Flying cars, sustainability, climate, and all that…

From the UNIVERSITY OF MICHIGAN and the department of “where the heck is that flying car promised 50 years ago?” department.

A Jetsons future? Assessing the role of flying cars in sustainable mobility

ANN ARBOR–In the 1960s animated sitcom The Jetsons, George Jetson commutes to work in his family-size flying car, which miraculously transforms into a briefcase at the end of the trip.


Artistic rendering of an electric vertical takeoff and landing taxi cruising through an urban center. CREDIT Dave Brenner/University of Michigan School for Environment and Sustainability

A new study of the environmental sustainability impacts of flying cars, formally known as electric vertical takeoff and landing aircraft, or VTOLs, finds that they wouldn’t be suitable for a Jetsons-style short commute.

However, VTOLs–which combine the convenience of vertical takeoff and landing like a helicopter with the efficient aerodynamic flight of an airplane–could play a niche role in sustainable mobility for longer trips, according to the study, scheduled for publication April 9 in Nature Communications. Several companies around the world are developing VTOL prototypes.

Flying cars would be especially valuable in congested cities, or in places where there are geographical constraints, as part of a ride-share taxi service, according to study authors from the University of Michigan’s Center for Sustainable Systems and from Ford Motor Co.

“To me, it was very surprising to see that VTOLs were competitive with regard to energy use and greenhouse gas emissions in certain scenarios,” said Gregory Keoleian, senior author of the study and director of the Center for Sustainable Systems at U-M’s School for Environment and Sustainability.

“VTOLs with full occupancy could outperform ground-based cars for trips from San Francisco to San Jose or from Detroit to Cleveland, for example,” he said.

The U-M-Ford study, the first comprehensive sustainability assessment of VTOLs, looked at the energy use, greenhouse gas emissions and time savings of VTOLs compared to ground-based passenger cars. Although VTOLs produce zero emissions during flight, their batteries require electricity generated at power plants.

The researchers found that for trips of 100 kilometers (62 miles), a fully loaded VTOL carrying a pilot and three passengers had lower greenhouse gas emissions than ground-based cars with an average vehicle occupancy of 1.54. Emissions tied to the VTOL were 52 percent lower than gasoline vehicles and 6 percent lower than battery-electric vehicles.

Akshat Kasliwal, first author of the study and a graduate student at the U-M School for Environment and Sustainability, said the findings can help guide the sustainable deployment of an emerging mobility system prior to its commercialization.

“With these VTOLs, there is an opportunity to mutually align the sustainability and business cases,” Kasliwal said. “Not only is high passenger occupancy better for emissions, it also favors the economics of flying cars. Further, consumers could be incentivized to share trips, given the significant time savings from flying versus driving.”

In the coming decades, the global transportation sector faces the challenge of meeting the growing demand for convenient passenger mobility while reducing congestion, improving safety and mitigating climate change.

Electric vehicles and automated driving may contribute to some of those goals but are limited by congestion on existing roadways. VTOLs could potentially overcome some of those limitations by enabling piloted taxi services or other urban and regional aerial travel services.

Several aerospace corporations and startup companies–Airbus, Boeing, Joby Aviation and Lilium, for example–and agencies such as NASA have developed VTOL prototypes. One critical efficiency enabler for these aircraft is distributed electric propulsion, or DEP, which involves the use of several small, electrically driven propulsors.

The U-M and Ford researchers used publicly available information from these sources and others to create a physics-based model that computes energy use and greenhouse gas emissions for electric VTOLs.

“Our model represents general trends in the VTOL space and uses parameters from multiple studies and aircraft designs to specify weight, lift-to-drag ratio and battery-specific energy,” said Noah Furbush, study co-author and a master’s student at the U-M College of Engineering.

“In addition, we conducted sensitivity analyses to explore the bounds of these parameters, alongside other factors such as grid carbon intensity and wind speed,” said Furbush, who is also a member of the U-M football team.

The study began while Kasliwal and Furbush were summer interns at Ford. The work continued when the students returned to Ann Arbor, with the help of a Ford-University of Michigan Alliance grant.

The researchers analyzed primary energy use and greenhouse gas emissions during the five phases of VTOL flight: takeoff hover, climb, cruise, descent and landing hover. These aircraft use a lot of energy during takeoff and climb but are relatively efficient during cruise phase, traveling at 150 mph. As a result, VTOLs are most energy efficient on long trips, when the cruise phase dominates the total flight miles.

But for shorter trips–anything less than 35 kilometers (22 miles)–single-occupant internal-combustion-engine vehicles used less energy and produced fewer greenhouse gas emissions than single-occupant VTOLs. That’s an important consideration because the average ground-based vehicle commute is only about 17 kilometers (11 miles).

“As a result, the trips where VTOLs are more sustainable than gasoline cars only make up a small fraction of total annual vehicle-miles traveled on the ground,” said study co-author Jim Gawron, a graduate student at the U-M School for Environment and Sustainability and the Ross School of Business. “Consequently, VTOLs will be limited in their contribution and role in a sustainable mobility system.”

Not surprisingly, the VTOL completed the base-case trip of 100 kilometers much faster than ground-based vehicles. A point-to-point VTOL flight path, coupled with higher speeds, resulted in time savings of about 80 percent relative to ground-based vehicles.

“Electrification of aircraft, in general, is expected to fundamentally change the aerospace industry in the near future,” Furbush said.

