VTOL On Demand Mobility

Foo Fighter

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What I miss most is a joined up logic when it comes to clean energy. Those who promote pure electric do not account properly for the production and shipping of gas for power stations for example. Add to that the huge pollution from marine diesels in for example, supertankers. For some time aviation has promoted clean aviation fuel but that has gone on the back burner for all the news there has NOT been. Apparently Virgin are pushing/investing in clean aviation fuels but also very quiet now. Apparently a source of pollution more impactful than the vehicles, animal farming. All that fart gas has to go somewhere.
 

TomcatViP

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Foo Fighter said:
For some time aviation has promoted clean aviation fuel but that has gone on the back burner for all the news there has NOT been. Apparently Virgin are pushing/investing in clean aviation fuels but also very quiet now. Apparently a source of pollution more impactful than the vehicles, animal farming. All that fart gas has to go somewhere.
Methane and fuel cells are your friends. Gentlemen... fart your engine.*

And most importantly it take away gases that would damage the bio-sphere before they can be harmful; and that on a cost-efficient way (states with clever ecological policies use to subsidize the removal of methane gas; hence removing it and using the harvested quantities to clean power a vehicle has a double effect on the level of harmful emissions... a double treat also for the taxpayer).


*the level of discussion was too good - thank you to the above posters - for someone not reasonably attempting to ruin it
 

Foo Fighter

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How about a high flying drone/satellite powered by recycling the atmosphere? A possible method of cleaning the air AND cheaper communications etc.
 

Foo Fighter

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A very pretty presentation but, where is the discussion on range and recharge?
 

TomcatViP

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Startup for dummies, rule One:
- Take a problem
- Simplify it
- resolve the simplified case
- Use marketing to claim you solved the problem
....

Rule 1bis:
In case of failure:
- restart
- reload
- repackage

....

Rules 1 (i_th iteration):
- Insist!
 

elmayerle

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AeroFranz said:
Indeed, many things that are "demonstrated" at the RC level do not scale up.
Even full scale vehicles can fly when carrying smaller amounts of batteries, and have very little range.
Ejector lift for vtol comes to mind. Neither the XV-4A nor the XFV-12A ever managed to make the full-scale article work, despite successful sub-scale deomstrations.
 

Zootycoon

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Also no discussion on battery power density, C rating, L/D at 300kph cruise, weight of megawatt rated power electronics, weight of 300kph bird strike protection on airframe, weight of ice/rain/hail protection, weight of crashworthness, crosswind limit, lightening strike protection, wing bending stiffness mismatch between wingborne & vertical flight.....to mention a few.

Fundamentally an e-vtol Jet has only a tiny fraction of the fan area of a helo or quad cop so has to compensate by giving the air much more acceleration, hence it needs very high rotational speed on the fans = megawatt power draw. And they claim this is really quiet;- Try overdriving the biggest electric garden leaf blower by a significant factor and then power up another eleven! yeah it’s going to be real quiet.
 

Archibald

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Lithium sucks, indeed, since the Chinese have most of it and hold the rest of the world at ransom. But sodium, really ? that thing is a bastard, just ask the nuclear industry (hello, Superphoenix, Monju and Clinch River). Corrosive, flammable, reactive, explosive... what's not to like ? :eek:
No need for fuel cells, folks. What we need is ammonia IC cars. Ammonia has zero carbon, the fertilizer network already in place, and, most importantly, any plain old IC engine can be modified from gasoline to ammonia pretty easily. All of this also applies to methanol, minus the carbon-free aspect.
Even if it has half the energy of gasoline, an ammonia car range would remain far, far better than any electric car. Or the technology used to make ultra light and ultra efficient electric cars... could be used for an ammonia IC car, beating lithium batteries into a pulp.
Unfortunately, ammonia for cars is like hydrogen peroxide for rockets: its (supposed) safety issues are completely overblown (toxicity, my ass: isn't gasoline dangerous if you smoke a cigarette, breath the exhaust, or try to drink it ? common...)

