This seems like the kind of thing that would be useful in specific situations, but won't be feasible for broad use until we come up with much cheaper electrical energy production (and probably storage too) than we have today, e.g. fusion power or much cheaper solar. At least I don't imagine it can be very energy efficient to expend power on moving up and staying up in the air instead of using the normal force from the ground 'for free' like a land-based vehicle does so it only needs to expend energy to move horizontally (for an intuition about this, think about how hard it is to jump half your body length upward, versus walking half your body length forward). So while it's cool that it's emissions free, it's not great if it ends up using e.g. 5-10x as much energy to make the same trip as an electric car, and it makes it that much more difficult to offset the environmental impact of its production and operation.
The Uber Elevate study from 2016 answers many of these foundational questions.
A traditional car achieves about 1 mile/kWh. An electric car achieves 3 miles/kWh, since the electric drivetrain is much more efficient. An electric plane might achieve around 2 mile/kWh. So, worse than an electric car, but better than a conventional car.
Some background: A car has aerodynamic and roll drag. At typical speeds (50 mph), they're of approximately the same magnitude. A plane has aerodynamic (parasitic) drag, similar to a car, but no roll drag, but instead an additional aerodynamic drag, the so-called induced drag, that is concomitant with generating lift. At typical speeds (higher than a car though), they're also approximately the same magnitude.
With lots of simplifications, one can thus say that one basically trades roll drag for induced (=lift generating) drag.
So whats the real power consumption? After all, getting that thing up into the air IS the problem and not flying it.
"These examples for car and VTOL have only considered the energy required to cruise at a
specific speed, and doesn’t include the additional energy required to get the vehicle to cruise
for either the car (acceleration) or VTOL (takeoff). "
hm, I tend to disagree. You might underestimate how much energy is spent on overcoming drag, and how strong the earth acceleration g is: One always needs to overcome it, and overcoming it just a bit more for a while is enough for a climb, basically.
If we take the performance section for the Cessna 172 N, for example, we see that it burns 8.4 gallons per hour at a (speedy) 75% power cruise. It takes 10 minutes to climb up to 6000 ft, and burns 1.9 gallons. In cruise, it would burn 1.4 gallons in that time. So, the climb requires about a third more.
So, given that PEVA (personal electric VTOL aircraft) would likely cruise at fairly low altitudes, and the climbing constitute only a small part of a flight, say a quarter, the total extra fuel consumption would be a fairly minor increase on top of the quoted numbers.
Note also that cars tend to accelerate and brake much more than aircraft tend to climb and descent.
You're right that powered lift is inefficient, however the whole point of this configuration is that you transition to forward flight/aerodynamic lift once aloft.
Yeah, I assume the airfoil of the wings gets it closer (anyone know how close?) to a car in efficiency once it's gotten moving, but I also imagine the energy overhead of the VTOL part of the flight is quite a significant chunk of the total if the range is only 62 miles. Improvements in battery weight could help here, but then again, they'd improve the efficiency of electric cars too, so it'd still be an unfavorable comparison. Don't get me wrong, I think it's great that this is being innovated on, but I don't see this being a feasible replacement for Lyft/Uber for most people until the energy math starts looking very different than it does today.
I don't see it being a point to point transportation option for most of it's potential use cases either.
One thing that often gets neglected when talking about aircraft range is the fuel requirements - you need to have enough fuel to get to your destination airport, decide not to land there, go to the next best airport, and potentially sit in a hold for a while before actually landing. This is especially hard on electric aircraft since they're already energy-strapped. I'm guessing that the 62 mile figure includes destination+alternate+reserve fuel.
In a mountainous area like NZ, a car might have to take some sort of serpentine road to reach the destination while this thing would fly in a straight line, thus saving energy even if it's less efficient. However such scenarios are certainly unusual.
