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# Re: tonnages was RE: DS2 Resins to FT or FTFB Mass

From: Jeff Lyon <jefflyon@m...>
Date: Wed, 25 Nov 1998 09:54:39 -0600
Subject: Re: tonnages was RE: DS2 Resins to FT or FTFB Mass
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At 01:18 PM 11/25/98 +0000, you wrote:
>...note that this works for floating in anything, so the
>displacements measured in liquid hydrogen that were mooted
>from traveller work out the same as water displacements.
>unless they were just measures of volume, of course.

I think that Traveller was using their displacement values simply as a
measure of volume, to simplify drawing deck plans.  It works okay since
large portions of their ships _are_ filled with liquid H due to the fuel
tanks.

>freighters?

I asked the question in one of the DS2 "how many power armor troops can
dance in the hold of cargo vessel?" threads about a week ago.

>it would be simple to work out, if it were not for the silly way
>bigger ships have less efficient drives in FT2. is this fixed in
>ft2.5? if power is proportional to mass times acceleration (which
>it isn;t, i think), then the thrust of a freighter is given by:

I'm not sure how it would work in FT2.	In 2.5, though, it makes a lot
of
sense.	Each point of thrust requires 5% of the ships total mass to be
devoted to engines.

For example:

A mass-200 freighter with FTL, thrust-2, and a fragile hull would have
25%
(10% + 5% x2 + 5%) of its mass devoted to structure and 75% to cargo
capacity.  Realistically, if that ship was running "light" its total
mass
would only be 50 and its engines would mass 20, so it should be able to
generate thrust-8.  Every 25 mass of cargo (or portion thereof) would
reduce thrust by a point.

A little tinkering and one could cook this into a spreadsheet which
would
calculate the thrust/load ratios at the time of design.

>this leads to the possibility that a carrier might dump its
>fighters or a missile ship its missiles in order to boost thrust
>and run away. not very clever if there is a chance you will have
>to fight, but if an FFG runs into an enemy battle fleet, it might
>be wise.

I would tend to discourage this however.  IIRC, its been stated that FT
fighters mass less than one each.  I think the mass requirements for
fighters and SLMs reflect the hangar bays, magazines and other support
equipment which would not be reduced significantly with a launch.

Jeff
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