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Post Reply Vaccum pressure jet engine enthusiast
Posted 8/13/17 , edited 8/13/17
Thread just got entertaining


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Posted 8/13/17 , edited 8/13/17
You basically want something that utilizes the Magnus effect. It has issues with stability, but it can be used.

Just youtube Magnus effect airplane or similar to find videos of people using rotating buckets as wings. It works, but .... there is much to be desired for.
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Posted 8/13/17 , edited 8/14/17

fredreload wrote:

But with a low or high pressure zone INSIDE the tube


Where does this zone come from in the first place? I mean, that's your first problem. You have a cylindrical "engine" that operates by having a low pressure zone in the middle... how, exactly?


I speculate it would attempt to SUCK in air


...from BOTH ends of the cylinder, creating nothing at all.

Seriously, this idea makes no sense.
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Posted 8/13/17 , edited 8/14/17
...never mind that all jet engines are "vacuum engines."

A significant part of the thrust from a modern jet is from sucking the air in the front.
Posted 8/13/17 , edited 8/14/17
Reducing pressure requires moving air, once you stop moving the air the pressure normalizes from both end of the tube. The output would never be more than the input so there would be no thrust since you aren't generating additional force. A Jet accelerates incoming air by using combustion to force it out a nozzle generate extremely high velocity. The difference in momentum and pressure between the air going in and that coming out is the thrust.

We have device that do this (create low pressure in a tube), they are called venturi tubes but they don't create thrust.
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Posted 8/13/17 , edited 8/14/17

cdarklock wrote:


fredreload wrote:

But with a low or high pressure zone INSIDE the tube


Where does this zone come from in the first place? I mean, that's your first problem. You have a cylindrical "engine" that operates by having a low pressure zone in the middle... how, exactly?


I speculate it would attempt to SUCK in air


...from BOTH ends of the cylinder, creating nothing at all.

Seriously, this idea makes no sense.


Right, air does go in from both ends, might need to tweak the design a little


prh99 wrote:

Reducing pressure requires moving air, once you stop moving the air the pressure normalizes from both end of the tube. The output would never be more than the input so there would be no thrust since you aren't generating additional force. A Jet accelerates incoming air by using combustion to force it out a nozzle generate extremely high velocity. The difference in momentum and pressure between the air going in and that coming out is the thrust.

We have device that do this (create low pressure in a tube), they are called venturi tubes but they don't create thrust.


Interesting, noted
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