Passenger drones are hovering over the horizon(economist.com)
economist.com
Passenger drones are hovering over the horizon
http://www.economist.com/news/science-and-technology/21701080-personal-robotic-aircraft-are-cheaper-and-safer-helicopterand-much-easier
17 comments
Right, this doesn't make much sense. You can add fly-by-wire and autonomy to a helicopter as well (it's been done). The two come from different backgrounds, though: people are familiar with "drones" being relatively cheap and easy to fly. So scale it up and add a person, and now it's both easy-to-fly and accessible to your average commuter.
Of course, this reasoning doesn't usually account for the cost of implementing all that safety and redundancy stuff that was previously just understood to be possible. Not to mention the cost of getting it FAA-certified when you're done.
Of course, this reasoning doesn't usually account for the cost of implementing all that safety and redundancy stuff that was previously just understood to be possible. Not to mention the cost of getting it FAA-certified when you're done.
On the other hand, having 12 rotors is already much better redundancy than a helicopter.
Maybe they're onto something.
Maybe they're onto something.
Well that's true to some extent, although it remains to be seen how the motors they're using compare in reliability to an engine and conventional rotor system. Engines and rotors are pretty reliable when operated within specs.
In any case, the controller is probably going to be the bigger reliability factor here, and having more rotors doesn't help with that.
In any case, the controller is probably going to be the bigger reliability factor here, and having more rotors doesn't help with that.
Ah, but don't forget that the rotors on a helicopter can be pitched (like wings). I'm not sure the rotors on this "drone" can do the same thing.
A helicopter can land with the engine out by using it's rotors like a wing essentially. If these rotors are fixed, then essentially it becomes a falling brick.
A helicopter can land with the engine out by using it's rotors like a wing essentially. If these rotors are fixed, then essentially it becomes a falling brick.
Ah, the dreaded 17-engine approach! :-)
On the Volocopter, the 18 rotors are fixed pitch, but yeah, a couple of engine/rotor failures are no big deal. Beyond that, ballistic rescue parachute: autorotation is not an option.
On the Volocopter, the 18 rotors are fixed pitch, but yeah, a couple of engine/rotor failures are no big deal. Beyond that, ballistic rescue parachute: autorotation is not an option.
AFAIK, helicopter's rotors cannot be used 'like a wing', that is, for gliding. They can be set to auto-rotate in the direction opposite to normal and thus slow down the descent (even a completely vertical descent) and provide some control during it.
I suspect that there can be a way to relatively passively control auto-rotation of drone-style rotors. Pitch control is much trickier. It's not unheard of (even model planes sometimes have variable-pitch propellers), but it would noticeably complicate the rotor, lowering its reliability. I suspect that a fixed-pitch rotor with an independent mechanical axis brake could be much more reliable with comparable efficiency.
I suspect that there can be a way to relatively passively control auto-rotation of drone-style rotors. Pitch control is much trickier. It's not unheard of (even model planes sometimes have variable-pitch propellers), but it would noticeably complicate the rotor, lowering its reliability. I suspect that a fixed-pitch rotor with an independent mechanical axis brake could be much more reliable with comparable efficiency.
Autorotation doesn't involve the rotor rotating in reverse. It involves changing the pitch of the blades so that an upward airflow keeps them moving while they generate some lift.
It's like a wing in the sense that it resembles the operation of an autogyro, which has an unpowered rotary wing.
It's like a wing in the sense that it resembles the operation of an autogyro, which has an unpowered rotary wing.
Anecdotally related: I was recently at Golden Gate park, and one of my co-workers was flying a tiny drone a few hundred feet over us. The noise was very annoying. I hope that if this technology does ever become mainstream, we find a way to make it quieter. The noise pollution is astounding.
The noise pitch of a blade cutting through air and its annoyance level seems to be proportional to the blade's size: Anecdotally, 40mm and 60mm server fans are annoying as fuck compared to 120/140mm size fans.
It's not like helicopters or planes are quiet either.
Moving large volumes of air in the downwards direction creates noise.
Moving large volumes of air in the downwards direction creates noise.
Helicopters and planes exist in relatively small numbers, and their movements are often modified to reduce the impact of their noise.
A nitpick: almost all fixed-wing airplane noise comes from the engines, not the downward movement of air. Listen to a glider and a light powered airplane of similar mass for a good illustration. Helicopter noise is more complex.
