VTOL On Demand Mobility

www.suasnews.com

Bleecker Street Research – Joby Aviation (JOBY): “Uber Meets Tesla In The Sky” Is Set To Crash And Burn

This is a very compelling report from Bleecker Street Research By 2024 the FAA will approve a new style of aircraft. It’s electric, and takes off and lands vertically, an “eVTOL.” These will immedi…
www.suasnews.com

An interesting critical analysis of Joby's long term projections of building thousands of evtol's versus the reality of what they're telling local authorities. Here are 2 relevant quotes :

"Joby tells investors it will soon have many aircraft coming off the production line. However, local government files obtained through a public records request show that Joby seems to have massively overstated its production plans to investors. "

"Joby is telling local authorities that its initial plan “is to build up to 10 planes per year in the next couple of years, and up to 30 planes in about 5-7 years.” Joby has told investors it will manufacture over 100 planes in 2024."

So basically they are flat out lying to their investors. This video was posted previously, but it analyzes Joby's evtol project in great detail and points out some problems with it.


View: https://www.youtube.com/watch?v=a717YZnhQ-s&ab_channel=AVweb
 
alberchico said:
This is one aspect of electric aviation that is never addressed.
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Yes. The other aspect that is never addressed is the energy efficiency of these electric solutions (in kWh per seat-mile) against the appropriate alternative.

Aircraft are extremely weight sensitive by nature… perhaps it is actually better for the environment to fly with weight-efficient kerosene/SAF powered turbines rather than heavy batteries that lead to poor energy efficiency. Instead put those batteries in land based applications such as cars, buses and trucks.

And once you start comparing kWH per seat miles I’m pretty sure the entire eVTOL industry’s environmental claims fall down like a house of cards compared to electric cars already on the road today.
 
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H_K said:
And once you start comparing kWH per seat miles I’m pretty sure the entire eVTOL industry’s environmental claims fall down like a house of cards compared to electric cars already on the road today.
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There's a German Prof doing this in a few papers. The appropriate comparison point is an IC powered supercar. Evtol is massive energy use per seat mile.
 
Nicknick said:
The specific disk load needs to be more than twice as high, this surly can"t be done with half the tip speed. You might increase the pitch angle for a fixed geometry rotor somewhat (it would help), but twice the disk load with less wing tip speed is surly impossible. Please note, the rear rotors have only two blades.

A starting noise of 45 db is incredible low, you could stand next to it and having a conversation by whispering.

Please correct me, but "lower rotor spin" sounds more like lower rpm to me.
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Noise is to the largest extent a function of tip speed. I have heard a NASA acoustics guy claim it varies with the fifth (!) power of tip speed. If you can successfully tackle that, then lower down the list of priority there's noise deriving from the thickness of the blades, and blade vortex interaction.
So yeah, the biggest measure to control noise is to limit tip speed. Unfortunately for a given rotor diameter, this means lower RPM, which turns into higher torque, which turns into more motor mass.
Anyway, you are correct in stating that these eVTOLs likely have higher disc loading than your run of the mill helicopter. This doesn't mean that you can't get the thrust; it simply means you have to pump more power through the rotor to get it. As a matter of fact, for a given power, thrust will vary with the square root of discloading. The blades might be designed with more solidity (i.e., chord, or number of blades) to absorb the increased power.
 
That's not very different from what I wrote. A higher disk load will require higher tip speeds which might be partially compensated by a higher "pitch angle" (to quote myself). But even with more soldity (that what I ment with an higher pitch angle), I doubt, that this could compensate the two times higher disk load.

For reducing the tip speed, using more blades would also be helpfull, but the rear rotors here have just two blades (for turning them out of the wind at level flight), this will require higher tip speeds than a rotor with three or four blades.
 
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newatlas.com

Plana joins the eVTOL race, with unique-looking 7-seat hybrid air taxi

Korean startup Plana Aero, founded by the guy that led Hyundai/Supernal's early eVTOL program, has begun work on a new long-range, hybrid-electric VTOL air taxi designed to carry up to seven people about 350 miles (500 km) at speeds up to 217 mph (350 km/h).
newatlas.com newatlas.com

At least they're smart enough to go with a hybrid propulsion system instead of only relying on batteries. But even then, this project seems very ambitious for a tiny startup.
 
alberchico said:
leehamnews.com

Pontifications: Total life cycle impacts missing from nearly all ecoAviation discussion - Leeham News and Analysis

Oct. 10, 2022, © Leeham News: Batteries are the best thing for the new generation of clean airplanes. Or so say those promoting the concept. However, few talk about the total life cycle of the concepts, whether eVTOL,... Read More
leehamnews.com leehamnews.com

This is one aspect of electric aviation that is never addressed.
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Ammonia. More exactly ammonia mixed with a little hydrogen to get more energy. Can't see any other solution for non co2 air transport.
 
