Electric Osprey-esque coaxial bicopter tiltrotor with ridiculously high disc loading and unguarded props sharing ground-space with pedestrians and then flying over densely populated urban centers? At a communter-friendly price which will enable "transportation at scale"? Oh, it's exactly as close as I think it is.
To my understanding the reason helicopters are expensive is the cost of acquiring and operating the airframe.
I would imagine a scaled up drone-like airframe would be a lot more cheaper than helicopter.
That's why I don't think "drones as flying taxis" is as silly as you make it sound. Helicopters are used in urban areas. I don't see any fundamental reason why drones would not work equally well but with more traffic since they would be cheaper.
Like you point out, the unguarded props and so on mean it wouldn't be sharing ground-space with pedestrians - not at least like cars do.
Unless..
I don't know if there any way to do an emergency stop to a large scale electric prop. At least power saws stop instantly to stop cutting limbs away. Maybe there could be a similar "proximity failsafe" in the props of urban taxi-drones.
Power saws don't stop instantly. There is a massive amount of energy in those spinning disks. There are some safety mechanisms available (atypically) that use explosive charges to move the blade away and/or physically destroy it (in the case of table saws), but you cant simply stop something with that much momentum.
There are several consumable components involved that have to be replaced every time it goes off. And it's less that the saw is stopped instantly which prevents the damage, but that it's explosively retracted away from the finger and then stopped. And, as lamented by many wood workers, damp wood can set it off as well.
Of course, that's a small price to pay in some cases.
The method these use, retracting the blade, and jamming it into a block of metal to stop the momentum would not work on a aircraft.
This method (whilst pretty amazing) does not work outside of a static machine. You would need a couple of tons of metal attached to each rotor, and thats before getting into what would happen when you actually try and stop the rotor.
I am sure it could be made to work. Some kind of shroud designed to crumble in the right way, maybe start rotating itself partly. Not tons of metal. But of course, it would make the airframe a heavier and you'd pay a cost for all flights.
To be clear - I wasn't saying manned multirotors are an impossible dream. I'd love to someday build one myself. They're not practical transportation (yet!) though, for a bunch of reasons:
- Carrying capacity is very limited. The best current tech is at its limit getting one human off the ground for a few minutes, doing better will need magic batteries from the future
- Multirotors using fixed pitch rotors need to vary the rotor speed rapidly to control the thrust and torque of the rotors, and you can't do that fast with big rotors (the rotors on this thing are already too big to control efficiently like this)
- Variable pitch rotors add too much weight and complexity, if you're going variable pitch you might as well just build a helicopter (and if this thing's using variable pitch it still doesn't have enough rotors to survive a single failure unless it has well over 2:1 max lift to weight ratio so you've gone from one critical point of failure on a helicopter to 4+ just on the rotors for this thing)
- Rotorcraft efficiency (lift per kW of power) is determined by disc loading, which means you need a ton of small rotors for a useful amount of lift with non-bonkers power usage (this thing's dual coaxial rotors are way too small to be efficient)
- A rotorcraft with a ton of small rotors (https://www.volocopter.com/en/product/ say) is going to have a ton of complexity and a high failure rate, this is actually an advantage of multirotors since (with enough rotors and enough spare power) they can tolerate single failures so you won't crash but your rotorcraft is still going to need fixing regularly
Helicopters aren't as expensive as they are because the airframe is expensive (it's just fibreglass usually) or even because the powertrain is expensive (it is though). They're expensive because they're regulated to hell and back by the FAA or your local equivalent and require exhaustive certifications, maintenance etc. You could build a helicopter for $10k in your back shed but good luck getting permission to fly it at all, much less as a taxi service, MUCH less over people's houses.
(All this is just my understanding, I'm not an aeronautical engineer, just someone who loves rotorcraft. :P )
What exactly do you think the differences are between a helicopter and drone airframe? They're both unibody constructs built for lightness that are designed to accommodate cargo/passengars via some active lift system; calling it a different name doesn't make it a disruptive technology
Why would you imagine a scaled up drone-like airframe would be a lot cheaper than a conventional helicopter? Have you actually analyzed the costs and engineering trade-offs?
No, I haven't. I would love to see some actual numbers.
I imagined a quadrocopter-like air taxi would have a lower total cost of ownership than a helicopter because:
* Toy-scale electric quadrocopters are cheap as dirt and all aspects of that platform are totally commoditized.
* Electric vehicles should be cheaper to operate and maintain than corresponding combustion vehicles
* I imagine a quadrocopter system would be easier to modularize and platformize than a helicopter system given the fair simplicity and disconnectedness of various components. This should lead to better economies of scale . I don't see why the total commoditization we see in "toy" quadrocopter components would not spread to larger vehicles once they mature.
But, I don't know. I would love to hear the opinion of someone who is better informed than me.
If quadcopters would be better you would’ve seen countless designs for the military by now.
Quad Copters work well in toys and any similar application because they fly primarily based on their insanely high trust to weight ratio.
Helicopters don’t levitate on thrust.
