Ring Aircraft And Submarines

[Johnny Pneumatic]

Would the "smoke ring" airship idea here work? If so that'd also mean submarines could work like that as well, since hydrodynamics is just aerodynamics in a thicker medium?

 

[c4ts]

I think there was some kind of experimental vortex aircraft that looked like a plane with a big hole in the middle.

 

[CaveDave]

Just make the entire structure roughly neutrally buoyant, Compensate for leakage of (leak-finding-small-molecule) buoyancy gas then solve the problem of bearing assemblies that don't waste too much energy, and while you're at, what does the spin do to the pilot/payload/supercargo/drive system, and then figure out how to handle strong/variable winds.

Nothing to it.

Dave

 

[c4ts]

Just make the entire structure roughly neutrally buoyant, Compensate for leakage of (leak-finding-small-molecule) buoyancy gas then solve the problem of bearing assemblies that don't waste too much energy, and while you're at, what does the spin do to the pilot/payload/supercargo/drive system, and then figure out how to handle strong/variable winds.

Nothing to it.

Dave

I like the method where you just fold up paper into a ring and spin it as you throw...

 

[Terry]

Would the "smoke ring" airship idea here work? If so that'd also mean submarines could work like that as well, since hydrodynamics is just aerodynamics in a thicker medium?

My advice is don't invest any money in it. I don't see what the advantage is over a conventional blimp. It is usually more efficient to utilise forces normal to the surface than tangential, and I see nothing here to make me think that rule of thumb does not apply. So just fill a bag with gas and attach a propellor to it instead.

--Terry.

PS, I have a degree in aeronautical engineering, but I'm not a practicing aero eng.

 

[geni]

since hydrodynamics is just aerodynamics in a thicker medium?

Air compresses water does not. this is a very important consideration.

 

[Terry]

Re: Re: Ring Aircraft And Submarines

Air compresses water does not. this is a very important consideration.

But compressibility is not important at typical blimp speeds.

--Terry.

 

[Ziggurat]

Would the "smoke ring" airship idea here work? If so that'd also mean submarines could work like that as well, since hydrodynamics is just aerodynamics in a thicker medium?

Not a chance. The thing about the smoke ring is that it's a stable configuration in which the viscosity of air doesn't quickly dissipate the moving air (the smoke ring). But there's still very little actual force involved - the only thing special is that the force doesn't become dissipative (unlike where if you just blow a gust of wind, it spreads out and rapidly slows down). It's not the spinning of the ring that propels the ring forward (your initial tap does that), that only keeps it from spreading out and decaying. Using this for an airship isn't a good idea, because there's simply no way to generate large force with it. And with a solid ship, dissipation is not a problem (or it better not be), the ship will hold itself together. Yes, it could literally work with a boyant aircraft like a blimp, but it would be fantastically inefficient (as in I doubt you could even overcome more than the mildest of breezes), and there's no way you could ever hope to run a heavier-than-air craft using this idea.

 

[luchog]

Re: Re: Ring Aircraft And Submarines

Yes, it could literally work with a boyant aircraft like a blimp, but it would be fantastically inefficient (as in I doubt you could even overcome more than the mildest of breezes), and there's no way you could ever hope to run a heavier-than-air craft using this idea.

I don't know. With a slight modification, using the rigid prolate spheroidal bladders that the author of the article suggests, it would probably work fairly similarly to a rotor-sail. It would still need to be lighter-than-air, since there wouldn't be enough force to power a heavier-than-air craft. Not sure if it would be faster or more efficient than a conventional blimp, though.

 

[Brown]

All I can say is that I used to own one of those air ring gun toys. It was a heck of a lot of fun. You pumped it with a handle and "fired" it like a bazooka.