ULTRA LARGE LIGHTER-THAN-AIR CRAFT

So an uber big blimp? Or maybe a huge platform with many thoughsands of compartments space out over its area to hold this helium? That would be cool!

My problem with blimps is that they can get holes and leak out all that helium...and i dont think you can leave aside financial constraints, since they rule this world

It would be cool! However it would have to deal with the same problems that have plagued past and present air-ships, times 1000 or so: thunderstorms and high winds.

Excellent, thank you. A reply within ten minutes of posting. I found CR4 whilst researching Helium containment articles. After two hours reading I joined.

Migration of the tiny Helium atom through a given material: Metallised Mylar would appear to be the current best option to reduce losses. However, given the absurd scale of this concept that material would only be required for use in the outer "cells"

Regarding financial constraints have a look at "Dynamic Towers" and the proposed one in Dubai, and I thought my ideas were far fetched.

its hard not to respond fast when there is a good topic I am going to make one a little later i think, so look for it About my platform idea, by spreading out the helium 'bubbles', would this not provide support to the whole system?

any idea about the weight of this whole thing? Assuming a minimized case of a sphere with that much helium, how much of this mylar stuff would it take? Assuming this mylar stuff is like nylon with a density of around 1150 kg/m3, i calculated it would weigh 42 million kg (assuming a 5 mm thickness). This thing should be able to hold 1 billion kg! so, it seems there is some significant leg room...

Could the helium be heated to provide additional lift?

Hmmm. I'm not nitpicking here, I'm just not sure I understand the question. For one think, the "never needed to land" bit. You mean like for a week, month, year, 50 years?

One thing that I've read (in online forums like CR4 - for what that's worth!) is that current blimps generally loose around 3% - 5% of their helium every 24 hours. Even assuming that you come up with a wonderful new material which limits loss to 1% per day and simultaneously limits any outside gasses leaching into the bag to near zero, you'll have to generate/take on/steal from passing weather balloons some helium to stay in flight.

If you really can't sleep at night because you're pondering this, here might be a good book to start with Airship Technology by Gabriel Alexander Khoury & John David Gillett. I've never read it myself (I only travel by astral projection) but I'm sure it makes pleasant bedtime reading.

Interesting, "Airship Technology" I'll source a copy.

However, I have given some thought to Helium losses and replenishment.

There are economies of scale, surface area to total volume mean that the bigger it gets the less Helium you lose proportionately.

Also, in much the same way an aircraft carrier produces drinking water by reverse osmosis using enormous amounts of power perhaps the airship could distill air to make up Helium losses? Or simply have it delivered. (by air) One thing is certain, it's too big to land.

Hello OPENDOOR:

I too have often wondered about LTA craft. Though nothing like as large you are thinking about.

I have thought about the enormous 'sale' like side view and to perhaps to reduce the wind on an airship it could be made of several wing shaped compartments which may provide some lift and guidance/steer-ablility etc.

The scale you mention though is like trying to lay something very much larger than the largest building on Earth on its side? And keeping it 'afloat' and stable enough to allow fuel, crew, cargo and passengers on and off.

It all depends on your definition of "never needed to land"?

Perhaps this could be accomplished by loading crew, cargo etc into 'pods' which could themselves be floated up to be joined with the Mother ship? These in themselves would be substantial creations and would have to 'touchdown', so would this defeat your idea of "never needed to land" aircraft?

This is one of the most interesting ideas I have seen on CR4.......Keep it coming.

stay safe

babybear

Stability; A correctly ballasted LTA craft is dynamically stable due to its center of gravity being well below its center of lift. If disturbed from a balanced condition it will naturally return to that state without any control input.

Winds aloft; An untethered helium balloon in a 20knot wind has a 20knot ground speed but zero airspeed. Although it will travel 20 nautical miles in one hour, from its point of view, it is stationary in a fluid medium.

Loading and unloading, resupply, passenger arrival and departure: Ship descends to a suitable altitude, say 1000feet AGL, to allow aircraft to land and takeoff on its 4000m runway on the top deck. Some cargo could could simply be dropped with automated self steering paraglidding type wings onto the required destination.

Possible?

