shynung

I don't think I can say it better than this. Let's just leave this thread alone, people. There's nothing constructive out of it.

Are not. Here we go again. An electric freight train powered by a hydroelectric dam doesn't drink fuel either. And it carries far more cargo, at a much cheaper price. An airship needs a landing spot at least as big as itself in order to unload efficiently. Plenty of people have pointed this out before, so don't bother telling it again. Ships are built out of structural steel. Airships are built out of lightweight alloys and some polymer canvas. Steel is considerably cheaper than aluminium. Even when approaching the production rates of ships, airships will never be cheap. What?

Government seeks maximum utility, as in, how useful will the thing become. In this matter, an airship-port serving purely cargo airships will see less use than a comparable airport or dock since the number of operational airships are low. Airships would have comparable loading times to a ship of a similar payload capacity, which is to say isn't very fast. Loading infrastructures aren't going to be much more different either, especially if we're talking about intermodal containers. The only time savings left is the one gotten from loading and unloading only once each in the entire trip, but that means dedicating an expensive airship for a single route, which won't play nice with the price. The transport company would probably charge more for that. Again, there are niches where a cargo airship can do what others can't (delivering wind turbine parts and assembling them on site, or other similarly difficult job), but getting into the market already dominated by ships, trains, trucks, and airplanes would always be difficult. The cost of airship building and maintenance must be lowered to unrealistically low levels in order to compete favorably with regular modes of transport. As a side note, anti-snow infrastructures for trucks and trains are already available. For high-throughput routes, snow usually don't become a significant problem.

Looks like I overestimated. Though, I never really thought that a direct route is actually that expensive. One thing I'd agree with is that a high-capacity airship is good at assembling wind turbines at the installation point. Though, that's probably more of a niche market, but still.

The return-of-investment time for airports and docks serving regular airplanes and ships are much shorter than ones serving airships, because there are thousands of airplanes and ships already in service, but very little number of airships. Any decent government seeking to maximize value, both in terms of profit and/or utility for the transportation system as a whole, would have chosen to build airports or docks rather than airship-ports without much consideration. It is possible that no demand exists for a middle option in any particular market. Very unlikely, but not impossible. While freight transport isn't one of those markets, the middle option has more or less been covered by direct-route ships (fast cargo ships also exist), and multiple-stop cargo planes. Even so, the larges percentage of transport has always been, and still is, transported by ship. No, it won't happen. Ever. No airship can travel a distance needing 7 days' worth of trip by plane, even going directly to the destination, unless it goes suborbital (if it does, there goes your cheap transport), due to enormous amounts of drag it would face. Even then, airline companies aren't stupid; they wouldn't choose to route their plane across an entire country just to deliver to a nearby city. All the intermediate stops will be more-or-less between the first and last airports in the entire route. Direct factory-to-factory ships and trains already exist. These are cheaper than airships, and the infrastructure is already there. Airships need some 150m long landing pads just to unload the thing. Combined with the fact that most factories are close to major cities (and therefore have pretty expensive real estate value), the only place left for airships to land is on the roof. Even more, most factory-to-factory cargo aren't time sensitive, so a faster transport vehicle is of little value (and significantly more costly) in such a market. The factory-to-factory cargo that are notably time-sensitive would be farm produce (grains, milk, livestock) delivered from farms to factories, and these industries are generally pretty close together that straight delivery by truck is already adequate. It matters a lot. There are numerous variables regarding what will sell in a market, including transportation market. Price alone won't be the final word. Besides, an airship would still be more expensive than the cheapest option, the ship and the train. Pushing these airships into the transportation market means squeezing between the ships/trains and the airplanes, and the price gap between them is getting smaller. Genetically Modified Organism. Go figure.

