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Fuelless Flight with Air Submarine?
An anonymous reader writes "Using the same physics principles as submarines, a new company is planning a fuelless air ship. Recent advances in ultra light and strong materials are making this concept a practical reality." There's no question that changes in buoyancy can be used to propel a vehicle, but "fuelless" is going to be tricky.
Isn't that what the sci-fi writers of the 1940s/1950s thought the future would be like? After all, the Empire State Building has a blimp port at the top. I'll stick with good old ozone layer killing cars, thank you.
Wouldn't something in the air be a Supermarine?
Want to improve your Karma? Instead of "Post Anonymously", try the "Post Humously" option.
Fuelless falling.
Using the same physics principles as submarines, a new company is planning a fuelless air ship.
Isn't a fuelless air submarine usually called a "balloon"?
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
It's a little creepy that this website looks like this other famous site and that they both advocate leaving the earth for a long trip in a high-tech airship. Coincidence?
HIV Crosses Species Barrier... into Muppets
All the same, it's still a cool idea. I want a small one to fly to work in (maybe add pedals for all the compression-> decompression stuff and you'll have a human powered plane ;)
Looks can be deceiving. Or CAN they?
The pontoons will be multiple layers of Kevlar and epoxy, which weigh as little as 1 lb/ft2, around a rigid carbon-fiber airframe
I've heard that there's a really bad problem from lightning strikes if you plane isn't made from an excellent conductor like metal. Various attempts have been made to make non-metal composites that don't get badly damaged by a strike. If this plan goes really high then this will be a problem.
Can some engineer tell me, have they solved this problem or is this idea just hot air?
Like all pain, suffering is a signal that something isn't right
However, just because it may not use fuel to continue on it's journey doesn't mean it didn't need some power to get it started...
Physics 101. Law of thermodymanics. Etcetera.
This issue is a bit more complicated than you think.
To save on the compressed air, just fill me full of mexican food, and I could provide a cheap source of propulsion. Or we can outsource that to Mumbai.
Oh, the backup engine is there alright. We just neglected to carry fuel for it onboard :D
Because you never know when you might run out of air up there!
You know... there's another name for flying without fuel. Its called skydiving!
The only thing necessary for Micro$oft to triumph is for a few good programmers to do nothing". North County Computers
In the even of a water landing your seat cushions may be used as a floatation device.
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
Well this PhD smells a quack (from the link on the page http://www.fuellessflight.com/techno/tech.htm):
"We humans can rarely invent any process that nature does not already use. Most of the science we know today merely copies nature. Our thermodynamic laws were formed by observation of nature. They are not proven, merely not disproved. Within this section of our website you will be taught a new science that mimics the earth's weather, by harnessing the dual forces of gravity -- buoyancy and gravity acceleration. Harnessing gravity may be more technically described as the science of harnessing mass differentials. High density mass falls within a low density lifting fluid, like rain falls from the sky, and low density mass rises in a high density lifting fluid, like a bubble rises in water or helium rises in air."
I think I understand the technology he is proposing (I'm confident it still requires input energy, beyond the environment), but he really should tone down the quack-o-meter. I think we can rest easily that the thermodynamic laws are intact.
-Sean
This thing is supposed to fly because of a combination of reduced bouyancy (by way of creating multiple vacuum's inside it) and stored energy (by way of a turbine invented by the apparent author).
The turbine is for compressing air, to be used as power storage. I think.
If your craft is dependant on creating a vacuum inside for easy lift, but your power supply is compressed air, don't the two kinda cancel eachother out?
Even if you made it and got it up, what would it be like to try to control a zero-weight plane with mass? I picture it flipping around in the wind like a feather...
The aircraft, still in development, will be similar to a submarine that changes its buoyancy, a form of gravity, to float on the surface of the sea or cruise 300 ft below it.
Stephen J. Mraz, "Senior Editor," is in need of a severe beating. Since when is buoyancy "a form of gravity?"
I stopped reading there. Nothing bothers me more than shitty pseudoscience.
According the the white paper on the "Technology" link:
.0755 pounds per cubic foot lifting capacity for air).
The gravityplane must be very large in order to be lifted by a lighter-than-air lifting gas such as helium that provides a very low amount of lift, thus a small gravityplane can never be built and models of the craft will always be very large. However, a scale model of the gravityplane can be built as a sea glider that is less than 30 foot long that will be capable of holding four passengers. The sea glider can work in water at this small size, because water has a lifting capacity 821 times greater than the lifting capacity of air (62 pounds per cubic foot lifting capacity for water and
If at 30 feet a gravityplane can hold 4 passengers, could this design ever provide a viable means of transport for larger groups of people?
