DS897: The Vacuum Balloon & The ElectroThermal AirCube
David Noel
<davidn@aoi.com.au>
Ben Franklin Centre for Theoretical Research
PO Box 27, Subiaco, WA 6008, Australia.
The vacuum balloon concept is a personal favourite with me, one of my earliest device ideas, dating from 1982 -- the "dark ages" before the Internet and the World Wide Web existed. Here is a summary on the concept, from an earlier AOI article (References [A] and [1] ):
Objects which float in a fluid, such as a ship in water or a balloon in air, do so because they are are subject to an upward force ("the upthrust') equal to the weight of fluid displaced.
A balloon floats if its average density is less than that of the volume of air which it displaces. Typical balloons use hot air or a light gas such as helium to reduce their average density. Their upthrust is equal to the weight of the air their volume displaces, less the combined weight of the balloon skin plus the light gas they contain. Hot air balloons work because the density of hot air is less than that of surrounding unheated air. Balloons typically have flexible skins, although rigid skins are also possible.
If the gas within the skin was replaced by a vacuum, the upthrust would be at a maximum, but the skin would have to be rigid enough to withstand the pressure of the external air without collapsing. That is the basis of the Vacuum Balloon.
Wikipedia has an article on the concept, its history, and implementation attempts, under the title "Vacuum airship" [2].
My History with the Vacuum Balloon
I thought of the idea of a vacuum balloon in 1982, and wrote it up and submitted it to the journal "Speculations in Science and Technology" (SST) who published it in 1983 under the title "Lighter than air craft using vacuum" [3]. This article is reproduced as a PDF at reference [B]. At the time, I assumed it was an original idea.
Around that time, I read a science-fiction story by Arthur C Clarke which was set on a planet with a hydrogen atmosphere. In this story, one of Clarke's characters said that the only sort of balloon feasible in a hydrogen atmosphere was a hot-hydrogen balloon. This was reasonable, as hydrogen is the lightest of all gases, but it did not consider the possibility of a vacuum balloon, which would also work in such an atmosphere.
I sent a copy of the "Lighter than air craft using vacuum" article to Clarke, and made this point about his story. He replied graciously and said the article was very interesting, but why hadn't I mentioned Lana's work?
They say that "There is nothing new under the Sun", but when I followed up Clarke's lead, I was very surprised to find (in the 1875 edition of Encyclopaedia Britannica) that as long ago as 1670, a Jesuit Monk, Francis Lana, suggested an aircraft based on the vacuum balloon principle in his book Prodromo dell'Arte Maestra, published in Brescia, Italy.
The Encyclopaedia Britannica article notes that this was the first workable suggestion for manned flight. It could not have been made very much earlier, because 1670 was not very long after the nature of a vacuum was first realized.
Figure DS897-F1. Lana's Aeronautical Machine. From [4]/
In 2001 I thought that maybe I could sell, on some sort of basis, the use of new or neglected invention ideas ("memons") through a website. I assembled some 27 of these memons and put them up on the IdeasBank Website. A total of 15 of these memons were to do with vacuum balloons, made up of an introduction and 14 specific uses or implementation techniques [D].
The 14 specific memons were on:
Cropdusting; Elevated Transmitter or Relay Station; Firefighting Station; Geodesic sphere; Glideline Transport; Inflated skin; Maintaining Vacuum from the Ground; Pumping Material from the Ground; Sky Dams; Sky Hydroelectric Station; Sky Solar Power; Skyhook Crane; Skyway to the Stars; and Videorecord of Development Process.
As it turned out, the IdeasBank Website did not lead to anything useful, although it is still online. The vacuum balloon introduction memon includes the following explanatory notes:
Lana's design used four evacuated perfectly spherical copper globes each about 8 metres in diameter, with skins about one-tenth of a millimetre thick. While such structures would never withstand the pressure of the atmosphere under real conditions, and his design could never have been built, the hydrostatic calculations involved were valid.