Heck in the 60's they made studies of ammonia and methanol fuel aircrafts and helicopters. The US Army had a grandiose project: portable, mobile nuclear reactors to split nitrogen from air and hydrogen from water and recombine that into ammonia to replace gasoline. And then... screw you, Saudi Arabia.
The usual jet or turbine could be converted to ammonia but the aircraft performance would take a big hit. Still far more realistic than any E-VTOL or electric aircraft.

As for hydrogen cars, being a space nerd since the craddle, I can tell you, they are a folly. Handling of liquid hydrogen is a complete and giant PITA, something that really can't be folded into your daily gas station. Unless you turn it into a miniature Cape Kennedy Launch complex, as far as drastic safety rules go. Plus the silly thing has 2.5 times the tank volume of gasoline, methanol or ammonia.
 

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Archibald

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mboeller said:
another interesting eVTOL Aircraft with fixed wing economics:

https://www.pterodynamics.com/transwing/

As an aviation nerd, I'm horrified by this thing. Just look at it this way: an electric powered, V-22 Osprey with many more failure modes, all over the design... and mass produced, and flying all over our heads in an urban environnement.
Ah, and asymetric with that ! :(

Repeat that, twice. Then check the V-22 Osprey flaws and abysmal safety records. Can't fly through dust, the washdown big issue, those things. Yeah. What could possibly go wrong ? ah, and Uber want to eliminate the pilot later. WTF ? ::)
 

Machdiamond

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The biggest problem I see with the Pterodynamics concept is that for proper stability in forward flight, the center of gravity needs to be near the quarter chord of the wing. This means that in a hover the two rear propellers are not allowed to provide any thrust or else the vehicle will flip forward instantaneously. So you end up with twice the thrust capability in horizontal flight than you have in vertical flight, while it should be the other way around.

With a few exceptions, most of the eVTOL projects do not pass the smell test of a sixth grade school science project and yet some manage to attract millions in investment from large corporations.

I wouldn't go as far as calling this fraudulent, I see more a bunch of enthusiasts who should know better but investors should certainly make a bit more due diligence, if at all.
 

VTOLicious

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Machdiamond said:
The biggest problem I see with the Pterodynamics concept is that for proper stability in forward flight, the center of gravity needs to be near the quarter chord of the wing. This means that in a hover the two rear propellers are not allowed to provide any thrust or else the vehicle will flip forward instantaneously. So you end up with twice the thrust capability in horizontal flight than you have in vertical flight, while it should be the other way around.

With a few exceptions, most of the eVTOL projects do not pass the smell test of a sixth grade school science project and yet some manage to attract millions in investment from large corporations.

I wouldn't go as far as calling this fraudulent, I see more a bunch of enthusiasts who should know better but investors should certainly make a bit more due diligence, if at all.
I have learned that the Transwing has batteries installed in the outer nacelles. Therefore the CG moves rearwards as soon as the wings fold and the center of thrust matches with the CG in hover.

However, I'm not sure if this concept scales up well... Did you see the video showing the seamless in / outbound transition of the subscale model? Pretty impressive!

https://www.youtube.com/watch?v=UAkWwbOE7CA
 

Orionblamblam

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Machdiamond said:
With a few exceptions, most of the eVTOL projects do not pass the smell test of a sixth grade school science project and yet some manage to attract millions in investment from large corporations.

I wouldn't go as far as calling this fraudulent, I see more a bunch of enthusiasts who should know better but investors should certainly make a bit more due diligence, if at all.
Replace "eVTOL" with a number of other concepts over the years, and your statement is timeless. Rather more prevalent than eVTOL right now is "system to create drinking water from thin air."
 

Foo Fighter

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Make that single malt whisky and you may have a winner.
 

TomS

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Orionblamblam said:
Foo Fighter said:
Make that single malt whisky and you may have a winner.
A system to create drinking water from single malt whisky?
I can do that, as long as you don't mind processing the water from urine...
 

Foo Fighter

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Single malt whisky from thin air, you can process ur-own.
 

