NASA's space missions may get all the attention, but the agency hasn't ignored the aeronautics element in its name, and has recently proved it by flying an electric-powered drone plane capable of taking taking off vertically like a helicopter.
Plenty of current drones do just that, of course, but after its vertical takeoff this particular unmanned 10-motored craft can transition to forward flight by rotating its wing with its eight electric motors and its tail with its two motors forward, the space agency says.
Dubbed the Greased Lightning or GL-10, it's the result of months of testing of models of different sizes and configurations, some of which were the victims of "hard landings," all part of a learning curve, the researchers at NASA's Langley Research Center in Virginia say.
"We built 12 prototypes, starting with simple 5-pound foam models and then 25-pound highly modified fiberglass hobby airplane kits all leading up to the 55-pound high quality, carbon fiber GL-10 built in our model shop by expert technicians," says aerospace engineer David North.
The engineers recently took the latest model, a battery-powered version with a wingspan of 10 feet and weighing 62 pounds, to a military base 2 hours from the Langley facility for the first test flight that would include a transition from hovering to forward flight.
The GL-10 had performed well in previous hover-only tests, but transitioning from hovering to forward flight involves some challenging aerodynamic issues, he explained.
The flights of the unmanned aerial vehicle were a success, according to NASA engineer Bill Fredericks.
"During the flight tests we successfully transitioned from hover to wing-borne flight like a conventional airplane then back to hover again. So far we have done this on five flights," he said. "We were ecstatic. Now we're working on our second goal - to demonstrate that this concept is four times more aerodynamically efficient in cruise than a helicopter."
Despite the number of motors - 10 in all - the drone is easy to control, says primary pilot Zack Johns, who explains that the four motors on each wing respond to a single command, while the two motors on the craft's tail also respond to a single command, making flying the drone more like controlling a three-engine plane, he said.
The technology could easily be adapted to commercial applications, Fredericks said.
"It could be used for small package delivery or vertical takeoff and landing, long endurance surveillance for agriculture, mapping and other applications," he said.