This group of memons considers practical ways of building vacuum balloons using modern technology, and the uses to which they could be put. Their lifting powers could be very large -- one with a diameter equal to the length of the Graf Zeppelin, the largest dirigible yet built, would have a theoretical lift of around 80,000 tonnes.
The time which conventional balloons can remain aloft is limited by leakage of expensive helium in gas balloons or heat energy loss in hot-air balloons. Vacuum balloons could remain aloft permanently by pumping out any air leaking in from the surrounding air.
CAUTION. Construction of equipment at pressures above or below that of ambient air should only be attempted by qualified personnel familiar with the hazards involved.
In the event, the IdeasBank concept was completely unrewarding financially, but has been left on the web as a monument to some sort of folly.
Towards the end of 2002 I retired and no longer needed to continue in the commercial world, but it seemed a shame that I had all these ideas which maybe somebody could put to good use, so I started writing some of these ideas up briefly in my Pandora's Box website [E]. Here are Pandora items involving the vacuum balloon:
*The Vacuum Balloon, a new approach to Building 'Skyhooks" with a great range of Uses (at www.aoi.com.au/pandora/frames5383.htm)
*A new More Practical Approach to a Space Elevator. (at www.aoi.com.au/pandora/frames7566.htm)
*Into Space Safely, Slowly, Cheaply: a new route using Vacuum Balloons and Orbit Rings
(at www.aoi.com.au/pandora/frames7507.htm)
*Space Webs, a potential framework for pumping material from the Earth to the Moon (at www.aoi.com.au/pandora/frames3638.htm)
The 1982 SST article included a summary, "Possible uses of Vacuum Balloons and their future", which is available at [F].
Is a vacuum balloon really a feasible device?
The Wikipedia article on Vacuum Airships [2] looks at past implementation efforts and whether such a device is really practicable. It suggests:
"The main problem with the concept of vacuum airships is that, with a near-vacuum inside the airbag, the exterior atmospheric pressure is not balanced by any internal pressure. This enormous imbalance of forces would cause the airbag to collapse unless it were extremely strong (in an ordinary airship, the force is balanced by the pressure of the lifting gas, making this unnecessary).
Thus the difficulty is in constructing an airbag with the additional strength to resist this extreme net force, without weighing the structure down so much that the greater lifting power of the vacuum is negated"
The Wikipedia article also mentions a number of patents or patent applications made for vacuum balloon craft, including a US patent granted in 1921 to Lavanda Armstrong [6]
Figure DS897-F2. Lavanda Armstrong patent application. From [6] .
Lavanda Armstrong's patent notes that "This invention relates to an air craft rendered buoyant and capable of ascending by the employment of a vacuum, or near vacuum. The prime object of my invention is to furnish a type of craft for air navigation in which a compartment can be used from which air is to be exhausted whereby to create a vacuum, or near vacuum, for lifting purposes".
So, with vacuum balloon devices under consideration for well over a hundred years, are they really within the realms of practical construction?
At this time, my view is is that construction may yet be feasible with modern materials, but that there would be no point in doing so (other than settling a scientific question). The inherent possibility of a catastrophic failure of a working piece of equipment will rule it out as worth putting money into.
But there is an alternative which appears possible without the danger of catastrophic failures. This alternative is one version of what are called AirCubes.
The ElectroThermal AirCube
AirCubes were the subject of an article, "Modular AirCubes: Attenuated-air Devices for Lifting, Transporting, Building, Energy Capture, and Agriculture", which I had published in a Brazilian journal in 2021 [4]. A revised version, "DS911: The Modular AirCube: A basis for all manner of lifting and transporting devices, structures, and edifices", was placed on the AOI Website in 2022 [C].
Briefly, AirCubes are a development of hot-air balloons and hydrogen balloons, intended to be constructed and used in modular fashion.
Consider a cubical structure made of plastic sheeting, measuring 2m x 2m x 2m, filled with air at ambient pressure. This is fitted with an electrical heating element, and a valve allowing pressures within and outside the Cube to equalize.