A nitpick: almost all fixed-wing airplane noise comes from the engines, not the downward movement of air. Listen to a glider and a light powered airplane of similar mass for a good illustration. Helicopter noise is more complex.
It wasn't until I moved into a house under the final approach (for the least commonly used runway) that I realised this is untrue.
On a calm night with no wind, the wake turbulence makes a significant amount of nose that lasts for several min after the plane passes. Normally wind noise drowns it out, but due to the longer duration the total amount of noise is equal-to or greater than the engine noise.
On a calm night with no wind, the wake turbulence makes a significant amount of nose that lasts for several min after the plane passes. Normally wind noise drowns it out, but due to the longer duration the total amount of noise is equal-to or greater than the engine noise.
It's also not like helicopters or planes typically hover over a park.
I've heard that the high pitch noise multi-rotors make is primarily from the motor ESCs, so those could potentially be made more quiet.
The Ehang 184 [1][2][3] looks like it's going to be the first usable flying car. It's all-electric, with four sets of two contra-rotating props. This provides redundancy if a motor fails. They showed a prototype as a static display at CES last January. This is from the people who make the Ghost drone. They're in Guangzhou.
The range will probably be short, but I expect that executives in Beijing will be using these to get around the traffic jams in a few years.
[1] https://www.youtube.com/watch?v=bs4nDFgVx2o [2] http://www.ehang.com/ehang184 [3] https://techcrunch.com/2016/01/06/the-ehang-184-is-a-human-s...
The range will probably be short, but I expect that executives in Beijing will be using these to get around the traffic jams in a few years.
[1] https://www.youtube.com/watch?v=bs4nDFgVx2o [2] http://www.ehang.com/ehang184 [3] https://techcrunch.com/2016/01/06/the-ehang-184-is-a-human-s...
Are you sure? Where are they in the production, flight testing, certification process? Have they even built a prototype (not a life-size plastic model to display at an airshow, but an actual prototype?)
The Volocopter VC200 [1] has had unmanned and manned flight tests [2], and they're actually working on the (laborious) certification process.
[1] http://volocopter.com/index.php/en/ [2] https://www.youtube.com/watch?v=OazFiIhwAEs
The Volocopter VC200 [1] has had unmanned and manned flight tests [2], and they're actually working on the (laborious) certification process.
[1] http://volocopter.com/index.php/en/ [2] https://www.youtube.com/watch?v=OazFiIhwAEs
BTW, irrespective of whether Ehang or Volocopter is first: range/endurance for the purely electric ones is going to be a sore point until batteries improve significantly, but yes, I could also imagine the rich zipping around (and to/from the airport) in these in metropolises such as Beijing, Shanghai, Jakarta, Sao Paolo, etc.
Can't wait for better batteries (or nice and light hybrid technology)!
Can't wait for better batteries (or nice and light hybrid technology)!
Except it can't drive?
I love this tech! If the FAA allowed for cheap urban short haul using these, it would be amazing. Its external operations (the need for helipads, maintenance etc.) would basically be like a helicopter though.
I'm very skeptical of their claims of better safety that regular helicopters. Thanks to "autorotation" a helicopter can safely land in most situations even with complete power failure. The claims of safety of this craft seems to derive from single rotor failure resilience and ease of use, which doesn't impress me much.
The volocopter can still fly and land safely when one or more engines or rotors fail (up to 6 out of the 18, provided they're not all adjacent, if I'm not mistaken).
In case of a complete power failure, a light-weight ballistic rescue parachute will let the whole thing glide to earth. There might be some altitude where the parachute doesn't have enough time to deploy, but that's really the same problem as with a helicopter (where autorotation is only possible from certain altitude/airspeed combinations) - so you have to avoid staying in that critical region.
I think it is premature to make pronouncements on the safety - piston engines don't really have a great safety record. Turbines are amazingly reliable of course, but the entire helicopter ensemble still fails occasionally.
Electric motors and batteries (plus maybe petrol powered generators, or fuel cells) are just an entirely different technology stack, whose reliability remains to be seen. I'm optimistic, though.
In case of a complete power failure, a light-weight ballistic rescue parachute will let the whole thing glide to earth. There might be some altitude where the parachute doesn't have enough time to deploy, but that's really the same problem as with a helicopter (where autorotation is only possible from certain altitude/airspeed combinations) - so you have to avoid staying in that critical region.