The study’s authors note that many other questions need to be addressed to assess the viability of VTOLs, including cost, noise and societal and consumer acceptance.

###

Other authors of the Nature Communications paper are from Ford’s Research and Innovation Center in Dearborn: James McBride, Timothy Wallington, Robert De Kleine and Hyung Chul Kim.

The Nature Communications paper is titled “Role of flying cars in sustainable mobility.” DOI: 10.1038/s41467-019-09426-0. Once it is published, the paper will be available at http://www.nature.com/articles/s41467-019-09426-0.

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116 thoughts on “Flying cars, sustainability, climate, and all that…

  1. From the article, “Emissions” nine occurrences “Economics” just two. Most people are concerned with cost and not CO2. At several hundred thousand dollars a copy, the skies won’t be crowded with these things anytime soon.

      • Aircraft prices haven’t come down, this thing is an aircraft, not a car, so I doubt it’s going to come down. An FAA Airworthiness Certificate has a steep price tag.

        • The flying cars will be ‘self-flying’ … therefore no air traffic control needed! Right!? Hasn’t Tesla PROVED it can be done?

          • Designated Traffic Airlanes and Altitude restrictions for direction of travel. With Pilotless autonomous vehicles, they will talk to each other
            Just ask my mother

          • I know that there is a bit of “/sarc” in your response, but you might just check how long the FAA has been working on regulations for “drones” to fly, pilot-less, in their airspace.

      • Since the 1950s, prophecies regarding VTOL vehicle have always been “just around the corner” awaiting that mystical technology leap and industrial scale construction to lower costs.

        It was fantasy in the 1950s and it is still fantasy in the 21st Century.

        1) Automobiles that operate on any highways are governed by a huge slate of safety regulations.

        2) Airplane equipment that flies any distance, carry passengers, enter controlled airspace fall under another massive amount of safety regulations and operating parameters.

        3) Batteries are currently near maximum efficiency. Even the lightest batteries are heavy when aggregated to supply rational levels of energy.
        * i) Storing energy in batteries is not efficient nor is energy pulled from batteries efficiently utilized.
        * ii) Again, batteries necessary for substantial use require reliable dependable energy sources. Which are not solar and wind power.

        4)

        “Hans Erren April 11, 2019 at 5:57 am
        Prices will come down, the first normal cars were also only for the rich and famous in the first twenty years.”

        Absurd.

        All that the earliest motor vehicles required was an engine, a wheeled conveyance, and blacksmith constructed gearing.
        Amateurs around the world were constructing and selling motor vehicles.
        Henry Ford, Stanley Steamers, Daimler and a horde of others were trying to mass produce vehicles at a price that people, unwilling to trust amateurs, were willing to spend.

        No such situation exists for flying/driving commutes today, almost seventy years after the first flying commuter vehicle predictions and exactly the same claims you espouse..

        • I tend to agree with you.

          The biggest problem is best described as this: physics.

          Physics puts hard limits on things. One of those things is lift-and-power-to-do-it. As any first-year physics student has beaten into them, “for every action is an equal and opposite reaction”. In a nutshell this is at the very center of why cost-effective personal air transport cannot use compact vehicles and especially small multicopters (“quadracopters”).

          All aircraft generate lift (upward force) by pushing down a flow of air/exhaust/etc. Airplanes have those big wings to deflect a large amount of air crossing the wing downward; this deflection in turn gives rise to Bernoulli’s Laws and equations, which more accurately encapsulate the every-action-requires-equal-and-opposite-reaction business.

          One of the things you find again as a well-beaten physics student studying aircraft and aerodynamics is that if it weren’t for friction, mass, strength and dynamic stability, you’d want to have wings really large, to deflect the maximum air, as slow as possible. The equations (physics side) are pretty simple:

          F = ma
          a = ΔV/Δt
          m = ρVA

          therefore

          F = ρVAΔV when Δt = 1

          with some simplification

          F = ρV² A … where A is m² area, and ρ is 1.28 kg/m³.

          However power is related to the energy imparted into the pushed-down mass (air) stream.

          E = ½mV²
          E = ½ρVAV²
          E = ½ρAV³

          Ah… the energy required goes up as a cube (x³) of velocity. Whereas the thrust goes up only as the square (x²) of velocity. Clearly, if one is trying to get the maximum thrust at minimal energy, one really would like to REDUCE the ΔV of the air deflected down.

          And as it is fairly obvious from the equations (right?) the way to do that is to increase the area of the wing / rotor / propeller / what-have-you. Increase the mass flow, do so at a lower ΔV air speed differential. This principle also coincidentally has guided the last 60 years of commercial aircraft jet engine design. Note how HUGE the intake mcowlings have become on the larger, newer aircraft. All in an effort to move more mass, more slowly. Lower invested energy to obtain the same thrust, all else equal.

          This is why small private planes can be built relatively cheaply and still get away with flying easily. The large wing deflects a LOT of air at speed, and the deflection is modest. The curvature of the wing in turn is designed to deflect that passing air as much as needed, while imparting the least amount of turbulence (and other dragging frictional modes) into it. A gentle acceleration and push; up goes the plane. Up it stays, as long as the engines provide power (or it has no power and is gliding to a not-crash landing).

          But in the end PHYSICS is what determines the energy-efficiency of small flying machines. There is no magic. Just dusty dry equations, and pretty straight forward principles.

          Just saying,
          GoatGuy ✓

          • Oh, but as CO2 levels go up, also does the value for ρ

            In conclusion, CO2 helps planes fly more efficiently.

