NASA engineers have successfully flown an unmanned aircraft that can takeoff, land and hover like a helicopter, and fly horizontally like a fixed-wing plane.
The team's battery-powered aircraft uses a system of 10 engines on tilted wings to achieve vertical takeoff and landing. During recent test flights near Langley Research Centre in the US, the prototype - known as Greased Lightning, or GL-10 - successfully transitioned to horizontal flight. You can watch the flight test in the above video.
"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," NASA aerospace engineer Bill Fredericks said in a press release. "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."
A hybrid aircraft that can fly vertically like a helicopter, but cover long distances at high speeds like a fixed-wing aeroplane, could offer enormous advantages for everything from military operations and search and rescue, to mapping.
One way of accomplishing this is by using rotors, or propellers, that tilt. For vertical flight, the rotor blades are angled along a horizontal plane, creating lift the way a helicopter rotor does. Then, as the aircraft gains speed, the rotors are progressively tilted forward, eventually reaching a vertical position where they generate propulsion. A good example of this is Boeing's V-22 Osprey.
But the NASA researchers were interested in developing a new system, which could be more aerodynamic.
The NASA researchers say they'd built 12 prototypes before this latest one, beginning with some good old foam models that were subjected to some pretty strong impacts. They eventually graduated to fibreglass hobby planes.
"Each prototype helped us answer technical questions while keeping costs down. We did lose some of the early prototypes to 'hard landings' as we learned how to configure the flight control system," said project engineer David North. "But we discovered something from each loss and were able to keep moving forward."
The GL-10 has a 3-metre wingspan, a takeoff weight of about 28 kg, and has four electric engines on each wing, and two on the tail section. The engineers are eventually hoping to scale this up to a craft with a 6-metre wingspan.
"It could be used for small package delivery or vertical takeoff and landing, long endurance surveillance for agriculture, mapping and other applications," Fredericks said. "A scaled up version - much larger than what we are testing now - would also make a great one to four person size personal air vehicle."
While space might be its forte, NASA's also committed to bringing us more efficient and cleaner airflight technology. Earlier this year NASA released details of its latest experimental plane - called the LEAPTech - which has very narrow wings and a system of 18 electric motors.
And just this week, NASA and the Air Force Research Laboratory in the US announced that they had successfully completed test flights of a plane with morphing wing technology, which they say has the potential to save millions of dollars annually in fuel costs by reducing the weight of aircraft.
We literally can't wait to see what they come up with next.