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Blade Runner, that's what *immediately* leapt to my mind too. I wonder if these things will have giant display ads on the sides? "Sponsored by the Exxon Corporation" maybe.

protip - active camouflage can be easily be repurposed as an electronic billboard. And vice-versa.

Actually, Goodyear Blimps do not drop ballast or vent helium.

http://www.goodyearblimp.com/faqs/faqs_construction.html#air

If the ship doesn't let off helium, how does it come down?

Inside the envelope are two air chambers called ballonets, one forward and one aft. They can be pumped up with air from the outside or allowed to deflate as the helium expands and contracts. Since air is heavier than helium, inflating or deflating the ballonets will add or subtract weight from the nose or tail, thus trimming the ship. Using the pilot controlled rudder and elevators the ship can fly up or down in the ocean of air and maintain its proper envelope pressure without having to drop ballast or valve off helium.

Ummm... Unless I'm completely misunderstanding you, the machine you describe is sometimes known as a blimp. It's nothing new.

But even if I am misunderstanding you, I think you (and the parent) are missing one fundamental point: While a deformable body certainly would seem to have advantages, it's not what they have invented. It's kind of like asking the Wright brothers why they didn't invent the 747, when it clearly has numerous advantages over the Wright Flyer. The Dynalifter has several very distinct advantages over current technologies, and those advantages do not require the use of a deformable body. It's entirely possible that the addition of a deformable body could provide additional benefits to a later version, but it would require a much larger technical breakthrough to achieve. The current idea is basically ready to go, so why spend several more years and hundreds of thousands-- or more likely millions-- more dollars working to achieve the ideal solution, when the current one is still pretty damn good?

Let's use the Goodyear blimp as an example, as they have a few stats available on their site.

Goodyear Blimp

Weight: 5,824 kg, Length of car: 6.9342 m

Volume: 5,739.8248 m^3, Buoyant Force of Helium: 1.1 kg/m3, Buoyancy of Blimp: 5739.8248 m^3 * 1.1 kg/m^3 = 6313.80728 kg

Guessed width of car: 3 m, Guessed height of car: 2 m, Guessed thickness of walls: 3cm

Density of Aluminum (material of car): 2700 kg/m^3 Guessed weight of car: 2* (6.9342 m) * (3 m) * (2 cm) * (2700 kg/m^3) + 2 * (6.9342 m) * (2 m) * (2 cm) * (2700 kg/m^3) + 2 * (3 m) * (2 m) * (2 cm) * (2700 kg/m^3) = 4,392.468 kg (in actuality probably more due to conservative estimates, the fact that some steel is used, and)

Approximate weight of engines: 2 * 181.436948 kg = 362.873896 kg

Approximate total weight of balloon part: 5,824 kg-4,392.468 kg-362.873896 kg = 1,068.6581 kg

If we assume that the blimp is about the surface area of a cylinder of length 45.72 m and radius 12.192 m (actually it is non-cylindrical length 192, width 50, height 59.5) then:

Surface Area: 2 * (pi * (12.192 m)^2) + (2 * pi * 12.192 m)*(45.72 m) = 4,436.32532 m^2

Approximate weight of balloon material: 0.241 kg/m^2

Weight added by adding largest possible vertical compartment separator: (pi * (12.192 m)^2) * 0.241 kg/m^2 = 112.542569 kg

So, leftover buoyant force of helium at 6313.80728 kg minus weight of blimp at 5,824 kg would allow for a few separators (note that any other separators would be lighter as you go to the extremities) ... and if you lighten the material a bit and use a balloon that is five times the size (like the one in TFA), you could add many more. Also, due to my conservative estimates, the material is probably lighter. There would probably be a critical number that would allow a couple to be pierced and still maintain buoyancy or nearly so.

So, in conclusion, I don't think it is impossible.

Just my estimates, but IANABE (I am not a blimp engineer).