Hello OPENDOOR:

your post is very interesting. I have thought about LTA craft for years but, have dismissed it at just not practical. And designing something which can't land sounds almost impossible.

I do wonder even if it could land where the hell would you land it as a whole craft? Would the weight it carries be its downfall? Because on planes that are only a fraction of the proposed weight of the aircraft which is 4 kilometres long, there is always fractures caused by flexing etc. I just do not know how you could get round that problem. After all, everything wears out?

Just some thoughts...............

stay safe

babybear

Hello again babybear,

Similar questions were raised when super tankers were proposed; too large to maneuver, nowhere to dock, would snap in half etc. Yet the worlds oil is now transported in them. The LTA craft could, like a tanker, at the end of its working life be "beached" or brought into land gently in some desert area and dismantled. Remember, that whilst airborne, although its mass is around a million tons its net weight is close to zero.

I have put a lot of thought into how the structure could hold itself together. It would not be possible to simply scale up a Zeppelin's rigid frame, it could not support its own weight.

Visualise a horizontal section through the craft in plan view. Helium containment in hexagonal cells running vertically. Each hexagon composed of six two meter wide Mylar 22micron panels 400meters high. At each point of contact between cells three panels meet and are radio frequency welded together around and bonded to a 2mm to 10mm diameter Dyneema line. (at most points along its length the load/lift forces cancel out)

This structure is inherently strong yet can flex without fatigue problems but more importantly could be continuously fabricated as a whole from the top deck down.

Every six cells enclose a seventh. Within the seventh cell is a smaller hexagon 600mm on a side connected point to point to the larger cell by six Mylar panels. Every four meters vertically this smaller cell is divided horizontally by a Mylar membrane with a remotely controlled valve.

As the cells are created and filled with Helium (or possibly Hydrogen) the small hexagons are filled with water to exactly balance the emerging structure. The idea may not work but the numbers do.

Whilst I'm on a roll I might as well finish the idea.

The top deck is constructed first, made out of a lattice of composite carbon fibre beams decked with Kevlar plates (total density needs to be around a kilo per square meter all up) Dyneema lines attached and cell construction commenced. The entire, ballasted to zero buoyancy but as yet unloaded, ship rises until completion.

Passenger accommodation, restaurants, anything needing a view hangs off the top deck all around the ship like an upside down curtain wall construction. As load is added water is removed.

All the ships systems, cargo, manoeuvring engines etc are suspended below from the hundreds of thousands of lines from the top deck.

This is why it can't land.

Thank you and everybody on CR4 who have posted replies.

I put this idea on CR4 to see if anybody could provide a definitive reason why it would not work. I've run it past people with engineering, aviation and physics backgrounds. Surprisingly, in the last few months, I have started to think that it could, actually, be built and not only would it have a practical application but that the investment capital required is available. To quote the late Issac Asimov when asked if his fictional idea of a space elevator would ever be built he said "Oh yes, it will be built 50 years after people stop laughing" Well recently a laboratory in Turin, Italy, created a carbon nanotube fibre with potentially the required strength.

I look forward to your comments.

Hello OPENDOOR:

by the way, a most inappropriate name for an aircraft builder/designer..............

I forgot to mention about the difficulties of maintenance of the engines and the ship itself.

Tell me, how did you figure out the payload of 960,000 Tons, when you do not know what the machine will be made of? Or was it a possible figure from the over all size, and so potential area for people, cargo etc?

I can see, just like super large ships, which will be about half the size of yours at least, you could carry your own water plant and possible [He] plant. As well as storage for restaurants etc.

stay safe

babybear

Hello babybear, amusingly I am actually a pilot. (fixed wing, heaver than air!) But no, I don't do parachute dropping.

Propulsion: One thought was to cover the top deck with photo-voltaic solar cells.

A rough calculation using 200watt per square meter panels (Sanyo make one) would yield around 60,000kilowatts. Enough to run some pretty big maneuvering motors.

More on that another time.

960,000 Tons is the total mass that can be supported by the proposed volume of Helium. Giving neutral buoyancy. And yes, a fair chunk of that would be water for ballast and trimming the ship.

What do you think?

Hello OPENDOOR,

You should change your user name to LTA!

Thank you for reply to my posts. Nice to know someone out there is listening!