If the heating element is switched on, the air within the Cube will heat up, and its increasing pressure will cause some of the heated air to vent through the valve. As more heat is added, the mass of the vented air will become equal to the mass of the Cube's plastic walls, and the AirCube will start to rise.
This is exactly the same physics as that of a conventional hot-air balloon. In a conventional setting, the AirCube will rise to the point where its average density (the sum of the mass of contained hot air plus the mass of the walls, divided by its volume) is the same as that of the surrounding air.
Because the pressure inside and outside the Cube is the same, the Cube will retain its shape. Manipulating the heat produced from the element and operation of the valve will allow the Cube to rise or fall.
How hot would the air within the Cube need to be? That would depend on the construction material (plastic) used and the outside temperature, but using typical values, the answer would about 80 degrees C. As the air in a typical hot-air balloon may be heated to about 90 to 100 degrees C above ambient temperature [5], there is plenty of scope for an AirCube to be heated up enough to carry a workable payload.
Figure DS897-F3. Mass production of AirCubes. From [4] .
An important feature of the AirCube proposal is that their usage would be modular, mostly involving ranks of multiple cubes, clipped or fixed together to meet any required payload. Details are given in [C] of a suggested method of mass-producing AirCubes from rolls of material. Because the modules are all same-size cubes, they would mesh together perfectly.
In many of the uses suggested in [C]. the arrays of AirCubes providing lift would be quite bulky compared to the payload. But that is the normal expectation with conventional hot-air balloons.
Figure DS897-F4. The payload of a hot-air balloon is small compared to the balloon.
An average hot air balloon with a volume of 2800 m3 can lift a payload weighing about 1000 kg [7] . Specialist hot-air balloons have been built to carry payloads of several tonnes. Because of their modular nature, there is no practical limitation to putting together enough AirCube modules to carry any desired load.
Many uses of AirCubes apart from simple transport are considered in [C] . An example is shown in Figure F5, of a Services Corridor floating above ground, carrying ducts, cables, and pipes to convey water, hydrogen, communications and internet, parcels and goods, and electricity.
Figure DS897-F5. Services corridor floating above ground supported by AirCubes. From [C] .
Here then is an alternative to the Vacuum Balloon which is clearly quite practicable to build and operate without any concerns about catastrophic failure.
* * * * * * * * * * * * * * * * * *
AOI articles with relevant evidence
[A]. Vacuum Balloon -- IdeasBank Memon.
[B]. Lighter than air craft using vacuum.
[C]. DS911:The Modular AirCube: A basis for all manner of lifting and transporting devices, structures, and edifices.
[D] Vacuum Balloon: IdeasBank Memon.
[E]. A Pandora's Box of concepts for the 3rd Millenium.
[F]. Possible uses of Vacuum Balloons and their future.
References and Links
[1]. David Noel. Vacuum Balloon - IdeasBank Memon. www.aoi.com.au/ideasbank/5813.htm .
[2]. Vacuum airship. https://en.wikipedia.org/wiki/Vacuum_airship .
[3]. David Noel. Lighter than air craft using vacuum. Speculations in Science and Technology, Vol. 6, No. 3 (1983).
[4]. David Noel. Modular AirCubes: Attenuated-air Devices for Lifting, Transporting, Building, Energy Capture, and Agriculture. CALIBRE - Revista Brasiliense de Engenharia e Fisica Aplicada, Vol 6 (3), 2021.
[5]. About Hot Air Balloons. https://www.outbackballooning.com.au/balloons/ .
[6]. Lavanda M Armstrong. Aircraft of the lighter-than-air type. US patent 1390745 . Published Sep 13, 1921.
[7]. Why do hot air balloons fly? A scientific explanation of the mechanics of balloon flight. https://proballooning.com/en/why-do-hot-air-balloons-fly-a-scientific-explanation-of-the-mechanics-of-balloon-flight/ .
Version 0.8 on Web 2006 Jul 22
Version 1.1 on Web 2006 Jul 24
V. 2.0 Redone as DS897*, 2025 Jul 20, incl. ElectroThermal.
