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They're going to be constantly landing and taking off to deliver the package, right near you.
For delivery, would using a (possibly guided) parachute be an option sometimes? For example if there is a landing target left in someone's yard.
First thing they should do is to cover propellers so that they don't hurt anyone.
Does anyone know why this isn't standard?
I Googled this question: "why don't quadcopters have safety cages" https://www.google.com/search?q=why+don't+quadcopters+have+s... ...
... and even saw cages that go around the whole quadcopter (not just the propellers as I was expecting). If those were a bit squishy they could seriously reduce any chance of concussion/property damage if landing on someone or something!
The YouTube video below is pretty amazing, it shows someone demonstrating such a cage.
"Spherical Cage Incased Quadcopter" - https://www.youtube.com/watch?v=5B3X6EvZ2XM
I've submitted it as a separate submission. (It's only 2 minutes.) He says it flies great, and he even seems to purposefully drop it several times from as high as the height of a building.
Also for anyone who hasn't been around drones much, in the middle of the video you can hear the annoying whirring noise people mention throughout this thread.
I thought iancmceachern asked a really good question. I was curious if it could work even theoretically.
I read the Wikipedia article on Active Noise Control. The third paragraph under Explanation: https://en.wikipedia.org/wiki/Active_noise_control#Explanati... mentions that if it's at the source, it needs to be just as loud as the source (as opposed to being by the ear, in which case even a whisper might be enough).
In addition to being as loud as the source, you need to blast it in all directions. So I guess it's hard/impossible to perfectly hit the same sound waves in all directions. If you ever miss, you'll just be doubling the noise.
Maybe that's why you'll be hard-pressed to find anything in a fixed installation that uses active noise cancellation at the source - even if it's heavy, periodic, and uses a lot of power anyway - such as a home air conditioner. Noise cancellation close to the ear seems much easier for this reason, and maybe at the source it's just impossible.