Just you know, I am not saying for one moment it cannot be built.

I think having a helicopter pad may be feasable............a landing strip, well I can't see how you could get strong enough materials to make it, that are also light enough to fit the idea.

Say bye bye to the landing strip and I will be ready to invest!

How would you load the cargo and or the people? In such a huge ship with 1/2 a square km for the loading area you could and should be able to load almost anything which fits that cube? Moving it about and, loading and unloading is the critical areas.

I like the photo-voltaic cell idea. And you could also have the whole sides of the ship as Advertising?

One good thing is almost all of the 'ship' can be pre-assembled off site.

I cannot see why it should not be built if the figures work out. You say they do and from what I have seen they certainly sound feasible.

The one thing I think you cannot control is the wind pressure on the side of this airship. I have not worked it out but, a ship 4 kilometres long and 1/2 a kilometres high (was it?) the wind pressure could easily exceed the weight of the craft. (Where I live anyway!

You mention water as a ballast. It is very heavy. Would it not make sense to have 'industrial sized' high pressure tanks to collect the 'He' when you need to ballast the ship? Otherwise would you not need to replenish the ballasted water? The tanks could be made from the hi-tec materials you have mentioned.

stay safe

babybear

"............a landing strip, well I can't see how you could get strong enough materials to make it, that are also light enough to fit the idea."

Since the vehicle is a big gas bag (or box, if rigid), I think the landing strip could be a flexible "air mattress". Yes, small wheels would sink in, but the fabric could take it. Better, if the aircraft were equipped with skis or floats, which would reduce the footprint pressure, a fabric strip would be more feasible. Such aircraft can land on and take off from wet grass, so it shouldn't be difficult to develop a fabric surface which is comparably slippery, something like Teflon, or a brush. (I have skied, more or less, on brushes) Of course, if the forward speed of the LTA vehicle was adequate, the aircraft could land or take off at "zero ground speed" (vertically) relative to the landing strip. An aircraft like the C-130 should be suitable.

It used to be that dirigibles could carry fighter aircraft, which took off and landed with a trapese which extended from the belly of the mother ship and could draw them up inside after a hook on the upper wing engaged the trapese. With a monster mother ship, a landing strip seems a better arrangement. It could function with various aircraft and helicopters. The weight of the aircraft, when unloading, will have to be compensated for, but it will be small, compared to the mother ship, and aerodynamic lift should suffice.

Water for ballast is not much of a problem, but not likely necessary. In the old days, they condensed water from the exhaust of the engines, to compensate for the reduced weight of fuel. If the "Stratuscloud" ship is solar powered, water could be condensed from the air as needed.

If the passenger compartments are not pressurized (why not?), altitude would be limited to about 10,000 feet, at most. If so, weather will be a problem. A hurricane is not dangerous as (A) they can be avoided, and (B) the airship can just go with the flow. However, smaller scale events, like thunderstorms or tornadoes could well tear a big ship apart. It might be well to make it "self repairing". Of course, with on-board doppler radar, lightning detection, etc., it may be possible to avoid local weather events, but one would have to do it with 100 per cent certainty for the life of the ship. Remember the Titanic; it was only a one-time error in spotting bergs.

Never is a long time away! Most light materials have a problem with UV degradation, especially at high altitude. To stay up without huge amounts of propulsion energy, it would have to fly above the Jet Stream, where the winds are less. I believe I've seen something not quite as big as your idea, proposed in Popular Science, Popular Mechanics, or some similar magazine, within the last year or so.

Thanks for the heads up on the "Sky Hook"... Here's link if interested in the problems of heavy lifting airships: http://www.xconomy.com/seattle/2008/07/11/boeing-and-skyhooks-zeppelin-copter-faces-safety-challenges/

I had an idea that something like this would be a good way to save fuel for launching spacecraft. A giant platform haf way to space.

I was thinking much bigger tho, like 5 or 10 milez in diameter and a mile or 2 thick. I am also under the impression that hydrogen duz not leak az much, so haz 2 advantagez over helium.

Have you heard about "Hindenburg"?

Hydrogen diffusivity is much higher than helium one and has a small difference: It likes to form explosive mixtures. If a spark reaches the hydrogen surely the explosion could be heard all around the world.

