FLD - Flagrum's Levitation Device

[Flagrum]

I am bored. I admit it. Therefore I invented a device that will revolutionize the way we will fly: the Levitation Device!

 

The basic principle is that it exploits centrifugal forces generated by rotating masses. We all know such masses: wheels, gyroscopes, etc. Those show an interesting behaviour: they tend to remain stable because of the centrifugal forces that "pull" the rotating mass equally to the "outside". These forces can be quite strong.

 

Now, what if we would redirect some of the force so that it is working into the same direction as the rest? Easy! We take a pipe and bend it into a ring, connecting both ends to each other. Somewhere inbetween we install a pump. This pump drives a heavy fluid (i.e. mercury) through that ring. This fast moving liquid that circles inside the ring generates centrifugal forces.

 

Now the tricky part (patent pending!): we bend the ring in the middle so we get two half-circles:

Now the centrifugal forces are applied mostly into the same direction that could overcome gravity and lifts our device up from the ground!

 

Pfffft ... wasn't that complicated, wasn't it? :o)

 

(yes, i bet all my DCS licence keys that this device will NOT work ... but as a layman in physics/math/everything else I don't exactly understand why not. What am I missing here? :o)

[Lizzard]

uhmm...would`t the 2 forces cancel themselves out..

[MTFDarkEagle]

The force excerted downward originating from the small diameter 180-s will cancel the force me thinks.

[sobek]

I am bored. I admit it. Therefore I invented a device that will revolutionize the way we will fly: the Levitation Device!

 

The basic principle is that it exploits centrifugal forces generated by rotating masses. We all know such masses: wheels, gyroscopes, etc. Those show an interesting behaviour: they tend to remain stable because of the centrifugal forces that "pull" the rotating mass equally to the "outside". These forces can be quite strong.

 

No, this is absolutely not how precession works. It's a bit more complicated than that. :)

 

It is hard to explain that effect if you do not have an understanding of vector algebra, but it has to do with conservation of moments of intertia. See http://de.wikipedia.org/wiki/Pr%C3%A4zession

 

 

 

(yes, i bet all my DCS licence keys that this device will NOT work ... but as a layman in physics/math/everything else I don't exactly understand why not. What am I missing here? :o)

 

Now i'm going to spare you the gory details (you'd need to build the line integral over all forces the fluid exerts onto the pipe) and break it down since this is a simple device.

 

If you look at your picture, look at the acceleration the fluid experiences in the long even curve, then look at the accelleration it experiences in the short curves from one long leg to the other. It should be apparent that all the accellerations will cancel each other out.

 

Depending on how fast your pump can accelerate the fluid inside the pipe, you might get the assembly to roll over a little, but not nearly as much as in a circular assembly.

 

Edit: To take this thought experiment a little further, as long as you stay within conservative fields and you neglect the effect of friction, there is no possible shape that you could bend your pipe into and have the assembly put out a net force. The sum of all forces will always be zero, such is the definition of a conservative field. Since i'm an engineer and not a physicist, i'm not quite sure off the top of my head if it holds true that gravity fields are conservative once you move from newtonian physics to the fancy stuff, but i think this is no longer the case. Still, for conditions present on earth the above is a sufficiently precise approximation. :)

Edited April 14, 2014 by sobek

[Lizzard]

 

so..cut it halfways..install the pump on the top..profit

[sobek]

Free energy. :P;)

[Flagrum]

uhmm...would`t the 2 forces cancel themselves out..

Blue is the direction the centrifugal force is directed to. So, in a ring the forces cancel eachother out (a free spinning wheel will not stay in the air, gravity works as expected). But my idea was to turn the part of the centrifugal force that is directed towards the ground also upwards so both half-rings generate centrifugal force in the same direction: upwards ... and thus lift the device from the ground. :o)

The force excerted downward originating from the small diameter 180-s will cancel the force me thinks.

That could be a slight problem, yes. That was also my first suspect ... :o)

 

No, this is absolutely not how precession works. It's a bit more complicated than that. :)

 

It is hard to explain that effect if you do not have an understanding of vector algebra, but it has to do with conservation of moments of intertia. See http://de.wikipedia.org/wiki/Pr%C3%A4zession

 

Now i'm going to spare you the gory details (you'd need to build the line integral over all forces the fluid exerts onto the pipe) and break it down since this is a simple device.

 

If you look at your picture, look at the acceleration the fluid experiences in the long even curve, then look at the accelleration it experiences in the short curves from one long leg to the other. It should be apparent that all the accellerations will cancel each other out.

