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> Did you create this account only to comment on this story? (just curious) Yes i did, usually i just let certain topics pass by me and never comment here. RF

> Did you create this account only to comment on this story? (just curious) Yes i did, usually i just let certain topics pass by me and never comment here. RF-cavities though are the very core to my line of research, so my acceptance for bs is very low in this regard. If one wants to convince me of a thrust effect: build a prototype where the power source (a battery for example) and the RF-source are strapped onto the cavity, put the whole setup in a vacuum of your choice (i heard NASA has very nice and !large! facilities) and show me a sustained increase in impulse (just let it rotate for a while)

eightysixfour 10y ago
Was the listed amount of force enough to overcome the friction of whatever your hypothetical device is sitting on? It isn't like vacuum chambers don't still have gravity to contend with.
- raverbashing 10y ago
  You don't need it to actually "move" (overcoming friction), you can just measure a force it is exerting or things like "hang it from the ceiling and measure a small displacement"
  - ricardobeat 10y ago
    That's kind of what this whole paper is about...
ncallaway 10y ago
> If one wants to convince me of a thrust effect: build a prototype where the power source (a battery for example) and the RF-source are strapped onto the cavity, put the whole setup in a vacuum of your choice (i heard NASA has very nice and !large! facilities) and show me a sustained increase in impulse (just let it rotate for a while) Okay, but they aren't trying to convince you yet. They're trying to convince themselves that it's worth spending the resources you describe.
- elcritch 10y ago
  Excellent point. They do mention performing an experiment with large angular displacement and a larger vacuum. > To definitively rule out any residual concerns about thermal error sources, future test campaigns could employ a test apparatus capable of measuring small torques over much larger angular displacements. For example, a Cavendish balance approach properly designed to allow very large rotation angles such as 90, 180, or even 360 deg will not be susceptible to this type of thermal false positive.

eightysixfour 10y ago

Was the listed amount of force enough to overcome the friction of whatever your hypothetical device is sitting on? It isn't like vacuum chambers don't still have gravity to contend with.

raverbashing 10y ago
You don't need it to actually "move" (overcoming friction), you can just measure a force it is exerting or things like "hang it from the ceiling and measure a small displacement"
- ricardobeat 10y ago
  That's kind of what this whole paper is about...

ncallaway 10y ago

> If one wants to convince me of a thrust effect: build a prototype where the power source (a battery for example) and the RF-source are strapped onto the cavity, put the whole setup in a vacuum of your choice (i heard NASA has very nice and !large! facilities) and show me a sustained increase in impulse (just let it rotate for a while) Okay, but they aren't trying to convince you yet. They're trying to convince themselves that it's worth spending the resources you describe.

elcritch 10y ago
Excellent point. They do mention performing an experiment with large angular displacement and a larger vacuum. > To definitively rule out any residual concerns about thermal error sources, future test campaigns could employ a test apparatus capable of measuring small torques over much larger angular displacements. For example, a Cavendish balance approach properly designed to allow very large rotation angles such as 90, 180, or even 360 deg will not be susceptible to this type of thermal false positive.