This is the main reason nowadays no hydrogen is used for balloons, just hot air or helium.

Cheers

Hello Kwetz, yes I have indeed. I have looked into the design and construction of many LTA craft. Do have a look at this link; http://en.wikipedia.org/wiki/LZ_129_Hindenburg

A fascinating aspect of the Hindenburg is that it was actually designed to use Helium but the American government of the day withheld the technology from the Germans resulting in the destruction of the worlds largest aircraft ever and the near complete cessation of LTA travel. What a pity. By all accounts it was an amazing way to go places.

Regards.

" If a spark reaches the hydrogen surely the explosion could be heard all around the world." How can you mix oxygen with all that hydrogen to acieve an explosive mixture?

The Hindenburg didn't explode. It burned. A huge craft with a small leak could possibly burn "forever', if the H2 were replenished.

Helium replenishment in flight is impractical, because the helium content of air is so low. By lowering a hose to the ocean and using the on-board electrical power for electrolysis, H2 replenishment is possible.

The size of the proposed craft is comparable to the size of a thunderstorm. How flexible (deformable) can it be, and can you tolerate large vertical velocities? Consider the downrushes of cold air that can occur, as well as tornado-like updrafts. It doesn't take a lot of imagination to think of the craft up-ended, with one end 4km higher than the other, rain/snow/hail pelting it, etc.

How about a lot of smaller "blimps" essentially flying in formation? Individual "cells" could be repaired or replaced, loaded or unloaded, analogous to cells in a larger organism. In the extreme, say an encounter with a tornado or collision with a 747, it could disassemble into survivable "cells" and reassemble later. (Note: you can mince a sponge, then pour the bits into a bucket and the sponge will reassemble.)

Does this huge craft have some economic purpose? You want to evacuate a major city in a hurry? Perhaps it could declare itself a sovereign nation, issue postage stamps, and provide a tax haven for billionaires?

esbuck; regarding your comments about Hydrogen and the Hindenburg, exactly.

I purposely did not mention Hydrogen because so few people understand about gas/air (Oxygen) mixes. I had actually considered that most of the lifting gas would be H2 surrounded by (inert) He filled cells. And of course on-board electrolysis of water (condensed from the atmosphere?) powered by PV solar cells is the perfect answer. The craft could also burn some of the stored H2 to power the manoeuvring engines or indeed use it to power H2 fuel cells for electricity.

(an interesting water ballast versus electrolysed Hydrogen lift capacity problem has just occurred to me)

"...size of a thunderstorm." Yes, at 400m high and the overall size of London's Heathrow airport, it's big. This fact should not however be a problem if it could maneuver laterally. Vertically is easy. Avoiding developed storm cells is what all aircraft do. Even the Airbus A380. Riding the low level jet stream around the world should be quite possible, although pressurised areas or supplemental Oxygen for the passengers and crew might be necessary.

Economic purpose; 80% of the worlds trade is still moved by sea. Then it has to be unloaded and delivered by land. The next cruise ship to be launched (under construction in Norway) will carry over 5000 passengers, not to mention the crew.

The "just-in-time materials delivered for manufacturing" principle has been long established. It does not matter when you order it so long as it arrives when you need it. A fleet of these monstrous airships could be the "green" alternative to global freight transport and the huge tourist industry.

I do like the idea of issuing postage stamps. Zeppelin did.

Regards.

Thanks for the info. I thought containment wuz a special problem for helium. Seemed like hydrogen shoud be worse since the atom iz smaller!

They did a Hindenburg episode on Myth Busters. The question wuz whether the doped cotton skin or the hydrogen wuz the main cauze. It burned twice az fast with hydrogen in it, so it seemz to me that it wuod hav burned & crashed anyway with helium. The real thing burned in only 34 secondz!

"Thanks for the info. I thought containment wuz a special problem for helium. Seemed like hydrogen shoud be worse since the atom iz smaller!"

Helium is monatomic. Hydrogen molecules are diatomic, roughly the same mass as a helium atom, but larger, I think.

Hydrogen has some problems of its own. It "dissolves" in metals, leaking through "leakproof" containers and embrittling the metal.

Hmm. That leedz to an interesting idea.

