You know... that sounds doable.

Quadcopter are very fast and can go very far before they lose power. And a single sandwich is not a very heavy load.

If you are outdoors and can give it your GPS coordinates, a single restaurant/quadcopter port, could serve a very large area.

Yep. You would need a) an iPhone app that you would use to place your order (it would send updated coordinates as you move around, and provide a perimeter within which you would have to stay) b) an army of quadcopters so that a subset of them could be charging while the others were making deliveries c) the quadcopters would have to be equipped with parachutes in case they malfunctioned so they wouldn't kill someone on the way down. d) The quadcopters would have to keep a persistent connection with the central server through wireless networks to keep in sync with your latest position and to send back their coordinates for you to see on your phone. e) there would have to be a mechanism in place to prevent mid-air collisions (buildings you could pre-encode, birds and other quadcopters you couldn`t) for bonus points, you generalize the whole thing and make it like an airbnb where people can exchange arbitrary goods and you just broker the deal and execute the deliveries for a fee that would be dynamically calculated based on distance and weight. DO IT. DO IT NOW.

Actually, you wouldn't even need to have extra quadcopters for charging purposes: you would just need extra batteries.

Given advances in ballistics I think a grilled cheese cannon would work just as well, and be cheaper.

I would be blowing $$$/week ordering grilled cheeses for unsuspecting friends.

Advances? In ballistics? Who are you Leonardo Da Vinci?

This could also be an awesome way to disrupt the courier business in cities.

e.g. sender logs a job online (& provides payment details), sender prints a barcode sticker, sender drops off package with the building doorman/concierge and/or walks to designated quadcopter landing zone adjacent building, outgoing package scanned and loaded onto quad-copter, quad-copter delivers package to recipient's landing zone, quad-copter/system sends notification to recipient to advise that package has been delivered, recipient goes to quad-copter landing zone to collect package, recipient scans barcode or provides electronic signature to acknowledge receipt.

Terms & Conditions: Anyone who implements this idea (or minor variation) must give hook and I a $1 royalty each for every job logged ;)

This is an interesting idea and some of the other commenters did a good job of fleshing it out a little, but IIRC it is illegal to operate a UAV in the US unless you can take manual control at any time and so long as the UAV is always within the "operator's" eyesight.

It's actually even more difficult than that. I participated in a UAV project in Idaho, and we had to secure airspace for the UAV, prove that if radio comms went down, the UAV would immediately go into a death spiral (to prevent it continuing on to a populated area), have a fully licensed pilot to guide it when not in automated mode, and who knows how many other requirements.

At this point, the FAA is _very_ serious about UAV safety, IMHO with good reason. Even with our extremely safe controls, we had one UAV crash due to launcher failure, and another get stuck up in the air a long distance away due to a sudden thunderstorm that rolled into our area.