Shawyer's EMdrive: Lift a Car Against Gravity?

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Discussion Overview

The discussion revolves around the claims made by Shawyer regarding the EMdrive, particularly its potential to lift a car against gravity using a superconducting cavity. Participants explore the scientific validity of these claims, including implications for propulsion and acceleration in space.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant highlights Shawyer's assertion that the EMdrive could generate 30,000 Newtons per kilowatt, sufficient to lift a large car, and questions its implications for space travel.
  • Another participant raises concerns about the conservation of momentum, suggesting that the momentum in the electromagnetic field may not be adequately considered.
  • A different participant argues that radiation pressure would not create a net force difference due to equal effective areas on either side of the cavity.
  • One post questions the relevance of the Lorentz Force in Shawyer's claims, noting that the force is presented without proper consideration of its directional components.
  • Another participant expresses skepticism about the validity of Shawyer's claims, labeling them as crank science and questioning the lack of peer-reviewed publication.

Areas of Agreement / Disagreement

Participants exhibit a range of opinions, with some expressing skepticism about the feasibility of Shawyer's claims while others explore the theoretical implications. No consensus is reached regarding the validity of the EMdrive or its proposed capabilities.

Contextual Notes

Participants note various assumptions and limitations in the discussion, including the treatment of momentum in electromagnetic fields and the lack of peer-reviewed support for Shawyer's claims.

Kosta
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http://www.shelleys.demon.co.uk/fdec02em.htm"
And check out new scientist's issue last week if you have subscription, http://www.newscientist.com/data/images/archive/2568/25681401.jpg"

What do you guys think of the science behind this? He says with a superconducting cavity he could get 30,000 Newtons per kilowatt - enough to lift(hover) a large car.

He says it wouldn't be useful for propulsion but if it can lift a car againts gravity for a long period of time.. remove that gravity (such as in space) would it not go flying? And would it not be able to achieve at least 1g acceleration? (ie eath-to mars(median 280mil km) in just under 4 days including turnaround)

Thanks, (whats my nick again?):confused:

P.S btw sry if this has been posted before, I searched.. nothing .. I am new..
 
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It seems to violate conservation of momentum, but I'm a bit rusty as to taking into account the momentum contained in the EM field. Also, I don't think the radiation pressure on one side of the cavity would be smaller than the other since the effective areas are the same once you take into account the sloped inner surface.
 
From the diagram, it is pretty simple to understand why it doesn't work: radiation pressure is what he's talking about and pressure is force over area. The pressure on one side would be higher than the other, but the net force is the same in both directions.

In the photo of his demonstration device, I notice there is something sitting under the side of the balance that his device is sitting on...
 
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What does Lorentz Force have to do with this machine? In his paper, he uses a shortened version for the force which neglects the cross-product between velocity and the magnetic field. In Shawyer's formulation the force is just placed there without regard for the direction.
 
By all appearances, this is a crank claim and not worth discussing. The paper has never been published in a peer-reviewed journal.

This thread should have been locked long ago.
 

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