            Is there anything CO2 cannot do?

            😛

          • Good explanation. Which is why a hovering helicopter, with low rotor downwash, is so much more efficient than a hovering Harrier or F-35, with high downwash.

  2. Oh great. With an already congested airspace above most metro areas, let’s add in a bunch of people commuting at 3000ft in the their flying cars. This is an ATC nightmare. Further, how many of us in our daily commute have encountered a large fraction of drivers who apparently do not know how to drive, or couldn’t care less about the rules of the road? And now we’re going to let them operate in 3 dimensions? Flying cars may be technologically viable, but I think there’s unintended consequences in the social and legal areas.

    • Totally agree. The only way it would work is if they were autonomous vehicles. Idiots on cell phones shouldn’t even be driving ground vehicles, much less aircraft.

    • These will be mostly autonomously guided aircraft that will fly very predictable flight paths and be constantly tracked by ATC sat-based systems as used on all other aircraft.

      • Says the non pilot. Ask Boeing how the path to autonomous aircraft is going. IT WILL NEVER HAPPEN in aircraft. PERIOD!

        • I would hate to say “never” when talking about engineering problems. I agree with Duane that if all the bugs can be worked out, these vehicles will have to be operated by the computer, not by a human. Human operation would be catastrophic. But given that solution, ground based automobiles would also be computer operated, which would be more efficient than human operated cars. No jackrabbit starts or stops, fewer accidents, coordination with traffic lights such that they rarely hit red lights, etc. I wonder if the people who did this study compared what the efficiency of computer operated ground vehicles would be compared to computer operated air vehicles.

        • Sorry, but autonomous aircraft are in flight all the time, including an autonomous helicopter. They just aren’t allowed into FAA-controlled airspace, except on a case-by-case basis, with a lot of prior planning, and last time I checked, they had to have a chase plane, as well.

        • Nope – so says the licensed pilot (for the last 43 years).

          Autonomous aircraft have been flying for years. Essentially ALL drone aircraft are at a minimum semi-autonomous, handling all the flight controls with human operators, if any at all, only handling high level control of the aircraft.

          Actually, autonomous aircraft are a lot easier to design and operate than are autonomous cars.

          Today’s commercial airliners are flown about 95% of the time by onboard computers, with position tracking via satellite (called the “NextGen Air Traffic Control” system), with position reporting accurate to within 3 meters.

    • Just imagine the number of flying cars hitting buildings. Or colliding with other flying cars and scattering debris all over the people below.

    • According to the article, these would be taxis, with a pilot and, always, three passengers. If it flies, and if it is in commercial operation, the FAA regulations for the vehicle, for the pilot, and for the maintenance facilities would be about the same as for any other air taxi.

      My gripe is that they are calling these VTOLs. VTOLs have existed for almost 100 years, since Igor Sikorsky first flew his helicopter. And almost all (if not all) are powered by fossil fuels. What this article is proposing are E-VTOLs. I wish they would call them that.

      • They also give absurdly optimistic projections about efficiency and usage of aircraft that do not currently exist, omit return journeys, and are always at full capacity.

        This is comparing apple carts to the Orange Bowl.

      • They are VTOLs – VTOL simply describes the normal flight regimes of vertical takeoff and landing.

        If an E is merited, that would only apply to 100% battery electric operations. Some are such, but there are many others that are hybrid electric, particularly the larger aircraft that fly longer range. For short range commuting, all electric certainly can make good sense. The problem is, however, a commercial air taxi service must be able to fly many hours of endurance each day, even if they don’t need to fly long range point to point. Therefore even for short range air taxi service, hybrid electrics, or fuel cell aircraft make much better sense.

        There are many dozens of hybrid electric and fuel cell electric aircraft under development now, with quite a few having already flown and others will be entering flight testing within the next 1 to 2 years.

        Electric powered (whether battery or hybrid or fuel cell) aviation is a much nearer term reality than most people realize. The advantages of electrically-powered aircraft are compelling:

        1) Much less noise – a key performance requirement for urban operations

        2) Much better resliience and redundancy – an engine failure essentially disappears as a significant flight risk

        3) Much lower operating costs – both due to much lower energy cost and much lower maintenance costs.

        4) Greatly reduces air emissions of all pollutants.

        5) Much lower noise and vibration levels for cabin occupants

    • “With an already congested airspace above most metro areas”

      ‘Congested airspace’?

      Whenever I look up in the sky I see… blue sky and clouds. Maybe one or two aircraft passing by at 30-40,000 feet and occasionally an aircraft heading to the airport to land (takeoffs rarely go over the city). Every once in a while, the air ambulance helicopter going somewhere or coming back.

      And that’s supposed to be ‘congested’?

      • He probably meant to say “around all major US airports”, but since most of these airports are near large cities, he is not entirely incorrect. And congested in Air Traffic Control terms is different than for land vehicles. For aircraft you need to maintain a much larger safety buffer around it than for land vehicles. In the US this varies by the type of airspace, however the smallest separation standard is 3 nautical miles laterally and 1000 feet vertically. Generally this is near airports where they have very good surveillance coverage (search radar and ADS-B, for example). For Enroute the lateral separation is 5NM, with some exceptions where it is greater. Oceanic is much larger both laterally and vertically because in most of those airspaces there is no radar or ADS-B coverage at all.

  3. … a fully loaded VTOL carrying a pilot and three passengers had lower greenhouse gas emissions than ground-based cars with an average vehicle occupancy of 1.54.

