eVTOL, is it going to change the way we travel?

Has anyone been following the world of eVTOL aircraft? Lots of companies worldwide are starting get some serious backing. Does anyone have any opinions on whether this is going to be a viable method of transport in the near future?

https://evtol.com/

Sort of.

An acquaintance of ours founded these guys, and I've kept a close eye on what they are doing. It's exciting stuff. As you say, money is pouring into the sector at the moment.

https://www.dufour.aero/

In time, these aircraft will gradually replace today’s helicopters

Glad to hear people who commute in helicopters have something to look forward to.

Ther argument (and I'm not saying this is valid or not), is that the largest costs relating to helicopter travel (other than environmental) are the cost of training and maintaining a pilot's license, cost of fuel and parts, insurance relating to mechanical and pilot error, and air traffic control overheads.

Evtol evangelists claim that the relative mechanical simplicity of the new aircraft combined with automated ATC and flight will drive down the cost of using them to the point of being an Uber style service for the masses. When the tech is more mature and embedded anyway.

It's also worth mentioning that there are a surprising number of people in the world who are dependent on helicopters for cargo and supplies. Far more than who commute using them.

The aim for many eVTOL companies is to keep the cost per passenger mile down towards that of a taxi: https://www.aviationtoday.com/2021/04/09/air-taxis-likely-to-not-deploy-in-early-to-mid-2020s-as-predicted-report-says/ . Lots of the big players are quoting around $4 per passenger mile.

There is also the community noise factor which will impact public acceptance, eVTOL a/c should be perceived quieter than a helicopter. Current helicopter are too noisy to make many flights a day, there are metrics such as Sound Exposure Level (SEL) which dictate how many flights can be made per day.

I am suspicious of a lot of the claims for these on general hype grounds; there's a heck of a lot of regulatory hurdles to overcome before you can even think about passengers. FWIW, my pal Prof. Brown the rotorcraft aerodynamicist is suspicious about the flow regime that most of these designs are operating in (disc loadings etc.); he reckons a lot of them will be susceptible to vortex ring problems once they get into real-world testing.

Well yeah These claims probably won't be tested for anorher ten or fifteen years.

I personally think it will happen though.

Vortex ring problems affect every single helicopter design ever constructed but the problem is controlled. I can't see it being an insurmountable problem for evtol aircraft to the point that it'll stop development.

Is that Richard Brown, I also know him if so!

Surely higher disc loadings compared to helicopter (higher induced velocities by the rotor) is only going to help prevent vortex ring state since higher gust velocities/descent rates will be needed to reach vortex ring state? Not saying it won't need to be something carefully monitored. Seems that a lot of eVTOL's will have advanced flight control systems which will help control things such as descent rate.

I knew him when he was plain old Doc Brown - he'd undertaken some highly experimental stuff with flux capacitators but had moved onto working on recycled fuel sources. Sounds like he's being a bit more measured and responsible about the risks involved in experimental modes of travel these days, but he was more fun back in time.

Dufour have a pretty useful FAQ page for some of these questions.

https://www.dufour.aero/q-a

The EASA are already on a path to regulate the design and safety of VTOL aircraft, and these are the regulations that prototypes have to comply with to progress.

https://www.easa.europa.eu/document-library/product-certification-consultations/special-condition-vtol

somehow feel uneasy getting in a helicopter flighted by someone willing to be paid $4/mile

'We' not a chance,
self-entitled Climate Emergency deniers: form an orderly queue.

The goal they are working to is that there won't be anybody flying them.

This applies to traditional passenger jets and evtol.

Absolutely, but they're not really the target market though, are they? In the context of Paris (where the quote is from), I can imagine ferrying well-off tourists from the centre to Eurodisney in 15 or 20 years' time. It might be "progress" from helicopters only carrying millionaires, but that's not really going to change commuter transit IMO.

@wjrh on that artist impression there's 6 or 7 aircrafts. A quick Google suggest there are 1550 taxis in Atlanta, on top of which you need to add Ubers and Lyfts. Do we really expect cities with several thousands of those in the air?

Do we really expect cities with several thousands of those in the air?

In enough time, yes. Traffic management tech is likely the future of ground vehicles as well as air vehicles. In the same way that drone corridors with automated ATC are in development.

Absolutely, but they're not really the target market though, are they?

The target market will be whatever/whoever has a need that can be met by paying for the service. I have no idea of how the split between cargo and passenger travel might look.

I see your point, but this likely assumes a min. of four passengers. Assuming a modest 30 miles are flown per hour, this gives $4/mile x 4 pax 30 miles x 8 hrs = $3,840 per day. Obviously there is maintence, fees & fuel. I don't have a feel for on whether or not that's profitable, but feels like it could be. 30 miles could also be conservative, I'm not sure.

Yes it is; small world! I can't recall the details (and it's decades since I took his rotorcraft course), but IIRC his work on the V-22's vortex ring state led him to believe that a lot of the eVTOL designs might encounter problems in a wider area of the flight envelope than might be expected.