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The (biggest) problem that keeps airships from practical use is that they are huge sails. Big sails mean even small amounts of wind can be powerful forces actin
by xnyan 2y ago
The (biggest) problem that keeps airships from practical use is that they are huge sails. Big sails mean even small amounts of wind can be powerful forces acting on the airship. In the air a big push from the wind might be safely managed, but if you're near anything solid such as the ground, you can get smashed to bits.
To safely operate a suitably efficient (large) airship, we'd need both huge specialized docks with extremely strong mooring structures to keep wind from smashing the airship into whatever is near it, and a system (such as a 3-axis propulsion system on the airship) that is capable of counteracting wind force acting on the airship when it's near the ground or other solid objects and not docked.
Despite the many attractive advantages of airships, there's yet been anything like a good solution to this problem. There are other challenges too (what do you do when you drop off your cargo and the airship wants to shoot up into the air? Vent gas? Rapidly compress your gas?), this is just the biggest.
- labcomputer 2y ago> There are other challenges too (what do you do when you drop off your cargo and the airship wants to shoot up into the air? Vent gas? Rapidly compress your gas?) Not to detract from your overall point, but you do the same thing you do when burning fuel while cruising: Add ballast. Yes, but how do you add ballast to an airship while it is underway? Simple: condense water out of the exhaust like the zeppelins did.
- aaron695 2y ago[dead]
- zabzonk 2y ago> Simple: condense water out of the exhaust like the zeppelins did. Citation? Would not the condenser need to burn fuel, thus lightening the ship?
- imoverclocked 2y agoYou are carrying fuel and using oxygen from the atmosphere to combust it. When it's hot, it's a gas. By simply cooling it and recovering most of it, you are potentially left with more mass than you started off with... and Oxygen is relatively heavy.
- sethherr 2y agoThe article describes electric airships
- mitthrowaway2 2y agoThe GP asked about burning fuel. But in the case of electric airships, you can run an electric condenser, extracting atmospheric water vapor.
- shiroiushi 2y agoThat seems like it would be really bad for energy efficiency: now you need batteries large enough for propulsion during the whole trip, plus extra for extracting water vapor. Why not just take on some liquid water at the destination when you drop the cargo?
- Qwertious 2y agoBecause that's less flexible and there may not be water at the destination in the first place. That said, Flying Whales are trying to do exactly that, because ballast tech just isn't capable enough yet.
- bondarchuk 2y agoYou're both missing the forest for the trees, when the airship is electric obviously you don't have to add ballast while flying because you don't have to compensate for burnt fuel.
- Qwertious 2y ago
- jandrese 2y agoIt has to be more energy efficient to re-compress your lifting gas back into storage bottles. What do modern airships do? This has to be a solved problem.
- 0xCMP 2y agoI think they're aware of all these problems because they do mention almost everything you said in the linked post thinking through the idea: https://www.elidourado.com/p/cargo-airships https://www.elidourado.com/p/cargo-airships Obviously that was simply a post thinking through everything hypothetically and I didn't read anything that seemed like they actually had the best solution, but at least they seem to be aware of the challenges to landing and off-loading cargo efficiently.
- ben-schaaf 2y agoReading that article I see no proposed solutions to this sail problem. They mention wind as an issue for delivery times but not safety. There's also no acknowledgement that the "scaling law" that makes building huge airships lucrative also makes these problems worse.
- wang_li 2y agoYou're failing to see the secret that is exposed by the fact that their Chief Engineer comes from hyperloop. They're going to dig tunnels connecting all their destinations and run the airships underground in a vacuum sealed network. No atmospheric drag at all! Bingo!
- withinboredom 2y agoHow can you call yourself an engineer and work on the hyperloop. Literally only takes about 30s of thought to realize it is an impossible idea.
- dr_dshiv 2y agoPlease reveal the impossibility of the idea?
- withinboredom 2y agoSure. If you put it above ground, you are a few short bullets from killing everyone in the loop. Hitting a wall of air in a vacuum at hundreds of miles per hour is going to be like hitting a brick wall. Ask any reentering spacecraft. The same problem exists underground, the weakest points being the stations themselves which can be bombed. A failure in the system itself (even just a power outage or malfunctioning equipment) would mean people suffocate inside after a matter of minutes. So, sure, it is possible to create it, but it is impossible to make any sort of safety guarantees. In other words, literally any other mode of transport would be safer, including a hydrogen-filled dirigible. So, sure, the concept itself might be possible, but an engineer doesn't concern themselves with possible. That is for scientists. An engineer considers what is realistic AND possible, because that is an engineer’s job: to make the possible real. This cannot be real; literally no regulator would ever sign off on it.
