Johnny Cab for the Skies!
Glad I'm away from big cities where this kind of madness is commonplace...
Two electric air taxi makers have demoed their craft in New York City as part of Mayor Eric Adams' plans to create the world's first heliport with infrastructure necessary to support the vehicles - eventually. Joby Aviation and Volocopter both flew short test flights at NYC's Downtown Manhattan Heliport (DMH) at the weekend, …
Don't be silly. These are just ordinary, piloted helicopters hoping to serve an established heliport. In the usual way, the FAA will not allow that to start until they are satisfied the things won't fall out of the sky. The only novelty is that fossil fuels have been replaced with batteries. And a good thing too.
They aren't quite helicopters. Their controls are very different. and they are completely dependent on a computer interpreting a humans inputs to make the necessary changes to engines and control surfaces. That is quite different from most helicopters which are still usually driven by mechanical linkages between the controls and egine/rotors/surfaces.
Having had a "taster" helicopter piloting session, I'd say that the average person (like myself) will take many hours of training to fly a helicopter safely, and that's ignoring all the business of how to file flight plans, make sure your aircraft is maintained properly, read NOTAMS etc. These piloted drones might be easier to fly, but the same flight rules apply to them. (minimum altitudes, where you can fly and where you can't etc.) The minimum standard of coordinating what two feet and two hands are doing might be lowered for one of these vehicles, but that doesn't mean you don't need to have a pilot mentality of following the rules.
More gullible idiocy there, I'm afraid. Of course they are "quite" helicopters; modern chopper control systems have not been standing still while the e-copter brigade have been doing their thing.
These "quite" piloted e-copters have the latest in flight automation, just like any other helicopter coming to market today. Oh, wow, who'd 'a thunk it! For more bullshit-popping, see for example
https://aviation.stackexchange.com/questions/92264/are-helicopters-easier-to-fly-nowadays-due-to-computers
These are not "helicopters" They are "powered lift aircraft"
Differences between the two are helicopters move themselves about by adjusting blade pitch on their main rotor, and stop themselves spinning (anti-torque), and manage yaw with the tail rotor. These quad things do all the above by adjusting the speed individually on their four rotors (basically speaking).
Why does this matter? Helicopters have been around for a while now and are established with numerous types being certificated, and pilots being trained and gaining experience on them. These new things, being new, not so much.
In the event of an engine failure, can these things possibly auto-rotate to a safe landing, as conventional helicopters can*? If one of its four motors fails, can the remaining motors keep it aloft? If one of its four motors fails, can it be effectively steered? The control computer is a single point of failure, as are the transmission and mechanical steering mechanism in a conventional helicopter. Mechanics can and do inspect helicopter transmissions and steering mechanisms for wear and tear, at regular intervals, replacing parts as necessary/prudent.
Can mechanics (or equivalent professionals) effectively examine the computer controlling these new machines for wear and tear (incipient component failure due to age and heat, etc.), and the code within those computers, understand that code, and detect flaws within it? If not, then you're taking a hell of a chance if you fly in one of these electric helicopters. (/me prepares for a downvote storm by the fanatically neophilic.)
*Depending on conditions and pilot abilities.
Drones with 4 propellers fall out of the sky when one fails. There are vids on VT, where some universities program the flite controller to then use the remaining three motors , but they basically put the machine into a nasty spin as it recovers and eventually lets itsself down. I dont think a human could survive the crazy spin that would prevent the crash even if it slowly landed.
Manned EVTOLs tend not to rely on only 4 propulsors (where, as you correctly state, the loss of one propulsor results in the immediate need for a ballistic parachute system or similar)
Even where it looks like there is only one propulsor, there tend to be 2 individual motors mounted back to back operating 2 individual propellers.
And still it will be hard to avoid a Design Assurance Level A (DAL A) requirement for EVTOL propulsors. Helicopters can autorotate once they are out of the coffin corner. EVTOLs without wings operate continuously inside their own coffin corner. This is why both Volocopter and Joby work with a multitude of propulsors. At some point, Redundancy takes over.
Just to correct one point - in any modern (read 90's or later designed) A/C including helicopters, there is never only a single control computer. It is always 3, operating in a voting system (i.e. if 2 computers give the same value, and a 3rd disagrees, the 3rd is ignored. I believe there's usually something to flag up to the cockpit that one of the computer's is not operating correctly at that point, but it's been a while since I worked on that stuff).
In the cases of the Air France crash over the Atlantic that was caused by some Pressure Sensors being damaged and freezing and feeding the wrong data to the computers, and in the case of the 787 MAX crashes, that was an additional side box that Boeing managed to smuggle in that was a single point of failure, and that was a massive failure by the FAA, and should never have been allowed (there's a whole raft of failures in the certification of the 787 MAX which should never have been allowed!).
Whilst I've not worked on Drone style Helicopters specifically, I would guarantee that the FAA/EASA requirements would require that a single lost rotor would not prevent the Helicopter from making a controlled landing without injury to the occupants. You would never get permission to fly if a single rotor going down guarantees a crash. No chance.
"(i.e. if 2 computers give the same value, and a 3rd disagrees, the 3rd is ignored. I believe there's usually something to flag up to the cockpit that one of the computer's is not operating correctly at that point, but it's been a while since I worked on that stuff)."
Pilot - Wheres my Minority Report?
CRUMP!
Hahah doesnt work like that with drones...
when one motor fails you dont get seconds too see theres a problem.. because by then you are already spinning oout of controll, the unbalanced forces of that lost motor will see to that.
