3 ms·

He ignores the forces on the sides of the tapered wave-guide, calculating forces only for the end caps[1]. If he was to include the forces on the sides, I'm qui

by DougBTX 18y ago

He ignores the forces on the sides of the tapered wave-guide, calculating forces only for the end caps[1]. If he was to include the forces on the sides, I'm quite sure he would find that F_g1 = F_g2 + F_sides exactly. [1] page 2, http://emdrive.com/theorypaper9-4.pdf http://emdrive.com/theorypaper9-4.pdf

nazgulnarsil 18y ago
He mentions that axial forces (the momentum imparted by deflection off the tapered sides of the cone) are taken into account, it might still be wrong but he didn't just ignore it. keep in mind that the force being produced here is tiny: 85 milli newtons, and it obviously needs a power source to run. assuming that the math doesn't add up to a 100% or greater efficiency in the conversion from electrical energy to momentum i see no reason why this is impossible. If the drive works as claimed i wonder what the efficiency is in the transformation from electrical energy to momentum.
- DougBTX 18y ago
  > He mentions that axial forces are taken into account If he does, he's not included it in his theory paper. Take a look, there is no mention of "axial forces" or "deflection" in the paper. In equation 7, he calculates the thrust T using only the difference in propagation velocity at each plate, but makes no mention of how the propagation velocity changes. If he did, it would be obvious that you have to account for radiation pressure on all sides on the tube, not just sides which happen to be perpendicular to the tube's axis. > efficiency in the conversion from electrical energy to momentum The efficiency will be about 0%, so no need to worry.
  - nazgulnarsil 18y ago
    you're right. in the paper he is simply doing F2-F1 to give the thrust without any mention of the surface area of the cone walls. he mentions constructing the cone to give a "reflection free transmission" which is impossible. i guess junk science is right. oh well. from page 6: Note that the reflection-free interface, with matched wave impedances , will ensure no forces are produced at the interface. <-- that doesn't sound possible.

by DougBTX 18y ago

nazgulnarsil 18y ago

He mentions that axial forces (the momentum imparted by deflection off the tapered sides of the cone) are taken into account, it might still be wrong but he didn't just ignore it. keep in mind that the force being produced here is tiny: 85 milli newtons, and it obviously needs a power source to run. assuming that the math doesn't add up to a 100% or greater efficiency in the conversion from electrical energy to momentum i see no reason why this is impossible. If the drive works as claimed i wonder what the efficiency is in the transformation from electrical energy to momentum.

DougBTX 18y ago
> He mentions that axial forces are taken into account If he does, he's not included it in his theory paper. Take a look, there is no mention of "axial forces" or "deflection" in the paper. In equation 7, he calculates the thrust T using only the difference in propagation velocity at each plate, but makes no mention of how the propagation velocity changes. If he did, it would be obvious that you have to account for radiation pressure on all sides on the tube, not just sides which happen to be perpendicular to the tube's axis. > efficiency in the conversion from electrical energy to momentum The efficiency will be about 0%, so no need to worry.
- nazgulnarsil 18y ago
  you're right. in the paper he is simply doing F2-F1 to give the thrust without any mention of the surface area of the cone walls. he mentions constructing the cone to give a "reflection free transmission" which is impossible. i guess junk science is right. oh well. from page 6: Note that the reflection-free interface, with matched wave impedances , will ensure no forces are produced at the interface. <-- that doesn't sound possible.