VTOL On Demand Mobility

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.

Ah let’s see;-
1 Noise, maybe for the prop designs but certainly not for the Lilium thunderjet. But maybe not, remember one slow revving prop is pretty quiet but some designs have x12.
2 Operating cost - Definitely not- it’s not only the electricity, it’s the fraction of the battery life that gets burnt every flight (renewal required maybe every 1000 charges so every few months), surprised if a hi spec, flight cert 1000kg + battery comes in at less than 500k , it’s the cost of the Megawatt sized recharging substation at that has to be shoehorned into billion dollar prime city real estate…. it’s not free of charge and eVTOLs are packed with control surfaces, prop pitch actuators for up to 42 blades etc, all duplicated, all viciously shaken by vibration, so all on hard cycle life overhaul.
3 Safety - Electric power exhaustion kills everything on board an eVTOL and indeed maybe those on board plus a few bystanders …. A 5 minute power reserve…. Safe?

Other objectionable points;-
- Visual intrusion - this makes up about a 10% of complaints about helicopters
- Prop downdraft damage
- Noise distribution, even lower noise levels get complaints if regular enough.

London’s helicopter noise complaints rose exponentially in the mid naughties as more flew over the city. So a maximum number airborne at any one time was introduced, which reduced the number in flight. Noise complaints dropped significantly, good job they thought, but strangely even though this cap has been in place there’s been an slowly increasing trend in noise complaints such that they’re nearly back at the same level…. Yes less helicopters are generating significantly more complaints.
 
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Fuel/Power system costs depends on the range. In very short range applications where long lifespan batteries can handle, the cost is lower as can be seen in the comparison between land based electrical vehicles and motor vehicles. The charger infrastructure can piggyback on land electrical vehicle infra, especially with adaption of large electric land vehicles. It is only when one is pushing range with deep cycle and low durability chemistries than you get into trouble.

The whole economics of electrical flight is also based on the low cost of electrical motors over things like gearboxes, large rotating assemblies of prop controls, long rotating shafts and so on. For a lot of applications, a simple fixed pitch multicopter lift stage combined with conventional airplane configuration should be sufficient.
 
Even the finest battery that exist today can’t lift an eVTOL with a commercial viable Pax load. The massive power draws for the’V’ bit, inherently kills charge life whatever the range is between destinations.

City centre power supply infrastructure is finite, and definitely not limitless. The high speed recharging of eVTOLs requires tens Megawatts on top of supplies that are already maxed out and will struggling with all the EV’s. The short range of eVTOLs makes the problem even worse as it demands a high density of charging location each one a tens of megawatts sized substation, which just don’t exist so haven’t the supply infrastructure.
 
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The big issue with these evtol's is that the overall business plan that revolves around air taxi operations is extremely shaky. Take Uber for example. They do not actually own the vehicles in their fleet, have relatively little physical infrastructure, force their drivers to work as independent contractors to stiff them on benefits, give them no real training on how to drive a vehicle properly, and they still have not made an actual profit. But yet these air taxi companies hope to make a profit operating complex composite electric aircraft with fly by wire controls that require all new infrastructure that will need to be built from scratch ? Also the idea that these startups keep pushing that existing structures like garages can be converted into rooftop heliports as a way of cutting costs will also struggle to get past the Nimby crowds. I have no idea how strong this phenomenon is in Europe, but here in NYC that idea won't fly. Not to mention that there's the issue of finding skilled workers to operate all these machines if they ever get built in large volumes. The article below is from 2008 but the quotes below still ring true:


"DayJet's collapse is grim news for a sector that promises to revolutionise the way the USA and the rest of the world does business by making regional on-demand private aviation available, if not to the masses, then to millions of ordinary business executives and middle-class leisure travellers."


"The price point and the need to raise capital are problematic at best for an air taxi system," he says. "There is always going to be a volume of demand that justifies charter operations, but nothing like the mass transit operation that was once envisaged."

"To work, the business model needs an airline-scale network, he says. "But the task of financing this sort of critical mass to achieve profitability is sheer daunting. It just eats costs."
 