Zootycoon

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I reckon certain e-vtol projects resemble Ponzi schemes. Here’s how it works;-

A group of naive youngsters, maybe a few older nefarious individuals insist that a mixture of start up mentally/nano-technology/quantum/agility/electricifcation/additive manufacturing/an I-phone has solved a problem which has foxed generations before hand, let’s say it’s a scheme to get talented folk from the middle of Paris to the middle of London in 40 mins. They make a CGI, you know the tech that has made donkeys talk and look intelligent. Clueless investors (A) is taken in and flips them a mill. The youths claim they’re on the verge of making a billion, but after a couple of years they’ve missed every target they’ve set themselves. Investor A smells a rat but isn’t prepared to lose, so finds bigger investor/s (b), then flogs his share for a tidy sum, and in so doing ensures a round two investment of a 100 mill. What do you expect the youths to do? Declare that in five years time the customers (the talented folk in Paris) might make it to Calais, spend the night while it recharges, hoop across the channel to Dover where they take another nights rest/recharge?...... no, they just keep saying with a few more million it’ll be cracked. They now appoint some big names to enhance credibility, who keep quiet in exchange for a big salary. The youth directors collude to ensure big cash remuneration while in office and just have to keep it going long enough to cream off a tidy sum. Investor (b) now’s had enough but has too much skin in the game so looks for the next bigger stage investor(C) ........... but like all Ponzi schemes, it’s not sustainable.
 

AeroFranz

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Hahahahaha...brutal...but most likely accurate.

I think the programs most likely to succeed are the ones heavily staffed with traditional aerospace engineers, and bankrolled either by big primes or by tycoons for whom money doesn't even factor in the equation.
 

TomcatViP

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The Wright brothers used their own money made out of a bicycle shop. The aerospace experience came to them out of their own curiosity for sciences (and trials and errors). On the other side of the Atlantic, some bankrolled experts achieved only a steam hopping machine that didn't lead anywhere.
Entrepreneurship is not faulty here. It's simply easy to fake toward the legions of credulous folks that just want to participate to something exalting.

The singular problem is that we live in a world where critics are tamed, too often ignored or muted.
 

AeroFranz

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I'm going to argue that some of the startups don't seem to know as much as the Wright brothers did...
When you put out a fancy rendering, and the hover centroid of thrust does not match the cg, you have to question how likely they are to succeed.
Entrepreneurship is not the problem, but it must go hand in hand with technical knowledge found in the traditional aerospace industry.
Blue origin and SpaceX are great examples of successful companies, but neither are startups, and both recruited heavily from the aerospace OEMs.
I look at the team page on the website of some of these startups, and they're pretty light on gray-bearded engineers and heavy on 'Media directors' (whatever the hell that means)!
 

TomcatViP

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I look at the team page on the website of some of these startups, and they're pretty light on gray-bearded engineers and heavy on 'Media directors' (whatever the hell that means)!
This is absolutely true.

But we have to admit that most of the early work of a startup is to raise money and public interest (both goes in pair in a synchronous way). Hence the focus on media and marketing.
An example is Aerion that had some fancy early project drawings with no realism. Yet those guys managed to raise enough money and market interest to achieve something that even the best of the Pack like Dassault (the one that should have done this breakthrough) couldn't reach. Now they have attracted some of the biggest Defense contractor that didn't shy to join the fray.

So let's not be over sarcastic over the startup industry that do succeed sometime where the majors tripped over.
 

Foo Fighter

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"So let's not be over sarcastic over the startup industry that do succeed sometime where the majors tripped over".

For the simple reason that there have been far too many of these start ups that had no intention of providing a product, they were after a nice little earner and nothing else. Easy to be sceptical over the latest "Emperors new suit" because we have seen it over and over et bleepin al.
 