    How about comparing apples with apples. A fully loaded train is more efficient than a single passenger luxury car. Big whoop!

    • I was going to make that comment. The fully loaded VTOL was only 52% lower CO2 emissions than the 1.54 occupant car. If the car had 5 people, or the VTOL had 1.54, it would appear that the car would have lower CO2 emissions.

  4. I have seen similar news items in the past 50 years, from flying cars, to self-driving cars, to magical batteries just around the corner, and lived through the original Nitrogen power craze in the 1980s (still waiting), though GM did produce a great power platform that seems to be the basis for the Tesla today.
    One day maybe we will find out how to produce hydrogen competitively, or a battery that defies physical limitations now limiting use, but we are not there yet.

  5. I think they should work the bugs out of self-driving highway cars before clogging up the air space over cities with flying cars. It’s bad enough to collide with another car on the road, but it just adds insult to injury when you also hit the ground after a mid-air collision.

    They also might want to concentrate on the weight of the power supply for the motors before they get too far into the project. We aren’t mass producing electric helicopters just yet. There’s a clue in there somewhere.

  6. I can’t for the life of me understand why so many people are entranced by such a stupid idea as flying cars. Think for a minute about what you encounter every day driving in traffic. Now imagine it 1000 feet over your head.

    No thanks.

    P.S. Any ideas how brakes are supposed to work in midair?

    • no brakes in flight, just means to fly slowly, like flaps and slats. However, an aircraft cannot fly more slowly than it’s stall speed, which in most light GA aircraft is about 50 mph .
      Molt Taylor did build and fly an ‘Aerocar’ in the 1950s . The wings and tail would be detatched and towed as a trailer. https://www.eaa.org/en/eaa-museum/museum-collection/aircraft-collection-folder/1949-taylor-aerocar—n4994p
      The big issue that I see is that any ‘road rash’ while driving it as a car will make it un-airworthy as an aircraft. An aircraft mechanic would have to repair and approve it for flight.

      • VTOLs can fly at 0.0 knots – called hover. They can fly sideways. They can fly backwards. They can fly vertically, both up and down. They don’t have a stall speed.

        Thanks for the reference to the “Aerocar”. Great concept, but it didn’t catch on.

        And a very good point about any damage to the vehicle.

        • I’m a ‘fixed wing’ pilot, so that was my reference. The electric vtols that I’ve seen are not roadable.

          • I agree absolutely. These recurring concepts seem to be a combination of “engineers” with a gleam in their eyes and a promoter very experienced at separating gullible people from their money.

            Another idea whose time came, and went, like the blimp with rotors on it.

      • For the record. I was being somewhat tongue-in-cheek. But seriously, stopping distance for any aircraft is at least an order of magnitude more than a ground vehicle’s. When it comes to stopping a moving vehicle, friction with the ground is your friend.

  7. They didn’t study anything since the only electric VTOLs out there are tiny quad copters. And even the largest of those can’t carry a human nor go anywhere close to 150 miles.

    • No, not really. There are a number of VTOL experimentals. Their projections are based on batteries that become remarkably better at rapid-charging, while magically offering far higher specific energy density (kWh/kg) and one expects, radically better specific energy cost (kWh/$). With deep irony, its interesting how well the (ahem, ahem…) conventional helicopter does at addressing most commuter-commuting issues. VTOL, check. FAA certified, check. 2 to 6 passengers, check. Rapid refueling, check. Death traps if they fail mid-air, check.

      Just saying,
      GoatGuy ✓

          • Not all together true. An autorotational descent is just steeper than a normal landing approach. And pilots (fixed wing and VTOL) are taught to always, alwasy, have a place to land within gliding / autorotational distance. We have fixed-wing aircraft occassionally landing on freeways and streets here in SoCal – I’m sure that a helo could do the same.

          • It is not only steeper. It is also rapid with a very high sink rate and very limited marginals for maneuvring. The only energy reserve available is in the autorotating rotor. To make a good landing you must hit just the right spot, and then pull collective at just the right moment.

            A split second to late, and you won’t have time to kill the sink rate, a split second too early and you will “land” in the air and do the last bit in free fall. In either case you crash.

        • If there is open terrain nearby (an helicopter has marginally better gliding ability than a brick) and a skilful pilot who knows how to do an unpowered autorotative landing, which in not at all easy.

          I know, I worked for a number of years for a company which made a lot of money repairing Swedish Army helicopters. The Army insisted that all pilots must be able to do unpowered autorotative landings, and had actually done so during training. Result: a lot of bent helicopters.

        • TTY said it fairly well.

          Autorotate asymptotically achieves a nearly fixed descent rate, one which is fast, but not necessarily lethal on its own. However, the big advantage is that it also harvests potential energy from that descent into keeping the rotor spun up. At the last second … and it is critical that the timing is nearly perfect, pulling the collective (tilting the rotor blades to turn rotational energy into lift) is a one-shot-and-you-are-done deal.

          While in a nearly-computerized cockpit, that autorotation plus perhaps soft landing is far less demanding: elevation sensors and computing can in real time turn descent rates and rotational energy into a complex … but ultimately quickly computed trigger to start pulling-on-the-collective. The thing should land with a bang-and-a-thud, but no one ought to be significantly hurt. At least that’s the idea.

          GoatGuy

        • The other side however is that while large-rotor helicopters can definitely harvest descent energy as rotor rotational energy, then cup it back to land, many-rotor “quadracopters” (or “anycopters”) cannot.