Archer Midnight Specifications:
Source: https://evtol.news/archer/
  • Capacity: 1 pilot, 4 passengers
  • Cruise speed: 150 mph (241 km/h)
  • Range: 20-50 miles (32-80 km)
  • Cruise altitude: 2,000 feet (610 meters)
  • Maximum payload: 1,000+ lb (456+ kg)
  • Maximum takeoff weight: 7,000 lb (3,175 kg)
  • Propellers: 12 propellers (Each tilt-propeller has 5 blades. Each VTOL-ONLY propeller has 2 blades)
  • Electric motors: 12 electric motors
  • Power source: 6 independent battery packs
  • Noise level during forward flight: 45 dba
  • Safety features: Distributed Electric Propulsion (DEP), provides safety through redundancy for its passengers and/or cargo. DEP means having multiple propellers and motors on the aircraft so if one or more motors or propellers fail, the other working motors and propellers can safely land the aircraft. In addition, the company is increasing the safety of their aircraft by eliminating critical parts, increasing component reliability and designing safe aerial batteries. The company has no single critical points of failure.
 

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I have no idea how strong this phenomenon is in Europe, but here in NYC that idea won't fly.

That is one of the things I am wondering about myself. The general trend in Europe is to restrict motorised traffic (other than e-bikes and the like) as much as possible in inner cities. I don't see them welcoming swarms of EVTOLs.
 
I have no idea how strong this phenomenon is in Europe, but here in NYC that idea won't fly.

That is one of the things I am wondering about myself. The general trend in Europe is to restrict motorised traffic (other than e-bikes and the like) as much as possible in inner cities. I don't see them welcoming swarms of EVTOLs.

I readily agree with the above. And still, Paris seems willing to introduce those things in time for the 2024 Olympic Games. Don't ask me the why and how of that decision. Then again, don't underestimate Mayor Anne Hidalgo inner knack to get herself in trouble with parisian people... :D
 

I readily agree with the above. And still, Paris seems willing to introduce those things in time for the 2024 Olympic Games. Don't ask me the why and how of that decision. Then again, don't underestimate Mayor Anne Hidalgo inner knack to get herself in trouble with parisian people... :D

But those will be transferring people from Cergy-Pontoise to wherever the Olympic Village is, right? I hardly see them zooming down the Champs Elysées.
 
I have no idea how strong this phenomenon is in Europe, but here in NYC that idea won't fly.

That is one of the things I am wondering about myself. The general trend in Europe is to restrict motorised traffic (other than e-bikes and the like) as much as possible in inner cities. I don't see them welcoming swarms of EVTOLs.
They restrict vehicles with fossil fuels to cope with particulates. For example you cant drive with Diesel cars in central London anymore. That is the argument for eVTOLs - all electric, no pollution.
 
I have no idea how strong this phenomenon is in Europe, but here in NYC that idea won't fly.

That is one of the things I am wondering about myself. The general trend in Europe is to restrict motorised traffic (other than e-bikes and the like) as much as possible in inner cities. I don't see them welcoming swarms of EVTOLs.
They restrict vehicles with fossil fuels to cope with particulates. For example you cant drive with Diesel cars in central London anymore. That is the argument for eVTOLs - all electric, no pollution.
Well, it goes beyond that: you have increasing pedestrianisation, restricting acces to vehicles of all kinds, turning car lanes into bike lanes and the like. In none of the renders of these urbanisation visions is the sky filled with EVTOLs.
 
I have no idea how strong this phenomenon is in Europe, but here in NYC that idea won't fly.

That is one of the things I am wondering about myself. The general trend in Europe is to restrict motorised traffic (other than e-bikes and the like) as much as possible in inner cities. I don't see them welcoming swarms of EVTOLs.
They restrict vehicles with fossil fuels to cope with particulates. For example you cant drive with Diesel cars in central London anymore. That is the argument for eVTOLs - all electric, no pollution.
Most particulates (about 90 %) are tire related and the heavy E-vehicels use to produce more particule emissions than Diesel (Euro 4 or better)
 
The concepts tend to look more and more uniform, almost all have a combination of propellers that can be tilted by 90° so that they can provide lift and propulsion in combination with two wing propellers for lift only which can be turned out of the wind for forward flying. This layout is reasonabe and much more efficient than the "jet" approach of Lilium.
 
