On 17 Aug 2017 at 21:31, Jonathan Clark wrote:

> Please point out at this stage how and where my understanding is
> flawed.

Ok, simplest bit is that it requires zero energy to maintain a
constant "height" in a gravity field. Simplest example is that your
chair doesn't require any energy to hold you up.

But a chair with a gas tube "riser" setup *does* use energy to lift
you when you push on the handle. The energy of the compressed gas in
the cylinder.

The best examle for the hovering ship is one of those "toys" that has
some magnets arranged ion the surface of a bowl (all with the same
pole pointing "in" towards the focal point. And there's another maget
with some clever counterweights to keep it from flipping over that
will hover indefinitely in that focal point.

No energy required.

For the hovering ship there *is* an energy cost. But that's due to
what it takes to keep the CG running. It doesn't *care* what height
above ground the ship is at.

It's essentially the same as if you built that toy using
electromagnets instead of permanent magnets in the bowl. It'd consume
power, but that's due to maintaining the field strength. It'd use the
same power whether the hovering magnet was there or not.

In either case (hovering ship, or hovering magnet) you'd have to feed
in more power to get it to hover higher, and you'd get extra power if
it went down.

Remember: Energy ids force times distance. That doesn't mean the
distance the object is hovering at. It means the distance the force
make the object move thru.

That's why hovering doesn't require more power than "standby" loading
(and can be done with permanent magnets).

But making the force lift a kilgram a meter in a 1 g field, requires
9.8 joules of energy.  But letting gravity force a kilo *down* that
same meter (say in a waterwheel) will *generate 9.8 joules of energy
(minus losses in the generator).

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