Drives and Controls Magazine
Nine-seater electric aircraft will have a range of 965km
Published:  29 June, 2017

At the recent Paris Air Show, an Israeli aircraft developer unveiled a prototype of an all-electric aircraft that could carry nine passengers and two crew a distance of up to 965km (600 miles) at speeds of up to 445 km/h (240 knots). Eviation Aircraft hopes to start trial flights of its Alice Commuter plane in late 2018 and to put it on sale in 2021.

The aircraft has been designed from scratch for electric power and is not an adapted version of an existing plane. Eviation claims that it will be up to 300% more fuel-efficient than a conventional aircraft of a similar size.

The main propulsion will come from a tail-mounted pusher propeller, assisted by two further pusher propellers on each wingtip. This arrangement is designed to reduce drag and to provide redundancy. The power produced during cruising will amount to 280kW.

Energy will come from a 980kWh lithium-ion fusion battery. The 12m-long aircraft will have a 13.5m wingspan and is expected to weigh 5,900kg. The cruise altitude of the unpressurised aircraft will be 3,050m (10,000 feet)

“In the next four years, Eviation aims to make regional air travel a cost-effective and clean option that rivals any existing form of transit today,” says the company’s founder and CEO, Omer Bar-Yohay. “With people working and commuting across greater distances than ever before, we believe the solution will bring mid-range cities like Seoul and Beijing, or London and Paris, closer together through all-electric air travel.”

One way that Eviation is accelerating its development programme is by making extensive use of 3D printing, allowing it to test the aircraft’s components before needing to invest in certifiable parts.

“Our ability to create new iterations of designs with 3D printing and see how they perform in real-time is helping us reduce critical capital costs, even as we accelerate our rapid prototyping phase,” explains Bar-Yohay.

Eviation's Alice electric commuter craft is due to take off for the first time in 2018

For example, the aircraft’s wing-tip motors were printed in a matter of hours (using 3D printing technologies supplied by Stratsys), allowing Eviation to evaluate them before the actual motors were available.

A key aspect of the plane’s design is its use of smooth composite surfaces to minimise interference drag. Eviation is creating the strong, geometrically complex, lightweight parts that support these surfaces by 3D printing composite lay-up tools, and covering these with carbon fibre.

“All in all, in two years of operation we have saved several hundreds of thousands of dollars with 3D printing and I would estimate six months or more of workforce hours, which made this project possible,” says Bar-Yohay. “Today we are using the technology for prototyping test parts and tooling. The ability to produce lightweight parts in complex geometries will also enable us to explore the possibility of 3D printing parts for the final aircraft.”

•  Eviation is also developing a pilot-less electric drone aircraft designed to carry payloads of up to 50kg or 150 litres over distances of up to 800km at speeds of up to 390km/h (210 knots). The 3m-long Orca aircraft is powered by a 38kWh lithium polymer battery and develops a peak of 144kW, which drops to 12kW when cruising.

To speed its development programme, Eviation has been using 3D-printed versions (left) of the aircraft's motors (right)