Well, it goes beyond that: you have increasing pedestrianisation, restricting acces to vehicles of all kinds, turning car lanes into bike lanes and the like. In none of the renders of these urbanisation visions is the sky filled with EVTOLs.
One possible exception to that, though it is related to the aviation focused UKRI Future Flight Challenge programme:
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Looks like Lilium is facing funding issues and is going to pressure its potential customers to firm up their orders so they can obtain much needed revenue in the form of deposits. I guess we'll now see how many of these potential customers put their money where their mouth is.
 
Initially their planed financing model was taking high deposits from investors which would in return just have a right to purchase one of the first Lilium jets. Therefor it was promised, that this priority could be delt for much more money to later investors. Seems like this fraud never worked out, but this clearly shows their mindset…
 
This is complete madness. There is nothing to order but celebratory pins and marketing adds.

Definitely, the only thing that really flies in all directions in this Evtol craze... Is the money!

All I can answer is "Well, wait until the bubble crashes - like an eVTOL running out of battery juice..."
 
Of course There Will Be Blood...

Opinion: There Will Be Blood: Dissecting eVTOL Business Models​


Eclipse Aviation and DayJet had a symbiotic relationship in 2008. Eclipse produced a very light jet loaded with technology for a breakthrough price of less than $2 millionDayJet was a Part 135 carrier aiming to connect poorly served business centers—initially in Florida—with an on-demand air-taxi business model. Eclipse needed huge volumes of orders to underpin its ultra-low pricing and garnered 1,400 of its 2,200 orders from DayJet. Hopes were high that a revolution was underway, until DayJet suddenly declared bankruptcy in September 2008.
This episode reminds us that even revolutionary aircraft need customers with viable business models to survive. This raises the question: As so many electric vertical-takeoff-and-landing (eVTOL) vehicles are nearing certification, how realistic are their operators’ business plans?
Consider the case of Lilium, which aims to redefine urban and regional air transportation, initially targeting those same “underserved” DayJet Florida city connections. It expects that its six-passenger Lilium Jet can offer $2.25 per-seat-mile pricing while operating 10 hr. per day.
Lilium faces the same challenges DayJet did—maintaining high load factors in thin markets and the back-breaking costs of deadheading.
The assumptions underlying Volocopter’s two-passenger VoloCity are similarly unrealistic. The 18-rotor eVTOL, designed for short urban flights, has a range of just over 20 mi. and similar seat-mile costs to the Lilium Jet.
The situation smacks of what AeroDynamic Advisory Managing Director Richard Aboulafia calls the Unsustainable Life Spiral: Someone offers a product or service with impossibly low unit costs. These low costs are predicated on impossibly high production rates or impossibly high utilization assumptions. These impossibly high utilization/production numbers are in turn predicated on impossibly low unit costs. Financial carnage follows.
While industry enthusiasts fawn over sexy new eVTOL designs, their operators are about to run into the cold, hard reality of economics, like DayJet did 14 years ago. There will be blood.
 
Unlike in the last link, the official operating range of Lilium is nowadys only 94 nm or 175 km (I guess, we will see it shrinking even more, so longer we wait...). They started with a range of 500 km and 400 km/h....

Lilium anounced, that they added a real landing gear for more range, I wouldn't be to suprized, if the mentioned 175 km operational range could only be archieved with conventional take of and landings...
 
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Since nearly all concepts for eVTOL are planed with some kind of miniature airport, I wonder if a much simpler STOL aircraft could do the job as well. Just 50 m of runway could be enough for a fast accelerating STOL plane which would surly be cheaper to operate and safe a lot of energy (=longer range) in comparison to a vertical take off and landing.
 
Yes, absolutely, it could.