Maybe a stable molecule can be made from hydrogen andor helium or whatever thats less dense than anything and too big to squeeze thru solid materialz.

The lesson is: "Don't use aluminum oxide dope to seal in the lifting gas inside the lifting cells."

Last I heard the Hindenburg caught fire because its outer fabric was covered with a highly flammable "dope" and the hydrogen containers within then caught fire. As best they could figure the H was too diffused to catch fire outside the containers which leaked slowly, but when the outside fire reached them ---WHOOSH! With modern materials it would likely be possible to build a much safer H dirigible, almost as safe as using He.

Yah Taganan,

Thats what I heard also. I think this may be an idea whose time has come. I have wondered about using a floating platform like this to launch space vehicles more economically. Perhaps a space elevator (carbon nanotube technology) could be started that way. This could even lead to weather modification by creating artificial clouds topped of course with solar fabric to harness the sun up where it could be gathered many more hours a day. We have the technology to make enormous leaps, not just here on earth but into space. The moon and then Mars would be just a hop away. I'm excited again. If NASA is paying attention I hope they don't drop the ball. If they do, hopefully they won't try to keep private ventures from doing something. I wonder who controls the airspace above the oceans. I mean, if we had a communal type platform made up of hundreds or thousands of separate cells, could we start our own country.

Computer analysis of the skeleton of some ancient giant birds of the dinosaur era, most of them with some 55 feet wing span, proved that those birds were extremely light.

Some authors estimate the weight of these birds as similar to the weigh of a 7 year old boy. All bones were as light as a plastic bottles filled with temperate air, and were formed by counter helicoidally fibers rolled at +/-45º angles, thus crossing as interlaced layers at 90º plus longitudinal fibers along those tubular bones. For sure it was easier to stay flying than to land.

Some great fossil sites have been found in Brazil and Normandy, France, with identical skeleton stiles, thus proving that those birds used to fly back and forth between Brazil and France every year. In those days Atlantic Ocean was slightly narrower, but anyway this implies a non-stop trip of about 7000 miles.

I guess Bart Rutan has something to say about those birds, may be that at Scaled Composites they are using some kind of carbon fiber rolled that way to get perfect tubes to assemble those magnificent flying machines.

In my modest opinion, Scaled Composites is the most beautiful company in the world, the perfect place where you should present your project.

Jaime Soto Figueroa

http://www.matharts.cl/

Fascinating Jaime Soto Figueroa, some wise person once said "study the past if you would divine the future", how true.

As a pilot I can honestly say that if I could remain airborne permanently I would, the Earth looks so peaceful from 5,000 foot plus.

Burt Rutan is a genius, the achievements of his company are extraordinary. You are quite correct that Scaled Composites would have no problem developing the required technology for my idea but I suspect that actually building it would require the GDP of a medium sized country!

Thank you.

One secret of making high resistance fiber tubes is air pressure inside the tubes. As you increase the air pressure to about that of car tires, the tube gets harder without need to increase the weight. May be that the bones of ancient birds were filled with high pressure tempered air, but to prove that it would be necessary to study current birds. In the case of Scaled Composites, they seem to use more shell like structures than tubes, and the fiber vector fields may be more at random than orthogonal fields.

Jaime

A number of years ago I submitted a design concept for a large airship with lifting numbers similar to this thread topic; It was sent it to Popular Science, which they did not publish but DID dialog back and forth with me for a number of months later. My idea was a helium raft of multiple cells holding helium AND having a moveable cover on the top leading and trailing and outboard topmost cell area's with a silver colored slip cover over a number of transparent air cells coated on their bottom with flat black. The slip covers were to be attached to pulley ropes on each side and moved back and were used for shade or to let in sunlight, controlled by small servo motors from a control cabin... These were for attitude control and over all fine balance during daylight operations. In addition solar electric cells would cover a large percentage of the top of the "raft airship," to charge batteries and power the ducted prop motors.

Suspended by cables, UNDER the relatively flat helium raft would be a platform for crew, amenities, cargo and a STOL aircraft strip for crew rotation and consumable replenishment as well as a ducted propeller propulsion system on 360 degree gimbals to move the continents that would be this heavy load hauler system's "commercial territory." The engines driving D.C generators, fuel for them and auxiliary lighting generators as well as water and waste of course would be along the keel of the lower platform to add gravitational stability if the platform had no working load for any period of time.