I think it is premature to make pronouncements on the safety - piston engines don't really have a great safety record. Turbines are amazingly reliable of course, but the entire helicopter ensemble still fails occasionally.
Electric motors and batteries (plus maybe petrol powered generators, or fuel cells) are just an entirely different technology stack, whose reliability remains to be seen. I'm optimistic, though.
It seems to me that it depends on how it's wired up internally, where we can't see it.
If all the drone controls are wired to one battery controlled by one computer, yeah, there's a lot of single-points-of-failure there, and the result is scarier than a helicopter to me.
On the other hand, if it was basically a whole bunch of independent drones with pretty much their own electronics (I'll permit for convenience a single charging bus), and communicating with active-acknowledgement protocols such that each drone assumes the others are failed unless there is active assurance they are on and working, the whole ensemble can come out much safer than a helicopter. In theory you could get to the point where it doesn't just have no single point of failure, but even no dual- or treble-points of failure either.
Depends on the details.
If all the drone controls are wired to one battery controlled by one computer, yeah, there's a lot of single-points-of-failure there, and the result is scarier than a helicopter to me.
On the other hand, if it was basically a whole bunch of independent drones with pretty much their own electronics (I'll permit for convenience a single charging bus), and communicating with active-acknowledgement protocols such that each drone assumes the others are failed unless there is active assurance they are on and working, the whole ensemble can come out much safer than a helicopter. In theory you could get to the point where it doesn't just have no single point of failure, but even no dual- or treble-points of failure either.
Depends on the details.
I'm pretty sure they've thought of avoiding single points of failures. It's my understanding that there are multiple busses, and I assume that failure of a single battery only shortens the range, not leading to a catastrophic failure.
The 18-rotor Volocopter can have several rotors fail with no problem before the ballistic rescue parachute becomes necessary.
The 18-rotor Volocopter can have several rotors fail with no problem before the ballistic rescue parachute becomes necessary.
It probably falls into the realm of safer than a piston powered R-22, but less safe that a multi engine turbine powered helicopter.
As someone who has been into ultralight aircraft in the past, I think this is actually pretty cool.
Ultralight flying has weight and speed requirements (as well as fuel) and no pilot's license necessary [1]. I believe that if one of these type of aircraft could get into the ultralight category, it would be a positive. I'd bet there would be fewer crashes/deaths in these drone type of aircraft than a conventional ultralight (which resemble anything from a hanglider or parachute with a propeller attached to an actual airplane).
[1] https://www.eaa.org/en/eaa/aviation-communities-and-interest...
Ultralight flying has weight and speed requirements (as well as fuel) and no pilot's license necessary [1]. I believe that if one of these type of aircraft could get into the ultralight category, it would be a positive. I'd bet there would be fewer crashes/deaths in these drone type of aircraft than a conventional ultralight (which resemble anything from a hanglider or parachute with a propeller attached to an actual airplane).
[1] https://www.eaa.org/en/eaa/aviation-communities-and-interest...
To quote Marc Andreessen: They promised us flying cars and they gave us... flying cars.
So fast forward 10+ years, what does this look like?
Can I get a drone Uber to pick me up? Where exactly? Are there helipads everywhere there use to be a bus stop?
For private owners, do they build a landing area in their backyard or rooftop? Or do you drive out to the airport?
Does the paramedic-flying-themselves-to-the-accident know where to land the drone with 18 chopping blades (for stability and redundancy)?
Can I get a drone Uber to pick me up? Where exactly? Are there helipads everywhere there use to be a bus stop?
For private owners, do they build a landing area in their backyard or rooftop? Or do you drive out to the airport?
Does the paramedic-flying-themselves-to-the-accident know where to land the drone with 18 chopping blades (for stability and redundancy)?
NASA had a workshop on that topic in 2015, the "TRANSFORMATIVE VERTICAL FLIGHT WORKSHOP" [1].
They were specifically asking: "Why is the Silicon Valley a great Early Adopter Market for civil VTOL?" [2] (Spoiler alert: getting from A to B on the road takes too long due to traffic...)
And yes, that study imagines 200 helipads scattered throughout the Bay Area.
[1] http://nari.arc.nasa.gov/tvf [2] http://nari.arc.nasa.gov/sites/default/files/attachments/Ant...