30 feet/4 people = 7.5 feet/person
Thats approx 75 feet per group of 10. Makes for quite a large plane for even medium sized groups.
For cargo I suppose this could be cost effective depending on the maintenance costs and its lifetime. Lets assume that an average person weighs 200lbs (I know it may be too large, but to allow for an optimistic view of the plane's carying capacity).
7.5feet/200lbs ~= 1foot/26lbs
May be good for cargo because shape, size and conditions don't really matter.
Nope.
Much older.
Carl Sagan, Robert Heinlein, Ray Bradbury, and a number of other scientists and writers were inspired by "The Martian Tales of Edgar Rice Burroughs". The first one, "A Princess of Mars" was published in 1912. (And it's on Project Gutenberg!).
In these books, John Carter was mysteriously transported to Mars, which was called Barsoom by the inhabitants. He became the Prince of Helium (a city/city-state -- not the element). The Barsoomian navies had huge airships that were held in the air by use of the 9th (or 8th?) light ray, so they needed no power to stay aloft. (According to Burroughs, we only know of 7 rays of sunlight, as seen in a rainbow, from red to violet, but Barsoomian scientists had isolated 2 other colors, never seen on Earth, and one of these colors is what gave light a repulsive power so it was repulsed from objects and reflected to our eyes, and it was used to keep the Barsoom airships in the air.)
The Martian Tales are far-fetched, but a ripping good time to read (at least the 1st 10 are -- skip the last one).
When I first read the story, all I could think about were E.R.B.'s descriptions of the huge naval vessels floating through the air of a dead planet (there were no sea going navies, since there were no seas, except one at the south pole).
Too bad these stories seem all but forgotten now.
That reminds me of the old joke back in the Navy... I think it went: There are more airplanes in the oceans than submarines in the sky.
I guess that's no longer true. :-)
The aircraft, still in development, will be similar to a submarine that changes its buoyancy, a form of gravity, to float on the surface of the sea or cruise 300 ft below it.
What's scarrier, flying without an engine, or that the general public won't think twice about this sentence?
In this house, we OBEY the laws of thermodynamics!
you need energy.
That would be the helium in this case. You could argues that it takes energy to build the thing, during which contained energy would be loaded via fuel powered vihicals, but thats a little overly semantical.
I mean, I can fill a ballon with helium, and it will rise without power.
The Kruger Dunning explains most post on
Even if you ignore the fuel needed to pump the helium in and out of the storage, they will need the power to propel the "gravy"-plane forward
They don't plan on pumping the helium in and out. It looks like they plan on leaving the helium static in the tanks, and pumping air in and out of other tanks, making the plane weigh more and less. However, it's not really the weight of the plane that matters, it's the density. The goal is to get the average density of all the materials onboard i.e. the people, instruments, seats, structure, tanks, etc to be less than the density of the air around it. This is where I think they will have problems.
Anyone familar with aviation or the atmosphere knows that the atmosphere gets much less dense as you go up. Here in Columbus, altitude 1,000 feet, the density of air is 1.2 kg/m^3 At 10,000 feet the density is 0.88 kg/m^3 and at 30,000 feet it is 0.41 kg/m^3. This plane would have to have an average density less than those values to reach those altitudes, and keep in mind that simply having the cabin pressurized for humans will make the entire cabin a bubble of "heavy" air.
The energy to pressurize air will come from a wind powered turbine which will be deployed when the plane is descending, but I don't know how much power they expect to get from this. Any power produced by this turbine would affect the plane in the form of drag, which decreases speed and range. This would have to be a very flexible air storage system, since the requirements would change every day depending on high and low pressure systems, temperature, and the weight of whoever is on board.
They may also have stability and control issues. I assume that this would have to be a large plane, even with today's light weight materials. Just look at how big blimps have to be to carry their minimal cargo. A plane like this with huge wingspan and extreme buoyancy would be affected by every gust of wind and bit of turbulence that affected it, and although it could be very stable, control inputs would have to combat huge wind loads, and control effectiveness would be marginal, to say the least.
From my armchair view of this project, it seems possible on a small scale, but not to the point of carrying "massive loads" of people and cargo as the website claims.
My $0.02
Tumbleweed.
next!
"You worthless post!"