 

Depending on how fast your pump can accelerate the fluid inside the pipe, you might get the assembly to roll over a little, but not nearly as much as in a circular assembly.

I don't see/understand what my approach has to do with precession - I only try to utilize the centrifugal forces. Or has it something to do with this: take a bicycle wheel and spin it while holding it at the ends of the axis. Now let go one hand - you can hold it with just one hand at one side of the axis. Something is working against gravity here ...

 

But that thing with the smaller diameter at the ends of my device and the resulting stronger centrifugal force there ... yeah, that was my first suspect, too...

Besides all kind of things that might prevent such a device from functioning. Maybe the mercury would cause high temperatures due to friction? Etc. ... :o)

[sobek]

I don't see/understand what my approach has to do with precession - I only try to utilize the centrifugal forces. Or has it something to do with this: take a bicycle wheel and spin it while holding it at the ends of the axis. Now let go one hand - you can hold it with just one hand at one side of the axis. Something is working against gravity here ...

 

What causes a gyroscope to remain stable is conservation of moment of inertia, not that centrifugal force is pulling it to the sides. Strictly speaking, centrifugal force doesn't even exist, it is a "Scheinkraft" if your reference system is not inertial but rotating. What centrifugal force is is merely inertia, the tendency of moving mass to continue on its path of movement.

[Lizzard]

Blue is the direction the centrifugal force is directed to. So, in a ring the forces cancel eachother out (a free spinning wheel will not stay in the air, gravity works as expected). But my idea was to turn the part of the centrifugal force that is directed towards the ground also upwards so both half-rings generate centrifugal force in the same direction: upwards ... and thus lift the device from the ground. :o)

 

look at your Pic..so cut that half Ring verticaly in the middle..you have for example on the left side force A that pushes down with let`s say 10 kg...and also force B that pushes up with 10 kg (same speed of the fluid..so same energy...o.k. Gravity..but it would make it even worse..)..same Effect on the right side...so 10 - 10 = 0..so unfortunately no free flight:)

[Flagrum]

look at your Pic..so cut that half Ring verticaly in the middle..you have for example on the left side force A that pushes down with let`s say 10 kg...and also force B that pushes up with 10 kg (same speed of the fluid..so same energy...o.k. Gravity..but it would make it even worse..)..same Effect on the right side...so 10 - 10 = 0..so unfortunately no free flight:)

Sorry, I don't get your example ...

 

The picture a) shows a ring from the side. Downwards is the ground and upwards is the sky. The forces push in all directions, so 50% upward and 50% downward. Now I bend the ring horizontally so that two half-rings point upward and none to the ground (pic b): 2*50% of the force go upward, 0% downward .... in my theory. :o)

(Yes, the forces are also directed partly to left and right, so horizontal movement would not be influence in either variant, a or b. The point here is, that at least more force is pointing upward than downward.

[Flagrum]

What causes a gyroscope to remain stable is conservation of moment of inertia, not that centrifugal force is pulling it to the sides. Strictly speaking, centrifugal force doesn't even exist, it is a "Scheinkraft" if your reference system is not inertial but rotating. What centrifugal force is is merely inertia, the tendency of moving mass to continue on its path of movement.

I think, I understand ... to some extend. At least in form of a "general picture" ... :o)

[sobek]

The point here is, that at least more force is pointing upward than downward.

 

No, this would be the case if the fluid "came out of nowhere" and would "vanish into nowhere". In that case, energy would be transfered from "out of nowhere" to your ring. In your case though, since this is a closed system you impound the same acceleration onto the fluid in the parts where it is directed downward as in the short parts where it is directed upward (what counts is just the accelleration in the direction down and up, everything else doesn't interest us as far as lift is concerned). The result is a net acceleration of zero.

[VincentLaw]

The best you could do with something like this is create a rolling device. If you pump fluid into one end of a ring, gravity will pull that side more than the other side, causing it to roll.

 

If you spin a ball on a string, there is no centrifugal force pulling the ball upwards radially as you depicted. If there was, then the ball would fly in the opposite direction of the string when released. Instead, the ball simply continues to fly on a line tangential to the circle and perpendicular to the string (in the direction it was going).

 

The forces in your example should actually pointing the opposite direction (centripetal force) and are being exerted by the tube on the fluid, not the other way around, and before you ask, no your design wouldn't work if you flip it upside down because the complete circuit the fluid is taking provides equal force in the opposite direction.

