Here’s a rather recent academic paper on EM Drives http://www.helsinki.fi/~aannila/arto/emdrive.pdf
From: David Roberson [mailto:dlrober...@aol.com] Sent: Thursday, March 17, 2016 2:28 PM To: vortex-l@eskimo.com Subject: Re: [Vo]: EM Drive(s) Does anyone recall how the force generated by the EM drive varies with cavity Q? I assume the force does not become infinite as the Q approaches that value. If if does, then that should raise all types of flags. For instance, it would imply that much more kinetic energy can be imparted onto the vehicle than is converted from the mass depletion. Dave -----Original Message----- From: Bob Higgins <rj.bob.higg...@gmail.com <mailto:rj.bob.higg...@gmail.com> > To: vortex-l <vortex-l@eskimo.com <mailto:vortex-l@eskimo.com> > Sent: Thu, Mar 17, 2016 4:38 pm Subject: Re: [Vo]: EM Drive(s) You can get about a 6% improvement in Q of the resonator by plating several skin depths of Ag on top of the Cu. This is frequently done to reduce filter loss where the loss is dominated by metal losses. It is possible to choose resonant cavity modes that have higher Q due to less coupling to the magnetic field. Generally the Q goes up with the volume of the cavity and as the sqrt(resonant frequency). It is also important that the source be appropriately impedance matched to the losses of the cavity. If the unloaded Q is Qu, then when the source is matched properly, the measured Q will be Qu/2. Cooling the cavity will also increase the Q because the resistivity of the metal decreases linearly with Kelvin temperature. On Thu, Mar 17, 2016 at 12:18 PM, Russ George <russ.geo...@gmail.com <mailto:russ.geo...@gmail.com> > wrote: In building a Shawyer EM Drive cavity copper is typically used but Shawyer notes a higher Q would result with silver. Would a cavity that was made of copper sheet then electroplated with silver suffice to give the cavity the Q of silver? Is there any potential for improved Q based on the design of the internal cavity antennae that emits the microwaves.