-Shakespeare, 2 Gentlemen of Verona, 1. 1. 147
When I first read the story, all I could think about were E.R.B.'s descriptions of the huge naval vessels floating through the air of a dead planet
I really don't want to sound like an Anime Fanboy here, but you might like to check out Last Exile if you haven't already seen it. It's a decent little series with some really impressive graphics, built around exactly that kind of concept...
3 more engines.
This plane (if possable) would have a very high glide ratio, so even if it crashes, unless it's a catastrophic failure, it could be a very soft crash landing.
To me this sounds like some intresting scifi, from a wild imagination, but not very well thought out. I'm shure that there will be something like this eventually, but most likeley not too soon.
The vehicle is really just a durigable with wings, I think that lighter than air flight has a potential to be come a really big thing in the next century, and that that is the angle to push, not the fuel-less flight aspect. Imagine taking an air cruise.
Well art is art isn't it, but then again water is water; and east is east; and west is west; and if you take cranberries
The idea that an airplane can fly endlessly carrying heavy loads of passengers and cargo without burning any fuel
So far so good.
The new hybrid "gravity-powered aircraft"
Starting to get bogus.
is formed by merging the capabilities of the following devices into a single new aircraft apparatus:
(1) an aircraft capable of aerostatic (lighter-than-air) lift to gain altitude; and,
Still OK.
(2) a glider aircraft capable of aerodynamic lift, having a high glide ratio to accomplish long range gliding; and,
Starting to get bogus.
("Glider"? Using diving planes to add a significant forward component to upward/downward motion is well understood. But a "glider" is something else - a high-speed device with significant aerodynamic lift - initially powered by atmospheric thermal energy in the form of updrafts storing energy by raising a NON-bouyant craft against gravity, then trading this stored energy for momentum as necessary by gliding downward. Raising a neutrally-bouyant object stores no energy.)
(3) a (patented, new design of Robert D Hunt) wind turbine that is capable of harnessing the force of wind to generate power as the aircraft glides downward. This cycle can be repeated indefinitely to allow the craft to stay aloft virtually forever.
Bingo! Perpetual motion.
You CAN get a lot of forward motion out of lift-driven vertical motion. But it takes ENERGY to adjust the lift. The submarines described in the original Slashdot posting are one example. Zepplins with diving planes that achieved speeds in excess of 200 MPH by this mechanism also existed in the mid 20th century.
But the Zepplins BURNED FUEL to change their bouyancy (by heating some of their bouyancy gas), just as the submarines use energy to compress or expand gas in their bouyancy tanks. This makes them a heat engine (though a slowly cycling one) and subject to the carnot cycle limit.
This craft proposes to use a turbine to collect energy from the wind of its passage and use that to adjust its bouyancy, use the bouyancy to produce forward motion, creating the wind to drive the turbine. Like a generator with its shaft connected to a motor which is also wired to its output, the energy goes around and around, with some being lost in every pass.
This is not to say it won't fly at all. But to the extent that it DOES fly it's getting its basic power from vertical air currents, just like any other glider. By being nearly neutrally bouyant it sacrificed the ability to store energy in the gravitational potential of its own weight at altitude, and it's replacing that by being able to convert the wind of its passage to stored electricity, then feed that back into forward motion via bouyancy adjustments rather than propulsive fans.
But I expect this to be more expensive and less efficient than other alternatives - such as an equivalent modification to the original 200-MPH zepplins WITHOUT the fixed wings.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Honestly, after reading this site, it smacks of all the hype around the Segway (and many similar, less-successful "revolutionary breakthrough" schemes).
Yes, it is possible to create a fuel-less aeroplane that can still maintain forward motion. Advanced glider technology certainly fits this description. However, there are a couple of things that are missing from the adware:
The physics of underwater motion are similar those of flight - basic fluid dynamics here. The problem is he's ignoring fundamental environmental differences between water and air. The density differences between the two make it possible to move large masses underwater, but only tiny masses in the air using the same principles. Not to mention that the fluid consistency and motion between air and water are radically different, which invalidates using the ocean as a model for the sky.
He's a fraud. Pure and simple.
-Erik
There are always four sides to every story: your side, their side, the truth, and what really happened.
You're forgetting that lift capacity goes by the cubic footage of the lifting body, not the length.
I'm too lazy to do the math, but a longer body would have a far larger volume in the lifting body than liner.
7.5 ft per person on a 30ft version != 75ft for 10 ppl.
"You worthless post!"