Sources: Goodyear blimp

On top of that, I looked at their website and it appears that the new blimps they're selling aren't even Zeppelins: they aren't rigid airships and they aren't filled with hydrogen.

I was hoping that somebody had gotten over the bad rap that hydrogen got after the Hindenburg accident, considering it really was the highly flammable skin of the Hindenburg that ignited.
If they used hydrogen, the blimp would be able to carry more than just 12 people.

If I wanted a soft, helium-filled airship that could only hold ten passengers, I could have just gotten one of these.

Nice idea, but crap physics. Here's why:

From chemistry and Avogadro's Law, the weight of one mole of a substance is the same as the atomic weight of that molecule, and has a volume of 22.4 liters at standard pressure and temperature (0C and 29.92 inches). So, for 78% N2 (28), 21% O2, and 1% H2O (32), air weighs about 1.28 kg/m3, or almost exactly 1kg per cubic yard. The same yd3 of Helium (2) would weigh only 68 grams. So a cubic yard of helium displacing air provides 932 grams of lift. (The mass != weight quibble isn't really relevant here, OK?)

Allowing the airship to have the same volume of the USS Akron, 6.5 million ft3 is 224 tonnes (metric) of air displaced by 16.4 tonnes of He, so the maximum potential lift is 208 tonnes.

Now the problems start.

Blimps use balonets to allow for helium expansion with heating and especially altitutde changes. For a maximum altitude of 10,000 feet (700mb), the blimp must allow for 30% expansion (1000mb at surface to 700mb at altitude) if it doesn't want to vent helium. Zepplins and other airships handled this through flexible bags containing the helium/hydrogen.

The movie in the article's website said their airship would rise some 10 miles before floating back down. Ten miles is 50,000 feet, or about 100mb. This requirement limits the on-ground volume of helium to only 10% of all available to allow for expansion. Thus the maximum lift would fall 208 tonnes to only 20.8 tonnes.

Okay, how about only five miles/25,000 feet? Pressure there is about 350mb, so you can only start with 35% helium volume, or 72.8 tonnes possible lift.

Now, somebody explain how to build a 6.5 million ft3 volume container for less than 20 tonnes (or 70 tonnes) that can be pressurized, as stated in the movie, to compress the Helium enough to start descent. Oh, not to mention the pressure tanks and multi-kilowatt vertical turbine to electically power the flyweight air pumps filling those tanks. The paint on the hull would weigh more than the cargo.

This might work on a planet like Jupiter, where the air pressure is around 10,000mb and more the deeper you go, but until somebody comes up with aluminum-strength aerogel, I think this plan is crap.

The Hiroshima bomb destroyed most buildings within a mile, so that's a two-mile diameter, so you'd need about five Hiroshima-sized bombs to have a significant blast effect over an area five miles across. That's 15 kilotons, so you'd need 15 x 5 = 75 kilotons, or 75,000 tons, or 150,000 pounds of conventional explosive. (Yeah, it might not snuff the fire, but the updraft under the mushroom cloud will tend to suck the fire inward and slow its outward travel -- ignoring the effect of flying flaming objects)

Maybe five aircraft would be more practical, but let's see if one can do it. It looks like a 707 or KC-135 can handle 150,000 pounds and have capacity for some fuel weight. I don't know what the safety requirements would be to allow unmanned flight for civilian use of something like that.

Now, about the foam.. The area of a circle 2.5 miles in diameter is 547 million square feet (pi * r^2), so if you're going to cover just the surface (not trying to cover all branches on trees) to a depth of one foot, you need 547 million cubic feet of foam.

One Goodyear Blimp has 202,700 cubic feet of helium, so we'll assume it can hold that much foam.

So, fill a 707 with explosives and strap around it 2,700 Goodyear Blimps full of foam. Probably want to add some more, as some of the foam will be vaporized by the blast. Well, might be easier to just drop the blimp-sized bags of foam separately. There ya go, it's all designed. The rest is just engineering.

So, why doesn't it exist yet?