Edited April 14, 2014 by VincentLaw

[sobek]

The forces in your example should actually pointing the opposite direction (centripetal force) and are being exerted by the tube on the fluid, not the other way around, and before you ask, no your design wouldn't work if you flip it upside down because the complete circuit the fluid is taking provides equal force in the opposite direction.

 

Actio = reactio. :)

 

Of course the fluid exerts a force onto the pipe. In fact, if you stopped saying that the pipes stiffness is infinite, you'd see that the pipe gets slightly warped when the fluid is in movement. Ever had a garden hose laid out into a circle and turned the water up to max? :)

[Suchacz]

I can only see a reaction. But where is the action? :huh:

edit: sniped:D

[Lizzard]

..there are more forces then just the centrigual one...the Gravity..the movement mass of the liquid (raises with the speed)..the friction of the liquid in the tube..and don´t forget..like Newton said..every force has an opposing force (mostly Fn -> normal force)..and all this factors combined will restult in a not flying tube...but you know..I am not a Scientist:D

[VincentLaw]

Actio = reactio. :)

 

Of course the fluid exerts a force onto the pipe. In fact, if you stopped saying that the pipes stiffness is infinite, you'd see that the pipe gets slightly warped when the fluid is in movement. Ever had a garden hose laid out into a circle and turned the water up to max? :)

Well fluids are a bit more complicated than a ball on a string. If there is motion that is not parallel to the wall, then the fluid exerts a force on the pipe (other than static pressure or shear forces). In the case of the ball on the string, the string will deform too, but that is caused by the momentum of the ball, not from the ball applying a radial force to the string.

 

Edit: Actually, it has been a while since dynamics, but I agree I was wrong there. The ball reacts to the string force, but since it is just a reaction, the force was balanced and immediately disappears if the string is cut so it doesn't move radially. In any case, all the forces are still balanced so you don't get levitating pipe devices.

Edited April 14, 2014 by VincentLaw

[sobek]

..there are more forces then just the centrigual one...the Gravity..the movement mass of the liquid (raises with the speed)..the friction of the liquid in the tube..and don´t forget..like Newton said..every force has an opposing force (mostly Fn -> normal force)..and all this factors combined will restult in a not flying tube...but you know..I am not a Scientist:D

 

Actually to correctly predict the behaviour regarding lift, it is completely sufficient to not look at friction, the pump, etc. Just imagine the fluid to be in perpetual frictionless motion inside the pipe.

 

Now look at the acceleration it experiences along the up down axis. Since (ideally) the fluid moves with uniform speed (relative to the pipe and over the whole length of the pipe) there is no way that the accelerations do not cancel each other out. It is simply impossible, regardless of how the pipe is shaped as long as the fluid returns to the point where it started.

[Lizzard]

Actually to correctly predict the behaviour regarding lift, it is completely sufficient to not look at friction, the pump, etc. Just imagine the fluid to be in perpetual frictionless motion inside the pipe.

 

Now look at the acceleration it experiences along the up down axis. Since (ideally) the fluid moves with uniform speed (relative to the pipe and over the whole length of the pipe) there is no way that the accelerations do not cancel each other out. It is simply impossible, regardless of how the pipe is shaped as long as the fluid returns to the point where it started.

 

..thats what I meant in my very first post..and that is why Perpetuomobiles will not work:)

[Flagrum]

..thats what I meant in my very first post..and that is why Perpetuomobiles will not work:)

To my defense: this device was never meant to be a perpetuum mobile as it surely needs energy continually(sp?) added to it. The pump would not work otherwise. :o)

[Lizzard]

haha..no need to defend yourself..we all just think about things we learned at School..years back..at least somehow..so to go a step further..would your Device work in a Zero-Gravity Environment while moving at the speed of light...Einstein?! Are you out there?!:D

[blackbelter]

If you look only at the two big curves, the total force indeed is nonzero and pointing upwards. But you still have the two small half circles connecting the two big ones. The total force exerted on the two small half circles is pointing downwards, and in fact cancels the force on the big ones exactly, due to conservation of momentum.

 

Specify a set of parameters, and you can do the math to demonstrate this.

Edited April 15, 2014 by blackbelter

[Wolf Rider]

Flagrum, heat the mercury

[Flagrum]

Flagrum, heat the mercury

... to archive what? :huh:

[Irregular programming]

... to archive what? :huh:

 

Warm mercury.