On Sat, Apr 12, 2014 at 10:23:27PM -0700, Asher Royce Yaffee wrote:
>    How many gee-seconds might the 100-ton Scout ship realistically
> get per ton of H2?

It mostly comes down to the output of the fusion reactor, and desired
thrust.  Effective exhaust velocity will be at most 2P/F, and
multiplying that by the mass fraction of fuel will give an approximate
delta-V.  Divide by 10 m/s to get gee-seconds.

Note: if you put typical Traveller figures in for fusion reactor
output and thrust force, you'll get a totally pitiful delta-V.  You'll
want to scale the output up *immensely*, or accept pathetic
performance.  Realistic drives are necessarily enormously more power
hungry than Traveller drives.

For example, a 50 GW power plant providing 10 MN thrust with 10% fuel
fraction yields only 1000 m/s delta-V.  That's 100 gee-seconds, not
enough to even leave Earth orbit.  To zoom around a solar system
freely like in Traveller, you'll want at least a few terawatts.

- Tim