Since this behemoth would be slow moving, axial and directional control of ducted fan props was deemed more positive for directional control, than kludgey, drag inducing fins and rudders although inflatable scags at whatever trailing edge was being used at the time, probably would be raised to reduce wasted steering energy at top design speeds (Not much higher than 60 MPH.).

Spiral stairways or one-man elevators would give access by the crew to the lifting cells above, gained by fabric covered tunnels stretching to every nook and cranny throughout the hundreds of honeycombed lifting cells. The tunnels of course would also be the routes through which monitoring and control fly by wire systems would be laid throughout the lifting cells; helping to reduce the crew size by having the needed data about the ship's condition centralized in a control and operations main cabin.

That is the gist of a 35 year old design concept that could not work because lightweight computers were not available at the time. Gimbaled ducted props are now common, STOL aircraft are off the shelf, Li Ion Batteries are to be had saving TONs of storage weight, etc., etc., etc. Only the will and imagination to be a Sky Sailor hauling lucrative loads at a fraction of railroad shipping costs, Internet weather connections to help make dodging weather systems routine, when needed, keeps the concept from being a reality, now.

LRH?--Taplin?--C-Mac

This idea has been around since ballooning started, safety has always been the big problem not technology to do it. It even came up when a new Sydney airport was being looked at, as new technologies in vertical take off and hovering stratocruisers that would only land at maintenance intervals were discussed. Should be some thing on the net some where.

The barrage balloon that protected British cities in WWII came through a guy who suggested putting anti aircraft guns on the clouds during a think tank meeting. The idea is a good one if you can stop them blowing up or falling down.

Here is a link to a proposed luxury cruisliner "heavier than airship." http://www.popsci.com/aeros/article/2006-02/flying-luxury-hotel

Thank you Tinker65, that's quite made my day. I'll give the guy a call. Seriously.

wonderful aircraft

My thanks to Tinker65 for this information.

To anybody who has been following this thread please have a look at this link;

http://www.aerosml.com/ml866/

Their method of controlling lift solves so many of the problems associated with LTA craft.

Hi to all,

this is turn out to be a great post!.

I have followed this link:

http://www.popsci.com/aeros/article/2006-02/flying-luxury-hotel

The craft is tiny compared to the proposed 4,000 metres of the original post.

It is more like flying a version of the entire passenger buildings of Heathrow Airport!

Wow.............How is something that huge controllable enough when it picks cargo and passengers and fuel up? Whats stopping it drifting into any buildings on the ground?..............Or, Would the airport have to be subterranean, so theres nothing to 'bump' (putting it mildly!) into?

stay safe

babybear

It is an interesting proposition and probably could be made to work. Whether it would be practical and profitable depends on a lot of other factors. How would it work in weather when trying to go from point to point? The methods of resupply, crew transfer and such could be a problem. As a huge freight hauler or platform for space launches it might be ideal.

To drop back to something smaller, what about the possibility of replacing jet airliners with dirigibles for the long trips at least? A jet plane uses a lot of fuel to get off the ground and stay in the air. A dirigible uses a lot less fuel. It may be slower, but much more comfortable than an airliner too. Modern weather prediction could easily steer them away from storms and into tailwinds. Since they float in the air, bad weather would mainly affect them in relation to their ground speed and they could rise above all but the largest storms. Bad weather could delay landings, but they could stay up until the weather passed. If on the ground, they would take off before bad weather or remain in their hangars. Some inconvenience to passengers in a hurry, but offset by the lower cost and greater comfort.

Using solar power would mean adding weight for the batteries to power it at night. You could use whatever combination of the cheapest fuel and most efficient engine that was best to make it economical and clean. If weight is not important, then solar power would work, or some hybrid system that didn't need batteries. It could even use steam engines fueled by coal if it came to that.

Hello Taqanan

Have a read through my replies to this thread, I've tried to address most of the points you raise.

In particular have a look at the link in post number 37. It looks like this craft will be built partly because there are plenty of people with enough money to buy one but more probably because the US military are interested.

Never saw one before, but this is very much as I imagined. Hope they do build it.