[acveilleux]

That would actually cause a net increase of fuel consumption. The drag on the truck would offset the drone's saving. Overpass clearance could also be problematic.

The net result would be lawsuits and damaged drones I'm afraid. At least until a drone operator enters into an agreement with a hauling company.

[TeMPOraL]

I don't think the increase would be that significant, after all you're adding a few kilos to a multi-ton vehicle. But I can see another solution: imagine that the company allows people (not only truckers, but even ordinary car drivers) to lease a roof-mounted drone docking station in exchange for free shipping of all ordered items and/or some meaningful discounts. This would easily offset additional fuel costs, create an incentive for a part of the population to participate in the program, and the dedicated roof station could have some guidance hardware that would help the drone land, as well as a charging station that would let the drone recharge from car's alternator. Seems like a win for everyone, though not very much in a hacker spirit. I'd love to see drones just hitching a ride.

[jahewson]

> I'd love to see drones just hitching a ride

Except that it might be the last thing you'd see, before the drone fails and comes crashing through your windshield. Seriously though, if you're in the car behind a drone trying to land on a car ahead when it fails, there's no failsafe.

[icegreentea]

I think the net change in fuel consumption would be largely dependent on a lot of factors - but mostly on the speed of the truck. Since rolling friction tends to dominate at lower speeds, and a quadcopter expends a lot of energy to stay afloat, then it's likely that for most truck - quadcopter configuration, there exists a critical speed where net fuel (or energy) consumption flips over. My wildass guess is that for most configurations, it would be somewhere above residential speeds (~40km/h), but far below highway speeds (~100km/h).

[acveilleux]

That's what I think too.

I've seen the figures on the aerodynamic roof air deflectors they put on semi-trailers and they can get as much as ~8-10% fuel saving at highway speed (ideal size/fit) where the aerodynamic drag is dominant.

Semis average around 6.5 mpg these days (flat, highway) so a 10% saving is close to 1 gph of diesel fuel or about 2.80-3.00$/h.

So I'd guess drones would add about 1-1.50$/h in fuel cost or so when they latch on. Enough to be noticeable.

[cbhl]

So what if we build special trucks that have "shields" on the front that provide a spot for drones to hide while not unduly reducing drag?

Or what if the drones hide on the back of the truck instead of the top?

[jahewson]

The shields would themselves increase both drag and weight. It's probably very challenging to land on the back of a truck due to the airflow around the truck, it would require a drone which can withstand high winds, turbulent air, and has much more powerful motors to perform the mavouvre. That would increase the weight of the drone significantly, so you're unlikely to see energy savings.

[nwatson]

So the drones take off and land from a purpose-built shielded dock/recharger station only when the truck is at a stop light or designated real-time-determined rendezvous where the truck and the drone(s) have agreed to meet or un-meet while the truck is stopped.

And fuel consumption concerns are negligible. Sure, there likely would be a net increase in fuel used, but the premium is on drone electric charge capacity, battery weight, and drone range. A coordinated network of drones hopping onto trucks would greatly increase total per-drone range and make it possible to centralize drone freight depots even more (making them more sparsely distributed). This would push down costs a lot. The drone actually flies only "the last mile" and delivers only higher-valued goods.

[jahewson]

That's much more reasonable, landing on a stationary truck is obviously going to be straightforward and safe. It's still probably best to do it away from major roads though.

The fuel was never an issue, sure there's a net increase in fuel consumed but not a net increase in energy as the drone is less efficient than the truck at transporting the same load.

A "last mile" drone is a pretty good idea, not just because it increases range, but because it avoids the need for the for the drone to return to the depot after each delivery. On the other hand, if the deliveries are tightly clustered it might sill be more efficient to just deliver them using the truck, as drones waste a lot of energy working against gravity.

[e12e]

> That's much more reasonable, landing on a stationary truck is obviously going to be straightforward and safe. It's still probably best to do it away from major roads though.

Well, even crossing a highway with a large number of drones, is bound to lead to some of them failing and falling down into traffic? I suppose in some way there's some safety margin, having the drone do a controlled crash as soon as one engine fails -- but there must be scenarios in which the (presumably rather cheap) devices suffer sudden failure (eg: battery pack failure?).

[cbhl]

That suggests to me that we might get better gains with purpose-built drone trucks (think "aircraft carrier") rather than leveraging existing (e.g. UPS) trucks.

I also wonder whether delivery trucks are in and of themselves as prevalent in China as they are in America, versus, say, bicycle carriers or other forms of delivery.