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-   -   Lilium vertical take off "jet" (https://www.pprune.org/rotorheads/578979-lilium-vertical-take-off-jet.html)

Winemaker 30th Nov 2021 02:32


It will be fueled by hydrogen, the most sustainable technology in development today.
Oh come on. Run some basic numbers re fuel energy density of hydrogen vs liquid hydrocarbons like petrol then do some basic calculations re volumes and storage (liquid hydrogen and/or compressed gas) and then look at the weight of the tankage..... etc. etc. Lets not even get into the weight, efficiency, and output of fuel cells; a battery system would be necessary for surge energy demands like take off, adding weight....

I have run these numbers many times and there is no way an aircraft is going to fly for any reasonable period of time using hydrogen as a fuel, especially a vertical machine; factor in endurance then just laugh. It just doesn't work, both from a weight and a volumetric perspective; let's not even talk about how hydrogen is produced, sources (probably a steam process on natural gas), energy requirements for chilling and liquefying the gas (pressure tanks would be WAY too heavy for aircraft), and the infrastructure to supply the fuel...... More grabbing headlines and money here, IMHO; buy stock early and then bail when the time is right..... The only hydrogen craft I see flying passengers are balloons, blimps, or dirigibles.

muermel 30th Nov 2021 16:13


Originally Posted by Less Hair (Post 11148543)
Will the noise and the blast when hovering make it acceptable for inner city and metro area flight operations?

Neighbours and local residents of hospitals in Germany are going to court against EMS helipads beccause of noise already nowadays. What makes people think that helipads for THESE things will be allowed in cities? There's a reason there's no helipads in larger cities except hospital pads. Not going to happen :=

Ascend Charlie 4th Dec 2021 00:57

And here's the latest wet dream from the "gimme some development money" crowd:

https://cimg3.ibsrv.net/gimg/pprune....bf433dce0c.png

Not a lot of lifting surface for forward flight, and the wing has big holes in it with drag-inducing fan stuff.

The noise from those 2 piddly propellors (nose, tail) must be a real scream.

Less Hair 4th Dec 2021 04:20

I am impressed by all the money they collected but does this new design mean their own original tilt-impeller concept finally did not convince them?
Now it looks more like a toy. Love those tiny front and tail propellers.

Winemaker 4th Dec 2021 04:43


Originally Posted by Less Hair (Post 11151094)
I am impressed by all the money they collected but does this new design mean their own original tilt-impeller concept finally did not convince them?
Now it looks more like a toy. Love those tiny front and tail propellers.

Pretty funny. But you have to understand they are turning a 50,000 rpm so the craft is supersonic....... I wish I could come up with one of these schemes for instant wealth.

Less Hair 4th Dec 2021 08:41

All the laurels for Bezos and Musk who fund their own visions. But should the more general financial community get a better technical education to prevent them from all this fantasy financing? How bad will risk capital investments be in other less visible areas, say bio, AI and quantum computing, if even this vapourware gets funded with hundreds of millions of dollars?
We might need stricter rules to prevent money getting extracted from funds on -hopefully not- intentional fake promises.

netstruggler 6th Dec 2021 12:03


Originally Posted by Less Hair (Post 11151094)
I am impressed by all the money they collected but does this new design mean their own original tilt-impeller concept finally did not convince them?
Now it looks more like a toy. Love those tiny front and tail propellers.

The photo posted by Charlie is not anything to do with Lilium.

Let me provide the missing source:

Ascendance revises the design for its long-range hybrid eVTOL (newatlas.com)

Less Hair 6th Dec 2021 13:02

Thanks for the clarification, a bit confusing to distinguish all those phantasies.

Ascend Charlie 6th Dec 2021 21:52

Oh geez, another one:


Sydney Seaplanes orders fleet of electric air taxis to provide escape from Sydney traffic


They have ordered the Embraer EVE toy.

Sydney Seaplanes has the advantage of Grandfather Rights on the Rose Bay flying boat base, and they do trips to Palm Beach and other places in Pittwater.

Back in the 90s we proposed a floating heliport to use this pre-approved water runway, the pontoons would have been designed for the task, but the EPA and Sydney MSB pounced on it for noise considerations. No landing was allowed within 1000m of the shore, which meant that there was a lot of moving the pontoons between flights, or using water taxis, both impractical. And the rabid Labor voters of Balmain stopped anything west of the bridge.

Be interesting to see how they plan on landing at Barangaroo, on the west side of the bridge and almost requiring an approach/departure under the bridge.

cattletruck 16th Dec 2021 10:26

The comments section in this link makes for interesting reading.

Monte-Copter Model 15 Triphibian helicopter - development history, photos, technical data

Even though the design still looks quite futuristic 60 years on I doubt the early investors will ever see their money back.


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