Evening PDT,

CT LBBs for simplification does not calculate  the power needed to operate the grav generators while CT Striker Book 3, and TNE FF&S, do provide guidelines.

CT Striker Book 3 p. 8 Each .02 m^3 of grav generators produces 1 ton of thrust and requires 0.1 megawatts of power from the power plant.

TNE FF&S p. 75 Contra-Grav Lifters
TL 9 Standard Lifters require 0.3 MW per displacement ton of hull
TL 10 Improved Lifters require 0.2 MW per displacement ton of hull
TL 12 High Efficiency Lifters require 0.1 MW per displacement ton of hull

Looking at MT Referee's Manual, T4 Book 1 QSDS, T4 Book 2 Starships SSDS, and T4 FF&S the thruster plate, reactionless thruster, and contra-gravity drives appear to be used to hover. However, these systems all have a power requirement.

Tom Rux

From: "C. Berry" <xxxxxx@gmail.com>
To: "TML" <xxxxxx@simplelists.com>
Sent: Wednesday, August 16, 2017 1:35:20 PM
Subject: Re: Landing vs hovering (was Re: [TML] What class of Port is this?)

There's zero energy cost for hovering. Otherwise, by your analysis, I would be expending a gigantic energy cost for hovering 400,000km over the surface of Luna. :) An object motionless in a g field has constant potential energy, hence no energy input is required to keep it there.

On Wed, Aug 16, 2017 at 1:26 PM, Christopher Sean Hilton <xxxxxx@vindaloo.com> wrote:
On Tue, Aug 15, 2017 at 06:35:24PM +1000, Tim wrote:

> I'm certain that a ship could hover instead of setting down, in a way
> that addresses all the safety concerns in this thread and so on.  I
> just don't see yet what advantages that would offer.
>

Agreed, hovering isn't hard. We've been doing it with ships and boats
on Earth since ~ TL3. It's a solved problem.

And I see a potentially big disadvantage. The energy cost for a ship
to hover in the manner is:

     Energy = (m) * (g) * (h)

Where:

     m -- Mass of the ship.

     g -- Local acceleration due to gravity.

     h -- Distance from the surface (?) to the CG of the ship.

This energy gets paid for no matter how the ship "lands". If it's on
landing gear then the real landing gear is acting like a spring and
storing the energy from the compression force between the ship's CG
and the ground underneath it. Or, if it's hovering in this way it burns
fuel. How fast, I don't know [1]. But, burning fuel creates heat because
our power plant is entropic and that heat is gonna have to be carried
away by radiation and convection with the local atmosphere.

Looks like a starship operator has a choice here not of: "wear and
tear" vs. "no wear and tear", but rather of what wears out, the big
hunks of metal that are the landing struts, or the: fusion plant, heat
dissipation, and contra-grav circuits.

----------------------------------------

[1] I'm at work but I'll do a back of the envelope calculation when I
get home.

--
Chris

      __o          "All I was trying to do was get home from work."
    _`\<,_           -Rosa Parks
___(*)/_(*)____.___o____..___..o...________ooO..._____________________
Christopher Sean Hilton                    [chris/at/vindaloo/dot/com]
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