NASA's 10-engine electric plane completes flight test

NASA has developed and successfully flight tested a battery-powered plane with 10 engines that can take off and land like a helicopter and fly efficiently like an aircraft.
The Greased Lightning or GL-10 prototype successfully transitioned from hover to wing-borne flight during several test flights, NASA said.
"We have a couple of options that this concept could be good for," said Bill Fredericks, aerospace engineer at NASA's Langley Research Centre in Hampton, Virginia.
"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," said Fredericks.

The GL-10 is currently in the design and testing phase. The initial thought was to develop a 6.1 meters wingspan aircraft powered by hybrid diesel/electric engines, but the team started with smaller versions for testing, built by rapid prototyping.
"We built 12 prototypes, starting with simple 2.3 kilogrammes foam models and then 11.3 kilogrammes, highly modified fibreglass hobby airplane kits all leading up to the 24.9 kilogrammes, high quality, carbon fibre GL-10 built in our model shop by expert technicians," said aerospace engineer David North.

The remotely piloted plane has a 3.05 meters wingspan, eight electric motors on the wings, two electric motors on the tail and weighs a maximum of 28.1 kilogrammes at take off.

"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 Fredericks.
"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," said Fredericks.
According to Zack Johns, GL-10's primary pilot, flying the ten-engine aircraft has its ups and downs, but it really flies more like a three-engine plane from a control perspective.
One other advantage to the GL-10 besides its versatile vertical take off and landing ability is its noise or lack of it.

"It's pretty quiet. The current prototype is quieter than a neighbour mowing the law with a gas-powered motor," said Fredericks.