RE: FT3, details of needed changes

On Wed, 2 Oct 1996, Samuel Penn wrote, in reply to a post I thought I
had 
cancelled:

> > What is realistic depends on your assumptions about engine masses,
of 
> > course. As long as we use standard rocket drives, we can make 
> > reasonable assumptions, but what about ion engines? Photon drives?
> 
> There was some guy at NASA who had some research done on this,
> and big rockets worked out cheaper and more efficient than
> smaller ones. 

Appearently not when it comes to lifting off from planets; or else we 
wouldn't have any problems in launching huge space stations... I think.
(I don't think air resistance would be that important - would it?)

> Of course, we're talking chemical rockets here,
> but ion drives etc all work on the same principle - you apply
> energy to some reaction mass, and chuck it out the back, so the
> same theory should apply to all reaction drives (I would have
> thought).

Depends on how much extra mass you have to allocate to cooling systems, 
supports and suchlike. I don't know enough to say anything very 
intelligent about it, but a big drive has less area per volume than a 
small drive - and because of that it has that much bigger problems to
get 
rid of excess heat. You could probably come up with other PSB factors to

improve small drives :)

...

> My feelings on the matter are that big ships should be fast,
> but having them as slow lumbering hulks fits in with a lot of
> science fiction much better.

Fast but unmanouvrable would certainly be an interesting option. Sure, 
you have lots of main drive thrust - but it turns much slower than the 
smaller ships <g>

Oerjan Ohlson

"Father, what is wrong?"
"My shoes are too tight. But it does not matter, because
 I have forgotten how to dance."
- Londo Mollari