Comment by headShrinker | Hacker News Reader

Comment by headShrinker | Hacker News Reader

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This article strikes me as a bit naive and overly cynical at the same time. I research, build and fly "drones". There is no question the technology now "hobby grade" will make the jump to industrial within maybe 2 years. What is really lacking to them is areospace efficiency, and computer science. All the most popular software and hardware to date was mostly written or built by tinkerers and RC aficionados, not computer science and areospace industry leading professionals.

You can get an article circulated by badmouthing the hottest tech news, but in this case, it's just a bad misleading article with little basis in truth.

Also the government just opened 6 commercial testing zones, and the FAA just laxed some of the regulations regarding commercial UAV experimentation and flight. Note that these moves happened at lightening speed for the government. Just weeks ago it was illegal for a company to fly with out FAA clearance and a pilots license. This is going to happen. I believe Amazon or Google are the most well positioned to make it happen.

Not only is Amazon talking about introducing drones, it's also entertaining the idea of making UPS or FedEx strictly Business2Business enterprise, as Amazon would be handling the final leg of delivery ultimately to the customers door. I haven't heard anyone mention anything about this. Personally, as bicyclist living in NYC, I can't wait until those disgusting aggressively driven diesel delivery trucks are moved to the strap yard, replaced by the distant buzz of a battery operated drone army.

Also to correct the inaccuracy presented in the article. The drones will be the final leg of the package journey, not the mid term. They will fly maybe 10 miles max, with a top speed of maybe 60 mph max within a city, not, 120 miles from city to city. It will start in one city like Amazon Fresh, and then 2 or 3 more years after that. Not every city all at once like the article insinuates then points out would be impossible. One city with in 5 years still makes Amazons plan a success and it makes this article completely wrong.

  I research, build and fly "drones".

Great, maybe you can bring some information to the discussion.

For the type of drone you are best informed about, what is the maximum round trip flying range, assuming you adjusted the weight of batteries to maximise flying range and there was no wind and no worries about radio range or line of sight?

What about if you were carrying a 1 lbs / 0.5 kg payload in the outbound direction?

What would the round trip time and average flight speed be?

What would the retail cost of such a drone be, if I wanted to order a kit today?

I'm not the parent poster and I don't know how representative of the current state of the art but here's a quadcopter going 12km (~7 miles) one way with an unspecified 'hd camera' payload [0]. They claim 88 minute hover endurance.

I don't know if ~tripling that performance is in the realm of non-breakthrough engineering improvements but it seems at least order-of-magnitude close.

[0] http://www.uasvision.com/2013/06/25/unmanned-microdrone-cros...

These are pretty specific questions and would vary depending on the model and config. So my answer will be purely hypothetical. I have built and flown quadcopters the most. My most efficient configuration with high quality motors was very fast at about 50mph and could sustain that speed for 8-12 minutes depending on battery size, making the maximum distance 10 miles. Currently that is extremely far for a quad copter to fly. It could hover for about 18 minutes. The quad weights in at 3 lbs so adding another pound would drastically reduce its range. Cost to build this cheaply; Motors $200, long range tx/rx $350, flight controller w/ gps $70, ESCs $60, frame materials $60, battery $50, remote controller $50, wiring $10, props $60. This drone could be built for around $1k. It should be noted that while quads are more efficient they are also the most limited by payload. Ramping to a hex octo or deca would increase payload and potential battery size, and potentially flight time/distance, however efficiency tends to tick down.

There was TED talk[1] a few months ago about some guys using the exact same tech to build a "matternet" in africa and south america to combat washed out roads. Their estimate was that to move a 2kg load over 10km would cost roughly $.24. This includes fuel, initial purchase price of the drone (3k or so) and wear and tear.

In their system, they use elevated platforms where the drones could drop off packages/change batteries. If feasible, this solves the distance problem. They estimated that to cover a 140km square area, it would cost 900k, require 50 towers and 150 drones.

[1] http://www.ted.com/talks/andreas_raptopoulos_no_roads_there_...

I'll add a few questions:

- Can you ensure safe failure modes for your in-flight drones?

- Who assumes liability when your drones crash?

- What is the blade tip speed during operation? What precautions do you take when flying in populated areas?

I'm not the original asker but these seem to have obvious first-draft answers:

- Add rotors. The demo video showed an 8-rotor drone, I can imagine that building it as a pair of parallel quad rotors from the power supply point of view would give you quite a bit of control even at a 50% loss. A single-engine loss is obviously fairly small beans. I'm emphatically not an expert so this is armchair engineering.

- I don't know why anyone would ask this question. The answer is trivially obvious (the operator of the drone, whichever legal entity that ends up being modulo whatever insurance they certainly have). Obviously "it could crash" is hardly novel in other delivery services and yet they seem to survive the liability question without issue.