          The upside is that with a handful-to-dozens of small fans, the likelihood of a significant number of them going down is small. The downside is, if the problem is electrical, then there’s every likelihood that the whole contraption will become either dangerously unstable (best case), or just drop like a brick (common case).

          Neither encourages the public to believe in taking the Lyft Lift.

          Just saying,
          GoatGuy ✓

  8. LOL. Small drones have caused major issues, from trying to redefine air property rights to shutting down airports, and they are touting personal aircraft?

    Surely Ford has better uses for their shareholders’ money than to sponsor this worthless research. How about trying to make a car equal in quality to that of a Honda or Toyota?

  9. Just remarkable.: based on projections of future VTOL flight, batteries, airframes, we’ve got a study. Which compares a rationalized-as-competent electric VTOL 4 seater against a conventional car on the road.

    The list of wait, what? is easy to state…

    • Cost of vehicle
    • Cost of maintenance, usage, ownership
    • FAA required safety-and-performance
    • Exponential increase in commercial VTOL pilots
    • Recharge rate issues
    • Failsafe improbability

    I too have been numerically modeling various kinds of VTOL aircraft for the last few years. In a nutshell, their flight energy efficiency is directly proportional to how much they look like a conventional airplane … with broad wings for in-flight lift, and also directly proportionate to the total frontal area of the rotors used to both get ’em off the ground, and give acceleration/deceleration force to the whole craft.

    Think a VTOL flyer will cost less than $250,000? I don’t. In fact, that’d be cheap for an FAA certified one. And what does the pilot cost per year? And the rapid-charging infrastructure? Its not like you can just fly one prosaically between San Francisco and San Jose (per article), then get a tank of gas, and go to back. Nope, el-VTOL has to be connected to a power snake, and allowed to suck up juice for a period. Along with the other 50 of them (as an example) loitering to become fully recharged.

    $200,000 or more for a single pilot, per year (insurance, wages, taxes, “all in”)
    $300,000 amortized for the aircraft, say $70,000 a year
    $40,000 a year for FAA required maintenance and re-certification
    $15,000 a year for shared VTOL recharging station services (not electricity)

    Each capable of what, 20 trips a day, each trip using 75–100 kWh of electricity… or more … 50–100 km a trip, for 1,000 to 2,000 km/day. Wow. 1,500 kWh or so a day. Well, at least the juice will be cheap. 18¢/kWh is under twenty bucks a trip for ‘fuel’.

    $200,000 + $70,000 + $40,000 + $15,000 + 20 trips × 300 days × 75 kWh × 18¢/kWh …
    $422,000 in operating costs
    $70 a trip (6,000 trips a year, per aircraft)

    Wonder what the profit margin is for the operating corporation. 30% like many airlines? One wonders.
    ________________________________________

    I personally do see applicability of these things, much constrained not by how much CO₂ is generated (which is a hopelessly banal measuring stick), but by the valuable time saved. If I were to fly into SFO from London say, and need to get to an important meeting in minutes down in Sunnyvale … shelling out an additional $250 for a flitter to get me there in less than a half hour, would be CHEAP. Millions of dollars of Big Deals need getting done, you know.

    But this isn’t for The Jetson’s dad, getting to work at his work-a-day job, along with another million odd commuters cursing at the traffic from the ‘burbs. Not at all.

    Just saying,
    GoatGuy ✓

    • Hi Goat guy
      for us who do not such financial resources, but still well to do, flying elephants are the next best thing, and finally for the poorest class of citizenry the flying pigs are only available alternative./sarc

    • Easy. Flying hamster balls made of Nerf material. In case of failure, they fall harmlessly to earth.

    • GoatGuy you are too optimistic. As a Part 135 air taxi the aircraft must have 30 minutes endurance on landing. It may have a dedicated ‘vertiport’ at the airport but will be going to an unprepared site at destination, but will need to recharge. Does the office, hotel or home destination have heavy duty recharging points? If instead a local vertiport is made the destination then I have to transfer to car or taxi.
      Then there are regulations like the requirement to fly under Instrument Flight Rules which requires separation of 3 nautical miles or 1000 feet. This reduces the number of VTOL vehicles. Then at destination as the aircraft is flying Instrument Flight Rules it must fly a defined published instrument approach procedure. Some hospitals and upscale hotels have these point-in-space procedures , but they will not exist for random landings.
      On the plus(?) side most plans by businesses such as Uber Elevate https://www.uber.com/us/en/elevate/ are costed on the ‘vehicle’ being unpiloted and autonomous which brings with it another set of considerations.

      • If you have ever tried to go from Santa Monica Airport to the Westin Bonaventure at 5 pm on a Friday, you would be willing to try an Uber Elevate.

      • You are making the assumption that existing flight regulations will not be changed in order to accommodate such VTOL craft. If control of these craft are automated/semi-automated then existing regs may not be germane and new ones would need to be implemented. If such craft were under positive automated control would 3 mile/1000ft separation be necessary? Considering a lot of these craft would likely not be flying at altitudes other aircraft operate, the traffic density and routing would highly likely be entirely different.

        Of course at this point the question is moot because there aren’t any such craft operating in regular service, Until then it’s still a lot of “What if…”.

        • The FAA Sep rules are mostly based on the reality of the physics involved in flying and uncertainty in the surveillance systems, not the human factor of the pilots. If the E-VTOL aircraft are limited to how fast they can fly, and there is sufficiently good ADS-B coverage in a specific area, then smaller Sep rules could be used, but I doubt they will ever get under 1NM and 500ft.