evtolinsights.com

Stock Market: Knives Are Out For Joby - eVTOL Insights

Dear oh dear, Joby has been taking a hammering on the Stock Market in recent weeks as market shorters seek out new companies to marmalise. Joby's share price is down over 33 percent in the last month alone on the back of certain ruthless business media outlets combining attacks and questioning...
evtolinsights.com evtolinsights.com
 
Excellent news! Just what the aviation industry needs! Another eVTOL start-up... Anyway, for those who are interested, here's the usual and somewhat predictable headline -

Alef Aeronautics launches eVTOL flying car​


The all-electric composite Alef Model A has a 200-mile driving range, a 110-mile flight range and fits within existing urban infrastructure for driving and parking.

Taken from - https://www.compositesworld.com/news/alef-aeronautics-launches-evtol-flying-car

Attached is a picture but frankly, does it matter? It'll hardly get built but hey, if you're still reading; here it is.


(too cynical? Nah ;) )
 

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leehamnews.com

Bjorn’s Corner: Sustainable Air Transport. Part 43. eVTOL IFR range. - Leeham News and Analysis

October 28, 2022, ©. Leeham News: This is a summary of the article Part 43P, eVTOL IFR range. It discusses the range of a typical eVTOL flying a feeder mission from a city center to an airport during... Read More
leehamnews.com leehamnews.com

This is another major problem with Evtol's flying commercial services that isn't being discussed by these startups, the fact that these machines might not have enough reserve range to fly in bad weather due to the limitations of battery tech.
 
Wow, that is a shockingly low figure. I guess analysts are now starting to take things like certification hurdles and infrastructure development into account. Not that long ago you had sensational reports like this one that were projecting a global market of 30.8 billion by 2030.

www.marketsandmarkets.com

eVTOL Aircraft Market Size, Share, Industry Report, Revenue Trends and Growth Drivers

The global eVTOL Aircraft Market in terms of revenue was estimated to be worth $1.2 Billion in 2023 and is poised to reach $23.4 Billion by 2030, growing at a CAGR of 52.0% during the forecast period.
www.marketsandmarkets.com

Even Morgan Stanley is still projecting a 12 billion dollar global market by 2030. They famously said back in 2018 that by 2040 the UAM market would be worth $1.5 trillion.

verticalmag.com

Morgan Stanley shifts its timeline but stays bullish on eVTOL market

Morgan Stanley says eVTOL aircraft could represent a $9 trillion global market, but that it will likely take decades for the sector to achieve its full potential.
verticalmag.com verticalmag.com

I know I've brought this up before, but to me this feels like the Very light Jet bubble all over again, but on an even bigger scale.

 
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Infrastructures are gonna drive this market. There will be so much money to make in re-orienting (upside down in effect) city access from low dow to roof top as of today to roof top down to ground level that inevitably investors are going to poor money in.

IMOHO, the 100% EV idea is just a concept that will gradually be tuned down to more practical mode of operations. So, let's not be discouraged by the decreasing market projections. Those are not taking into account the variety of solutions for on-demand mobility.
 
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I've seen this morning that EVSTOL are coming to Paris next year and in time for deployement for the 2024 Olympic Games.
 
TomcatViP said:
Infrastructures are gonna drive this market. There will be so much money to make in re-orienting (upside down in effect) city access from low dow to roof top as of today to roof top down to ground level that inevitably investors are going to poor money in.

IMOHO, the 100% EV idea is just a concept that will gradually be tuned down to more practical mode of operations. So, let's not be discouraged by the decreasing market projections. Those are not taking into account the variety of solutions for on-demand mobility.
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I agree. I think what will happen is that some of these designs will enter service, but not in the large numbers so many analysts are confidently predicting. So the air taxi revolution that companies like Joby are counting on will not happen on the scale that they are hoping for. And that is a big issue because the business plans of many of these start ups depend on building these machines in large volumes in order to make a profit. So there will definitely be a bloodbath down the line with many of these companies either going out of business or being bought out by stronger rivals. However the low noise profile of these aircraft will help ease acceptance in many potential markets. But cranking these things out in large numbers at an affordable price point is going to be a massive challenge. Icon tried to do this with their A5 which was a much simpler aircraft to build and flopped badly.

www.avweb.com

Icon's Reality Check: Demand is Elusive - AVweb

Icon launched the A5 with a bold stroke, envisioning disruptive volume. But it's had to retool and retract in hopes of modest growth.
www.avweb.com www.avweb.com

www.avweb.com

What's the Outlook For Icon? - AVweb

Price escalation has eroded demand. Now the company has to develop a market for the most expensive LSA in U.S. market.
www.avweb.com www.avweb.com

airfactsjournal.com

The dream v. the reality: it's a tough world : Air Facts Journal

It might also be true in other areas, but it has always seemed to me that general aviation is littered with more broken dreams than any other field. As an observer for about 60 years, the length of the list of failed projects amazed me when I wrote down the ones that I remember.
airfactsjournal.com airfactsjournal.com


