Raytheon Technologies Speeds Hypersonic Testing with Adaptable ‘Tanning Bed’ Technology

On a global scale, interest in hypersonic flight is heating up.

As the U.S. looks to remain on par with peer competitors delving deep into research and testing of hypersonic weapons, defense agencies and contractors are making good headway demonstrating concepts such as the Hypersonic Air-breathing Weapon Concept.

But as the U.S. looks to ramp up R&D for hypersonics, it must keep pace with testing the technology — a difficult task when accommodating weapons that reach speeds above Mach 5 and create intense temperatures that bend and contort most durable materials.

“For very complicated systems where you’re pushing the edges of your knowledge and technology, like hypersonics, you want to learn as much as you can before you put the vehicle into the air,” says Adam Wood, an engineering fellow at Raytheon Missiles & Defense, a Raytheon Technologies business, who focuses on mechanical analysis and testing. “Hypersonic flight induces extreme levels of heating and air pressure on the vehicles; you need to ensure an airframe won’t distort or deform under those conditions and that its internal architecture can hold up to the stress.”

The Challenges of Hypersonic Testing

While testing is crucial to ensure the technology can endure the rigors of actual flight demonstrations without bending, warping or losing control, test locations are highly limited. In fact, high-temperature wind tunnels, like the one crafted by NASA in Langley, Virginia, are currently among the only places available to test hypersonics. And, while Wood emphasizes that high-temperature, high-pressure wind-tunnels like the one at NASA are amazing feats of engineering and “a national asset,” with interest and scrutiny increasing, hypersonic testing sites are quickly becoming crowded.

“You can think of these as being like a really popular wedding venue: You have to make reservations far in advance, and if you're not ready on the day that you reserved it, you have to get back in line,” Wood says.

That type of arrangement can, understandably, slow timelines and hinder R&D. Moreover, even advanced wind tunnels like NASA’s are limited in terms of dynamic condition testing.

“As a vehicle flies through the air, just like on a commercial flight, the conditions are constantly changing,” Wood says. “Heating rates, distribution, pressure, that's all changing. The wind tunnel can't do all that variation; it can only reproduce one condition at a time.”

While the wind tunnel can generate different conditions, it can only produce one per test. And given that a tunnel can usually run one to two tests per day, that can prove limiting for testers.

Speeding Hypersonic Testing with the Tanning Bed

So, as the U.S. looks to move full speed ahead with hypersonics, how can it get the testing environment up to pace?

Enter Raytheon’s “tanning bed” technology, a more modular, mobile way to test some elements of hypersonic flight that aims to complement wind-tunnel testing and help speed R&D.

What is the tanning bed? Picture a metal box filled with high-power quartz lamps that replicate the complex, dynamic distribution of temperatures across a missile as it flies at hypersonic speed. The challenge Raytheon engineers faced was assembling and controlling these components so their output matched the complex, dynamic thermal environment a hypersonic missile would see in flight. The result was a configurable test capability that could be used to conduct hypersonic tests in its own lab, quickly and easily, and then adapt the design before it gets locked down for fabrication of flight hardware.

“Because it is modular and mobile, we can move it from lab to lab, from building to building at any given plant site or even from plant site, to plant site. We can bring the test to the people, instead of having to have them move the hardware to the test,” says Wood, noting the tanning bed can be broken down into pieces the size of a washing machine on wheels.

Moreover, the tanning bed can provide valuable dynamic heat testing.

“One of the things that the tanning bed can do that a wind tunnel can't is it can replicate the time history of the flight for the heating,” Wood says. Much like a large toaster oven, testing teams can “turn the dial” on temperature throughout a test to reproduce more realistic flight conditions, he says.

The tanning bed can help supplement wind-tunnel testing, allowing testers to move forward with design iterations around heating effects quicker and make the best use of their time with pressure testing in the wind tunnel. Ultimately, that means Raytheon can move hypersonic testing into hyperdrive.

The biggest opportunity for the tanning bed is faster learning, Wood says. Because the technology is modular, customizable and generic, it allows for faster configuration of a high-temperature test for different designs.

“We don't have to wait for custom fixtures to be designed for new test hardware to arrive, be assembled and tested out,” Wood adds. “It truly saves us on cost for each new design that we want to test. All that time that we save is time we can spend learning.”

Learn more about Raytheon’s hypersonic technology.