VTOL On Demand Mobility

Rhinocrates said:
CycloTech has released renders of its vehicle, which uses drum rotors (unless they're wheels for the hamsters powering it).

https://www.cyclotech.at/
https://www.cyclotech.at/cyclotech-presents-first-air-car-with-cyclorotors/
https://www.carscoops.com/2023/10/w...drum-shaped-fan-instead-of-propellers-to-fly/
You might notice that it has six, not four rotors. Two are fore and aft on the main axis and apparently for lift only.
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While cyclorotors do work and have found a use case in the maritime world (Voith-Schneider Propeller), I doubt that they are efficient enough to provide meaningful endurance and sufficient payload for eVTOL aircraft.
 
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VTOLicious said:
I doubt that they are efficient enough to provide meaningful endurance and sufficient payload for eVTOL aircraft.
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Apparently so. They claim this, but...

the CycloRotors will be able to carry the CruiseUp up to 62 miles (100 km) on a single charge, at speeds of up to 93 mph (150 km/h). This, the manufacturer says, is more than enough for trips within most major cities and their suburbs.
 
VTOLicious said:
While cyclorotors do work and have found a use case in the maritime world (Voith-Schneider Propeller), I doubt that they are efficient enough to provide meaningful endurance and sufficient payload for eVTOL aircraft.
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I did not know they had found application in the maritime world - very cool!

But that said - some of the calculations that tout their 'efficiency' comes from a juking of the reference areas used when computing various of the non-dim aerodynamic coefficients.
 
View: https://www.youtube.com/watch?v=4HkqZeiZckY&ab_channel=EHang


A good overview of the rigorous testing that this design was subjected to.

The video below is a bit old but it gives you a good close up look at one of the early prototypes as well as the massive control room that is required for autonomously operating multiple aircraft at the same time. Even though this prototype is extremely cramped the definitive version which will enter production is more roomier.

View: https://www.youtube.com/watch?v=AGVwrWYyjYg&ab_channel=EHang
 
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Congratulations, they did the right thing and focused on something which could be done with existing technology! Most other companies went down the rabbit hole with complex designs to enable more range and speed, often reliying on non existant battery technology.

Despite that, I prefere the volocopter design because here you dont have to walk through a forrest of sharp edged propellers to get inside....
 
I think they pretty much know what they want. See the accent on IR signature, quietness and quick recharge.
In that sense, starting with the CTOL variant is logical.
 
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TomcatViP said:
I think they pretty much know what they want. See the accent on IR signature, quietness and quick recharge.
In that sense, starting with the CTOL variant is logical.
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IMHO hybrids might make make sense for TOLanding but 'in extremis' missions in the current context require rng & payload that only the Energy density of fuels being combusted in ICEngines can provide.
 
alberchico said:
https://electrek.co/2023/10/13/ehan...ation-china-will-begin-commercial-operations/
Looks like Ehang has crossed the finish line and will be the first to start commercial eVTOL service.
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I had a closer look at the EH216-S Type Certificate published on the CAAC website: https://amos.caac.gov.cn/#/certificate

EH216-S_ops limitations.PNG

f. Unmanned aircraft system operational limitations

It is prohibited to operate under known or forecast weather conditions such as rain, snow, thunderstorms, ice, sandstorms, heavy fog, etc.;
Day operation only;
The aircraft flies within segregated airspace;
Aircraft flying over sparsely populated areas;
The aircraft is flying within the line of sight of the remote crew;
Aircraft are prohibited from operating over water, including takeoff, landing and forced landing.

To put it mildly, this is pretty restrictive for a certified aircraft!
 
So... not dissimilar to the flight rules for a model aeroplane ;) However, based on the Ehang I saw a few years back (DSEI?), there's quite a few aeromodellers that I'd trust far more to build something that I was to fly in...
 
VTOLicious said:
f. Unmanned aircraft system operational limitations

It is prohibited to operate under known or forecast weather conditions such as rain, snow, thunderstorms, ice, sandstorms, heavy fog, etc.;
Day operation only;
The aircraft flies within segregated airspace;
Aircraft flying over sparsely populated areas;
The aircraft is flying within the line of sight of the remote crew;
Aircraft are prohibited from operating over water, including takeoff, landing and forced landing.

