius. If you place a piece of pork belly on it, it will be cooked in just a few seconds. The aircraft was mostly made of titanium alloy to withstand such high temperatures. 32 were produced, but all have been retired since the last flight on October 10, 1999.

The official successor to the retired supersonic reconnaissance aircraft SR-71 is the SR-72. Lockheed Martin’s Skunk Works announced the development plan on November 1, 2013, to conduct test flights in 2024 and deploy it in practical use by 2030. It is currently under development to regain effective reconnaissance assets against China’s anti-satellite system. The aircraft is expected to maintain almost the same size as the SR-71, but its maximum speed will be raised to Mach 6, double that of the SR-71. The number 72 was given in the sense of succeeding the concept of the SR-71, following the number 71.

To improve speed, two types of engines were overlapped vertically. It has a structure that combines one air intake and spray nozzle. Typically, a conventional jet engine is used to reach Mach 3, but after that, a dual-mode ramjet engine that can operate in ramjet mode or scramjet mode is used to raise the speed to a maximum of Mach 6 and above. The SR-72 is equipped with two of these engine structures; strictly speaking, it carries four engines.

The initial development cost is expected to be about $1 billion per unit. The body is made of a composite material using carbon and metal. The SR-71’s design was also adopted, which allows for thermal expansion due to air friction heat at supersonic speeds by leaving a gap between metal plates.

High-Power Laser and Other Light-Speed Weapons Can Be Installed

The expected armament is believed to be designed without any particular armament due to its title as a reconnaissance aircraft. However, it is said that it must be armed because the entire globe is the target. It is presumed to be designed to bomb by storing bombs inside like a supersonic bomber and opening the bomb bay to bomb.

One sure thing is that there is a high possibility that high-energy light-speed weapons such as high-power lasers, which are most suitable in hypersonic or extremely high altitude environments, will be installed. For example, it is highly likely to play an active role as the ultimate BMD platform, capturing and tracking enemy ballistic missiles from the ascent stage and destroying them with lasers while orbiting near space at hypersonic speeds.

Another weapon is a ballistic missile. It is designed to launch a ballistic missile at a high altitude and a fast speed, attacking enemy aircraft and conducting unexpected ballistic missile attacks from areas such as air defense network blind spots.

Of course, hypersonic cruise missiles propelled by scramjets alone without the need for an uncomfortable acceleration propulsion system such as a solid rocket or ramjet before hypersonic entry can also be considered.

The high-altitude unmanned reconnaissance aircraft Global Hawk is also being developed as a hypersonic aircraft. The U.S. plans to retrofit retired Global Hawks at Grand Forks Air Force Base in North Dakota as a hypersonic technology test platform.

According to defense company Northrop Grumman, the U.S. government has requested the retrofit of four retired Global Hawk (Block 20) aircraft. Northrop Grumman plans to move these aircraft to the Grumman Grand Sky facility for retrofitting, then use them in hypersonic technology tests to be conducted over the Pacific.

Through this, the Global Hawk will be equipped with an Integrated Air Communication System (BACN) to serve as an airborne base station. The 319th Reconnaissance Wing of the U.S. Air Force has been flying over 10,000 hours a year since the introduction of four Global Hawk (Block 20) aircraft in 2011. It operates 8 to 9 Global Hawk Block 30 and Block 40 aircraft.

Unmanned Reconnaissance Aircraft Global Hawk Also Flying Hypersonic

Last year, the U.S. Air Force’s Global Hawk flew over the Korean Peninsula to monitor preparations for North Korea’s military parade. It flew east-west over Gyeonggi and Gangwon provinces adjacent to the Military Demarcation Line (MDL), monitoring signs of ballistic missile launches from mobile launchers (TEL) and nuclear-related trends. Meanwhile, our military plans to actively use the Global Hawk as a frontline unmanned aircraft after introducing four last year and building a TCPED (Tasking, Collection, Processing, Exploitation, and Dissemination) system. The Air Force has already held a formation ceremony for the 39th Reconnaissance Squadron in Chungju, Chungbuk, which will operate the Global Hawk along with the tactical reconnaissance aircraft RF-16, Geumgang reconnaissance aircraft, and the medium-altitude unmanned reconnaissance aircraft (MUAV) under development with domestic technology.

By. Hyun Ho Lee