        • The FAA has been working on regulations to allow “drones” (both remotely-piloted vehicles and autonomous vehicles) to fly in FAA-regulated airspace for well over a decade now – don’t hold your breath. The FAA is extremely conservative, and I wouldn’t want it any other way.

          There are a hundred or more fully-autonomous flight vehicles deployed with the US Armed Forces, both fixed wing and helos. They only fly through FAA airspace under extremely limiting conditions. But they are out there, building up a database of real flight experience.

    • Opener Blackfly, single person VTOL electric 100km range 120km/hr On sale this year for “the cost of an SUV”
      https://www.opener.aero/faq/

      Once they start to get manufactured in large numbers the costs will come down dramatically. They are simpler and lighter than cars(about 2-300kg per passenger) and in million quantities will probably end up cheaper than cars.

      • Would be interesting to see an actual video of an actual flight instead of the CGI videos shown on their website.

  10. I love a good fantasy in the morning, back to coffee and reality. Four inches of snow the day after 80 degrees…

  11. What they are failing to mention is the amount of energy these will consume. Just because they are powered by electricity it does not mean that we can afford to waste that much energy.

  12. For those here bloviating about “flying cars” despite the headline this post was mostly about electrically powered VTOL aircraft. These machines don’t drive on the ground. They are aircraft only.

    They already exist and are in development testing .. and range in size from very small to commuter airliner size, and ranges from a few tens of kilometers to hundreds of kilometers.

    Some are battery electric, at the shorter ranges … while the longer ranged aircraft are mostly hybrid electric.

    Some are being developed by small startup companies, and others are being developed by the world’s largest aircraft manufacturers, including Airbus and Boeing.

  13. The flying “CAR” in the article isn’t a car, it’s an aircraft e.g. it doesn’t operate on the streets.

    This one, the flying Ford Pinto (In German)
    https://www.youtube.com/watch?v=eF_TUrQjT44
    does operate on the public highway and it looks great until you find out these guys killed themselves in it.

  14. See Moller International at moller.com. Moller has been plugging flying cars for almost 50 years using his rotary gas engines. He must have been reading the literature because the latest version of the Sykcar 200 includes an electric lift fan. Moller’s never been successful with this and I think the electric sky car is just unicorn dreams

  15. Lots of good comments already. One other element is simply physics.

    First, this ecological niche is already well populated with helicopters, so we know how it works.

    You have to move the same amount of air to lift an object regardless of the propulsion system. The absurd illustration at the top looks like some kind of flying electric razor. The idea that these things would noiselessly arrive in front of your house, pick you up and depart silently like a Uber is not going to happen. They need the same amount of space as a helicopter with the same precautions.

    Finally, there is zero chance of ordinary people flying them. Autonomous is possible, as the cost of a trained pilot is one of the major cost drivers for helicopters. We can se how difficult it is to get this working with cars.

    • Helicopters are very inefficient aircraft compared to fixed wing aircraft, and as a result cannot fly anywhere near as fast nor as far as equivalent-sized fixed wing aircraft. The VTOL aircraft described here and most of the others only fly in the vertical lift regime for takeoff and landing, not for cruising. In cruise they convert to fixed wing aircraft.

      Fixed wing aircraft are fare more fuel efficient than helicopters. That is why a tilt-rotor aircraft like the MV-22 and its newer cousin, the V-280, have radically greater range as well as airspeeds than do helicopters.

  16. Models schmodels. We have a market for urban VTOL already, with well known costs & benefits. They are called helicopters. We have landing fields. They are the big circles marked with an “H”, and appropriately lit, charted, equipped and monitored.
    Only the highest value and highest vanity trips generally qualify, with a smattering of affordable tourism routes that can be added to the medical emergency and executive trips to ring down the averages.
    The default FAA licensing and airspace regimes for planes & pilots being already in place, they will be subject to very ordinary and mundane rulemaking and evoution when and if the hardware evolves. A VTOL that uses volts or pretends environmental improvement is no different from the vehicles that it wants to share the airspace with when it comes to rules of the road or pilot licensure. There are well understood rules for off-airport operation, ATC communications, etc. that protect the extensive trafic already airborne in urban areas. Your gee-whiz-mobile neither needs nor deserves special treatment.

    • Helicopters require a lot of maintenance. Something like the VTOL pictured probably wouldn’t require a fraction of the maintenance a helo does. All of the ‘propulsors’ are electrically driven (electric motors are quite reliable). There are no transmissions, there’s a fraction of the mechanicals of a helo, no main rotor or tail rotor (which can take up a lot of space), and no piston or turbine engine to maintain. The VTOL craft could land in a much smaller area than a helo.

  17. “The study’s authors note that many other questions need to be addressed to assess the viability of VTOLs, including cost, noise… unknown FAA regulations, risk of accidents, legal liability…

    So, they haven’t considered cost? Good grief. This will compete with cars the same way that helicopters compete with limos. This isn’t for someone commuting to work, unless they’re the CEO of a major corporation. Or to fly from Denver to Breckenridge for a day of skiing before heading to Augusta to play the back nine. This seems more applicable for the final leg of a trip from the private airport to the cabin.

    Emissions and sustainability will be the LEAST of the market concerns.

  18. Funny, some things today are kinda amazing from a perspective of a couple decades ago, but yet some things haven’t progressed as expected and even deteriorated.

