What has 10 engines, can hover like a helicopter and fly like a plane?
Answer: NASA’S latest drone prototype, GL-10.
Better known by it’s pop culture-inspired moniker, Greased Lightning, it is an innovative new concept for an unmanned vehicle (UAV) from NASA’s Langley Research Center in Hampton, Virginia.
The battery-powered drone has a 10-foot (3-meter) wingspan, 10 electric motors (eight on the wings, two on the tail) and weighs 28kg at takeoff. It has a tilt-wing design that allows for vertical takeoff and landing — similar to existing tiltrotor aircraft like the Bell-Boeing V22 Osprey.
“All four engines on the left wing are given the same command,” said Zach Johns, the prototype’s main pilot. “The four engines on the right wing also work in concert. Then the two on the tail receive the same command.”
Successful flight tests have not only demonstrated its hovering capabilities during its vertical takeoff — the way a helicopter does — but the team has also triumphed in some of the aerodynamically trickier situations.
We have liftoff!
“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,” said Bill Fredericks, one of the aerospace engineers working on the project, in a NASA 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.”
This prototype is the 12th iteration in the development phase but as another engineer from the project, David North, explained, the research team needed to design each model to get to where they are today.
“Each prototype helped us answer technical questions while keeping costs down,” he said. “We did lose some of the early prototypes to ‘hard landings’ as we learned how to configure the flight control system. But we discovered something from each loss and were able to keep moving forward.”
A different kind of eye in the sky
Fredericks explained how the research could move past the current development phase and into real-life applications.
“We have a couple of options that this concept could be good for. It could be used for small package delivery or vertical takeoff and landing, long endurance surveillance for agriculture, mapping and other applications.”
He added: “A scaled up version — much larger than what we are testing now — would make also a great one to four person size personal air vehicle.”
An additional strength is the UAV’s lack of noise inflight, said Frederiks.
“It’s pretty quiet. The current prototype is quieter than a neighbor mowing the lawn with a gas-powered motor.”
The team will continue testing the concept design to ensure aerodynamic efficiency, as well as demonstrating the drone at various NASA events throughout the year.