- Probably quite dangerous. I imagine you want to fly quite high for cruising for obstacle-avoidance and noise anyway so 90% of your distance this isn't a problem. I think the answer here is "don't hit people" just like with existing forms of transportation (or more realistically "be as careful about not hitting people as your liability insurance continues to reward you for").

>Add rotors. The demo video showed an 8-rotor drone, I can imagine that building it as a pair of parallel quad rotors from the power supply point of view would give you quite a bit of control even at a 50% loss. A single-engine loss is obviously fairly small beans. I'm emphatically not an expert so this is armchair engineering.

Well, the thing about a multirotor is that a motor failure is going to drastically throw off the stability of the aircraft. The controller would have to be able to recognize the failure, kill the faulty rotor hub, and compensate on the remaining motors in very short order to keep the airframe from getting so far off balance that it tumbles out of the sky.

Though, honestly, I'd think the controller or battery failing is a more likely mode of failure than one of the brushless motors suddenly dying.

The controller is already responding to changes in balance at an extremely high rate. How do you think these things fly in the first place?

Like an earlier poster acknowledged, the current hobby grade gear is not really engineered with industrial use in mind, but that's a fairly simple engineering problem which has already been solved by the groups who are using drones commercially (i.e. the military)

I have no doubt what so ever that Amazon, Google etc have the engineering chops to bring the software and hardware being used in drones up to an industrial grade.

Don't assume that because the first thing that you thought of upon hearing "delivery drones" is infeasible that the whole idea is unworkable. It just needs an engineer with a little more imagination

Edit: a couple of obvious solutions to your battery/controller failure mode would be a) use redundant controllers. They're small enough that you could easily have two or more running in tandem and checking eachothers integrity, and b) if you lose main battery you can autorotate down and land somewhere reasonably safe. If you use EDFs/shrouded blades they aren't a safety issue, and building a map of safe landing zones for a city is not a huge ask for somebody like Google.

Now for somebody else willing to use their imagination: what do you do about cheeky individuals interfering with your drone during delivery?

>The controller is already responding to changes in balance at an extremely high rate. How do you think these things fly in the first place?

You really don't see how there's a huge difference between balancing thrust between relatively equal power sources and losing so much thrust that the aircraft is inherently unstable?

Because that's kind of a huge issue - multirotors fundamentally rely on having power at each corner for aerodynamic stability. Even brief loss of power to one is going to put you into a tumbling state with no way to compensate for it.

>that's a fairly simple engineering problem which has already been solved by the groups who are using drones commercially (i.e. the military)

What multirotor UAS systems does the military have in service for reliable flight over moderate distances?

I'd also take issue with the suggestion that controlling an aircraft which has become unstable over an axis that you no longer have control over is "a simple engineering problem."

>They're small enough that you could easily have two or more running in tandem and checking eachothers integrity

I was referring to the speed controllers that convert the battery power to AC for the brushless motors. I'd expect commercial grade ESCs to be overbuilt, but they put out a good bit of heat that has to be engineered around. They're also one of the more common modes of failure for the brushless motor systems used in mutlirotors.

>It just needs an engineer with a little more imagination

This is the equivalent to saying "we're going to magic away any problems with this idea."

EDIT:

I missed this.

> If you use EDFs

Seriously? Do you even realize how terrible a suggestion that is? EDFs are even worse in terms of energy efficiency and they'd compound stability issues since they have relatively poor throttle response.

But I suppose we can imagine those problems away too.

Aha! I couldn't find the video quickly for my first post but I finally stumbled on it. Granted this is in ideal laboratory conditions but: http://www.youtube.com/watch?v=bsHryqnvyYA&t=22

Yep, the 8 rotor setup is largely for redundancy. There are examples of quads flying with half of their rotors damaged, albeit in a very degraded sense.

And with regards to the blade speed, you can make it largely a non-issue by using shrouds/wire mesh. People don't worry about the blade speed of a floor standing fan even as they brush up against it.

I think most people imagine these things buzzing around at treetop level but there's no reason not to go up a bit higher, just below aviation floors (500 feet in US I think). As long as it was at altitude a simple parachute could save it from a majority of (bad) crashes. It would only need a vertical "tunnel" to safely descend/ascend within.

"- What is the blade tip speed during operation? What precautions do you take when flying in populated areas?"

I've been thinking that a SawStop-type of technology might be a possible solution there.

I think shrouds are probably safer. For saw-stop to work the blades would need to be quite heavy duty (vs. the thinner blades that are common now - those would simply snap off if you tried to stop them in a hurry!), and heavy duty means more load on the motors, lower response time etc.

Additionally, if you're going to allow the blades to hit anything you more or less need to accept that it will result in a crash, even if you stop them immediately. Better to just guard them from contact in the first place.

Interesting comment (upvoted) but...

"I can't wait until those disgusting aggressively driven diesel delivery trucks are moved to the strap yard, replaced by the distant buzz of a battery operated drone army."

Distant buzz? Are you sure about that? Drones sound like insects, yuck.

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