This. The problem is that the costs of transportation are externalized to a shipper, and the environmental costs the shipper incurs are externalized to ... future generations? And the cost of the eventual replacement is externalized to the consumer ten years from now. It may be wise for us as a society to find ways to fully account for all costs of products to use market forces to make better decisions for society as a whole, rather than enriching a segment at the expense of another.
And being "capable" in the first place is largely due to luck also. What is being "capable?" Intelligence, education, discipline, motivation? Intelligence is largely genetics and your socioeconomic status as a child. Education? Intelligence plus socioeconomic status as a child and young adult. And a fair bit of luck too (i.e., admissions, etc.). Discipline? Parent's socioeconomic status and probably some genetic/psych/environmental influences. Point being, just being capable of being "capable" has much to do with things outside of your control. Most are unaware or dismissive of this. Goes back to the old adage of being born on third base and congratulating yourself for hitting a home run.
Dirigibles require huge volumes, because the lifting power of gas is small. Those huge volumes make for a relatively weak, slow, and difficult-to-maneuver craft. A big reason why airships disappeared in favor of airplanes was that airships had a really tough time handling or avoiding bad weather because of these limitations.
I have a blurry recollection of seeing an aircraft design that was a combination of an airplane and a dirigible. It looked like a poofy manta ray, an inflated rigid lifting body or flying wing. It wasn't quite VTOL & needed a very short runway, but it also gained more maneuverability in flight. Maybe it was too much of a compromise though.
There's actually been more than one of these types of aircraft (known as Lighter Than Air - or LTA Aircraft), either as an idea or prototype throughout history.
Hydrogen doesn't buy you that much additional lifting power.
Air is about 1.2kg/m^3 at STP, so that's the theoretical maximum you can lift with a cubic meter of gas bag. (And you can only get that value if you could somehow hold a vacuum, of course.)
Hydrogen is about 0.09kg/m^3 at STP, so you can lift about 1.1kg/m^3. Helium is about 0.18kg/m^3, so you can lift about 1kg/m^3. Helium is twice as dense, but that only costs you about 10% of your lifting power since both are so light compared to air.
I see no reason you couldn't use hydrogen, but I don't know if anyone would want to take the risk. (Specific flaws of the Hindenburg aside, hydrogen is explosive across a distressingly wide range of mixture ratios with air.) If you did use hydrogen, I think the main motivation would be avoiding the use of scarce helium, not the minor increase in lift capacity.
But still critical enough to make it impractical. How would you do maintenance on a hydrogen airship without risking the people doing the maintenance? And you'd never be able to fly over populated areas.
Seems reasonable. All else being equal, your radar cross section is proportional to your actual cross section. Plus it's probably easy to spot a blimp with your eyes.
weather balloons are typically not up for that long, 90 or so minutes on average. So I don't think that's solving the extended air time. In fact they are pretty much designed to go up and pop and come back down. Lighter than air in general can be used to solve extended air time, and we're back to dirigibles, not weather balloons.
The Stanford Student Space Initiative's valbal is an interesting project where they add a lightweight set of ballast and a valve to a weather balloon so it can maintain an altitude. They're limited by power, the amount of ballast, and how much gas they can bleed but they can get flight times of days. https://stanfordssi.org/blog/ssi-52-breaks-world-record-agai...
Well, I'm disappointed that the majority of their flights are this short. I thought there were some of them which were permanent atmospheric weather stations.