They were specifically asking: "Why is the Silicon Valley a great Early Adopter Market for civil VTOL?" [2] (Spoiler alert: getting from A to B on the road takes too long due to traffic...)
And yes, that study imagines 200 helipads scattered throughout the Bay Area.
[1] http://nari.arc.nasa.gov/tvf [2] http://nari.arc.nasa.gov/sites/default/files/attachments/Ant...
Why bother with helipads ? Silicon valley has plenty of parkings and it is actually perfectly legal to land on them (assuming of course your plane is capable of that, which most aren't).
This is assuming you have permission from the owner, of course, but that seems likely not to be a problem.
This is assuming you have permission from the owner, of course, but that seems likely not to be a problem.
Flying cars can generate flying car crashes which seem inherently dangerous. A drone is nothing more than a flying car without a driver. If it breaks down and kills the passenger (and anyone unlucky beneath) who is responsible?
Car traffic has to flow through a 1D cross-section (N lanes) one after another.
Air traffic can flow through a 2D cross-section. Which also means that vehicles don't have don't to line up like a pearl necklace. That should reduce collision probabilities if vehicles talk to each other and are able to reserve sufficiently large safety buffers around each other.
Air traffic can flow through a 2D cross-section. Which also means that vehicles don't have don't to line up like a pearl necklace. That should reduce collision probabilities if vehicles talk to each other and are able to reserve sufficiently large safety buffers around each other.
That's all I can think about when I watch SF movies with flying cars (e.g. Fifth Element, Star Wars, Natl Lampoon's Vacation).
Where do you park?
What happens if the battery dies?
Why is there so much cartoon physics?
Where do you park?
What happens if the battery dies?
Why is there so much cartoon physics?
1) You park in a garage or a parking lot, as you would a normal car of comparable size.
2) There's no "the battery", there are several cells, each capable of giving you enough juice for a landing if all others die. OTOH catastrophic failures are of course possible, as with cars. A parachute pushed out by a small charge can help if the altitude allows.
3) Because cartoon physics look good (and funny) on screen. I suppose the rest of Fifth Element does not look boringly realistic to you either.
2) There's no "the battery", there are several cells, each capable of giving you enough juice for a landing if all others die. OTOH catastrophic failures are of course possible, as with cars. A parachute pushed out by a small charge can help if the altitude allows.
3) Because cartoon physics look good (and funny) on screen. I suppose the rest of Fifth Element does not look boringly realistic to you either.
The Fifth Elements dudes in the rubber masks was not a high point.
But I was thinking more about Jedi jumping out of cars and not going splat on someone's windshield.
But I was thinking more about Jedi jumping out of cars and not going splat on someone's windshield.
Something about dying in a crashed aircraft that was piloted by someone in a comfy seat 2000 miles away bothers me.
Especially when that someone was an evil hacker because you didn't have enough bitcoins to get the controls unencrypted.
That should be a writing prompt!
IBIWISI @ Paris or Oshkosh airshow. I mean, not in person because I don't get to visit such places with my budget and schedule, but I'll watch the coverage closely. Until then, yay, another article about how promising technology is these days!
The Volocopter VC200 was displayed at the AERO Friedrichshafen 2016, just after its maiden (manned) flight:
https://www.youtube.com/watch?v=xC9YWvKX0lY
Maiden flight is nice but like I said I'd like to see something proven to the point of being flown at a major international airshow - not just put on display with a video.
Yeah, you've got a point there... And even that might not be enough: Remember the Icon A5 [1] (cool amphibian light sport plane) or the Terrafugia Transition [2] (flying car)?
They've flown, been presented at Oshkosh, even partially certified - but will they ever really (wait for it...) take off?
(BTW, though, the AERO is probably _the_ major European general aviation show.)
[1] https://en.wikipedia.org/wiki/ICON_A5 [2] http://www.terrafugia.com/aircraft/transition
(BTW, though, the AERO is probably _the_ major European general aviation show.)
[1] https://en.wikipedia.org/wiki/ICON_A5 [2] http://www.terrafugia.com/aircraft/transition
How would this be able to land in the event of complete electrical failure? A helicopter is able to glide by twisting the rotor blades but this would just fall like a brick. I would be really scared to be in that.
>How would this be able to land in the event of complete electrical failure?
this is why you'd have 2 independent set of rotors/motors and batteries (or other source of power). Each set alone at maximum power should allow for controlled descent. It may happen that in this "emergency" mode it can work only for limited time and become non-serviceable afterward, like the battery discharges beyond repair, etc...
