By Mike Mount
Who needs business class when your overseas flight will last less than an hour? Some of the first tests of such a technology happened Tuesday off the California coast as the Air Force tested its hypersonic X-51A Waverider vehicle.
At just 25 feet long and only a few inches in diameter, the Waverider is a far cry from an aircraft that can carry people anywhere. But the technology one day could send people or troops across the world in just minutes.
Hypersonic travel, meaning speeds of Mach 5 (3,800 miles per hour) and above, has been a focus of the military as it looks to perfect a technology that can become the new stealth. The Pentagon says that countries are becoming wiser to US stealth technology and it is increasingly becoming a less effective tool.
Hypersonic flight does away with stealth because its speeds allow for greater flexibility and control for missions that are not possible with current jet technology.
But in the commercial world, it can mean flights are so quick a flight attendant hardly would have time to serve drinks and a meal, and there would be no more groggy feeling after those transcontinental flights.
The technology is significant because a hypersonic aircraft breaths oxygen, like a regular jet engine, but reaches speeds five times that of commercial aircraft. To get similar results, the only other option is rocket power.
"You would have to have bulky fuel tanks, nozzles and plumbing and that makes rocket power more heavy and more expensive," says Dora Musielak, an adjunct professor of physics at the University of Texas at Arlington.
Musielak's research focuses on high-speed propulsion.
"Hypersonic technology only requires the aircraft to stay in the atmosphere and is much lighter and efficient," she says.
As it cuts through the atmosphere, the design of the craft captures the shock waves it creates as it goes beyond the speed of sound, adding lift to the airframe.
"All of that adds to better engine performance and better aerodynamics, making it a more aerodynamically efficient aircraft," says Mark Lewis, the former chief scientist for the Air Force.
How far away are we to seeing this technology as a reality? It's hard to say, according to analysts. But the Air Force says that by 2016, it would like to have a working weapon flying with hypersonic technology.
"The vehicles need to be predictable, more cost effective and there still is a need to design on-board flight control systems, so it is several years away," Lewis says.
But while the military is in a rush to seize this technology, Musielak says commercial aviation should focus on mastering supersonic air transport first.
"First we need to travel at supersonic speeds.I think we need to first develop the technology to go beyond the Concord, and we still need a step between what we have and hypersonics," Musielak says, referencing the only supersonic commercial aircraft that entered service.
That said, can humans even withstand hypersonic travel? With the break-neck speeds and airframe temperatures reaching highs in the thousands of degrees, are there limits?
It turns out speed is a factor, but only when you are traveling at Mach 20, then it becomes a bit bumpy.
"Staying at Mach 5 or 6, you can have an aircraft that would give passengers a smoother ride," according to Musielak.
"But higher speeds would produce higher forces on the body and a more jittery ride like astronauts face while launching into space," she said.