A team of engineers at NASA’s Langley Research Center recently tested a 10-engine, battery-powered hybrid drone that can take off like a helicopter and transform mid-flight into an aircraft.
This drone-copter prototype, called Greased Lightning or GL-10, is a smaller scale version of something NASA hopes will turn into an aircraft with a 20-foot wingspan (6.1 meters) and powered by hybrid diesel/electric engines. “We have a couple of options that this concept could be good for,” explains aerospace engineer Bill Fredericks. “It could be used for small package delivery or vertical take off and landing, long endurance surveillance for agriculture, mapping and other applications. 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.”
NASA’s rapid prototyping approach to design and testing
To cut costs, NASA is smartly pursuing a rapid prototyping model of development. Instead of attempting to construct a full scale model, and making adjustments as needed thereafter, NASA is starting small and building a series of increasingly larger versions. “We built 12 prototypes, starting with simple five-pound (2.3 kilograms) foam models and then 25-pound (11.3 kilograms), highly modified fiberglass hobby airplane kits all leading up to the 55-pound (24.9 kilograms), high quality, carbon fiber GL-10 built in our model shop by expert technicians,” said David North, another aerospace engineer working on the project. North goes on to explain that “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. But we discovered something from each loss and were able to keep moving forward.”
Greased Lightning drone-copter takes flight
The most recent iteration of GL-10 is a remotely piloted hybrid drone-copter that has a 10-foot wingspan powered by eight electric motors on its wings and two on the tail. Weighing approximately 62 pounds, the GL-10 drone-copter is unique in its ability to take off and hover like a helicopter, and then change the angle of its wings to fly like an aircraft.
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. 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
The GL-10 drone-copter will be showcased from May 4 to May 7 at the Association for Unmanned Vehicles Systems International 2015 conference in Atlanta.