1929 ZMC-2 all-metal airship

[aerohead]

https://www.youtube.com/watch?v=JLUPNddrvdE

This may be the lowest drag airship ever constructed, due to it's fineness-ratio.
It wouldn't necessarily make it the most popular, as motion-sickness was an issue with crews.
When you consider that the 450-hp engine was pushing a 'building' through the air at 65-mph, it dawns upon you, what they had actually accomplished.
Main hull is around Cd 0.04, compared to the Cd 0.07 LZ-126/ USS Los Angeles.

https://www.youtube.com/watch?v=hyslqI7TPDE

[freebeard]

....as motion-sickness was an issue with crews.

Imagine what they could have done with accelerometers and dynamic thrusters.

[aerohead]

Originally Posted by freebeard

Imagine what they could have done with accelerometers and dynamic thrusters.

So true! Just like flying wings and flying saucers, with fly-by-wire, or now, fly-by- wi-fi, the electronics react faster than the human even senses, and maintains craft within parameters.

[Piotrsko]

Friends who flew the B2 say they get motion sick AND you cant accurately drop dumb munitions due to the yaw hunting. electronic control or not you still have the physics of air to deal with.

[aerohead]

Originally Posted by Piotrsko

Friends who flew the B2 say they get motion sick AND you cant accurately drop dumb munitions due to the yaw hunting. electronic control or not you still have the physics of air to deal with.

Didn't know that.
A relative flew the first Lockheed F-117 'Nighthawk' bombing mission over Bagdad in the Iraq War.
I never got to meet him. He's now a Captain with Southwest Airlines ( after many years of flying right seat in the 737 ). Military pilots have to be 're-programmed.'
The enormous fineness-ratios of the great airships helped make them very stable reconnaissance and weapons platforms, not to mention 'luxuriously smooth' transoceanic cruise ships.

[redpoint5]

What's the payload?

I'd like to see a vacuum lighter than air ship that has no gas requirements. Would probably need nanotube tech to finally be developed to achieve the materials strength and weight requirements to make such a thing feasible.

[aerohead]

Originally Posted by redpoint5

What's the payload?

I'd like to see a vacuum lighter than air ship that has no gas requirements. Would probably need nanotube tech to finally be developed to achieve the materials strength and weight requirements to make such a thing feasible.

1) 750- LBs / 340-kg.
2) Only a sphere could structurally survive the stress of a vacuum.
3) Which would be an aerodynamic fail.
4) Enclosing metal vacuum balloons inside a streamlined outer hull would be a weight fail.
5) And we'd have to prove the buoyancy of an evacuated metallic sphere.
6) Hydrogen and helium are known quantities.
7) Additive manufacturing a cubic-octet, 3-D laser-printed hollow sphere would be an extremely interesting proposition.
8) Flying 'above' the weather would probably be a mandatory limitation.

[redpoint5]

I just watched a video on the subject. Hydrogen is only 7% the weight of air, so there's limited benefit to a vacuum over hydrogen from a buoyancy perspective.

I at least expected to find an example of a vacuum sphere being buoyant, but I didn't find any working examples.

A sphere is the strongest shape, but it isn't a requirement to avoid crushing. Submarines don't crush, and they aren't spheres.

The concept would require a breakthrough in materials technology though.

[aerohead]

Originally Posted by redpoint5

I just watched a video on the subject. Hydrogen is only 7% the weight of air, so there's limited benefit to a vacuum over hydrogen from a buoyancy perspective.

I at least expected to find an example of a vacuum sphere being buoyant, but I didn't find any working examples.

A sphere is the strongest shape, but it isn't a requirement to avoid crushing. Submarines don't crush, and they aren't spheres.

The concept would require a breakthrough in materials technology though.

1) The sphere is the strongest structure for this type of loading. Symmetrical loading is transferred uniformly throughout the entire structure.
2) The submarine has a pressure-hull beneath it's hydro-hull.
3) This elongated cylinder possess 'hoop-stress' due to it's non-geodesic architecture, and you'll notice uniformly-spaced reinforcing bulkheads which reduce buckling failure.
4) Wall thickness resists 'oil-canning' deformation failure.
5) Submarines will definitely crush if taken beyond their operational envelope. That would be classified information.
6) On the deepest-diving, manned submersibles, like James Cameron used to visit geo-thermal black-smokers in the deep ocean, you'll notice the convex, hemispherical clear plastic viewing bubble, and extremely-thick walls of the craft.

[freebeard]

I'd like to see a vacuum lighter than air ship that has no gas requirements. Would probably need nanotube tech to finally be developed to achieve the materials strength and weight requirements to make such a thing feasible.

A subject dear to my heart. From 2014:



The tensegrity icosahedron is dispalyed at v=1 for simplification. A higher frequency would be more spheroid. It would contain hot hydrogen at a partial vacuum.

The orange cage would also be spheroid, but instead of containing the hydrogen core and Helium, it would be steam, which has similar lift to Helium. And which would maintain the temperature of the core. I went to look up the ratio, but my old source www.flyingkettle.com/ has gone dark.

But we still have Wikipedia! en.wikipedia.org/wiki/Thermal_airship

In 2006, a new type of envelope employing a tensile membrane structure was developed by Skyacht Aircraft. This design uses an unpressurized envelope and an internal structure that uses ribs made of aluminium to keep the envelope in shape. When not in use, the structure folds up in a manner similar to an umbrella. The structure also permits the mounting of a steerable engine/propeller on the tail of the aircraft.