- SR-72 will reach hypersonic speeds for fast global deployment, focusing on stealth and evasion.
- PAK DA is a subsonic stealth bomber dedicated to dropping ordinance undetected.
- SR-72 is revolutionary but costly, while PAK DA is cheaper with existing technology.
Pitting Lockheed Martin’s SR-72 and the Tupolev PAK DA against each other seems futile. Other than being next-generation stealth aircraft, these two have little in common. One is a hypersonic reconnaissance aircraft, while the other is meant to be a subsonic bomber. But it’s the difference in philosophies that brings about the comparison.
Russia argues that stealth is more important than speed. However, the US is focused on developing an aircraft that is stealthy but fast enough that it won’t even matter when it shows up on radar because it’ll already be out of range.
So, how do these two philosophies stack up against each other? What are the advantages and disadvantages of each one, and what will win if it comes down to blows? Let’s dive in.
Son of the Blackbird
The Lockheed Martin SR-72 is being developed by Skunkworks, the same top-secret division that created the iconic SR-71 Blackbird. The division has been tasked with making the SR-72 fly twice as fast and higher than the original, which is no easy feat given that the original reached a top speed of Mach 3.4 (2,300 mph, 3,650 km/h) and altitudes of 80,000 ft (24,400 m).
Superior Speed
This means the SR-72's targeted speed is Mach 6, and anything above Mach 5 is hypersonic territory. Being capable of hypersonic speeds will allow the US to deploy the SR-72 almost anywhere on the planet quickly, revolutionizing military operations.
The US is developing aircraft to go faster than any other aircraft because it believes speed and stealth go hand in hand. The aircraft will be stealthy, but the focus will be on evasion. The SR-72 will be too fast to be picked up on radar, and even if it is detected, there won’t be a chance to gain a missile lock in time. It’ll be out of range.
The SR-72 will be an Unmanned Aerial Vehicle (UAV), primarily a reconnaissance aircraft like its predecessor. However, the aircraft will not be a one-trick pony. As previously reported by Simple Flying, the SR-72 will be attack-capable. Lockheed Martin expects the aircraft to carry various armaments, both conventional and nuclear, and be able to deliver hypersonic payloads as well.
Lockheed Martin expects the aircraft to enter service in 2030 and plans to test-fly a demonstrator in 2025.
Challenges
Hypersonic flight is a completely different beast from supersonic flight and is exponentially harder to achieve and sustain. All of the challenges faced by the engineers of the SR-71 are present, but they’ve been dialed up to 11.
First, the aircraft has to be capable of both slow and high-speed flight while being extremely agile. This agility will help it navigate enemy airspace and evade enemy aircraft. Agility in aircraft is achieved through instability. However, being inherently unstable during extremely high speeds has its risks. An inadvertent control input can instantly overstress the airframe, leading to disaster.
The aircraft’s engine is also a big question. It must be a scramjet engine to propel the aircraft at hypersonic speeds. However, it will also need to be able to power the aircraft at subsonic speeds. The concepts don’t mesh well, so seeing the final solution will be interesting.
Overcoming the high temperatures is also a massive challenge. The airframe must function without issue at temperatures exceeding 2,000 C (3,600 F).
Pros and cons
The main advantage of the SR-72 is that it will set the stage for aviation technology going forward. The research and development that goes into the aircraft will have applications in other areas and be useful for commercial aviation and even space travel.
The disadvantage is the program's high cost and difficulty level. In addition, the aircraft will almost certainly be expensive to operate, just like its predecessor. It will also have a limited flight time and need aerial refueling to stay airborne for long periods.
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The aircraft will be twice as fast as the SR-71 BlackbirdSoviet stealth
In sharp contrast to the SR-72, which is hypersonic and aims to fulfill roles, the PAK DA, known as the Poslannik (lit. ‘Messenger’), is focused on being a subsonic bomber that excels in stealth. Once completed, the aircraft will be Russia’s first-ever stealth bomber. The aircraft will replace the country’s current bombers, the Tu-95 and the Tu-160, which have operated since the 1950s and 1980s.
The aircraft’s goal is to reach a target, drop its conventional or nuclear ordinance, and leave without ever being detected. The aircraft follows the philosophy of the Northrop Grumman “Stealth Bomber” B-2 Spirit.
Flying wing
Its design is also similar to that of the B-2 Spirit. The PAK DA will follow a flying wing design, which means the entire aircraft will be blended and will not have individual areas such as the tail, empennage, fuselage, and wings. Any remaining physical radar signature will be neutralized by an array of onboard stealth and jamming technology to make the aircraft virtually invisible.
Speed is not considered a factor because the PAK DA will be capable of firing hypersonic weapons. Russia argues that it removes the need for the aircraft to travel at hypersonic speeds to have similar capabilities. The weapon systems will manage that. The PAK DA is simply the delivery method.
Tupolev has been working on the PAK DA since the early 2000s. It has been suggested that the aircraft will enter service by 2027. However, if the timeline of the Sukhoi Su-57 is anything to go by, it will be a while before the Messenger is operational.
Pros and cons
Focusing on stealth technology is problematic because it can be beaten. The useful life of the PAK DA entirely depends on whether Russia can maintain an edge in jamming and detection methods. If its adversaries develop a new form of detection, Russia will have to rush to counter it with clever electronic jamming.
The advantage of the PAK DA is that it will be significantly cheaper to build and operate because the technology already exists. It just has to be improved to reach new levels of stealth.