Things simply don’t scale in this manner, the cost of the components isn’t even the issue here the cost of maintaining a system that is certified for manned flight is, buying a helicopter is cheap keeping it flight worthy is the expensive part especially when it comes to commercial application.
Literarily nearly every commercial aircraft has about as many maintanance hours as flight hours and in fact many have more.
Just to put into perspective here is what the Airforce considers an aircraft that is efficient to maintain:
>Reliability and maintainability are two outstanding benefits of the C-17 system. Current operational requirements impose demanding reliability and maintainability. These requirements include an aircraft mission completion success probability rate of 92 percent, only 20 aircraft maintenance man-hours per flying hour
While smaller aircraft don’t require as much as 20 hours per each flight hour they would still require plenty of it to make scalability very difficult.
Sure, the mechanical components don't scale up. I wasn't referring to upscaling a toy drone. But, if - and it's an if until someone actually solves all the problems - someone comes up with an electric airframe that works well enough for personal transportation - then I think it's more likely than not to have economies of scale to kick in and drive the cost down together with commoditization of personal flight.
Sure, there are lot of if's there. But mainly my guess "an electric 'quadrocopter' will be cheaper for personal transport than helicopter" is based on two things:
* it will become popular, hence driving unit costs down
* the vehicle will be cheaper to operate than a combustion engine powered helicopter
I think there are two separate issues: electric vs. combustion, and quadrocopter vs. traditional helicopter.
> But mainly my guess "an electric 'quadrocopter' will be cheaper for personal transport than helicopter" is based on two things: * it will become popular, hence driving unit costs down
Why? Is this because of the electric part or the quadrocopter part and how does either make it more likely to be popular?
> * the vehicle will be cheaper to operate than a combustion engine powered helicopter
Again are you getting this from the electric aspect or the quad aspect, and what's the reasoning?
I don't know. I'm pretty sure lots of aeronautics engineers have an actual professional answer to this. I mainly hoped with my comment that someone that had actually ran the numbers could chime in.
Taneq's answer above sounds fairly credible so I'm probably wrong about this.
I could see the business model working for short haul direct to destination flights, think Bay area -> Tahoe/Yosemite. where driving is slow and conventional airline infrastructure is ineffective. I am however quite doubtful of their ability to engineer a safe consumer-grade osprey at an appropriate cost-point.
Whatever capacity that drone will have, it will cost more than a taxi. Now you have already something with high risk and higher price. Who will use it? The avg John Doe? Nope.
It is only usefull for a handfull of people. Probably people who have enough money to use something quicker than a car on the road. Do i wanna have some rich ass idiot flying above me in a city legally?
It's a different use case than a taxi. Think 4-6hr drive times down to an hour or so by air - without the hub-to-hub / security restrictions of commercial jets.
What I distrust about a race is there is often the willingness to cut corners to be a winner. In the case of an automobile, as long as it doesn’t spontaneously explode, flip over when turning a corner at “moderate” speed, or fail to stop when you break, the corner cutting results mostly in annoyance and costly repairs. In the case of a flying vehicle, the list of potential ways to have a very bad day goes up very quickly. The main reason we don’t have it yet is because it isn’t necessary yet. It would require new dimensions of traffic laws and safety precautions.
> Uber is partnering with a variety of aerospace companies to develop a VTOL vehicle that can overcome the limitations of using helicopters for transportation at scale: noise and cost.
What about energy efficiency?
Perhaps that's covered under cost? But if not, this could be a step backward in a way.
Isn't the primary noise of a helicopter the airflow? Sure the engines make some noise which you could reduce but how do you remove airflow noise and generate enough lift?
Please correct me if I'm wrong, but it seems to me that those drones would be bigger than what most people think of as drones.
The typical consumer drone is small, lightweight, but has a range of a few hundred meters even without payload.
The drone Uber is talking about is probably the size of a large suitcase with rotors the size of bicycle wheels; the size would allow it to have a bigger battery to carry some payload and to have a bigger range. I'm not sure if I'd like to see this type of drone flying around in swarms in my city.
The article has a marketing video of their concept drone. It’s showing a drone that’s small-airplane sized, capable of transporting multiple passengers.
Uber's opinion might be distorted by the high importance of being first to autonomous drones / autonomous cars to keep their business model intect and justify their valuation.
I'm worried about emissions from the aircraft, which I am guessing will probably be gas powered. Airplane emissions are not as tightly regulated as automobiles. In fact, airplanes are allowed to use leaded fuel [1]. Now imagine a fleet of uber planes flying around constantly over your city.
Leaded avgas is going away, although slowly. No one is developing new piston engines or complete aircraft that use it. Any liquid fuels for new aircraft are going to be unleaded gasoline or (more likely) kerosene.
Sounds the same than Samsung annoncing a foldable smartphone in 2012 and doing the same every year until it inevitably becomes true. I highly doubt we are that close to air transportation but I truly wish I were wrong.
A few "drones" flying through the air with 2-4 people aboard, looking down on a traffic jam with hundreds or thousands of cars and this is going to "solve" something?
