I'd had heard the adage before, but I thought this was an especially clever application.
I just picked up a copy of the January issue of Aerospace America with an article detailing the bumpy road ahead for unmanned a/c. Bezos got the 2015 date from a 2012 law that requires the regulations be in place by then. But regulations can prohibit just as easily as they can permit. They speculate that initially all unmanned flights will be limited to line-of-sight of the operator, which rules out the 10 mile delivery range (unless the operator is in a really, really high observation tower), and autonomous flights. Plus the a/c must weigh less than 55 lbs (although later in the article they make references to a 55 kilo limit, so I'm not sure which is correct, although I have yet to see a Federal Aviation Regulation that used metric units), which will severely curtail payload weight.
If you've not been around them much, you can't believe how inefficient helicopters are compared to airplanes. Very few turbine-powered copters can lift their own "nominal weight," weight empty except for essential fluids. And electric motors are far less powerful than turbines, plus electric copters lose a lot of payload because the require heavy batteries. I didn't invest a lot of time researching this but a couple of 'hits' indicate the best electric copters can lift less than 20% of their own gross weight (even a wimpy little Cessna 152 can manage >50%). I'm sure Bezos has his finger on the pulse of what's happening so I presume his 5# package was based on what's being proposed, which works out a bit less than 10% of a 55# electro copter.
What is written as "see and avoid" (which is the cardinal rule of the visual flight regs) in the current FARs becomes "detect and avoid" for the UAVs. The problem is, there's not yet been much progress even in writing the standard for detection and avoidance. The article mentions one robotics researcher at Carnegie Mellon suggested using the same transponder system required in commercial a/c, which includes a computer called
TCAS (Traffic Collision Avoidance System).
When there is a possible conflict between two TCAS-equipped a/c, their computers talk to each other, discussing what their status is -- whether they are capable at that instant of climbing, descending, turning, etc -- and mutually agree on the best and least disruptive courses of action. Then they announce their decision(s) to the respective cockpit crews in synthesized voices, and indicate what is to be the new course/altitude/airspeed on the flight instruments. The pilots by law are required to comply. The problem is, that gizmo will suck up a healthy portion of that 55 lbs (I figure at least half). And it is an 'active' system, which means more draw on the batteries and a shorter range. And general aviation a/c aren't required to have them, which means it would be near as makes no difference useless in low altitude flight.
To make matters muddier, 43 states already have proposed or passed 118 separate bills controlling use of UAVs in their airspace. And this is before there's really any threat of the skies being darkened by these things. So imagine how many more roadblocks the states will throw up once the possibility is more tangible, and the usual Luddites and fearmongers start stirring up the general populace. There's even one town in Colorado that licenses UAV hunting because the bunny huggers have been using UAVs to shoo game animals away from hunters.
Kinda prophetic that Bezos's demonstration flight couldn't even take place in the US because the FARs limit such flights to amateur use only.
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