The opening sequence of the blockbuster film Top Gun: Maverick depicts Tom Cruise piloting a futuristic aircraft up to Mach 10, or ten times the speed of sound. In reality, decades of research has only brought us to hypersonic speeds in excess of Mach 5.
But now a private company has announced plans for a new hypersonic aircraft they hope to test in the next couple of years, called the Stratolaunch Talon-A.
When it comes to flight, going faster comes with costs. The faster an aircraft travels, the more air resistance it faces, requiring more thrust and more fuel. Above about 1,200 km/hr, depending on altitude, the air compresses so much there’s a sudden increase in aerodynamic drag — the famous sound barrier.
While rocket-powered missiles and missile-like space vehicles routinely achieve supersonic or hypersonic speeds, achieving controlled flight with those speeds in a winged airplane has been a more difficult task.
Chuck Yeager flew a specially developed rocket plane, the Bell X-1, to break the sound barrier in 1947. A series of ever-faster experimental supersonic X-planes followed, culminating with the famous X-15 rocket-plane that first flew in 1959. It inaugurated the era of hypersonic flight by ultimately reaching Mach 6.7 on flights that touched the edge of space.
In 2004, NASA flew the X-43A hypersonic test aircraft up to Mach 9.6. This unpiloted test aircraft was initially boosted by a rocket, and then fired up its “scramjet” engine — a special type of high-performance jet engine. The X-43A holds the record for an air-breathing aircraft, which means that the engine takes in air from the atmosphere to help burn its fuel.
However, the hypersonic portion of its flights lasted only about ten seconds: it turns out that keeping an engine running at that speed is very challenging.
In the new top gun movie, Cruise flies a hypersonic plane called the Darkstar. This fictional aircraft may have been inspired by plans for a hypersonic military plane called the SR-72, or “Son of Blackbird.”
The original 1960s Blackbird was the A-12 reconnaissance plane and it evolved into the larger legendary SR-71 with room for two passengers and more fuel.
The SR-71 was capable of Mach 3 flight. Its manufacturer, Lockheed (now Lockheed-Martin), has made announcements about developing an unmanned hypersonic spy plane that would be a successor to the SR-71 for about a decade. Secrecy surrounds the SR-72, which is currently in development, but it is intended to fly at Mach 6, twice the speed of the Blackbird.
So the aircraft shown in top guna plane that can take off from the ground and fly up to Mach 10, was all a computer-generated fantasy.
But a new hypersonic aircraft called Talon-A could make the fantasy real. It was announced by Stratolaunch, a Mojave, Calif. company that also built the world’s largest aircraft, a carrier called the Roc. The enormous Roc will serve as a mothership to lift the Talon-A into the air.
Talon-A is an unmanned vehicle designed to test the aerodynamics and materials for hypersonic flight. The first version, which the company says is complete, won’t be hypersonic — in fact, it won’t even be powered. It’s meant to test the structure that carries the smaller plane under the Roc’s wing, and how it affects the flight of the carrier aircraft. It will also be dropped from altitude to test its glide and landing characteristics.
Future versions of the Talon-A, which the company says are under construction, will be equipped with a rocket engine. That engine will be fired when the Talon-A is released from the mother ship at 35,000 feet, where, according to plans, it should accelerate to Mach 6. So it seems much of the hard work of developing this aircraft remains to be to be done.
Hypersonic flight has been a goal in aviation for decades but the challenges are immense, not just because of the amount of power needed, but also the heating effect of the air, which can raise skin temperatures on the aircraft above what conventional materials can withstand. A lot of research will be focused on finding the right composites that can take the heat.
The long-term dream is for hypersonic aircraft that could take passengers halfway around the world in a half an hour.
But the more likely application will be for the military, who want aircraft that fly high and fast for reconnaissance, getting in and out of enemy territory without being caught. Hypersonic aircraft could also provide easy access to space, with the ability to take off from any major runway and return to land at the same airport, which is much simpler than complicated rocket launches.
Going almost has been an obsession for humans since Roman chariot races. Now that need for speed continues through the air.