The company that builds the infrastructure and the ones that drives the vehicles aren't always the same company. If there are no airship transport companies around, no one will build the airstrips/landing pads able to support their operations. Even when given free tax for the first few years to stimulate growth, the airship landing pad would be beaten chiefly by regular airports and ship docks that don't need to do such things, and are able to return the investment faster. All made worse by the fact that there are literally thousands of airplanes and ships already in service, but almost no airships. Over long distances, a small increase in speed can hasten the trip time by days. The price differences would follow. What's available today is this: Truck->Ship(roundabout route)->Truck->Final Mile: $40-50 in 1 month (30 days) Truck->Ship(direct route)->Truck-Final Mile: $75-100 in 2 weeks (14 days) Truck->Airplane(roundabout route)->Truck->Final Mile: $125-175 in 1 week (7 days) Truck->Airplane(direct route)->Truck->Final Mile: $200-300 in 3 days There's your middle option. There aren't much of it. Not a lot of people has something needed to deliver to space. SpaceX may drop its prices, but there won't be much new markets in the space industry. Unless space stations turn into floating cities, that is. The difference between this and Concorde is that the Concorde planes are so horribly expensive, the manufacturers never got a profit from them. This cargo airship thing is trying to compete in a market already dominated by far more developed and cost-effective vehicles, and does so by offering something the competitors are already able to do. I bet the people is going to cry 'GMOs are evil!' and boycott this fruit from the market. Jokes aside, if I wanted to experience the taste of such a fruit, I'd mix apple juice and banana juice in the same glass. Fruit juice bars already do that. There are cases where having some sort of super-heavy aircrane-capable transport is useful, like installations of wind turbines, but for regular freight transport, there are competitors already doing what it can do using already-available technology. It won't do much good there.

You said the same hangars that made them can be used to maintain them. Thing is, these hangars aren't everywhere, and some airplanes and ships go on routes in which no maintenance hangars are available all along the route. Airships will have similar circumstances. Even then, unloading cargo would still need some support infrastructure. One wouldn't expect a container box dropped in the middle of a field to unload itself. Even for unloading cargo, a patch of grassland would have a rent cost associated with them. On most ports, simply loitering in one of the empty docks, not even unloading, will incur a parking tax. Unless you're parking out in the middle of nowhere, simply stopping somewhere would have costs. In the same way that a single patch of road is driven on by at least several cars, a single transport hub (an airport, dock, or truck depot) is visited by several vehicles. The owner of these infrastructures charges the vehicle owners for the provision of infrastructure, and this cost is spread over all vehicle owners, rather than just one. To the individual vehicle owners, the provision charge (road tax, airport tax) is just a fraction of the cost of the infrastructure itself. So yeah, aside from the cost of building a garage, the infrastructure costs of using an automobile, from the view of a car owner, is effectively the road tax. There is a middle option, but not from using a different transport vehicle. I'll explain a bit. Trucks move at speeds of up to some 100 km/h (at least, in Indonesia, they do), and deliver straight to the door. For short distances on land, and for last-mile delivery, they are the vehicle that are used most often. Trains and ships travel slower than trucks (around 60 and 20 km/h, respectively. Again, this is in where I live, so it may vary in other places), but use less fuel per mass-distance traveled than trucks. These are used for long-range, cost-effective travels between large transport hubs (docks and stations). Airplanes travel much faster than either of them, but are more expensive per mass-distance, and restricted to places that have airports. So there goes your express delivery. Another thing to put in mind is that a single piece of cargo (say, a copy of a PS4 console) very rarely arrive on the final delivery address on the same vehicle it left the sender's address in. Along the way, it will be unloaded and loaded, over and over again, from one vehicle to another. This loading process takes time, since it is likely that the console isn't the only one being loaded onto another vehicle, but along with literally tons of other cargo items. On another analogy let's look at the ticket prices of a regional train. You will find, among other things, trains that go through an similar route (defined as the terminus/end stations that they go to-and-from), using a similar set of passenger carriages, pulled by a similarly-powerful locomotive, yet offers a different price for a given class (say Economy), most of the time. This is because the cheaper train almost always stop at more stations along the route than the pricier train, the end result being the expensive train arrives faster to the destination than the cheaper train despite having similar mechanical performance, because the pricier train spends more time on the move than the cheaper train. If you haven't gotten the analogy, this is the picture: The middle option for cargo senders, faced with a variety of transport options that are cheap but too slow (train/ship), and fast but too expensive (airplane), is to either choose the slower vehicle that takes less stops, or choose the faster vehicle that takes more stops. Both options are available (there are cargo ships that go to less docks than others, and cargo planes that land at more cities than others), and both generally have a price somewhere between the slowest, cheapest choice (container ships often stop at dozens of docks) and the most expensive, fastest choice (passenger planes often go long distances between airports, on multi-hour flights, without landing anywhere along the way). In countries with a lot of land mass like the USA, a truck-only transport route is often faster than a truck-train-truck route, and cheaper than an airplane route, so that will be their middle option. Apples and bananas are a bad analogy for transport modes, but whatever. People who work at an industry generally knows what a typical customer expects from the service/products they offer. They will always adjust their offers so that the customer gets what they want at the price they are willing to pay, taking into account their service/product procurement costs to acquire profit. If they found out that a combination of products would serve better than each of them separately, they would have done so as soon as they could, for being the first to offer the product combination may give them a marketing edge over their competitors. Soon, others will follow suit, and it will become the industry norm. Even so, companies and industries often try offering new products at the market, to experiment with new ways of serving their customers (for profit). These new offerings aren't always in line with current market trends, and occasionally they become successful in their own right. Even so, there are offers that, even when anticipated by the market (customers), failed to be profitable enough for the company to continue pursuing it. There are many of these 'abandoned' offers, some more popular than others (Concorde flights, for example). In the end, if a fruit salesman that sells both apples and bananas say that his customers always buy either apples or bananas, but never both simultaneously, chances are that's what the market for fruit demands. If the market demands otherwise, either he or his competitors would have seen some customers demanding both apples and bananas, and told you of his experience directly (or through his sales reports).

