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Goodyear Inflatoplane

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Re: Goodyear Inflatoplane

#21

Post by scubazealous »

londons_explore wrote: post #4

I think there are lots of possibilities for inflatable vehicles which cannot be deflated . For example, make a flimsy structure out of thin steel foil, then pressurize it to give it far more strength than it would otherwise have. Same as the strength of a coke can. Except with steel as the tensile material, you can probably use pressures up around 1000 psi, making the whole structure have an amazing strength to weigh…

It would be cool, especially with advances in plastics you could layer over the steel to protect it from corrosion like what they do with soda cans.

For reference, a steel or aluminum SCUBA tank is usually filled to 3000psi and when I fill steel tanks I can hear and sometimes see the metal start to slightly balloon. This is normal because steel is not brittle but it is very strong.

There is a lot of rules put in place for safety though. A tank has to be visually checked by a professional every year and hydro statically tested every 5. The danger is any rust/corrosion weakening the metal and causing it to rupture. More often seen in aluminum tanks, which is one reason I prefer steel.

Re: Goodyear Inflatoplane

#22

Post by throwup238 »

rbanffy wrote: post #19
mysterydip wrote: post #3

I wonder how much it could be impoved if this project was revisited today with modern materials and manufacturing techniques.

Not sure modern safety standards would be friendly to it.

It’s 225 lbs empty so it qualifies as an ultralight aircraft like powered hand gliders. It’s a class that’s much easier to certify and has many fewer safety requirements.

Re: Goodyear Inflatoplane

#23

Post by usrusr »

mysterydip wrote: post #3

I wonder how much it could be impoved if this project was revisited today with modern materials and manufacturing techniques.

Rigid flight needs exactly this, rigidity. But we do have inflatable flight: paragliders, first flight only a few years after the inflatoplane. Inflated only by the dynamic pressure from forward movement, but they make up what they lack in pressure differential with using more bracing wires (much more). But the inflatoplane relies on bracing wires as well, so the difference could be considered surprisingly small.

Re: Goodyear Inflatoplane

#24

Post by scubazealous »

Today this would most likely have the same drawbacks as the inflatable kayaks we see for sale. Saves on space (and money?) and could be good as an entry into a hobby but at any intermediate to advanced level there are better options to choose from. With the high barrier to entry to flying I think most pilots would opt for the most reliable option from the start.

I would not want to be caught in inclement weather in an inflatable anything.

Re: Goodyear Inflatoplane

#25

Post by plasticchris »

_yb2s wrote: post #14

I wonder if this is more practical nowadays. Modern “drop stitch” inflatable kayaks and paddle boards are extremely rigid, strong, light, and reliable. They also have precise 3D shapes determined by the length and position of the internal drop stitch threads. Has anyone tried using that tech to create an inflatable airplane?

Feels like an opportunity to make a very cool ultralight given the weight savings, and no pilot license is needed (though still recommended…)

Re: Goodyear Inflatoplane

#26

Post by GuB-42 »

rbanffy wrote: post #18
Gare wrote: post #8

Earlier quoted context omitted.

> Except with steel as the tensile material, you can probably use pressures up around 1000 psi, making the whole structure have an amazing strength to weight ratio. Congratulations, you have created a bomb.

Wasn’t the Centaur upper stage pressurised. I remember an incident where one collapsed under load because the tank lost pressure.

Well, rockets are essentially bombs we try to make explode in a controlled manned. The "controlled" part is not always successful.

Fueled rockets are treated like live bombs. No one around except for people who really need to be (like astronauts).

Re: Goodyear Inflatoplane

#28

Post by londons_explore »

buran77 wrote: post #16
londons_explore wrote: post #10

Earlier quoted context omitted.

You certainly need to think about that in the design. But by rolling a 'texture' into the sheets the structure is made from, you can make sure that any hole can't 'rip' bigger, and therefore fails slowly rather than rapidly. You also need pressure regulator valves in case of fire. And you might want to make the whole thing double or triple skinned so the highest pressures can be deeper inside where they are less like…

At that point you're not dealing with a "flimsy structure out of thin steel foil" that you can inflate to hundreds of psi. You described what's basically a submarine, multiple high and low pressure hulls able to withstand hundreds of psi of pressure. Just for some reference, 1000psi is the kind of pressure you get ~700m depth (2300ft), double what a submarine would regularly withstand. Pressure in your average propan…

A CO2 fire extinguisher is about 1000 psi.

Re: Goodyear Inflatoplane

#29

Post by londons_explore »

usrusr wrote: post #13
londons_explore wrote: post #10

Earlier quoted context omitted.

You certainly need to think about that in the design. But by rolling a 'texture' into the sheets the structure is made from, you can make sure that any hole can't 'rip' bigger, and therefore fails slowly rather than rapidly. You also need pressure regulator valves in case of fire. And you might want to make the whole thing double or triple skinned so the highest pressures can be deeper inside where they are less like…

But when do you really need a structure that has this exceptional strength on the happy path, but would still be good enough in terms of safety when pressure is lost? Unmanned aviation comes to mind, but the ratio between structural mass and battery+payload is already so low, even a zero-mass structure would not make a meaningful performance difference. It's all about the battery tech. Scaling up foil boating perhaps…

> still be good enough in terms of safety when pressure is lost?

You might not design for that case. A suspension bridge can't survive a tower falling over, or a cable snapping.

The pressurized structures wouldn't be able to survive leaks over X size, and for leaks under X size, compressors would be used to maintain pressure.

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