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How Rwanda Built A Drone Delivery Service
Real Engineering
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All the comments and stories posted to Hacker News that reference this video.For those blocked by a paywall, Real Engineering did a video on it [https://www.youtube.com/watch?v=jEbRVNxL44c]. The most interesting aspects to me were:- The drone is not a quadcopter, they are too inefficient. Mini plane design.
- GPS device is directly attached to the swappable battery unit to ensure it is always connected to a satellite, eliminating satellite connection delays when the drone powers up.
- It is launched into a sky by a powered rail. It doesn't need to land to deliver the goods, the items get parachuted down. No infrastructure needed on the receiving end, the item just drops from the sky.
- For landing the drone flies past an aircraft arresting wire while hooking onto it which decelerates it and causes it to swing down (suspended above the ground). Easy to retrieve.
⬐ ge96Yeah I think that swappable battery design is pretty slick it's a big unit⬐ kumarvvr⬐ tomcamIts not just the swappable part. I think they have modularized all the electronics and GPS communication systems inside it, so that it is always booted and on standby. As soon as it is incorporated into a drone, it will be ready for work.Another innovation is the clip on wings.
I think this is clever engineering and a necessity for their time to fly requirements.
⬐ sgtnoodleIt's been great for streamlining operations. The first generation of aircraft we deployed to Rwanda didn't yet have blind-mate connections for the battery pack. Operators had to reach in and connect two connectors. The plastic tabs that retained the connectors would tend to break off after a while, requiring the operators to secure them with a zip tie, on every flight! I forget what generation of vehicle was featured in Real Engineering, but I suspect we're one generation past that one, and the batteries are a bit more streamlined from that.I haven't paid attention to the statistics in a while, but these days the busiest distribution centers can launch a vehicle once per minute or so, and they do.
⬐ sgtnoodleYeah, I just skimmed the video, and that aircraft is one generation behind the current design. It was a good aircraft! The new one looks very similar externally, just a lot more optimized internally.One of the sound bits I heard while skimming was that the recovery system misses 10% of the time. We've dialed it in to be considerably better since then. I'm going to forward that timestamp to a particular coworker and see if it causes his eye to twitch... :-)
⬐ ge96Man that's such a cool job/place to work. I was curious, I don't know if you can answer this or if it's public info.Do the aircraft boards/computer get tied to some kind of simulator and (autonomously) fly around/run the actual control surfaces (in reality) as it flies in the simulation that would be neat. Although it might not make sense.
⬐ sgtnoodleYep, that's a thing. It's called "hardware in the loop". There are indeed control surface servo motors plugged in, and they move around to wherever the flight computer commands them to based on what the simulated vehicle is doing. Unlike a real vehicle, though, the boards and wire harnesses are quite a bit messier. All the important wires run through additional equipment so that folk can automate tests where things break.One thing that we don't have plugged in normally is the propulsion motors. The noise would be rather obnoxious considering the HIL setups are in the office. Also, I believe we still omit the wing tip LEDs; not only would they be obnoxiously bright, but they would melt themselves for lack of actual airflow!
⬐ ge96oh dang that's a good point about the temperature, guess LEDs can get hotthat's cool, I'm gonna look into that "hardware in the loop"
Beautiful summary. Thank you very much.⬐ micromacrofootI love how the modularity makes for quick recovery from hardware failure and makes it easier to carry aroundit seems the operations have been cleverly simplified too, I hope they can successfully expand!
I was also going to mention zipline in Rwanda, last video I saw was two years ago but it looks like they’re doing well enough to be hiring interns in San Fran. Really cool tech, the way they have a sort of assembly line for getting ready-to-fly parts on the package in the space of minutes - these are life and death deliveries out here!
> Even if they're literally worse at everything than the alternatives, cost more, are less reliable, etc.Drones may be better for very quick delivery or where road network is very poor.
See https://news.ycombinator.com/item?id=28070084 with amazing https://www.youtube.com/watch?v=jEbRVNxL44c (delivery of medical supplies in Rwanda) and mentions ship-to-ship transport.
Oh wow - Zipline is so inspiring. This video showing their setup in Rwanda is fantastic: https://youtu.be/jEbRVNxL44c
There's an American company[1] in Ghana sending medical supplies around the country with small launchable planes.[2]
⬐ tsjqthat was an amazing watch. thanks for sharing the links. !⬐ mklThat's not at all ballistic though.
flyzipline is so cool! I saw an AMA they did on reddit a while ago and their tech for the thing landing where it hooks onto the the wire is really neat! https://youtu.be/jEbRVNxL44c?t=284
If we're talking about fixed wing drones in rural environments then it does makes sense. A good example of that is this drone delivery service in Rwanda https://www.youtube.com/watch?v=jEbRVNxL44c
I learnt about Zipline in a talk at JuliaCon by Tucker McClure who spoke about how they use Julia for designing and tuning their aircraft. Had the great fortune of spending an evening at the conference to learn more about the company itself, how it got started and their use of Julia.Recommend the 2019 JuliaCon video on how Zipline uses Julia for vehicle simulation: https://www.youtube.com/watch?v=K8rPZVotroY
And this video by Real Engineering that does a great job of explaining how the whole thing works: https://www.youtube.com/watch?v=jEbRVNxL44c
The website includes a video [0] that explains how it works in more detail too.It's quite interesting how they evade issues with landing and lifting the plane, lifting the plane by shooting it off a rail seems like a common approach but landing it by catching it using a small hook at the tail of the plane isn't that common I presume.
