Time： 2024-09-14  韋克威科技

Lockheed Martin's SR-72 hypersonic aircraft

According to different sources, in the early 21st century, Skunk Works, a division of Lockheed Martin, began developing a future hypersonic aircraft, codenamed SR-72, with excellent flight technology performance and the ability to carry out special combat missions. This project is still shrouded in mystery, but it is evident that in order to efficiently carry out the task, the most advanced future technologies and components are needed.

The SR-72 project was first exposed in 2007, when it was reported that the development work had been underway for several years. Subsequently, professional magazines reported on the goals and techniques of this project multiple times. But there was no official news until recently.

The representative of Loma did not provide any explanation, but has repeatedly mentioned that the company is conducting research on hypersonic technology. In mid-2017, relevant media reported that the first flight test had been completed, but later the development company pointed out that this aircraft could only be built in the early 1920s.

In February 2018, news about the SR-72 development plan was denied. At that time, it was confirmed that the key technology was not mature and the development of the aircraft was not reasonable. In November of that year, foreign media quoted Lockheed Martin as saying that the first flight of SR-72 would be completed before 2025. The new aircraft will become an interceptor equipped with hypersonic air-to-air missiles.

According to public reports, the speed of SR-72 will reach Mach 6. Hypersonic flight ensures combat stability, so the stealth of the aircraft is not the top priority. In order to achieve hypersonic flight, specialized engines are being developed. This is an unmanned or selectively manned aircraft.

The SR-72 may become a high-altitude reconnaissance aircraft, which modern air defense systems cannot match; Alternatively, as an interceptor, it can quickly reach the boundary of weapon use and may also have ground assault capabilities. At this time, the combat model can carry various hypersonic weapons.

The SR-72 can reach a speed of up to Mach 6 and requires a special body to accommodate all necessary components, pilot (optional presence), and payload inside. At this time, the aerodynamic shape should meet the requirements of hypersonic flight, and the structure should withstand mechanical and thermal loads.

Despite some research on the structure, it is still necessary to develop a body that meets the above requirements from scratch, made of heat-resistant steel alloys, titanium, and other materials with necessary strength, and advanced composite materials, ceramics, etc. can also be used. The relevant system cools surfaces and components subjected to high thermal loads to ensure structural stability.

In recent years, the United States has conducted extensive scientific research to explore the optimal aerodynamic design for hypersonic aircraft. Obviously, these research results will be applied to the SR-72 scheme. Therefore, future aircraft will resemble several previous missiles in appearance.

It is highly likely that the SR-72 will feature a smooth surface, swept or delta wing layout, and a wedge-shaped bucket inlet. Obviously, according to the task being carried out, the payload is located inside the fuselage.

This aircraft does not possess stealth in the traditional sense, and during hypersonic flight, the plane will be exposed. However, this is not the main issue. Hypersonic flight itself is a means of protection, and even if current and future technologies can achieve it, intercepting maneuvering targets flying at a speed of 6 Mach is still quite difficult.

The development of the power plant is a key issue for the SR-72 project. The turbojet engine cannot achieve hypersonic flight, and the ramjet engine requires the initial booster. The use of various rocket engines is not very reasonable. Therefore, it is necessary to develop a completely new power unit.

It should be pointed out that Pratt& Whitney was used on the previous SR-71 reconnaissance aircraft; Whitney J58-P4 turbojet, ramjet circuit engine. When the speed is less than 1.6 Mach, the vortex jet provides the main thrust. Further acceleration is achieved through the stamping part. At this time, the engine is quite complex and expensive, requiring special fuels, specialized lubricants, etc.

Around 2005, Lockheed Martin and Aerojet Rocketdyne developed a composite circuit engine similar to the J58-P4, which included a ramjet circuit to ensure hypersonic flight. According to professional magazines, the design has been successfully completed and several tests have been conducted, but the finished engine has not yet been unveiled. Either it has not yet achieved final success, or it does not want to announce a breakthrough plan too early.

The manned or unmanned versions of SR-72 require various advanced electronic devices. Efficient flight control is required at various speed states, without relying on pilots. Automated equipment should closely track flight parameters and respond promptly to dangerous changes. For example, excessive maneuvering and prohibited overloading should be avoided.

Higher requirements for unmanned versions. During hypersonic flight, it is almost impossible to communicate wirelessly with the operator, and the autopilot should independently pilot the aircraft and perform assigned tasks in various states.

According to media reports, it is possible to use the SR-72 as a reconnaissance aircraft. But now and in the future, it is not very reasonable for this aircraft to achieve optical reconnaissance. It is not yet clear that aerial cameras can penetrate the plasma clouds around the aircraft for photography. The existence of plasma clouds makes it impossible for airplanes to conduct radio technology reconnaissance.

Using it as a fighter jet or missile carrier looks more reliable, although there are also some issues. Especially the deployment of combat payloads. Opening the embedded magazine to launch missiles during hypersonic flight is a highly complex engineering task that determines whether the aircraft can achieve combat use. If the speed is reduced to an acceptable level before deployment, it will completely eliminate the advantage of hypersonic flight.

Through decades of research, the United States has accumulated certain experience in the field of hypersonic technology. It has been applied to multiple missile and combat module projects. In addition, according to different sources, real hypersonic aircraft are being developed based on this foundation. The missile and combat module have been showcased in public materials, and even if the hypersonic aircraft project exists, it is highly confidential.

It is not difficult to see that Loma and related companies have the technology, materials, and ideas to solve some tasks within the SR-72 project. At the same time, there are currently no answers to other important questions. It is likely that a solution already exists, but there is currently no decryption. It may also be explained as not mastering the necessary technology.

It is unknown whether the Pentagon will support the development of the SR-72. Obviously, multi-purpose hypersonic aircraft will arouse strong interest from the Air Force. However, the actual combat effectiveness, prospects, and project feasibility of this aircraft are still shrouded in confusion.

In this way, in recent years, the US hypersonic program has entered the stage of military system development, but the results are currently limited. The development and testing of new combat modules, missiles, and hypersonic aircraft, even in the most optimistic scenario, have not yet completed the design and development stages of individual components. Let's wait and see if Loma and other organizations can master the necessary technology to build the long-awaited SR-72.

Source: Frontiers of Maritime Defense