Once the limitations of battery density become fully understood, I think there will be a transition to hybrid designs to solve the range issues. Rolls Royce is already preparing for this by developing a lightweight turbogenerator.

newatlas.com

New Rolls-Royce turbogenerator upgrades any eVTOL's range and payload

Battery-electric VTOL aircraft should do a superb job as short-range cross-town air taxis, but there are a whole lot of other trips they could handle quicker and more conveniently than existing transport options if they could just fly a bit further. Several companies are now planning low-emission…
newatlas.com newatlas.com
 
tech.slashdot.org

Paris Opens Flying Taxi Hub Targeting Flights for 2024 Olympics - Slashdot

France opened a hub for testing electric air taxis as it seeks to introduce the world's first service with the new category of aircraft in time for the 2024 Summer Olympics in Paris. From a report: Aeroports de Paris, which runs the French capital's major airports, will operate the facility...
tech.slashdot.org
 
https://www.thetimes.co.uk/article/...ke-off-over-home-of-the-dam-busters-k6d5cxhmr (subscription or registration may be required)
Elstree, home to the film studios that spawned The Dam Busters and Star Wars, is to play host to something new: flying taxis that are expected to be criss-crossing city skies within the decade.

An aerodrome on the outskirts of the Hertfordshire suburb north of London is set to be used as a test bed for “urban air mobility”, becoming a base for two- to five-seater electric aircraft that take off and land vertically.

Elstree Aerodrome, close to the M1 and abutting Haberdashers’ independent schools, is understood to be the favoured location for the development of a “vertiport” for plug-in air vehicles.

[snip]
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I still struggle somewhat to see the extra value of this eVTOL vs. a 25 year old H120, AW009 or a newer B505 that do the same or better while weighing half as much.

Especially with the possibility of developing a hybrid electric backup system to make single engine operations safer.
 
Me too. I don't understand why would eVSTOL succeed where classic helicopters failed in the 1950-1970's.

I mean: point-to-point flight from a city rooftop to another city rooftop (Pan Am building disaster 1977, cough cough).

Bottom line "hey, look, a flying taxi cab !"

What are eVSTOL advantages, compared to classic helicopters ?
- pollution ? ok, they are electric when helicopter use kerosene turbines that stink and emits CO2
- noise ? ok, rotors are noisy. But won't eVSTOL be noisy too ?
- more compact shapes ? less dangerous ? because the rotors are smaller and enclosed in tubes ? not sure about that.

Something else ?

The more I read about that eVSTOL thing, the less I understand the ongoing craze. Wait until the first eVSTOL falls from the sky like a led brick and makes a carnage on the pavement. Helicopters were banned from New York (and aircraft from flying over Paris) for that reason alone.
www.thisdayinaviation.com

16 May 1977 - This Day in Aviation

16 May 1977: At approximately 5:32 p.m. Eastern Standard Time, New York Airways Flight 971, a Sikorsky S-61L helicopter, landed at the Pan Am Building rooftop heliport (JPB) in New York City. Flight 971 had originated at John F. Kennedy International Airport (JFK) and carried 20 passengers and a...
www.thisdayinaviation.com
Sooner or later, this will happen to an eVSTOL. What will happen next ?
 
Archibald said:
Wait until the first eVSTOL falls from the sky like a led brick and makes a carnage on the pavement. Helicopters were banned from New York (and aircraft from flying over Paris) for that reason alone.
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That’s the genius of the first route that Archer & United have chosen for their pilot. Newark to the Downtown Manhattan heliport is one of those magical unicorn routes that doesn’t require flying over any residential areas, mostly overwater and about as safe as you can find in any big city. (Ignoring snow, icing, summer thunderstorms, other aircraft and a few “small” risks).

True urban taxi ops will be a lot more complicated.
 
EVTOL has following potential advantages:
1. Noise: distributed propulsion enables greater design space than those limited by mechanicals
2. Operating Cost
- Trade mechanical complexity with electrical system complexity, which should be cheaper
- Wings
- Electrical operation when applicable, means low cost for amount of energy used
3. Safety: Distributed propulsion redundancy

I see hybrid EVTOL eating the helicopter market far before (decades) general flying taxis stuff. If the point of the helicopter is VTOL transport, EVTOL would be better, since helicopter is a poor configuration and only used because more efficient configuration has too much mechanical complexity, a lesser issue with electrical architecture. You'd only want helicopter if the point is to do things while hovering.
 

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