Scale matters. Compare a small animal falling and a large animal falling (i.e. compare what happens when they hit the ground). A "drone" large enough to carry a human or two will be much more heavily damaged by an impact that appears to be similar to one that leaves a much smaller drone intact.

A parachute system only helps if you are high enough. Looks like the flying thingys we are talking about here will be close to obstacles a lot and not very high up much of the time given how they are to be used.

Battery redundancy: The scale argument again. This is an order of magnitude harder to achieve on a much larger man-carrying "drone".

> Battery redundancy: The scale argument again. This is an order of magnitude harder to achieve on a much larger man-carrying "drone".

Isn't it much easier because you have capacity (weight carrying ability) for many more cells, and the chances too many of them fail is much lower? If you have 3 cells, 1 of them can fail at any given time, and you're left with 66% of power, but if you have 200 cells, and 1 or 2 of them fail, you don't even notice. How do you mean that it's harder? Electric cars certainly don't seem to have any problems with this and their batteries are much more reliable than the ones available for drone usage.

Also with big size/capacity you can easily include additional systems like temperature control which increase reliability because they don't weigh as much in relationship to the whole vechicle.

> Isn't it much easier because you have place for many more cells

Don't think space (not the biggest issue here as you say), think weight, power and the ratio.

Yes, of course. I was using "space" as a more general term, as in "capacity". Should have been more clear.

Human-scale drones would have much more powerful batteries and room for redundancy. More powerful motors and blades.

If a helicopter is doing it with a single main rotor, I'd be surprised if it can't work with a hexacopter and redundancy.

I'd be more worried about noise. A consumer drone is noisy enough, though mostly just noticeable because it's a new thing people are yet to get used to.

If you drop a mouse down a mineshaft it will likely have a bit of a jolt on impact, then scurry away looking for some bit of cheese. If you drop a horse down a mineshaft there will be horsebits splattered on a very large area around the point of impact. Noise problems are inherent to fast spinning rotors, gravity is where the real problems are, and redundancy in drones is more along the lines of controlled crashes than emergency landings. I'd be very much worried about the performance of the system if one or more rotors failed to do their job.

Helicopters auto-rotation is not at all comparable to a drone with one or more failed rotors, a helicopter that is autorotating is comparable to a gyrocopter, it will fly relatively well, a drone with one or more failed rotors will not fly well or even at all.

Maybe they could put an airbag at the underside of the vehicle for when it flies a few meters above the ground

From what I have read and seen a drone with only 4 props has almost no chance of recovery if one prop fails. This is also why drones for high end expensive video have six or eight props to prevent a catastrophic failure resulting in loss of equipment.

There are algorithmic solutions to maintaining some semblance of flight with a damaged quad copter, even down to one remaining prop, however it involves spinning the entire air-frame to stay aloft -- which means it is probably not suitable for a human passenger drone

https://newatlas.com/quadcopter-failure-algorithm/30031/