On 29 Aug 2017 at 13:54, Tim wrote:

> On Mon, Aug 28, 2017 at 04:41:51PM -0700,  (via tml list) wrote:
> > On 25 Aug 2017 at 12:37, C. Berry wrote:
> >
> > > Similarly, show me a CG technology that requires constant power
> > > input in a given g-field, and I will happily use it to create a
> > > free-energy generator using a classic perpetual motion "unbalanced
> > > wheel" that actually works.
> >
> > Depends on *how* you apply the CG.
> >
> > If it "supports" the ship against gravity with a constant power
> > input, your perpetual motion idea won't work.
>
> Yes, it will work.  Divide the power requirement by the weight
> supported, giving a figure with the units of speed.  While the device
> is operating, move it upward with speed greater than that figure (e.g.
> on the rim of a large spinning wheel).  Then turn the device off at
> the top and let the mass fall (e.g. on the downward part of the
> wheel's turn).
>
> Example: suppose a certain contragrav device costs 10 MW to run, and
> can cancel about 100 tons of weight (1 MN).  Put two such devices and
> associated weights on the rim of a wheel with radius 100 m, rotating
> once per 20 seconds.  Each half-turn, one device consumes 100 MJ of
> energy (10 MW x 10 seconds).  The other is not operating, and the
> associated 100-ton weight falls through 200 metres, converting 200 MJ
> of gravitational potential energy (mass x gravity x height) into
> electrical energy via a generator at the wheel's axle.  100 MJ of this
> is used to power the ascending device, while the other 100 MJ is free
> to be used for anything.

Nope. Even with the CG operating it still takes energy to lift the
*mass* of the vehicle those 200 meters. The exact same energy you get
by dropping the other one thru 200 meters.

It's hovering, but it's not *weightless*. The force of gravity is
being *countered*, not negated.

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com