Intra-city, I have been sketching forced airflow landing system for STOL (something like a a high power blower mounted on high rise platform and some little tricks) and some other solutions, and it could work for eSTOL. That way, the peak of power (what kills most of the practicality of eVSTOL) is deported on something that can be plug on a high voltage line.

Many people still do believe in the imbecile idea that they are going to land everywhere whenever they want, in total contradiction to what has been air transportation history (WWI biplane where STOL per se).

While there is no evolution on this side, not much will probably change and that peak of e-power will continue to be delivered via transportation means relying on heavy fioul and diesel and plague all design with an excessive battery weight fraction.
 
Some eVTOLS like the early Volocopter are indeed only useful for VTOL operation. There will be a market for flying from rooftop to rooftop (to airports), as it is in Sao Paulo or London (before the Crisis of 2008). Nowadays, most eVTOLS companies focus on the connection between cities or cities with airports (like Joby) which offer enough room for parking lot, tram station, several aircrafts and waiting facilities. Adding a short runway will not meaningfully increase the required space, especially if it would be built above the parking lot or tram tracks.

If I had to design such an eSTOL plane, I would take a look on the Custer channel wings or the Breguet 941.

BTW: If there is any investor who will invest 500 million Dollars for this approach, please feel free to contact me (I will even use a Play Station during the call…). I mean, I haven’t invested much effort in this and it is just pretty obvious without anything new which could be patented, but it is still much than everything Lilium had to offer when they started their company….
 
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A brutally honest assessment of the evtol industry. Makes for depressing reading, but it confirms what many people on this forum were saying all along.
 
Thanks @alberchico. That’s a must read. I imagine not everything is quite as dark for eVTOLs as portrayed by Bjorn, but even if only half of his points are true eVTOLs are irrelevant and will never represent a meaningful solution for clean transportation.
 
I believe they should focus on simple designs and short ranges, like the Volocopter City or the Ehang AAV. With this approach, short trips from rooftop to rooftop will become feasible and current battery technology is sufficient for such inner city flights. They could open a niche market where they would be indeed a lot cheaper than an Helicopter. The mechanics are simple with their fixed rotor positions and the controls are well understood from millions of drones.

In the race for investors, they all became too ambitious with making promises of high range and speed to compete with helicopters in a marked which is small (individual city to city flights) and will remain to expansive for the mass of the people.
 
I believe they should focus on simple designs and short ranges, like the Volocopter City or the Ehang AAV. With this approach, short trips from rooftop to rooftop will become feasible and current battery technology is sufficient for such inner city flights. They could open a niche market where they would be indeed a lot cheaper than an Helicopter. The mechanics are simple with their fixed rotor positions and the controls are well understood from millions of drones.

In the race for investors, they all became too ambitious with making promises of high range and speed to compete with helicopters in a marked which is small (individual city to city flights) and will remain to expansive for the mass of the people.

I think the big issue with designs like Volocopter or the Ehang 216 is that while they are mechanically simple, they consume massive amounts of energy with their flight profiles. So unless a drastic change in battery density comes along you're not going to be able to achieve any meaningful improvements in range and payload, which makes these types of designs a technological dead end.

For example, the latest version that Volocopter is working on is a more advanced design than what has been flying all these years.


Ehang is also moving towards a different design in order to achieve more range. The one advantage that Chinese companies like Ehang have is that the govt will likely place large orders once their designs are certified in order to give the industry a helping hand, something that I don't see happening in the U.S. Heck, they're already playing around with the idea of using these machines for aerial fire fighting purposes.


 
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A range of 20 km is fully sufficient for that purpose and the very low disk load of the Volocopter (somewhere here is a diagram..,) will safe a lot of energy during take off and landing compared to tilting rotor concepts for higher speed and range.

Volocopter is still promoting the Volocopter City, the later model is no replacement but additional.
 
In Sao Paulo I would prefer the eVTO for safety reasons...

In London, a lot of bankers prefered Helicopter over the Tube on much shorter distances. Traveling 20 through a city durung rush hour is no fun at all...
 
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