-Shakespeare, 2 Gentlemen of Verona, 1. 1. 147
Loosing power on only one side is not a picnic even. The remaining engines will have to push harder to maintain speed but this makes the entire aircraft want to turn constantly. Very few runways come in corners.
Gliders on the other hand are designed to ehm well glide. This thing would never suffer an engine failure. Power system (it does have one) fail? Simply glide gently down giving you a far wider range in wich to find a suitable landing splot.
There are many reasons this can fail but worries about safety because of a lack of engines ain't one of them . Note that it isn't a balloon. With wings that size it could exchange hight for speed and with that control over its direction.
MMO Quests are like orgasms:
You may solo them, I prefer them in a group.
Not quite. The idea is to use a large area of vacuum to provide normal lift. Then a second ballast tank can be adjusted will cause the thing to decend. When it decending, it uses the forward energy to spin the turbines which then powers the compressors. The steady state of this thing will be floating at 100,000 ft or so.
I think it can work if they can solve the "magical box that can hold a total vacuum that weighs less than the air its going to displace" part of the problem but thats been know about since the days of Boyl and Dalton.
This system uses the energy of the wather system to move around a device that wants to float at a n altitude above ground level. In that way its much like a sail boat. The reality is if anyone can build a large vacuum chamber, they can stick engines on it and get from LA to London much quicker than current jets if they can get up high enough. I figure this will happen about the time someone finds the right stuff to make a space elevator out of.
Since buoyancy is caused by gravity pulling the fluid (air/water) around you toward the earth and you moving away from the earth to take its place. "Form of gravity" is probably a less accurate term than "effect of gravity." Still, Stephen J. Mraz was right, you're wrong. How about that severe beating?
Nothing bothers me more than shitty pseudoscience.
Be careful when you deride things you don't understand. This isn't new technology. It's been in use in autonomous submarines for years. Employing the same principles in the air hasn't been done yet because it's a bit more complicated: The speeds are a lot higher, the weather becomes a factor, and the margin for error is a lot smaller.
"With sufficient thrust, pigs fly just fine. However, this is not necessarily a good idea...."
RFC 1925
The work required to pump all the air out of the ship to make it buoyant and rise to some height is more than the work required to just lift the ship that distance. Drag and any forward kinetic energy given to the plane implies that the energy recovered by the turbines during fall is not sufficient to pump all the air out of the ship again to once again make it rise, thus you will have to carry along fuel to run an engine to drive the pump that changes your buoyancy. If you use external power to evacuate the buoyancy chambers on the ground, then it can be said that the pressure differential represent stored energy. As the ship rises, gas pressure potential energy is traded for gravitational potential energy (altitude) and kinetic energy (forward motion).... So both the compressed helium and the evacuated chamber represent stored energy which must be loaded onto the ship while on the ground, thus this ship requires fuel like any other ship. Not only this but the inefficiencies in recovering kinetic and gravitational potential energy demand that the ship carry much more stored energy that that required to lift the ship through one up and down cycle.... So you may not hear the phrase "filler up" that the air park, but "emptier out" if effectively the same thing DN
The structural requirements of a vacuum are much greater than helium. The entire structure goes into compression and bending when in a vacuum, meaning it will need to be extremely strong in order to resist bending. This is a bit like sucking the air out of a 2 liter pop bottle, it will collapse easily, and the pop bottle will need to be substituted with a steel canteen in order to keep its form. Unfortunately, this kind of structure is heavy, and in terms of air ships are extremely inneficient.
A regular blimp inflates, so the forces on the skin are entirely in tension, the only bending forces are caused by loads the ship is carrying and more importantly, sudden wind gusts which could tear a weak ship apart. Structurally speaking, this is vastly more efficient and completely eliminates bending due to a vacuum, and the tensile force alone in the skin is often enough to provide a stiff but flexible frame, just like a ballon once inflated keeps its shape even under tremendous strain. It is a very resiliant structure.
There are two huge problems that have always existed with airships, and fuel is not one of them. The first problem is landing the craft. They have a tendency to blow around with even slight gusts of wind, and if anything happens like a downdraft, they can get smashed into the ground. The second problem is weather related. In violent weather, the thin skin on these ships can get torn easily. The larger the craft, generally speaking, the bigger the problems. This is not to say these problems are inherently unsolvable, but why bother using zero fuel when fuel already will cost next to nothing if it uses solar power or fuel cells.
Is a sailboat a perpetual motion machine? Is a windmill a perpetual motion machine? This ship could sail in 3 dimensions and draw power from a turbine. Theoretically, that is possible. Althoug it does need some additional power, hard tack and beans possibly.
