EmDrive test ... somewhat successful Jeffrey Schwartz (01 Aug 2014 16:39 UTC)
RE: [TML] EmDrive test ... somewhat successful Anthony Jackson (01 Aug 2014 18:04 UTC)
Re: [TML] EmDrive test ... somewhat successful Bruce Johnson (01 Aug 2014 18:14 UTC)
Re: [TML] EmDrive test ... somewhat successful Jeffrey Schwartz (01 Aug 2014 19:01 UTC)
Re: [TML] EmDrive test ... somewhat successful Bruce Johnson (01 Aug 2014 20:01 UTC)
Re: [TML] EmDrive test ... somewhat successful shadow@xxxxxx (03 Aug 2014 18:52 UTC)
Re: [TML] EmDrive test ... somewhat successful Richard Aiken (04 Aug 2014 10:48 UTC)
Re: [TML] EmDrive test ... somewhat successful Tim (04 Aug 2014 14:30 UTC)
Re: [TML] EmDrive test ... somewhat successful Ian Whitchurch (04 Aug 2014 22:24 UTC)
Re: [TML] EmDrive test ... somewhat successful Bruce Johnson (04 Aug 2014 22:47 UTC)

Re: [TML] EmDrive test ... somewhat successful Tim 04 Aug 2014 14:30 UTC

On Mon, Aug 04, 2014 at 06:48:54AM -0400, Richard Aiken wrote:
> It sounds to me like their measurement gear is imprecise. The vibrations
> from a passing semi could have given the "non-thrust article" apparent
> thrust . . .

I've got a copy of the actual paper now.  He did go to great lengths
to isolate external vibration sources.  He didn't go to any lengths
whatsoever to eliminate convection currents in the air around the
device.

In the "Summary and Forward Work" section of the paper, he talks about
how he had to test it in air because the device uses electrolytic
capacitors, and looks forward to a future version that would operate
in vacuum.  Although the torsion balance used to test this device was
physically within a vacuum chamber, it was not depressurized for the
tests.

The thrust graphs he presents in the paper are completely consistent
with convection effects.  Despite his claim that the force is due to
unbalanced quantum field forces operating in the resonant cavity over
microsecond timescales, the measured force slowly builds up over about
30 seconds, then takes another 30 seconds or so to drop to baseline
after the power is turned off.

That's just what you should expect to see if hotspots were causing an
air circulation pattern to build up, then slow down as the spots
cooled.  The forces measured are also consistent with this, being
somewhat smaller than aerodynamic forces generated by warm air rising
from a person's hand.

Contrary to the perception of a full-time "NASA team" working on this,
it was actually done by one person, with some mentors (who were listed
as co-authors), and performed within a short span of time.

- Tim