NASA moves to begin historic new era of X-plane research
25 April 2016
NASA is preparing an array of experimental aircraft, each intended to demonstrate advanced technologies that will push back the frontiers of aviation.
Goals include showcasing how airliners can burn half the fuel and generate 75 percent less pollution during each flight as compared to now, while also being much quieter than today’s jets – perhaps even when flying supersonic.
NASA’s renewed emphasis on X-planes is called, “New Aviation Horizons,” an initiative announced in February as part of the President’s budget for the fiscal year that begins Oct. 1, 2016. The plan is to design, build and fly the series of X-planes during the next ten years as a means to accelerate the adoption of advanced green aviation technologies by industry.
“If we can build some of these X-planes and demonstrate some of these technologies, we expect that will make it much easier and faster for U.S. industry to pick them up and roll them out into the marketplace” said Ed Waggoner, NASA’s Integrated Aviation Systems Program director.
Built by Bell Aircraft, the X-1 was the first plane to fly faster than the speed of sound, thus breaking the “sound barrier,” a popular but fundamentally misleading term that spoke more to the romantic notion of the challenges of high speed flight than an insurmountable physical wall in the sky.
The X-1 marked the first in what became a long line of experimental aircraft programs managed by the NACA (and later NASA), the Air Force, the Navy, and other government agencies.
But in this age of high-speed computers capable of generating sophisticated simulations, and with the availability of world-class wind tunnels to test high-fidelity models, why still the need to fly something like an X-plane?
The answer has to do with what Waggoner describes as the necessity of a “three legged stool” when it comes to aviation research.
One leg represents computational capabilities. This involves the high-speed super computers that can model the physics of air flowing over an object – be it a wing, a rudder or a full airplane – that exists only in the ones and zeros of a simulation.
A second leg represents experimental methods. This is where scientists put what is most often a scale model of an object or part of an object – be it a wing, a rudder or an airplane – in a wind tunnel to take measurements of air flowing over the object.
Measurements taken in the wind tunnel can help improve the computer model, and the computer model can help inform improvements to the airplane design, which can then be tested again in the wind tunnel.
“Each of these is great on its own and each helps the other, but each also can introduce errors into the inferences that might be made based on the results,” Waggoner said. “So the third leg of the stool is to go out and actually fly the design.”
Whether it’s flying an X-plane or a full-scale prototype of a new aircraft, the data recorded in actual flight can then be applied to validate and improve the computational and experimental methods used in developing the design in the first place.
“Now you’ve got three different ways to look at the same problem,” Waggoner said. “It’s only through doing all that together that we will ever get to the point where we’ve lowered the risk enough to completely trust what our numbers are telling us.”
“Que” the Ssupersonic technology
Although it may not wind up being the first of the New Aviation Horizons X-planes to actually fly as part of the three-legged stool of research, design work already has begun on QueSST, short for Quiet Supersonic Technology
A preliminary design contract was awarded in February to a team led by Lockheed Martin. If schedule and congressional funding holds, this new supersonic X-plane could fly in the 2020 timeframe.
QueSST aims to fix something the X-1 first introduced to the flying world nearly 70 years ago – the publicly annoying loud sonic boom.
Recent research has shown it is possible for a supersonic airplane to be shaped in such a way that the shock waves it forms when flying faster than the speed of sound generate a sonic boom so quiet it hardly will be noticed by the public, if at all.
“We know the concept is going to work, but now the best way to continue our research is to demonstrate the capability to the public with an X-plane,” said Peter Coen, NASA’s supersonic project manager.
It is hoped data gathered from flying QueSST will help the Federal Aviation Administration and its international counterparts establish noise-related regulations that will make it possible for commercial supersonic airliners to fly over land across country.
Meanwhile, other experimental aircraft also are under consideration, including those with novel shapes that break the mould of the traditional tube and wing airplane, and others that are propelled by hybrid electric power.
Exactly what these X-planes will look like, how they will be operated and where they will be flown all have yet to be precisely defined.
“We’re going to let the marketplace and the community help us inform our decisions on the direction we want to go,” Waggoner said. “But we’re really excited about all of the things we might demonstrate.”
For more information visit the NASA website.