This is Getting Real. NASA Working on Electric Flight
August 31, 2016
One more research initiative where tech breakthroughs could ripple through just about every aspect of society.
With 14 electric motors turning propellers and all of them integrated into a uniquely-designed wing, NASA will test new propulsion technology using an experimental airplane now designated the X-57 and nicknamed “Maxwell.” This artist’s concept of the X-57 shows the plane’s specially designed wing and 14 electric motors. NASA Aeronautics researchers will use the Maxwell to demonstrate that electric propulsion can make planes quieter, more efficient and more environmentally friendly.
“With the return of piloted X-planes to NASA’s research capabilities – which is a key part of our 10-year-long New Aviation Horizons initiative – the general aviation-sized X-57 will take the first step in opening a new era of aviation,” said NASA Administrator Charles Bolden, during his keynote speech Friday in Washington at the American Institute of Aeronautics and Astronautics (AIAA) annual Aviation and Aeronautics Forum and Exposition.
NASA’s aeronautical innovators hope to validate the idea that distributing electric power across a number of motors integrated with an aircraft in this way will result in a five-time reduction in the energy required for a private plane to cruise at 175 mph.
Several other benefits would result as well. “Maxwell” will be powered only by batteries, eliminating carbon emissions and demonstrating how demand would shrink for lead-based aviation fuel still in use by general aviation.
Energy efficiency at cruise altitude using X-57 technology could benefit travelers by reducing flight times, fuel usage, as well as reducing overall operational costs for small aircraft by as much as 40 percent. Typically, to get the best fuel efficiency an airplane has to fly slower than it is able. Electric propulsion essentially eliminates the penalty for cruising at higher speeds.
Finally, as most drivers of hybrid electric cars know, electric motors are more quiet than conventional piston engines. The X-57’s electric propulsion technology is expected to significantly decrease aircraft noise, making it less annoying to the public.
If there were no need for massive batteries, electric propulsion could dramatically reduce aviation’s contribution to climate change from carbon dioxide emissions. But what if the plane, itself, were the battery?
Suppose an aircraft’s skin or floor, for example, could serve double-duty by storing and dispensing electrical energy without adding substantially to the weight of the materials currently used. That could bring us a lot closer to practical electric flight on a meaningful scale.
What’s wrong with batteries? For one thing, they’re very heavy. Today’s best batteries would increase a small plane’s weight by about a third. A large plane’s weight would go up by a similar fraction even with highly improved batteries, four times as efficient as today’s best. Lifting all that battery weight eats up a lot of the energy that would be better put toward moving people and cargo.
Batteries take up a lot of space, too. And accommodating them, whether inside or outside the plane, increases drag—air resistance that wastes still more energy.
The goal of eliminating—or at least reducing—the need for separate batteries drives a team of some 35 scientists and engineers, working at four NASA centers and led by Patricia Loyselle of NASA’s Glenn Research Center in Cleveland, Ohio. Their project, called M-SHELLS (for Multifunctional Structures for High-Energy Lightweight Load-bearing Storage), falls under NASA’s Transformative Aeronautics Concepts Program. TACP supports efforts that have a high risk of failure because of their ultra-challenging nature, but which will pay off big if they succeed. And in this case, the benefits could potentially go far beyond aeronautics.
“We would love to see our developments incorporated in things like cars as well as aircraft,” Loyselle said. “You could use it for some of the structures that go up into space. It could be for buildings. It could be pretty much anywhere you need energy and a structure at the same time.”
For the M-SHELLS project to succeed, it needs to create material that is as strong as today’s aircraft-construction materials, can store large amounts of energy and both charge and dispense that energy rapidly. “You don’t want to sit around for four hours waiting for the battery to recharge,” Loyselle said. “And if somebody wants to change altitude, we want to be able to deliver the power quickly.”
The team is trying to merge two kinds of energy technology. “We are developing what’s called a hybrid supercapacitor that’s got the qualities of a battery as well as the qualities of a supercapacitor,” Loyselle said, noting that batteries are able to store a lot of energy whereas supercapacitors are speed demons for charging and discharging.
Some newly available materials may provide the means. “Some of these new nano materials are very, very strong,” Loyselle said. “And if you have that real small particle size, reactions happen much faster.”
Large all-electric planes will require the ability to pack much more energy into a given amount of battery—whether M-SHELLS or the standard kinds—than any developments currently visible on the horizon. So when it comes to commercial transport aircraft, M-SHELLS products in the near term are most likely to be used for hybrid planes that use a combination of electricity and jet fuel much as a Prius uses electricity and gasoline.
Hybrid turbo-electric planes hold a lot of promise, according to Jim Felder, a NASA aerospace engineer specializing in aircraft propulsion. “If electrified propulsion really works out for large aircraft,” he said, “it could be as big a change as the transition from piston-engine propeller planes to jet engines.”
And NASA’s not alone. There’s a global race to solve this problem. Small armies of engineers now involved – huge rewards for the winner. That should remind you of any number of technological revolutions we’ve seen in recent decades.