But what I don't understand is why he doesn't just create a giant inflatable airplane hybrid, that would probably work better. It could get 90% lift from helium and 10% from forward movement from a turbo fans powered by solar power. The helium ballon aspect of it could be the structural system as well, it would be an active system (inflatable), rather than a very heavy and expensive rigid frame.
My goodness, that video is so verbally twisted virtually anyone not having a clue would buy into it.
Of course that is the intent. Their perpetual motion is a complete farce. If you listen to the explanation (I know, it's ludicrous) they're basically saying you can get more air going down then you can going up.
Some other fallacies is the "lighter than air" effect. If you've ever seen a blimp, then you realize the size this craft would have to be in order to carry even the lightest loads. Helium is only "lighter than air" when it's density is lower. This is the whole "which weighs more, a pound of lead or a pound of feathers" argument.
Along those lines, you'd also need to take into account the expansion effect. Let's use weather balloons as an example. The higher they go, the bigger they get. Air pressure drops as you go up, therefore the greater air pressure in the balloon expands it outward. If it didn't, then the balloon would reach an equilibrium and go no higher. This craft would need to also take this into consideration. This could be quite a technical hurdle, gliding an aircraft that is constantly changing dimensions.
Regardless, the craft would at least need to carry some onboard power source.
I take this "article" with a big salt lick.
~X
Random Quote:"If it's too good to be true, then somebody is getting rich and it isn't you."
~X~
>To be safe they re-ran the numbers three times to be absolutely, positively sure the refuelers hadn't made any mistakes; each time using 1.77 pounds/liter as the specific gravity factor. This was the factor written on the refueler's slip and used on all of the other planes in Air Canada's fleet. The factor the refuelers and the crew should have used on the brand new, all-metric 767 was .8 kg/liter of kerosene.
Lessons: a triple-check doesn't help you if there's a systematic error. Standardized measurements are a Good Thing.
>the EICAS issued a sharp bong--indicating the complete and total loss of both engines. Says Quintal "It's a sound that Bob and I had never heard before. It's not in the simulator."
Lesson: in a safety-critical system, train the users for "impossible" situations.
>Hydraulic pressure was falling fast and the plane's controls were quickly becoming inoperative. But the engineers at Boeing had foreseen even this most unlikely of scenarios and provided one last failsafethe RAT.
Lesson: when your engineers go paranoid, if there are lives at stake then for God's sake listen to them. "Belt and suspenders" engineering saved lives in this incident.
>Quintal "got busy" in the manuals looking for procedures for dealing with the loss of both engines. There were none..
Lesson: learn from experience. There have been incidents, like volcanic ash injection, that have forced shutdowns of all engines on a jetliner. If your statistics say the engines can't fail at the same time, and the graybeards say they can, then you left something out of the statistics.
>The avoidance of disaster was credited to Capt. Pearson's "Knowledge of gliding which he applied in an emergency situation to the landing of one of the most sophisticated aircraft ever built."
Lesson: there is no substitute for a wealth of experience. Downsize your 20-year veterans to save money, watch things go wrong.
Sorry for the diversion, but these are things I'm passionate about.
Mr. Hunt describes it convincingly. Buoyancy is caused by the differing force with which gravity pulls on heavy and light things. Gravity pulls with more force on heavier things, (F=MA; mass is higher), and less on lighter things. Hence, the heavier thing sinks relative to the lighter thing. Buoyancy.
Not that anyone ever actually follows a link and reads what is there, but I recommend that all the "non-believers" here take a look at Seaglider.
Or follow this google search for even more.
Seaglider applies much the same principles as this vehicle but to an underwater environment. It has a small onboard power supply, but it alternately uses gravity and bouyancy to propel itself.
I may not be an Aerospace Engineer but I am an Ocean Engineer and Fluid Dynamics in air is the same as Fluid Dynamics in water. Just change your value for rho.
Just call it an airship and be done with it.
The blimp thing. Blimps are basically oval balloons. They hold their shape because they are pressurized. (blown up!) as such the gas inside is under pressure, I imagine quite a bit ~5 lbs/square inch at least. This is in direct conflict with the goal of being bouyant, as pressurized gas is more dense.