We saw the same thing with starship when it lost control.
lg: Just to correct one point - in any modern (read 90's or later designed) A/C including helicopters, there is never only a single control computer. It is always 3, operating in a voting system (i.e. if 2 computers give the same value, and a 3rd disagrees, the 3rd is ignored. I believe there's usually something to flag up to the cockpit that one of the computer's is not operating correctly at that point, but it's been a while since I worked on that stuff).
cow: And yet your next paragraph shows your statement to be false.
lg: I would guarantee that the FAA/EASA requirements would require that a single lost rotor would not prevent the Helicopter from making a controlled landing without injury to the occupants. You would never get permission to fly if a single rotor going down guarantees a crash. No chance.
cow: A heli only has a single rotor, and ONE rotor makes for auto rotation, but you cant do that with multiple motors, feel free to point to a commercial (non human flite) drone thaat supports your claim
"In the event of an engine failure, can these things possibly auto-rotate to a safe landing, as conventional helicopters can*?"
NO
"If one of its four motors fails, can the remaining motors keep it aloft?"
YES
Although if you are on the ground take off probably isn't gonna happen
"If one of its four motors fails, can it be effectively steered?"
YES - you have lost lift capacity, but not flight control
"The control computer is a single point of failure"
THIS SHOULD BE FALSE
Normally this sort of system would have multiple flight controllers and rely on a majority vote for changes of command and control. A single failed controller is easily detected and ignored.
The big issue is even with different hardware platforms, different software tools, and independent development teams, the squishy meatbags implementing the system are still liable to make similar mistakes.
"as are the transmission and mechanical steering mechanism in a conventional helicopter. "
Again NOT TRUE with reasonable fly by wire, and even push/pull rods
"Mechanics can and do inspect helicopter transmissions and steering mechanisms for wear and tear, at regular intervals, replacing parts as necessary/prudent."
THIS IS TRUE FOR THE MECHANICAL PARTS OF ANYTHING, AND SHOULD BE THE CASE FOR ELECTRIC PILOTED DRONES
Can mechanics (or equivalent professionals) effectively examine the computer controlling these new machines for wear and tear (incipient component failure due to age and heat, etc.),
SERVICE INTERVAL CAN AND DOES CALL FOR REPLACEMENT ELECTRONICS AFTER <some> FLIGHT HOURS. THIS IS NORMAL FOR ALL AVIONICS
ALSO TRUE FOR STRUCTURAL ELEMENTS
and the code within those computers, understand that code, and detect flaws within it?
I DOUBT IF ANY SERVICE MECHANIC EVER SEES CODE. IT IS A CLOSED BOX.
THIS IS ALSO THE CASE FOR ALL EXISTING AVIONICS
If not, then you're taking a hell of a chance if you fly in one of these electric helicopters.
YOU DON'T NEED TO GET IN ONE
But for your sake don't get in any aircraft designed after the 1980's because they all contain digital avionics. Trains and Cars don't look good for you either
"(/me prepares for a downvote storm by the fanatically neophilic.)"
NO DOWN VOTE
Just an attempt to explain why you are incorrect in this case
:-)
/Rattus
@Rattus: Clarifications -
"If one of its four motors fails, can it be effectively steered?" - I'm looking at the thrust imbalance in the three-working-rotors situation: the (say) left side will be having half as much lift as the right side, or, if the rotors are in a diamond arrangement, the (say) rear will be having half as much lift as the front. If the answer is, "the computer will stop an additional rotor to eliminate the lift imbalance", the new question becomes, "Can it effectively fly with only TWO motors functioning?"
"the computer is a single point of failure" You're right about multiple computer systems and voting, but such brings up a further question: does a computer or digital circuit tally and report the results of the computers' votes? Wouldn't this be also be a single-point-of-failure? Who watches the watchers? (It's 'watchers' all the way down.)
The big issue is even with different hardware platforms, different software tools, and independent teams, the squishy meatbags implementing the system are still liable to make similar mistakes.
You're right, but that's an incomplete accounting. There are multiple areas of errors in flight-control systems. One is in system design, where the rules-and-desired-reactions (system specifications) are established. One is in the selection and integration of mechanical, electric, and electronic components. One is in software implementation. The error-type I most am concerned about is the one which rarely-if-ever detected in advance of a system failure: the failure of imagination of the system designers. This shows up post-incident as, essentially, "Oh. I/We never thought of that possibility ..."
I DOUBT IF ANY SERVICE MECHANIC EVER SEES CODE. IT IS A CLOSED BOX.
You are absolutely right! And that, my friend, is what I believe to be a terrible problem.
I can envision myself flying an electric helicopter with a mechanical control mechanism: the cyclic control hooked up to four big-ass rheostats controlling power to each of the four motors. Oh, yeah, it'll be inefficient as -- and hot as -- hell, but easily understandable, easily inspectable, and easily repairable. Have a look sometime at the ACM's The Risks Digest, https://catless.ncl.ac.uk/Risks/
Your point is taken about modern planes, trains, and automobiles; I've been increasingly bothered by all that. I'm not getting into a fly/drive-by-wire vehicle or aircraft, or a "self-driving" anything.
Corporations are creating and deploying all sorts of technologies heedless of the potential flaws, or of how those technologies might be used by the evil (or the evil masquerading as good). Yet society in general ignores the potential issues. It's like we're driving down a dark country road at 100 MPH with our headlights showing only 50 feet of road ahead of us, giving us insufficient time to stop or swerve should danger appear.
Thanks for your post, Rattus, and have an upvote.