Assuming an aircraft got its entire flight control surfaces inoperable and stuck in the neutral position (where the aircraft does not veer into any direction, but simply flies straight and level), but retaining control over engine thrust, is it possible to control and safely land and aircraft by shifting its center-of-mass around?(Say, by pumping fuel around tanks in various places around the plane.)

Shipyards and docks are two different places. There are ports around the world that can unload and load ships, but unable to do maintenance on them. One would certainly need to, since this thing is much bigger than planes. At the very least, the aprons (parking space) for unloading these things would be bigger. To the transport companies, since the business started. The docks and airports are rarely owned by the same company which owns the ships and planes, most of them owned by the government. To them, infrastructure costs are equal to airport/dock tax. Credentials require actual work experience. Reason and logic make only arguments, but can never support them as strongly as working experience.

Try finding any place in a big city with tall skyscrapers in which it is safe to dock a large zeppelin-type airship without it bumping into things. Or get punctured by lightning protector rods. On land, I'd go with trains. Low resistance due to smooth, low-friction steel rails, and low frontal-area-to-mass ratio compared to other land transport. On the seas, the ship wins, due to higher payload-to-vehicle mass ratio than airships (easier to float on water than in the air using buoyancy alone). For time-sensitive cargo, airplanes. Not fast enough? ICBM.

Old topic is old. Frankly, I see no reason why we should restart the discussion under a new thread.

Like a helicopter. As in, the blades' individual angles-of-attack can be varied in reference to its position relative to the craft, i.e. blades on the ventral side had their AoA decreased, the craft veers into that direction, etc. Modern helicopters used a swashplate mechanism to do this. Anyway, I found an old discussion related to this matter.

I was thinking of alcohol fuel, actually, just using this instant-alcohol-powder and water rather than straight alcohol fluid.

Mmm. I'm thinking of water-fuelled cars with these powders in the tank. Not really sure how would it run, though, if at all.

No offense, but can I see your calculations?

It's been mentioned earlier in the thread that refrigerators reduce their local systemic entropy by raising the entropy of their surroundings.

Filters are simpler than designing high-temperature-resistant chips. As magnemoe noted, filter-equipped cases are already available in the market.

Common misconception. Most of the fuel in rockets is used not to gain altitude, but to gain orbital velocity. http://what-if.xkcd.com/58/ Launching the rocket from higher locations (top of a mountain, or from some sort of airship) will reduce the needed delta-V, but not dramatically.

You would have been well-advised to ask this kind of thing in Samsung's own customer service networks.

My solution would be to put filters on (or in) the case air intake ducts. That way, only the filter gets dirty, rather than the components inside. The filter itself does need routine cleaning, though, otherwise cooling performance will suffer.

It's pretty informative, actually. I've tried playing it, and think that, aside from the somewhat macabre theme and annoying video ads, it's a decent way to pass the time. Though, I have the feeling that it's meant more to educate the population than to entertain.

Ah, missed. Thanks.

1 cubic meter of LH2 only weighs 70 kg. A typical fuel oil of the same volume weighs almost a ton in comparison. Any vehicle carrying any significant amount of LH2 will have very large tanks, which, along with all the insulation to keep the hydrogen liquid, will invariably be heavy in comparison to a tank carrying the same mass of kerosene. Tankage weight and drag penalties (due to its size) will be significant, despite the propellant being lightweight. Remember the Space Shuttle External Tank? Around 3/4 of the volume inside is liquid hydrogen, yet it only represents about 16% of the total propellant mass, the rest being taken up by liquid oxygen.

What about fuel mixes? As in, acetylene with some hydrogen mixed in? It has a higher flame temperature, though just by a few hundred degrees.

Disregarding the price (for now), is there any sense in using acetylene (C2H2) as rocket propellant, either plain or in a mix?