On their website it says "Gas combustion vehicles break down, get stuck in traffic jams that prevent urgent response, and put human drivers at risk behind the wheel, particularly when the route is rough and treacherous. Zipline’s drones are battery powered and fly quickly and directly to their destinations, leaving ground vehicles behind." That sounds like an unfair comparison, a more accurate comparison would have been to gas powered drones. Is it still the case for gas powered drones that they're more unreliable than electrical drones? It's probably because of the weight of a gas powered engine in such a small drone no?
⬐ TylerE> but landing it by catching it using a small hook at the tail of the plane isn't that common I presume.Been used by the Navy since 1911.
⬐ GekkePrutserGas powered model engines are not that unreliable, even for model airplanes. One made it all the way across the atlantic: https://amablog.modelaircraft.org/amamuseum/2017/03/29/trans...Ok, the first 4 were lost but this is a huge journey with limited fuel and bad weather. And navigation was a problem too.
The big benefit of gas powered in larger vehicles is both the easy fast refueling and the higher energy density of fuel. Combustion engines for model airplanes are heavier than their electric counterparts because you can only scale things down so much, you still need to contain a constant fire and the associated pressure.
And in this usecase the slow recharge isn't really an issue anyway. It also makes sense for marketing reasons, being 'green'. Even though if fuel were used, you could probably run this entire company for a year on the fuel a semi truck would burn to drive 100km :) I don't think it would be a bad thing for the environment if a company like this would use fossil fuel, it's still a lot less wasteful than the alternatives.
⬐ giantrobot⬐ jasonwatkinspdxI doubt slow recharge is even an issue since they can just pop in a new charged battery pack and put the depleted one on a charger. With swappable battery packs a drone can be relaunched within minutes.⬐ baybal2> Gas powered model engines are not that unreliable, even for model airplanes.Still incomparable to any other option. Having 1 in 1000 crash chance will disqualify it as a DHL alternative.
Putting 2 of them on the drone will surely make it cost more than $500
And putting even the cheapest turbine on it is out of question, unless you talk about toy turbines that are as unreliable as RC piston motors.
⬐ TylerEI wonder if a pulse jet (as used on the V-1) would be an option?I've seen hobbyist level plans for them, and a pulsejet requires zero moving parts, so reliability should be excellent. The geometry of the engine does all the work.
⬐ baybal2> pulsejet requires zero moving parts, so reliability should be excellent.Valves, and pumps are moving parts too.
⬐ TylerEModern pulsejets don't use valves.https://en.wikipedia.org/wiki/Valveless_pulsejet
Fuel can be either gravity fed or possibly a pressurized system (e.g. fill the deadspace in the tanks with compressed nitrogen)
> landing it by catching it using a small hook at the tail of the plane isn't that common I presume.A lot of military drones have a hook at the end of one wing, and they hang a vertical wire under tension from a boom arm, with a differential gps receiver at the top of the wire. Ends up it's all accurate enough for the drone to catch the wire. I presume zipline went with their more complex approach as wings strong enough to just snag and stop would be past their weight limits.
⬐ balderfer> That sounds like an unfair comparison, a more accurate comparison would have been to gas powered drones.It's a comparison for customers, showcasing the difference between zipline's solution (electric drones) and the existing solution (gas trucks) to the problem zipline is trying to solve (medical logistics). If gas drones or electric trucks were to enter the space then it should be updated.
⬐ xmaayyyThe tail hook grab is actually the method that fighter jets use to land on aircraft carriers. Same with using a rail to launch the plane.
Are you working on Zipline [1] ?
⬐ andrei_says_This is incredible and gives me engineering fomo!* higher purpose project saving lives and helping people: check
* well-engineered, reliable, smart solutions quadrupling efficiency: check
* planes, Africa, autonomous flight, landing and take off hacks, app based pre-flight checks, oh my!
* all for peaceful, life-supporting, humane purposes!!!
⬐ jborichevskiyThat's what I thought of as well. Great video explanation for anyone interested in learning more.⬐ NetOpWibbyJust finished watching the video. Wow. Incredible.⬐ iandanforthPro Tip: Search "<HN handle> + github" frequently gets a real name, and if not current job, then look on linkedin.The answer to your question is: Yes.
The catapult launches the drones into the air, which then parachute the package to the location.Real Engineering [1] and Wendover Productions [2] have really nice videos about their system currently deployed in Rwanda.
[1]: https://www.youtube.com/watch?v=jEbRVNxL44c [2]: https://www.youtube.com/watch?v=bnoUBfLxZz0
⬐ mehrdadnThat's just incredible. Thanks so much for sharing.
Delivery drones are definitely unnecessary in densely populated areas. It's cool and futuristic, but it's not economical at all, it's very unsafe and also loud. However it's a wonderful thing for rural places with poor infrastructure. For example Zipline in Rwanda, one of the most interesting solutions an engineering perspective too: https://youtube.com/watch?v=jEbRVNxL44c
⬐ mingodadVery well thought project, and they use small planes 12KG.⬐ rohmanhakimThis is great. I'm always like stories about how technology solves problems in developing areas.