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      CommentAuthorAngus
    • CommentTimeMay 1st 2015
     
    Posted By: Andrew Palfreyman
    Posted By: AngusFoM becomes the rate of change of angle with the rate of change of angle.
    Not quite; FoM is the change of angle with respect to the rate of change of angle - not the same thing. Like dividing position by velocity.


    You can if you want.
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      CommentAuthoralsetalokin
    • CommentTimeMay 1st 2015 edited
     
    Well, at that description it's easy to see that the units of FoM must be Time, that is, seconds. Or maybe, tiny little differential slices of seconds.

    (Does this belong in the Pi=0 thread?)
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      CommentAuthorAngus
    • CommentTimeMay 1st 2015
     
    Mysterious comments on a forum for space flight fanatics could be a clue to secret Nasa technology


    says it all, really.
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    I had an exchange w/Paul, and he sent me also some private data and graphs. They've been seeing thrust in vacuo (down to 10-6 Torr) between 50 and 100 uN. The chamber is stainless steel. The thrust is reversible as should be expected.

    I suggested using FM for various reasons. Turns out they are already prepping that.
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    So..hmmm. Speaking of bucket lists....

    What's the best way to make a copper frustrum without spending a load of dosh on copper?
    Maybe get a bucket - aka a frustrum with an open end - and line the inside with copper tape.
    Put a copper-taped lid on it and viola.

    Ya Think?

    Better yet, a small plastic garbage can, so long as it's not a perfect cylinder.
    Conical ish is best

    I'm trying to find out the optimal geometry.
    And copper tape on something very light is the way to go for minimum mass.

    My Mettler goes down to 10 ugm. That's 0.1 uN. Ought to see something.
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      CommentAuthorAngus
    • CommentTimeMay 1st 2015 edited
     
    Frustum. Which it isn't, actually. It's a truncated cone.

    I'm waiting for more info before I start lining pails with copper paint.
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    I don't think you'll get very good Q from that. Eagleworks is getting about 5700.

    Appreciate the correction on the spelling. But it is indeed a frustum
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      CommentAuthorAngus
    • CommentTimeMay 1st 2015
     
    So what is the dominant loss? Joule heating or the radiation of the momentumless particles that nevertheless give thrust.
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    Getting 50 Watts at 1.5 - 2.5 GHz is the hard part
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    Joule heating in the copper is the dominant loss.
    And is why Cannae went superconducting
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    "We only looked at variation in frustum angle in simulations which appear to point to 20-to-30 degrees being the sweet spot. However angles over 20 degrees require spherical endcap instead of flat ones needed to keep the E&M wave-fronts parallel to each other."

    Fine. 20 degrees and flat caps.
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    Getting 50 Watts at 1.5 - 2.5 GHz into the cavity is the next hardest part
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      CommentAuthorAngus
    • CommentTimeMay 1st 2015 edited
     
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    Frequency modulation is harder
    • CommentAuthorloreman
    • CommentTimeMay 1st 2015
     
    "20 degrees and flat caps"

    Sounds like a heat wave in Lancashire
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    Hee!
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      CommentAuthorTrim
    • CommentTimeMay 1st 2015
     
    Posted By: pcstru
    Posted By: TrimShawyer claims it is all within classical and quantum physics, but I suppose he would.


    Blimey. Has anyone seen the real Trim?
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      CommentAuthorAngus
    • CommentTimeMay 1st 2015
     
    Posted By: Andrew PalfreymanFrequency modulation is harder

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