Aircraft

Lilium releases 5th-gen eVTOL flight test footage with sound

Lilium releases 5th-gen eVTOL ...
Lilium's 7-seat air taxi design is quite a departure from the rest of the industry
Lilium's 7-seat air taxi design is quite a departure from the rest of the industry
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Lilium's 7-seat air taxi design is quite a departure from the rest of the industry
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Lilium's 7-seat air taxi design is quite a departure from the rest of the industry
36 small electric ducted fans provide propulsion, giving the Lilium jet a unique set of advantages and disadvantages
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36 small electric ducted fans provide propulsion, giving the Lilium jet a unique set of advantages and disadvantages
A 7-seat cabin makes this one of the largest air taxi designs headed for production
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A 7-seat cabin makes this one of the largest air taxi designs headed for production
The Lilium Jet's small-fan design makes it more suitable for medium-range inter-city flights than short cross-town hops, says the company
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The Lilium Jet's small-fan design makes it more suitable for medium-range inter-city flights than short cross-town hops, says the company
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Lilium's eVTOL is vastly different to anything else in the air taxi world, using 36 small ducted fans in place of larger open rotors. This has advantages and disadvantages, which we've discussed in detail before. Essentially, smaller fans make for vastly lower hover efficiency, but the company says they create less drag than large rotors in forward flight, improving efficiency over longer range flights.

Lilium also says they'll make these aircraft much easier to scale up to 15 seats and beyond without losing the ability to land on standard helipads.

And it also says that with cutting-edge acoustic treatment they should have a significantly lower noise signature than large-rotor competitors, which will make them much more friendly to people living under the flight path or close to a vertiport.

Now, the company has released a pair of videos showing its 5th-generation tech demonstrator prototype – an older 5-seat model first flown in 2019 – in flight with the sound included, one of which handily gives a measure of distance as the aircraft approaches. It's more a measure of the quality of the sound than the quantity; there's no decibel readout, and really nothing to compare the volume against. Take a look:

Final approach with our 5th generation technology demonstrator

One thing is apparent: the Lilium jet will make a sound much higher in pitch than the Joby S4 – something you could've guessed since small fans will spin much faster to produce the same thrust with less swept area. Skip to the end of the video below for a listen to the Joby in a hover.

A Special Message from our CEO and Founder, JoeBen Bevirt

We wouldn't try to draw too much from the comparison here. The sound in the Joby video is likely taken from a highly directional mic pointed at JoeBen Bevirt, and it looks like it's been shot at a fairly high zoom, which would make the aircraft appear closer than the Lilium Jet looks in its wider-angle video.

And of course, both these aircraft are being remotely piloted with zero passenger load on board. Fill them up with meat and both will be louder.

Still, if these eVTOL air taxis are to flood our cities as promised, with super-fast, cheap air transport, their sound signature will be paramount to public acceptance. People won't tolerate them if they add an unpleasant level of noise pollution when they're near the ground. It's definitely an angle to keep your ear out for.

Check out another new Lilium video below, with some more sound.

Flight tests with our 5th Generation Demonstrator

Source: Lilium

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9 comments
9 comments
jerryd
Still haven't seen it transit to forward flight or carry anything but the pilot. I have my doubts it can take off at even half the full load,
BryanA
This “fifth generation” plane is a five-place hangar queen built in 2018. The lead photo of your article shows the seven-passenger version rendering; the five-passenger version has been deprecated by Lilium and will NOT be produced. BTW, the first example of the five-passenger version was destroyed in a fire while charging. What’s up with Lilium? Why are they flying an old version which was never able to demonstrate transition to wing-born cruise flight? This looks uncomfortably like investment-driven desperation…
Steven Clarkson
Transitioning is the easy part if it can hover already its golden, forward flight will be natural.
Towerman
Sometimes i wonder who's side your'e on Loz. Helicopters are loud with an "off the chart" intimidation factor.

Not Evtols !

Yet helicopters fly over our heads everyday.
ljaques
Finally, real sound of the aircraft, but still only as close as 327 feet from overhead. We want to hear what it sounds like flying over us, you ninnies! Still, it's quieter than I had thought it would be. We'll know once someone actually flies over the camera, IF THEY EVER WILL.
Adrian Akau
Good, safe technology which will show itself up even more as batteries improve.
Daishi
@Towerman Yes helicopters fly over your head every day (at altitude) but they take off and land at airports. If one were to land at the closest parking lot to you instead of an airport you would find it to be significantly louder. For me the elephant in the room is that it is yet to be disclosed that these things will likely achieve below 2 or 3 MPGe carrying a passenger.
Towerman
@daishi
It is understood for quite some time now that they will land on designated landing pods or rooftops of buildings such as car parks.

They will not land next to your car landing space for these will be seperate.

@ljacques fly a helicopter over a camera you won't be able to hear yourself talking. Its all negative "hype"
Talk those against evtols.

Jets and helicopters are raging loud Yet certified to fly.
Koziol
It is all about the range. If these aircraft cannot get 300-400 miles of range they are not profitable. Many of the trips required will be 45-50 minute trips with take of and landing using most of the power. 5 people at 150-175 pounds each is a lot of weight even for gas engine aircraft or rotorcraft.