    I still want my flying car that was promised!

  19. “Electrification of aircraft, in general, is expected to fundamentally change the aerospace industry in the near future,” Furbush said.
    Translation of “in the near future”: “Maybe in 50 or 100 years, maybe not. Hey, we’re just spitballing here”.

  20. Sheesh!
    And then there are the guys that like the concept of a car that is also a boat.
    The “Amphicar 770”.
    Twas, at once, a bad car and a bad boat.
    Descartes would throw up his hands and say:
    I wish therefore I am.

  21. “VTOLs with full occupancy … a pilot and three passengers …”

    If you can fill a VTOL with people. If you can pay someone to pilot it. If you can find three passengers coming from and going to the same locations. If. If. If.

    The beauty of the personal car is that it sits quietly in your garage waiting for you and goes exactly where you want it to go when you want it to go there.

  22. Need for big buildings with openings so the landing is inside.
    Perhaps an opening every 17 floors.
    Designs for such could copy buildings with turbines now in the building.

    But, I’m not interested in such things when the main design criterion is CO2.

  23. I hope the artist did not draw the illustration from actual plans. Those protrusions (I won’t call them wings) are definitely not lift-producing airfoils, and the little “propulsion units”(?!) on top are almost perfect spoilers.

    I suspect we have all just wasted a cumulative day or so commenting on click-bait.

    “There is no Moore’s Law for batteries”
    Fred Schlachter
    https://www.pnas.org/content/110/14/5273

  24. “The U-M and Ford researchers used publicly available information from these sources and others to create a physics-based model that computes energy use and greenhouse gas emissions for electric VTOLs.

    Our model represents general trends in the VTOL space and uses parameters from multiple studies and aircraft designs to specify weight, lift-to-drag ratio and battery-specific energy,” said Noah Furbush, study co-author and a master’s student at the U-M College of Engineering.

    “In addition, we conducted sensitivity analyses to explore the bounds of these parameters, alongside other factors such as grid carbon intensity and wind speed,” said Furbush, who is also a member of the U-M football team.

    Another self satisfaction fantasy with sufficient parameters to guarantee desired results and popsci fame and glory.

  25. It’s much much safer to be on the ground when you run out of fuel or when the engine fails.

  26. ““Electrification of aircraft, in general, is expected to fundamentally change the aerospace industry in the near future,” Furbush said.”

    Yeah, sure it will. Just like rubber bands will.

  27. In the world of theory, everything is possible and nearly free. Reality has an unpleasant habit of correcting such wishful thinking.

  28. Screw flying cars. I want one of these. Amphibious 4-wheeler would be the bomb on the Outer Banks.

  29. Did anyone notice that this and similar schemes are exact analogues of the current renewables scam? Trillions of dollars are now wasted on pie-in-the-sky ‘modeling’ real systems that should never have gotten beyond the grad student study phase.

  30. Why did he leave it until the end of the article to write “Electrification of aircraft, in general, is expected to fundamentally change the aerospace industry in the near future” ?

    If he had only put it at the beginning of the article I wouldn’t have wasted five minutes of my life reading the rest.

  31. Like I am going to believe anything written by A**hat, er Akshat and Furbush?? Is this paper for real?

  32. For Pete’s sake we already have VTOLs … they’re called helicopters. So instead of 2 LAPD choppers and 3 networks up in the sky over LA there will be 50,000? All going in different directions?

  33. You could imagine the damage a hacker or terrorist could do if they hacked into an autonomous aircraft!!

    Self driving cars can be ‘herded’ into danger.

  34. Sounds like this would be a wet dream for anyone who wanted to be a terrorist and mimic 9/11, no on a personal scale, no?

  35. So, flying automobiles are more efficient and generate less Co2 because of no traffic lights, and shorter distances from A to B. Which reminds me of something I’ve NEVER heard the CAGWists ever suggest … timing controls of stop lights. We could save billions of tons of wasted petrol burning if we simply added sensors and controls to traffic lights, allowing the most efficient timing and sequencing of stop lights based on traffic demand … not a simple rotation timing. Yes, I know we have done this to some limited extent … but we could go much further and much more sophisticated.

    Virtually EVERY high rise building has an array of lighting and heating controls systems which have saved tons of Co2 and $$. Why aren’t we doing the same with traffic signals. We could dramatically reduce the start-stop inefficiency of motoring and help the air quality at the same time.

    The reason the “greens” have never embraced this idea? Because they HATE the automobile. They HATE doing anything to help drivers. They HATE the FREEDOM of the automobile. They HATE your freedom.

  36. I’m afraid that this just represents the same-old/same-old. We have the technology almost ready but…..fifty years later, we have it again.

    I like having the “flying family car” as an ever elusive dream — and it has not failed me yet.

  37. It would be cool to run one of these on 4th July when the fireworks go off.. you could replicate your Grandpa’s raid on Dresden!

  38. Flying cars? just take your existing car and get a hover conversion at Goldie Wilson Hover Conversion Systems. They’ve been in business at least since 2015! Why you’re at it, get a Mr. Fusion installed, it easily supplies 1.21 gigawatts of energy. 😉

  39. Won’t be marketable until functional antigravity systems are available. Until then, you’ll just have to settle for remote-controlled drones, helicopters, and those wingsuit things.

  40. moller m400, after 40 years and 100 million $ of development, FINALLY hovered in 2003 and still none actually sold.
    moller filed bankruptcy protection few years later.