- fulafel 2y agoI think if that was the biggest problem, they'd be used much more. There are a lot of places with light and regular winds, and we're also pretty good at predicting winds in the 1 day forward timescale. And of course there's the regular and predictable high winds that were traditionally used by sail ships.
- eptcyka 2y agoThe article is talking about atlantic freight trips - middle of the ocean is not one of those places with light winds.
- dole 2y ago"Hindenburg made 17 round trips across the Atlantic in 1936 — its first and only full year of service — with ten trips to the United States and seven to Brazil."
- withinboredom 2y agoA modern ship can make the same number of trips and not be dependent on weather at all.
- fulafel 2y ago... with unsustainable CO2 emissions. We need to be ramping down fossils use rapidly.
- Numerlor 2y agoShips are pretty good emissions wise because if the sheer amount of cargo they carry, even with burning the absolutely worst crap they can
- fulafel 2y agoShipping sector is a huge co2 emitter and this claims to cut "fuel burn and carbon emissions by 75 percent without any sustainable fuel breakthroughs". As we ramp down fossils we this kind of thing would enable eg international agreements to limit and progressively lower shipping sector co2 credits over time. We need to do this for all co2 emitter sectors since all the slices of the pie are fairly small so focusing on eg top-3 doesn't solve the problem.
- dylan604 2y agoJust cover the thing in solar, and run it on electric. Add a couple of wind turbines too. I mean, the whole concept is preposterous, so why not just lean into it?
- bee_rider 2y agoSolar powered airships floating around the world, following the prevailing winds, accepting durable goods by… catapult or something, delivery by chucking it out the window over populated areas. Paint them some nice pastel colors and we’re in Solarpunk world.
- Ekaros 2y agoJet packs and tax free shopping as next step. Wait for your friendly airship to come around and go get your duty free stuff somehow... Surely there is some places they can visit on the way so it counts...
- jandrese 2y agoWouldn't delivery be done by quadcopter drones? There have already been pilots projects where Amazon does delivery by drone in a couple of places. I don't think they were a success, but an airship adds some constraints that might make the more viable. Downside is the copters needs to return to whatever altitude the ship is currently cruising at, which might be close to their ceiling. But on a side note my first reaction to the headline of this article was "no they are not". Airships have a number of fundamental drawbacks that I don't think we are any closer to solving. Ultimately they're as slow as a cargo ship, can only carry a relatively small and light payload like an airplane, require specialized ports like ships and airplanes, and are expensive to build and operate. They just don't have a viable niche.
- dylan604 2y ago> Wouldn't delivery be done by quadcopter drones? But if you drop them via cheap parachute, you wouldn't need anything to return. I bet they'd only be slightly less accurate delivery than what their "don't give a damn" delivery system in place now.
- mschuster91 2y ago> what do you do when you drop off your cargo and the airship wants to shoot up into the air? Vent gas? Rapidly compress your gas? As long as it's just one small bubble with hydrogen, you can flare it off or combine with oxygen from the air outside to reduce lift.
- Ajedi32 2y agoWhat makes you think "docks with extremely strong mooring structures" is a particularly difficult problem to solve? A giant metal hook anchored in concrete attached to the ship with some steel cables doesn't seem like it would be that difficult for a team of smart engineers with a multi-million dollar budget to figure out a good design for. Certainly not so difficult or expensive as to threaten to make the entire concept nonviable.
- jandrese 2y agoHistorically the difficulty isn't in building the mast, it is in preventing the airship from being smashed into the mast by the wind. Or in dramatic cases flipping end over end because it was only moored on one location.
- Ajedi32 2y agoInteresting. Why a mast and not just the ground? Pull up the mooring lines (probably more than the amount needed to actually hold the ship, for redundancy), connect them to the ship, then pull on the lines with winches until the ship is on the ground. That's basically how seafaring ships work... are there any unique challenges with airships?
- jandrese 2y agoThe unique challenge is that everything is way up in the air and constantly moving around.
- fulafel 2y agoBuild two masts and anchor from bow and aft?
- Log_out_ 2y agoCouldn't the sail factor be reduced by ionizing wind coming at the vehicle who then keeps away from the vehicle while going around it, depositing little energy?
- d13 2y agoIs there any evidence that this is really a problem? Zeppelins were in use for decades completely safely, as are modern airships.