| From: | Adam Getchell <acgetchell@*******.EDU> |
|---|---|
| Subject: | Alternity, physics, and scramjets (was Re: rocket pistol) |
| Date: | Mon, 26 Oct 1998 12:48:38 -0800 |
>>that is called
>> Sabbot Guns. Those fire slugs with a scramjet engine (guess its a
>>fantasy name for a
>> small rocketengine)
A friend runs Alternity. I have to bite my lip when they refer to anything
in there relating to physics. I just pretend it's like Champions: not
supposed to approximate reality.
It's possible, in that game, to take several full power shots from a plasma
rifle in the chest with no armor and survive.
On the other hand, the rules seem to be written a lot clearer than
Shadowrun. It's just that it is quite physics-challenged (regardless of the
claims they make in the front cover about reading up on the latest physics
theories). Space Opera rather than Science Fiction.
>A scramjet is a high-speed ramjet, IIRC. (Ramjets being, AFAICR, jet
>engines that do not use turbines to compress the air flowing into them,
>but rather a duct that gets narrower the closer you get to the combustion
>chamber. They only work at high speeds, though.)
A scramjet is a supersonic combustor ramjet. Ramjets do not deal with
supersonic choked flows very well, because the shape for a subsonic
compressor is identical to a supersonic diffuser. There are other problems,
usually involving heating and air density.
A scramjet must get up at least past the speed of sound, and usually well
into the hypersonic regime (Mach 3+) before it starts becoming efficient.
>> and actually anti graviton beams and the like, maybe its a bit way to
>> advanced for our 2060, ne?
>
>It does sound like something that doesn't fit in with my perception of SR
>technology, but that doesn't mean you can't use it if you want to (and can
>preferably find a believable explanation for why it exists).
Physically speaking, anything that can manipulate gravity must be able to
manipulate energy on an enormous scale, like several solar masses worth.
The simplest explanation is this: to produce a one-gee gravitational field
of the same size and distributions as the earth's would require assembling
the energy-equivalence of the earth's mass. Since the Earth is about 6.6
sectillion tons ( ~ 6 x 10E24 kg) you are talking 5.4 x 10E41 joules, which
is a fair fraction of the Sun's total energy output over its 10 billion
year lifespan.
If you want to get even one gee at one meter you need to assemble the
energy equivalence of 1.5 x 10E11 kg, or 1.3 x 10E30 joules.
So, if someone can find a plausible way to do this (and the necessary
gyrations in General Relativity) I would be interested to know of it ...
>Gurth@******.nl - http://www.xs4all.nl/~gurth/index.html
--Adam
acgetchell@*******.edu
"Invincibility is in oneself, vulnerability in the opponent." --Sun Tzu