  41. Hopeless. For people commenting on a science and engineering site – just hopeless.
    The point of VTOL is vertical TAKEOFF and LANDING. Some of these projects don’t get that either but all the hand wringing about vertical flight efficiency forgets that it will be for a maximum of a couple of minutes per flight.
    Use a conventional engine and prop for horizontal wingborne flight.
    The design tradeoffs are good. Much smaller wing as it isn’t sized for takeoff and landing, just for cruise. Smaller, lighter, landing gear as it isn’t going to be thrown at the ground at high rates of descent and high horizontal velocity. Much lighter airframe. Batteries only need to be small as only used for a couple of minutes per flight.
    Autopilot/autonomous is way easier in a airplane than a car. As is collision avoidance. 3 dimensions helps. Drones are already doing it.
    Certification? Look up Part 21 Experimental. A homebuilt kit will do it with next to no issues. (C’mon EAA’ers)
    The autonomous all electric vehicles won’t cut it but the R&D will give us the motors, controllers batteries and other systems for a nice VTOL two seat homebuilt kit. Airplanes are fast and fun but are limited by needing large pieces of land called airports. Helicopters are horribly complex and expensive and cruise L/D is so poor that range is limited.
    Safety enhanced, as if bad weather is encountered, find a small space and land. Same for engine failure of cruise propulsion. Use batteries for last couple of hundred feet in VTOL mode.
    Time for aviation 2.0 where airplanes are freed from large airports and th whole activity is dragged out of the 20th Century. Light aircraft haven’t advanced in over 80 years. See Messerschmitt 108 4 seat touring aircraft.

    • Your concept of using the rotors for vertical takeoff and landing, and wings and normal propulsion for flight, was tried many, many decades ago by Fairey, with the Rotodyne. There were some serious technical problems, so no market success. Then there was the tilt-wing concept. Again, technical problems that meant no production. The there was the tilt-rotor – the NACA – Bell Helicopter XV-3, the NASA – Bell Helicopter XV-15, and the USAF / USMC / USN V-22 Osprey, in all its variants. Bell and Agusta talked about a commercial variant, but it still isn’t flying. If you think a helicopter is complicated, each of these other concepts are much more complicated. By the V-22, the tilt-rotor became practical, but I doubt we’ll see a commercial version anytime soon.

  42. Multiple well financed firms (Joby, Airbus, Lillium) are flying evtol prototypes now, with around 80 different other organisations developing evtol craft and something like $2 Billion invested to date. Typically 2-300km range, 2-300km/hr, 2-5 passengers. Most aiming for initially piloted, but working to go autonomous as soon as regulators allow (it’s easier than autonomous cars). They are (in some cases) nearly as quiet as a cars when passing by and similar to a lawnmower when landing, and have redundant safety systems to ensure safe landings after any failure. For commuters autonomous systems will allow smaller more efficient, quieter and safer 1 person craft.

    They weigh a little less than a car – 3-400kg per passenger, and if winged use less energy than a car to travel the same distance (particularly as can use direct routes) and at speeds high enough to make them relatively insensitive to wind. Takeoff and landing energy will quickly reduce as greater confidence is developed in the autopilots (really only 5-10 seconds of powered lift is needed). While short catapults and elevated landing pads are an option for even quieter safer and more efficient urban performance.

    Batteries are still the big issue, but rapid increase in battery production worldwide and industry realisation that cars and trucks are going battery electric in next 2 decades (will be cheaper) means that there is enormous growth in battery research, and their will inevitably be huge leaps in performance. 260Wh/kg in Model 3 now, several low volume producers at 450-500Wh, and one just announced 1000Wh/kg that is supposedly being tested in the field now. So batteries are good enough now, and will get better making the planes even lighter and more efficient.

    The huge benefit is that they let people live extra-urban in cheaper houses. Devaluing cities and saving vast amounts of money spent on building and maintaining high density urban infrastructure (motorways, railways, bridges etc). Everyone can live in villages and commute to high intensity industries or workplaces in 10’s of minutes. High speeds means only about 10% of traffic in sky at any time compared to cars and the sky is really really big. If cities are no longer necessary far future air traffic is never going to be a big problem.

  43. I’m 63 years old and been hearing about our future with flying cars coming as the standard form of individual/family transportation for long as I can remember and it ain’t happened. I’m pretty sure that if I live to see 100, it still won’t have happened.

  44. We will get fusion first.

    Let me tell you a short yet related story.

    Two weeks ago while driving to work the sensors in my car decided there was air (or something) in the fuel lines and decided that to protect my diesel pump from damage the best course of action was to shut off the engine.

    Driving at about 70kph and first thing I noticed was the steering suddenly got heavier.

    Fortunately I had the momentum and space to pull over onto the shoulder safely, switch everything off, wonder what just happened and restart the car.

    (then “We have re-set your sensors. Only $88 today. Cash or card?”)

    So that was in my conventional ‘road’ car.

    How, in my VTOL Flying Car… Well if I was lucky I would still (7 days later) be filling in incident reports. If I was unlucky you would all be now making comments about the article reporting how ANOTHER VTOL flying car suffered a fatal accident in Australia.

    VTOL will not be allowed to operate in ‘Western Countries’ purely from a safety view in our lifetimes. Some tin pot backwater where life is cheap? Maybe. But over a Western urban area? Tell em their dreaming.

  45. Right … and what happens to all these lovely, sustainable electric VTOL taxis when the next “bomb cyclone” wanders in? Sheesh …

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