Manned Electric Aircraft: Progress and Potential
Apr 07, 2017
Recently, there has been a sharp increase in development activity with electric aircraft, as examined in the new report from IDTechEx Research, Manned Electric Aircraft 2017-2027. This development activity falls into three types -
incremental improvement of existing airframes, "born electric" radically different approaches carefully aimed at identified markets and the heroic pushing of limits with no clear path to commercial viability.
Incremental improvement has been seen by the relatively trivial electrification of hang gliders, sailplanes and the like by Electroflyer and Pipistrel for example. That has been followed by Bye Aerospace taking a more radical step forward, beating Pipistrel and others to the single-engine born-electric Cessna replacement with 30% extra range coming from feeding the pure electric powertrain from solar wings not just a battery. It has a very compelling business case in pilot training, tourism and other applications and is already selling well. Logically, linear progression should be to hybrids for even longer range but although Equator Aircraft and others have been developing them, little has been seen on the market. In 2017, one company made the rather silly announcement that it would make pure electric feeder aircraft using existing airframes and "a better battery when it arrives". Would that it were that easy! For example, the development of distributed electric power along a wing using a profusion of electrically driven propellers is deeply significant because the wing can be half as large, greatly reducing weight and take-off distance.
In the heroic category, in 2017, PCAero of Germany and partners are preparing to have a solar aircraft take off and rise to 75,000 to 80,000 feet with power from the structural photovoltaics alone, this even powering the pilot's spacesuit as it does so. This SolarStratos project is planning to offer brave passengers a five-hour flight in 2018 as part of plans to revolutionise air travel. The craft will take two hours to ascend to space and spend 15 minutes with the stars then take three hours to descend. Extreme temperatures of around -70C await the pilot and passenger, who will witness the curvature of the earth and the incredible spectacle of seeing stars during the daytime. The hi-tech plane is just 8.5 metres long and built by PC Aero, runs on a 32-KW electric engine and 20 kWh lithium-ion battery. It is charged by the craft's 22 square metre solar cells, which cover each wing.
Vertical take-off pure electric aircraft are often portrayed as part of the elusive flying car dream of the last 100 years but with up to one megawatt needed from inadequate batteries, they are something of a "run before you can walk" approach. Nonetheless, all advances and failures teach the industry something.
Sikorsky announced development of a pure electric helicopter demonstrator but it did not arrive and now the company itself has changed hands. Hirobo, famous for toy electric helicopters, promised a manned pure electric helicopter for sale in 2016 but did not deliver. Undeterred, a start-up company hosted in a European Space Agency business incubator is developing the world's first vertical take-off and landing aircraft for personal use. The electric two-seater will "open the door to a new class of simpler, quieter and environmentally friendly planes available from 2018". Will it happen this time?
"Our goal is to develop an aircraft for use in everyday life," explains Daniel Wiegand, CEO reiterating the usual rationale. "We are going for a plane that can take off and land vertically and does not need the complex and expensive infrastructure of an airport. To reduce noise and pollution, we are using electric engines so it can also be used close to urban areas."
Flying taxis have been energetically developed for a long time and work by NASA and many others continues with dreams of operating from the cloverleaf road patterns at freeway feeder roads for example but the problems are so formidable that this tends to look like a commercial program unintentionally becoming an heroic dream.
Nikhil Goel, Uber's head of product for advanced programs, says the company wants to organize the industry to help spur development of flying cars and it has hired NASA visionary Mark Moore who first examined the feasibility and challenges. Google's Larry Page has funded two personal-aircraft startups Zee.Aero and Kitty Hawk. Tetrafugia and many others have failed to produce a flying car that is more than a poor car merged with a poor aircraft. Their objective itself is questionable because few people can drive down roads and then fly themselves from an airport even if the vehicle is fully Category 5 autonomous: it does little to improve traffic congestion compared to a new railway or even a fleet of electric double decker buses.
Nevertheless, in January 2017, Airbus announced that it is planning to test self-piloted personal aircraft by the end of the year as a way of reducing traffic on inner-city roads. The announcement was made by the aerospace group's CEO, Tom Enders who said Airbus is investing in driverless technologies and artificial intelligence, which could lead to them developing a fleet of flying cars. "One hundred years ago, urban transport went underground. Now we have the technological wherewithal to go above ground," he said, adding that he believed the company would be testing flying single-person transport by the end of the year.
"We are in an experimentation phase. We take this development very seriously," he said. "If we ignore these developments, we will be pushed out of important segments of the business."
Enders also noted how the development could affect city planning and infrastructure, saying that flying means you do not need to pour billions into concrete bridges and roads. The personal aircraft is being explored in Airbus' Project Vahana derived from its Urban Air Mobility initiative, dedicated to less-conventional vehicle concepts, like vehicles to transport individuals or helicopter-style vehicle that carry multiple riders. The aim would be for people to book the personal aircraft using an app, similar to car-sharing schemes such as Uber. Airbus has also been working on VTOL technology that would allow vehicles to pick up passengers in busy urban areas and has said it expects to be putting them into production by 2021.
However, Elon Musk prefers to develop robot buses next and to dream of intercontinental airliners that are pure electric thanks to solar and batteries with at least 400 Wh/kg. He thinks flying cars are a dumb idea, at least for city travel. As long as the laws of physics hold, he explains, any flying car will need to generate a lot of downward force to stop it from falling out of the sky, which means wind and noise for those on the ground, not to mention debris from mid-air fender-benders. "If somebody doesn't maintain their flying car, it could drop a hubcap and guillotine you," he says. "Your anxiety level will not decrease as a result of things that weigh a lot buzzing around your head."
The new IDTechEx report, Manned Electric Aircraft 2017-2027 takes a sober look at all the options in this frenzy of activity. It provides roadmaps and forecasts. A road-legal solar car will be on sale from Sono Motors in Germany in 2018 and Hanergy of China demonstrated longer range ones in 2016 slated for production in 2020. Facebook's Titan unmanned solar aircraft will be aloft for five years at a time. These and other remarkable advances will benefit manned electric aircraft too. For more on the big picture, attend IDTechEx Show! Berlin May 10-11 with 200 exhibitors and nine parallel conferences for the 3000 paying delegates including Energy Harvesting and, with five solar car and solar commercial vehicle presentations, Electric Vehicles: Everything is Changing.