Helicopters obviously don't have such an option so the engine cutting off puts you on a brink of catastrophe and requires highly trained pilot to avoid it. Electrically driven multi-rotors are completely different in that regard. With just a DMV driver license your grandma would be able to land one with half rotors off.
this is why you'd have 2 independent set of rotors/motors and batteries (or other source of power). Each set alone at maximum power should allow for controlled descent. It may happen that in this "emergency" mode it can work only for limited time and become non-serviceable afterward, like the battery discharges beyond repair, etc...
Helicopters obviously don't have such an option so the engine cutting off puts you on a brink of catastrophe and requires highly trained pilot to avoid it. Electrically driven multi-rotors are completely different in that regard. With just a DMV driver license your grandma would be able to land one with half rotors off.
There are so many planes that cannot land in the event of complete electrical failure ... starting with every last modern passenger airliner. There the problem is that human strength is not enough to control flaps and hydraulics are too heavy (translation: possible but too expensive), but if the electrical infrastructure completely fails ... it's over. Plane will lose control, rapidly spin out of control and dive chaotically into the scenery.
It hasn't happened yet.
It hasn't happened yet.
The Volocopter has a ballistic rescue parachute. A failure of a few of the 18 rotors/engines is not a problem and can be compensated; complete electrical failure (or failure of more than a few) would require deployment of the parachute.
On the other hand, mechanically a multicopter is much simpler than your average heli (rigid rotors, i.e. no collective/cyclic/swashplate/articulation, no anti-torque, no gearbox, etc.) - so I'm wondering what the relative safety turns out to be.
On the other hand, mechanically a multicopter is much simpler than your average heli (rigid rotors, i.e. no collective/cyclic/swashplate/articulation, no anti-torque, no gearbox, etc.) - so I'm wondering what the relative safety turns out to be.
Parachute?
Doesn't a parachute need some free fall before being completely deployed? Plus there would be no way of gliding somewhere safe to land.
A small rocket can be used to deploy the parachute from low altitude. This is already in use on some light aircraft today.
https://en.wikipedia.org/wiki/Ballistic_Recovery_Systems#Com...
Powerless plane makes parachute landing: https://www.youtube.com/watch?v=kQyrPVIIQdE
This is a vehicle that allegedly requires no training to operate and might even be autonomous; parachuting requires a shit-load of training.
The ballistic rescue parachute is attached to the top of the drone. It's basically just a big red button that you have to press to deploy (and even that could maybe be automated).
[deleted]
I don't think this is going to be mainstream very soon because these multi rotors can only fly for a few minutes.
Right now batteries are way too heavy. And combustion engines can't alter speed that quick.
Right now batteries are way too heavy. And combustion engines can't alter speed that quick.
Yes, batteries don't have the energy density of petrol yet, but they're improving. Also, hybrids are an option, with a combustion engine (running at optimal speed throughout) driving a generator recharging a battery - best of both worlds, potentially.
What of fuel cell vehicles or series hybrids? You'd still have electric motors, but with a more potent power source.
This is really the only way that "flying cars" could have ever worked, unless people were truly willing to embrace a future of mid-air collisions and raining debris.
The people I encounter on my commute will find a way to mess this up.
"Whenever you make something idiot proof, God invents a better idiot."
I really wish that I didn't know what you meant, but since I almost died today when someone turned left across THREE lanes illegally... yeah you're right.
Thinking a bit bigger — when do we stop involving pilots in commercial aircraft flight? Much like trucking, flight is something computers can do very well.
Currently, pilots have the primary function of monitoring the automation, and exercising critical thinking when things go wrong. This can be everything from flight computers misbehaving, dealing with weather, avoiding turbulence, troubleshooting an engine fault indicator. Their secondary function of flying the plane is more or less because they have to be there anyway, and for almost all larger aircraft the autopilot takes care of everything except for maybe the first few minutes and the last ~1 to 10 minutes of the flight (although this varies based on airline, aircraft type, and individual pilot preference).
Autoland does exist (google cat. 3 ILS), but it hasn't really been refined to perfection because the pilots aren't going anywhere as of yet and they are quite excellent at performing the last 200 ft of the landing sequence (once the runway is in sight in low vis conditions).