But short flight times don't really have to be the case, because it seems that they can fly for extended periods of time: one of NASA's balloons stayed up for 46 days [0]. The US air force also uses balloons as surveillance stations, though I don't know the actual flight time of these [1][2]. JLENS was supposed to stay up for 30 days at a time.
sure but these aren't really weather balloons. the last two are basically tethered dirigibles. the first one is the closest and it's more like what project loon is doing. Yes, it's true, balloons can stay up for long periods of time, but this is not how weather balloons are made or what they are designed for. Weather balloons are designed to pop at a specific pressure and fall. As the balloon rises, the volume of gas expands due to there being less atmospheric pressure. At a point the balloon pops and it falls back to earth. The loon and the balloon in your first link probably use a system that adjusts the pressure in the balloon by compressing it into a storage container. This allows it to "hold" an altitude and keep the balloon from ascending until it bursts. Also, at least in loon's case, it uses a different material than a standard weather balloon. This probably also plays a roll in it's expandability, resistance to long term UV and keeping itself from popping.
Helium is rare and expensive and becoming even more so as time goes on.
Hydrogen has this nasty habit of being extremely flammable.
Rigid or semi-rigid airships when scaled up are really difficult to moor and arrange ground handling for, which is why some of the recent prototypes that have been flown integrate skirts and reverse-hovercraft like suction apparatus that can hold them down on a flat field.
The empire state building was originally intended as a Zeppelin mooring location, but the plan was abandoned due to wind and inability to control a zeppelin to that level of precision.
I wondered why this wasn't applied to suitcases to make them lighter and then common sense kicked in regarding just how much actual helium would be required to lift even an empty suitcase...
It's not even an issue of how much helium is needed; no amount of helium will make a typical suitcase buoyant.
Filling it with helium at ambient pressure wouldn't produce nearly enough lift, and increasing the pressure would make it heavier, not lighter. What's needed is not mass, but volume.
I feel like you're being deliberately obtuse. I think jianshen meant how big of a helium balloon you'd need, not how much helium you'd have to put inside the suit case.
The article said that the lighter than air aircraft got blown around by the wind too much. They needed a drone that could loiter over a specific area for an extended period of time, presumably acting as a communication relay for disaster or war zones.
Now, seriously, allow me to doubt that flying some 2 minutes a plane (model or not) that has (or has the possibility to carry) on board five days worth of fuel actually means that the engine is capable of reliably running 5 days no-stop.
This particular decrease of demand is of work hour and jobs, and thus an increase in misery of particularly vulnerable people. If an economist is both rational and compassionate, they would need to believe that such price fixing has benefits that outweigh the increased misery.
I'm not familiar with those offsetting benefits. If they exist, please enlighten me.
And what is the value created by labor? Let's split the discussion into service jobs and non-service jobs, as we all know most of these minimum wage positions are service jobs. So, what is the value of one hour of service labor? Whatever someone will pay for it. Which is set by a market of service providers all decreasing their prices to the lowest they can tolerate. Because if you can undercut a competitor, the free market says you will win the business. Which, for the people who make minimum wage, is how little a wage they will accept. Ok, what sets the floor for what people will tolerate to be paid? When looking at the minimum wage sector of the population, what is their bargaining power? What is the bargaining power of the employers? Is it a free market? What other options do the workers have? Is it a voluntary transaction if the alternative is starvation and homelessness?
No, you're telling the customers that their food is subsidized by ultra cheap labor. Of course, higher prices will decrease the number of goods sold, which the free marketers regard as a deadly sin. Rather, when costs are fully internalized, the free market works better! Externalizing costs onto labor by perpetuating a below-living wage is a market distortion held up by government! They should hate it!
And to the free marketers who point out that companies could voluntarily pay a living wage, you're not wrong! But it exposes the fault in the free market religion. The market, on a whole, will gladly enslave and abuse a small minority for the benefit of the majority.
Also, as an Amazon shopper, their fulfillment is a known quantity to me. If I buy from your shop with your shipping, I am taking on the risk of potentially longer shipping. And I also have an increased suspicion of fake or knock off goods. So, even if I saw both listings side by side, I'd pay 10% to Amazon for their fulfillment and a perceived lower risk of knock off (despite reading much about Amazon sold knock offs). In fact, I've often bypassed the buy box to buy the same item from amazon at a higher price for these reasons
