Earlier quoted context omitted.
That might stop being true if the air is as crowded as the roads.
The air won't have pedestrians and bikes!
Para/hang-gliders, small drones, birds. There's plenty of stuff you don't want to hit :-)
SureFly – a personal helicopter designed for safe and easy flight
111–120 of 157 posts
Re: SureFly – a personal helicopter designed for safe and easy flight
#112Earlier quoted context omitted.
Actually that's a benefit of the quad-copter design. It can sacrifice an axis of control in that situation (a "minor" one, like rotation about the gravity vector). In this case it would likely make the passengers sick, but it would still be able to fly in a controllable fashion. See this video: https://www.youtube.com/watch?v=ek0FrCaogcs
with the counter-set props probably less spin even
Yes, you go from 8 df in the control to 7 df (instead of from 4 to 3). So, you could basically "hang" the weight off the remaining diagonal, and then use the working off-diagonal rotors to keep roll/yaw/pitch in line. But then the rotors on the diagonal have to generate twice the force. I'd rather not be a pax in this when two rotors fail.
Re: SureFly – a personal helicopter designed for safe and easy flight
#113Earlier quoted context omitted.
That's the whole point of these drone-like copters: instead of one engine and main rotor with mechanically complicated collective pitch, you have many fixed-pitch variable speed rotors sitting directly on an electric motor. The complexity thus wanders from hardware to control software.
Having written both (albeit only at a hobby scale), I'd argue that the control software for a collective-pitch helicopter is substantially more complex than for a quadcopter, and especially this style of over/under counter-rotating octocopter. To me this almost seems like an effort to simplify the automation and control software at the expense of safety and efficiency. I do agree that the mechanicals are much simpler…
Interesting. Now, clearly, humans can (with considerable training) fly helicopters with controls that influence the mechanics fairly directly (cyclic, collective, rudder, thrust).
Can humans fly quadcopters with controls that influence the mechanics fairly directly, or do they always require mediation via complicated control software?
Come to think of it, presumably you can (as you have 4df in the controls, and you could have rotors next to each other rotate in opposite direction, and then control the sum of all speeds (=height), sum of left vs sum of right (=lateral movement), sum of front vs sum of back (=forward movement), and sum of diagonal 1 vs sum of diagonal 2 (=rotation) independently, thus translating human inputs into your 4df. Nice!)
> simplify the automation and control software at the expense of safety and efficiency.
At any rate, I continue to think that the much simpler mechanics and motors are the main drivers. Let's see how the accident rates turn out, but I'm optimistic.
> The over/under counterrotating prop design is both inefficient
How is it inefficient? I understand that over/under counterrotating props are more efficient, inducing less air rotation.
Re: SureFly – a personal helicopter designed for safe and easy flight
#114A part of me thinks this is really cool tech and it would be amazing for anyone to be able to just hop aboard their personal helicopter and fly wherever they want, but then another part of me thinks of the future this would create, skies no longer clear, filled with objects buzzing around and what hell that would be, on top of the already stressful and crazy life we have now. It's the kind of situation where I think…
This would have to fall into the ultralight classification for someone to fly this without training. The FAA could easily classify this otherwise if they perceived any problem. Also, getting your pilots license is nothing like getting a car license, the training is much harder and requires a certain amount of hours in the car with a licensed flight instructor before they can fly on their own (I believe it's 50 hours…
Its way to heavy to fly as an ultralight under Part 103, which has a 254 lb maximum dry weight. Its probably too heavy to fly as a light sport, which has a 1,200 lb max gross weight limit, compared to the SureFly's 1,500 lb max gross weight; if you derated the max gross to make it LSA legal, then you'd only have a useful load of 100 lb, including fuel.
Re: SureFly – a personal helicopter designed for safe and easy flight
#115As both a rotorcraft and fixed wing pilot, I really don't want this to succeed. Most people have no business on the road, let alone in the sky.
That's without even getting into the safety issues with this thing that are being conveniently glossed over in the marketing material, which would lead anyone who didn't know better to think a BRS is some kind of foolproof sure thing.
Re: SureFly – a personal helicopter designed for safe and easy flight
#116> Flight ceiling: 4000ft
I’m wondering if that’s the absolute service ceiling or it’s legal operational ceiling due to its classification.
I suppose they won’t be selling them in Denver if it’s the former.
Re: SureFly – a personal helicopter designed for safe and easy flight
#117Couple of people mentioning the Robinson R22 (a 2-seater small helicopter that costs about $280k.) I didn't see any mentions of the Yo-Yo 222 though, which seems very interesting and only costs €135k. The SureFly is substantially slower and has a lower payload compared to both.
It's worth noting, though, that any small aircraft will have very similar payloads (300-400 lbs max.) This will almost certainly not get better in the near future, even with battery improvements (you'll note that all current light aircraft, including this one, are gasoline powered.) Speed is also difficult to increase for VTOL aircraft like this one.
I build custom VTOL (and sometimes horizontal) aircraft, typically electric, usually smaller than this one. If anyone else here builds VTOL aircraft/large drones, send me an email! I'd be curious to talk to other HNers doing the same thing. (And if you're just curious about the subject in general, feel free to send me an email also - it's in my profile.)
Re: SureFly – a personal helicopter designed for safe and easy flight
#118I'm very skeptical of their claims of "unparalleled safety". Thanks to "autorotation"[1] regular helicopters can safely land in most situations even with complete power failure. The claims of safety of this craft seems to derive from N+1 battery redundancy which isn't that impressive. They say they have 8 independent motors, but don't say how many are needed to stay aloft. [1] https://en.wikipedia.org/wiki/Autorotati…
Small "personal" helicopters like the Robinson R22 are quite difficult to autorotate safely in a real emergency, due to low rotor inertia. [0] For the SureFly, Hypothetically if loss of several motors caused the aircraft to be unable to maintain altitude, the aircraft would not suddenly drop like a brick, but drift down to a controlled landing. [0] http://philip.greenspun.com/flying/robinson-r22
Robinsons in general have this problem (among others, such as their tendency to disassemble their own rotor systems in flight, and their incredibly awkward t-bar cyclic controls), but I'd still rather take my chances with a Robinson autorotation than rely on a ballistic parachute system.
That said, I would never willingly fly this thing or a Robinson, so I guess I'll never have to deal with either situation.
Re: SureFly – a personal helicopter designed for safe and easy flight
#119Re: SureFly – a personal helicopter designed for safe and easy flight
#120> Flight ceiling: 4000ft I’m wondering if that’s the absolute service ceiling or it’s legal operational ceiling due to its classification. I suppose they won’t be selling them in Denver if it’s the former.
I don't recall there being anything special about 4000' from a regulatory perspective so I suspect that's the service ceiling.