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March 03, 2011

Controversial EMdrive claims to have transferred technology to a major US aerospace compan

a high temperature superconductor emdrive thruster, which operates at 3.8 GHz, and was designed using an update of the software used for the previous S band designs. Super-conducting surfaces are formed from YBCO thin films on sapphire substrates. Small signal testing at 77 deg K confirmed the design, with a Q of 6.8x106 being measured.

The heart of the controversial Emdrive is a resonant, tapered cavity filled with microwaves. According to Shawyer, a relativistic effect generates a net thrust, an effect confirmed by various Emdrives he has built as demonstrations. Critics say that any thrust from the drive must come from another source. Shawyer is adamant that the measured thrust is not caused by other factors. In 2008, professor Yang Juan of the College of Astronautics at Northwestern Polytechnical University (NPU) in Xi’an was happy to confirm that they were building an Emdrive which would be tested by the end of 2009.

EMdrive claims - In August 2010, a technology transfer contract with a major US aerospace company was successfully completed. This 10 month contract was carried out under a UK Export Licence and a TAA issued by the US State Department. Details are subject to ITAR regulations.



The claim of technology transfer is the main new thing since we last updated the highly controversial Emdrive back in 2009

Note: I have highlighted in the title of the article and in the introduction how controversial this is. Basically critics thinks this is all crap and/or fraud. I am updating this to indicate that they are still plugging away. The interesting thing is what happened with the Chinese work, but there is no word on that.

In June 2010, a paper was presented at the 2nd Conference on Disruptive Technology in Space Activities. The paper reviewed their experimental work.

The EMdrive enables superconducting cavities to very efficiently create static thrust. Thrust is measured in "pounds of thrust" in the U.S. and in Newtons under the metric system (4.45 Newtons of thrust equals 1 pound of thrust). 300 pounds of thrust is 1335 Newtons of thrust. 6 kilowatts of input means that 222.5 N/kW.

Apparently the 6.8 million Q device should have 143 kg of thrust from 6 kW input.

Effect of increased Q for the Emdrive

Q=50,000 (1st gen.) Static thrust=315 mN/kW Specific thrust at 3km/s=200mN/kW

Q=6,800,000 (supercond) Static thrust=222 N/kW Specific thrust at ??km/s=??N/kW

Q=5 X 10^9 (supercond) Static thrust=31.5 kN/kW Specific thrust at 0.1km/s=8.8N/kW

Q=10^11 (supercond) Static thrust=630 kN/kW Specific thrust at 0.1km/s=??N/kW


It is commonplace for a 1.3 GHz niobium SRF resonant cavity at 1.8 Kelvin to obtain Q=5×10**10 [50 billion]. Such a very high Q resonator and its narrow bandwidth can then be exploited for a variety of applications. At present, none of the "high Tc" superconducting materials are suited for RF applications. Shortcomings of these materials arise due to their underlying physics as well as their bulk mechanical properties not being amenable to fabricating accelerator cavities.


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