The flying machine in your back garden

A German startup called Lilium is working on a 100% electric short-haul private jet that may at last fulfill the promise of the flying car.

The company was founded in 2015 by a quartet of engineers and doctoral students from the Technical University of Munich and nurtured in a European Space Agency-funded business incubator. "Our goal is to develop an aircraft for use in everyday life," says one of Lilium's founders, CEO Daniel Wiegand.

As the Lilium team sees it, the problem with personal aviation is airports, which are expensive to operate and utilise, and usually sit well away from city centres, negating their use as commuter hubs. "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," says Wiegand.

The company's aircraft concept promises to remove the airport, requiring just an open space of just 225 square metres — about the size of a typic al back garden — to take off and land. The Lilium Jet can cruise as far as 500km (310mi) at a very brisk 400kph (248mph), and reach an altitude of 3km (9,900ft). And it recharges overnight from a standard household outlet.

Is it better than a helicopter? Well, on paper, the Lilium Jet presents some distinct advantages over traditional rotorcraft flying machines. For one, its battery powered ducted fans are significantly quieter — and cleaner — than the fuel-burning turbine and piston engines in helicopters. And, significantly, because the mid-flight failure of a helicopter's single engine could be catastrophic, they are expensive to engineer and build, and they require meticulous daily maintenance. The Lilium jet, however, uses 36 — yes, 36 — tiny electric fans: 12 on each wing and 6 each in two swivelling nacelles that emerge from nose producing a total of 436 horsepower. The propulsion system (including the batteries and power controllers) is designed for redundanc y; the failure of one or more of the electric fans won't prompt an emergency landing on the M25.

And, of course, helicopter pilot training — which includes extensive schooling in safe-landing techniques after an engine failure — is exhaustive and expensive, running at least 45 hours and upwards of £30,000. The Lilium jet, in contrast, will be classed as a Light Sport Aircraft for two occupants, for which licensing requires a scant 20 to 30 hours of training and usually runs less than £6,000. The trickiest part of Lilium flight — those vertical take-offs and landings — will be autonomously controlled, similar to the planned EHang 184 four-rotor personal drone and the Terrafugia TF-X.

Naturally, there are trade-offs. The Lilium Jet's LSA classification limits its operation to uncongested air space during daytime hours, and only in fair weather. And even with the the aircraft's promise of quiet, emissions-free operation, it may be a while before aviation authoriti es allow vertical take-offs and landings — even computer-guided ones — from the Joneses' back garden. And unlike such ambitious drive-and-fly projects as the Terrafugia, the Dutch-made PAL-V One and the Aeromobil from Slovakia, the Lilium Jet is strictly a flying machine, limiting its everyday usefulness and requiring at least a little forethought as far as landing spots are concerned.

Even so, Lilium's vision of the future may be closer than you think. The company has successfully demonstrated the concept with a flying 25kg prototype, and is presently crafting a full-size version. Lilium plans to have a production model ready by the stroke of midnight on 31 Dec 2018.

In short, you have plenty of time to install that wind sock atop the garage.

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Source: The flying machine in your back garden