On the other hand, this plane would be a rigid airship. It would hold it's shape regardless of pressure inside (within limits, too much or too little, pop or squish.) My point here is that comparing rigid airships to blimps in lifting volume is not that simple. Also, rigid airships can have much better areodynamics than blimps. Oh, and they do not constantly change shape. If you want to go higher, either have the gas bags inside only partly full at the fround (limits lift, does not waste gas) or add valves and vent it (limits range, cause you will not have enough lift when you decend again, unless you use ballast . . .)
I take this article with a large bucket of salt too, but not for any of the reasons you listed.
Laws are horrible moral guides, moral guides make even worse laws.
just as the submarines use energy to compress or expand gas in their bouyancy tanks. This makes them a heat engine (though a slowly cycling one) and subject to the carnot cycle limit.
The followup poster has exposed an error in the above, (though not the one he thought.)
Actually, as long as you compress and expand gas adiabatically, then the Carnot cycle is irrelevant.
Actually, adiabatic expansion and compression are two of the four cycles of a carnot engine. (The others are adding heat to the compressed gas at constant volume and removing it at constant volume.)
My carnot cycle argument applies to the case of the mid-20th-century airships where the bouyancy was adjusted by heating the gas. It IS irrelivant when you're adjusting the bouyancy by, say, using an electric motor to compress it into a tank. (Though other heat engine arguments do apply. See below.)
The conservation of energy argument also applies. I'll show you where the detailed physics of the process make it show up when we get a little further along.
Obviously you cannot make an engine that works in this way [losslessly], because the point of an engine is (1) to do net work or (2) to cause a heat transfer. So the efficiency of any engine cycle has a Carnot limit.
Right.
But the process you have described need not be an engine. In fact, this should be completely obvious. Since there is no net work being done, and no heat transfer, how on earth can you even define an thermodynamic efficiency for the cycle?
Even the process of compressing and expanding the gas makes this into a heat engine. Compressing the gas heats it. The heat must be dumped. Expanding the gas cools it, and heat must be applied from an external source to bring it back to temperature.
This doesn't make carnot apply, though. But it DOES lead to additional losses if you don't do your compression and expansion adiabatically.
You must compress slowly, and dump the resulting heat without forcing it across a significant temparature difference. Similarly you must scavange the energy when it expands by running it through an airmotor to extract the energy and recharge your energy storage. (Otherwise the energy gets dumped.)
But the temperature change takes place in the compressor/airmotor. This makes it very hard to add or dump the heat across negligible temperature gradient in order to perform the operation adibatically.
(You also get losses in the generator/motor/battery system, or whatever you're using to store the energy for reuse. The total of these losses is so high you're probably ahead to do the bouyancy adjustments with heat in the first place. But then you ARE a carnot cycle heat engine.)
All of the above are efficiency issues, however. They represent precentage losses of useful energy as it it transferred from one form to another (gas pressure, temperature, height of mass in gravity field, momentum, etc.)
You ARE an engine, by the way, because you're doing work: Lifting and lowering the mass of the vehicle, driving the vehicle against air resistance.
And you don't even need to get this complicated. (Slow) compression and expansion of an isolated volume of a gas is reversible and adiabatic. Hence it is isentropic.
Right.
But that doesn't mean the total cycle is reversible.
In the airship case, the compression occurs when the ambient pressure is low, and the expansion when the ambient pressure is high. Even if your compressor/airmotor was perfect, the difference represents a loss of energy - specifically, the energy necessary to raise and lower the vehicle, which is lost to air friction from the vehicle's motion. (Thus conservation of energy is not violated.)
So why not just use a propeller?
If you're heating the gas to adjust the bouyancy, on the other hand, you ARE a heat engine. So you don't beat carnot, (and have to input maybe three or more times as
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
It my be the second most common element in the universe but we have a hard time getting it. Helium is mined from limited reserves and like fossil fuels takes millions of years to be produced. For this to actually be reusable (for years to come) it has to use vacuum, or dare I say it, hydrogen. Hydrogen is easy to get hold off and only dangerous when mixed with oxygen. It also has much better lift. But I suppose I shouldn't complain when someone puts forward an idea for clean flight AND gets some attention.
One thing that everyone keeps forgetting is drag / weight / size. The type of equipment that this guy is talking about is going to take up a lot of space. Usually things that take up space weight something. Things that also take up space require energy to move them through the air. His only form of propulsion is gliding / compressed air, but gliders are usually extremely aerodynamic vehicles with a high glide ratio. Drag and the weight of the aircraft are directly related to such a ratio. So in theory, the super marine would go up, glide a foot, and then have to repeat. Not to mention maneuverability. Highly impractical.