Your average airline flight, in daylight and good weather, can really be quite a simple exercise. The outliers, with equipment out of service, bad weather, icing, or really serious things like an engine failure, are extremely cognitively demanding in a very "human" way and certainly outside the capabilities of perhaps anything short of an artificial general intelligence. I think the future of computing in the cockpit for the foreseeable future involves collaborating with humans to help them navigate these challenging situations and focus on higher level problem solving, rather than replacing them.
Also, not implementing autolanding means pilots constantly practice landing airplanes. This is surely invaluable in the case of an emergency landing.
The fact that we can't reliably land planes automatically even though we can use beacons and we have fixed targets with tons of observable data is one of my main sources of skepticism about driverless cars.
I have nothing to base this on, I always thought we could do that. The airlines just don't, because (most) passengers won't get on a plane if they don't get to hear that Air Force baritone come over the intercom and say "This is your captain speaking...". I didn't think it was a matter of tech but of psychology.
Flight is something computers can simulate very well, but are unable to adapt and make intelligent decisions in real-world situations on par with pilots. Airbus A320 Pitot Tube freezes that caused fatal and non-fatal issues is a good example.
I couldn't find any info on flight times. I'm guessing anything up to 15 minutes?
It's in TFA, 20 - 30 minutes, although they mention one with a hybrid engine that can use gasoline, presumably to recharge the battery.
would make a cool battlefield ambulance if it could fly itself, just needs a bit more endurance.
Curious, at what speed the rotors must go so that if you kill all power it doesn't plummet. How high would that fail altitude actually be
Curious, at what speed the rotors must go so that if you kill all power it doesn't plummet. How high would that fail altitude actually be
[deleted]
I'm going to let the term "Passenger drone" slide, but I will feel a hint of aggravation when CNN reports on "Manned UAVs"
> but I will feel a hint of aggravation when CNN reports on "Manned UAVs"
Well, yeah, "manned UAVs" would just be wrong -- drone passengers are passengers, not crew, and "manned" refers to having a human crew.
(Though I suppose a long-endurance drone with human maintenance crew might be properly considered "manned" despite being unpiloted. But, then, an Unpiloted Aerial Vehicle could have the same natural initialism as an Unmanned Aerial Vehicle...)
Well, yeah, "manned UAVs" would just be wrong -- drone passengers are passengers, not crew, and "manned" refers to having a human crew.
(Though I suppose a long-endurance drone with human maintenance crew might be properly considered "manned" despite being unpiloted. But, then, an Unpiloted Aerial Vehicle could have the same natural initialism as an Unmanned Aerial Vehicle...)
Also, the "U" stands for Unmanned. "Manned UAVs" is like the opposite of RAS Syndrome
https://en.wikipedia.org/wiki/RAS_syndrome
https://en.wikipedia.org/wiki/RAS_syndrome
What's the aversions? A drone is a plane that is remote controlled or flies itself... a passenger drone or a manned uav would be a remote/self controlled airplane that has cargo: people.
Not that people won't butcher the terminology (ATM Machine), but even at the worse, these shouldn't be to bad...
Not that people won't butcher the terminology (ATM Machine), but even at the worse, these shouldn't be to bad...
(U)nmanned (A)erial (V)ehicle = UAV. A manned UAV would be a bit of an oxymoron.
Passengers != manned. They aren't operating the vehicle, they're cargo.
even if that is the definition of manned it still doesn't make sense. because the "U" in UAV stands for Unmanned not Unpiloted. However "Manned space flight" would still apply even if the astronaut was just ballast right?
A trip to mars would be completely automated but you still wouldn't call it unmanned if a scientist was on board that did nothing but scientist stuff.
A trip to mars would be completely automated but you still wouldn't call it unmanned if a scientist was on board that did nothing but scientist stuff.
Which is exactly why 'manned UAV' makes no sense.
Yes but UAVs are built to an overall lower standard of reliability and safety precisely because there are no people on board.
[deleted]
UAV = Unmanned Aerial Vehicle
"Manned Unmanned Aerial Vehicle" = nonsense
"Manned Unmanned Aerial Vehicle" = nonsense
How about autonomous multi-rotor? There's no assumption regarding the payload then.
I mean I love my little racing quad just as much as anyone, but it's not like the three (or 5.. i also have a hexa) extra props/motors increase the dependability of the device. Lose one of those and it's a shitshow headed into the ground.