Can Reactionless Drive be Possible?

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The discussion centers on the feasibility of a reactionless drive, specifically through the concept of inertial propulsion using a rotating disc and magnets. Participants debate whether forces generated by the disc's rotation can create propulsion without an equal and opposite reaction, ultimately concluding that such a device cannot exist according to the laws of physics. The idea that electromagnetic waves could provide a small amount of momentum is acknowledged, but this is deemed inefficient compared to traditional propulsion methods. Concerns are raised about the misunderstanding of forces involved in the system, emphasizing that internal stresses do not yield net propulsion. Overall, the consensus is that while the theory is intriguing, it lacks practical application and violates fundamental physical principles.
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Is this possible?

Inertial propulsion.

If we take that nothing is faster than speed of light than we can take that reaction of force through matter can not be faster than c.

If one body act on other body by force, than other body react with same amount of force to the first body.

https://fbcdn-sphotos-g-a.akamaihd.net/hphotos-ak-prn1/1017601_10201279962618692_1778939648_n.jpg

Lets take that in our system second body rotate certain speed around its axis.
Example will be housing with rotating disc. Magnets will provide force. Every full circle magnets will push disc up according to housing.

https://fbcdn-sphotos-a-a.akamaihd.net/hphotos-ak-ash4/999308_10201279962698694_2034001389_n.jpg

Disc rotate, so force on axis will not be in same direction as forces applied in first position

https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-prn1/1009916_10201279962538690_1502604373_n.jpg

At this point we don`t have forces witch are in 180 degree opposite direction.
We have force that push down and second one that push housing up through axis in certain angle. Because of angle we have resultant force Fr applied.

https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-prn1/1013931_10201279962818697_1789739154_n.jpg

For example

disc rotation speed 1 000 000 rpm, which is 104 666,66 rad/s
r=10 m

we have time t1 when magnet act with force on rim of disc
we have second time t2 which is 3,34 e-8 s when force acts on axis of disc
difference between t1 and t2 is 0,003495 rad which is 0,2 degreehousing push against the disc in t1 and reaction to the axis happened at t2 time and act on housing in 0,2 degree
 
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Your links are incomplete. Please correct them.
 
Without functioning links it is not possible to tell, however a device with spinning magnets will generate EM waves and those EM waves will contain a small amount of momentum. That small amount of momentum can, in principle, propel the device. It is not reactionless, it uses the momentum of EM waves.

Of course, such a device will be horribly inefficient, like using a rocket with no nozzle and just hoping that a little more exhaust goes one way rather than the other. You will be much better off simply shining a laser off the back.

Other than the very small amount of EM momentum there will be no net force on the device. Specifically, the internal stresses and strains that you seem to think will provide propulsion will not. Any propulsion will be purely due to asymmetric radiation of EM waves.
 
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Oh I see now. You are suggesting a force applied at the circumference takes time to propagate to the axle and in that time the disc has rotated.
 
CWatters said:
Oh I see now. You are suggesting a force applied at the circumference takes time to propagate to the axle and in that time the disc has rotated.

Yes, that is idea. I see there is no practical usage, just wondering if this theory is correct.
 
Well no it can't be correct because the laws of physics say you can't build a reactionless drive. It's one of those situations where it's not obvious (at least to me) where the problem is but there will be one somewhere. The question is really is it worth spending time on it?

My thinking is that you haven't considered all the forces involved in the initial "collision" between the magnets. For example it's not obvious to me that the initial forces are radial.
 
Kasko32 said:
Yes, that is idea. I see there is no practical usage, just wondering if this theory is correct.
The stresses and strains which propagate at the speed of sound do not cause any net force on the system at any time.
 
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