AeroFranz

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TomcatViP said:
But we have to admit that most of the early work of a startup is to raise money and public interest (both goes in pair in a synchronous way). Hence the focus on media and marketing.
Yeah, it may be naive or unrealistic of me to think that you can maintain your engineering integrity and still get funding. I just get frustrated when i see claims that are demonstrably false. It only takes one of these eVTOLs to start crashing to set back the industry a decade.
So far the startups haven't exactly had a stellar rate of success in the aerospace world, but I do wish Aerion the best.
 

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One of the problems in e-vtol is that funding will be tending to flow towards those that promise the most but don’t have a clue how to deliver. This will be disastrous for those with a more attainable goal and/or development strategy as they’re seen as uncompetitive.

I’m not having a pop at the entrepreneurial spirit which is generally present in aerospace today;- it’s a real breath of fresh air compared to the nineties, when if your name wasn’t Rutan, the best you could expect from an investor was a speech on how stupid you were in even asking. I wholeheartedly agree there are some really impressive and exciting successes, but e-vtol just seems to be heading towards a bubble burst. I hope it doesn’t make a mess for the whole industry.
 

Foo Fighter

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A well funded flying car that went on and on and on, never doing anything near a proper product. https://newatlas.com/moller-m200g-jetson-flying-vehicle-on-sale-in-2009/9652/
 

GTX

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Foo Fighter said:
A well funded flying car that went on and on and on, never doing anything near a proper product. https://newatlas.com/moller-m200g-jetson-flying-vehicle-on-sale-in-2009/9652/
Yeah. Anything that small but needing 8 engines (or more if you include their latest hybrid versions) is not a viable option.
 

AeroFranz

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typically the multi-engine (or multi-motor) is driven by the need to be failure-tolerant.
Of course with eight piston engines you have a high probability of having a failure....with electric motors, that probability goes down quite a bit.
The amount of oversizing of the motors also goes down. I'm oversimplifying here, but if you have four motors and you lose one, the remaining three have to be sized for 133% of the thrust. If you have twelve motors and you lose one, you only lose something like 8% of the thrust.
 

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Burt Rutan thoughts on the subject,

https://medium.com/@hangerspace/a-conversation-with-burt-rutan-93da77fa44d
 

yasotay

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X-22A meets carbon and composites.
 

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Even with electric power I would bet this thing will push enough air around to get pretty loud unless fan speed is a lot slower than I think.

https://www.youtube.com/watch?v=AdlcoU4cO8k
 

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Assembly and component testing of Bell Nexus.

https://www.youtube.com/watch?v=ejJ6b2pX6Ts
 

sferrin

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Reaches all the way back to the X-22. :D
 

Mark Nankivil

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Thought the same thing too referring to the X-22. The rotor blade design seems rather plain - would have thought it would have a different shape/layout (broader chord at the root and taper to the blade) which can have some impact on noise levels.

Is that a new Bell logo with the dragonfly styled artwork? I like that....


Enjoy the Day! Mark
 

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Yes the dragonfly logo came with their rebranding to just "Bell" recently.

With the Safran turbine going there will be a decent amount of noise anyway, might have decided going too overboard on quieting wasn't worth it.

The wings and "cruise mode" are pretty interesting. And it's good to see a hyrbid vtol back on the front burner.
 

GTX

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sferrin said:
Reaches all the way back to the X-22. :D
Indeed. To be honest though it would have been good to see it with only 4 ducts rather than the 6.
 

Sundog

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GTX said:
sferrin said:
Reaches all the way back to the X-22. :D
Indeed. To be honest though it would have been good to see it with only 4 ducts rather than the 6.
It's most likely for safety/redundancy as this doesn't have the weight and complexity of all of the interconnected drive shafting the X-22 was saddled with for drive power and safety.
 

GTX

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Sundog said:
GTX said:
sferrin said:
Reaches all the way back to the X-22. :D
Indeed. To be honest though it would have been good to see it with only 4 ducts rather than the 6.
It's most likely for safety/redundancy as this doesn't have the weight and complexity of all of the interconnected drive shafting the X-22 was saddled with for drive power and safety.
I realise that - I was just commenting on the aesthetics.
 
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