To put it mildly, this is pretty restrictive for a certified aircraft!
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I wonder if the Volocopter will face similar restrictions on its type certificate when it commences commercial operations. Is it possible that CAAC might relax some of these restrictions once more operational real world experience with passengers is obtained ? I'm not a pilot, but it seems to me that if the onboard computer can fly the Ehang 216 successfully in daytime VFR conditions with a level of precision that a human pilot can't match, then surely it can also conduct flights in IFR conditions as well ?
 
alberchico said:
I'm not a pilot, but it seems to me that if the onboard computer can fly the Ehang 216 successfully in daytime VFR conditions with a level of precision that a human pilot can't match, then surely it can also conduct flights in IFR conditions as well ?
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Sufficiently performing and reliable sensors are more the key than the computers. And these sensors are safety critical so need lots of qualification evidence.

e.g. if it has visual cameras only then these probably don't work that well at night or in cloud
 
@shin_getter It is a simple design and propably quite efficient compared to typical drone designs like Ehang or Volocopter. Despite that, it is not suitable for public transport, it has no doors so you have to climp inside and the take of and landing is quite rough as can be seen in the video. Could be a nice toy.
 
Nicknick said:
@shin_getter It is a simple design and propably quite efficient compared to typical drone designs like Ehang or Volocopter. Despite that, it is not suitable for public transport, it has no doors so you have to climp inside and the take of and landing is quite rough as can be seen in the video. Could be a nice toy.
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But a very expensive one
 
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the olympics are a prestige event - and anything is possible if people actually want something to happen
 
https://www.ainonline.com/aviation-...tol-start-ups-may-have-embrace-crawl-walk-run
"The latter point on energy reserves is especially critical and could potentially limit the already constrained range of eVTOL aircraft dependent on current battery technology"

I think the FAA's position regarding minimum energy reserves is a huge looming issue that will affect the business model and overall viability that these aircraft have.
 
alberchico said:
https://www.ainonline.com/aviation-...tol-start-ups-may-have-embrace-crawl-walk-run
"The latter point on energy reserves is especially critical and could potentially limit the already constrained range of eVTOL aircraft dependent on current battery technology"

I think the FAA's position regarding minimum energy reserves is a huge looming issue that will affect the business model and overall viability that these aircraft have.
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This is the dilemma:-

The FAA position on reserve is entirely correct as it’s based on e real world experience.

The e-VTOL industry can’t comply in the short to medium term so need it removed.

If e-VTOL don’t get it removed then the investors will lose because of the unacceptable pay back time.

If they exert political pressure on the FAA to remove it, then there’s gonna be crashes which will kill the industry (number one rule, don’t kill your customers).
 

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VTOLicious said:
"...Butterfly deploys two technologies Overair says have never been integrated on an eVTOL design: optimum speed tilt rotor (OSTR) and individual blade control (IBC)..."

Interesting project indeed.
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Could it be, that this fancy "IBC" just means that it has a variable propeller pitch? The super fancy "OSTR" means just variing the rotor speed which isn't a great innovation either...
 
Nicknick said:
Could it be, that this fancy "IBC" just means that it has a variable propeller pitch? The super fancy "OSTR" means just variing the rotor speed which isn't a great innovation either...
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Rotorcraft usually have constant speed rotors and the blades are controlled via a swashplate. Variable rotor speed and individual blade control have been tested before, but never made it into production aircraft. Let's see how this turns out.
 
VTOLicious said:
"...Butterfly deploys two technologies Overair says have never been integrated on an eVTOL design: optimum speed tilt rotor (OSTR) and individual blade control (IBC)..."

Interesting project indeed.
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Both of the technologies mentioned have been in dynamic hardware testing for a number of years. Karem built a full scale prop-rotor and nacelle for the JMR Technology Demonstration and put a good number of hours on the assembly. They put a full scale dynamic system on a truck for Butterfly as well. Looking forward to seeing the demonstrator get into the air. But be patient as they are VERY methodical.

https://helihub.com/2023/12/20/us-navy-awards-overair-sbir-contract-to-advance-ibc-technology/
As posted elsewhere.
 
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