
-------- TML Message #1258 --------

Archive-Message-Number: 1258
Date: Wed, 25 Apr 90 19:35:41 PDT
From: gwh%ocf.Berkeley.EDU@lilac.berkeley.edu
Subject: Why we don't see methane or ammonia-fuel starships

Ok, went home and thought about it and cranked some numbers.  Figured out why
you don't want to use different fuels.

The average starship has much if not most of its fuel volume as jump fuel.  
Now, from Starship Operators Guide [yes, it's not GDW but they approved it so
i figure it's official], the Zuchai energy storage capacitors in a Jump drive
can't be held charged for more than two hours safely; three max.  Thus, the
jump powerplant must generate its power within [let's say for safety's sake]
an hour.  And it needs enough fuel to run for an hour...

Now, if we're going to purify something else on the fly, this means that we
need six times the usual purification plant [which will take 6 hours].  At
TL 15, the purification plant is 20% of the fuel volume for the 6hr version.
For our faster requirements, it rises to 120%.  This means that the total
of jump fuel volume and purification plant is now 220% of what we started 
with...and even with a fuel of relative hydrogen density 1.9 we are still
16% over the volume of pure hydrogen.  You Lose...

Even if we're optomistic, and assume that we can push the two-hour lower
limit on crystal charge, we're at 160% volume, divided by 1.9 to 84% of the
origional volume.  We only gain 16%, and in the process lose reliability 
[if the purif plant breaks we're stuck], safety [how long do you WANT to hold
those crystals charged???], and convenience [ya want WHAT instead of hydrogen?]
compared to hydrogen.  Plus, the added cost of the purification plant [a not
inconsiderable 150kCr/kl ] makes this a touchy option.

It is no longer the wonder-fuel.  Go home, people, and have a good night.  If
you really want to trade off the 16% for the added headache i won't mind if
I'm GMing, but i warned ya what's going to go wrong :-)

*******************************************************************************
George William Herbert              JOAT For Hire: Anything, Anywhere: My Price
   UCB Naval Architecture undergrad: Engineering with a Bouyant Attitude :-)
- -------------------------------------------------------------------------------
"Who?" the man managed.                    Whip me, Beat Me, Make me learn C...
"The Rastafarian Navy," Case said,         ++++++++++ gwh@ocf.berkeley.edu  OR
"...and all we want is a jack into your    ========== gwh@soda.berkeley.edu OR
custodial system." -neuromancer            """""""" maniac@garnet.berkeley.edu

-------- TML Message #1259 --------

Archive-Message-Number: 1259
Date: Wed, 25 Apr 90 22:39 EDT
From: METLAY@vms.cis.pitt.edu
Subject: Yo! PBEMers!


I don't know about y'all, but I've been at a Conference getting my pointed
little head stuffed full of neat physics! What're YOUR excuses? I haven't
seen a single piece of PBEM-related mail (except Jaron's probe designs) in
over a week! WHERE IS EVERYBODY?

metlay

PS. And Richard Johnson, having just lain down to sleep for the first time
in a month, bolts out of bed screaming, "NO! WAIT! SHUT UP! ARRRRGH!" |->

-------- TML Message #1260 --------

Archive-Message-Number: 1260
Date:     Thu, 26 Apr 90 1:50:47 PDT
From: Orcinus orca <jokim@jarthur.claremont.edu>
Subject:  Why you SHOULD see ammonia-fuel starships

Good reasoning George.  One problem.  We got on this alternate fuel
stuff by challenging GDW's universe with real universe physics.  You
then went back to GDW physics to disallow this.  But if we stick to
real world physics (or chemistry as it turns out)...

Ammonia is synthesized from N2 and H2 by the Haber-Bosch process.
One of the big problems with this process is that for the reaction
N2 + 3 H2 --> 2 NH3  to proceed quickly, you have to raise the
temperature.  But raising the temperature shifts the equilibrium
back towards N2 and H2.  This is a big problem when you're trying
to make ammonia out of N2 and H2, but it is exactly what we want
if we're out to purify ammonia into H2.  In fact, at 800K the
equilibrium constant calls for:

          (pressure H2)^3 * (pressure N2)
          ------------------------------- = 25000
                  (pressure NH3)^2

i.e.  You don't need a purification plant.  All you need is a bit
of empty fuel space (to allow for the gaseous ammonia, N2, and H2).
>From there:
     Heat the ammonia to 800K
     It vaporizes and splits into N2 and H2
     Separate the gases with a grav plate.
     Dump the N2 into space
     Send the H2 into the power plant and jump drives

The only other thing you'll need is insulating partitions dividing
your fuel into jump-1 amounts.  It wouldn't do to vaporize all your
fuel when all you wanted was a jump-1.

Wow, it's even easier to purify than water!
- --
John H. Kim
jokim@jarthur.claremont.edu
uunet!jarthur!jokim

-------- TML Message #1261 --------

Archive-Message-Number: 1261
Date:         Fri, 27 Apr 90 01:00:34 CDT
From: "C. Patrick Simons" <UD078317@vm1.nodak.edu>
Subject:      Ramblings on a Sniper theme



     Lately there has been some traffic on subsonic and supersonic
rounds for sniper rifles.  Well, perhaps I can help a little here.

     There are exactly two things paramount in mind with a sniper
with a mission:  1) getting away alive 2) getting the target.
Notice that personal survival is of a higher priority.  This is
emphasised over and over again in training.  You can always come back
for another try at the target (that is, if you get away ok).

Now, before you blow up, no, I have not seen live combat (thank GOD!).
However, I have participated in excercises that were damn real, and
that I was 'killed' because either I was detected approaching, on
hitting the target, or on leaving.  The first and last were my fault.
The last is dependant on how the mission is set up.  If it is a
relatively easy hit, you can stand off a nice long distance and
deliver the present at conveniece.  However, on most targets that
snipes are sent after, you have to get in relatively close, and
that is where you want the quietest damn shot in the world.  This
really works.  I've succeeded on penetrating a hard target, making
the tag, and getting away safely because I waited until the conditions
were right.

     Ok, ok.  Enough rambling.
1)  Long distance shot.  Use the high velocity rounds.  It makes for
    a better shot.

2)  Short distance shot.  Use low velocity, cause anything you can
    do to cut down detection in ANY WAY increases your life expectancy
    tons.

This really is a decision that has to be made by each man.  I can
think of only one 'mission' where two shooters actually choose the
same approach and all the rest.  Everything else is personalized to
extreme detail.  Each has different methods, approaches, styles,
etc, etc, ad nauseum.  You may think the shooter as an impersonal
bastard, but in ways we live more in a short time than joe normal
lives his entire life.

(Personally, I like this chemical sliver stuff..they'd never notice me!)
- -------------------------------------------------------------------------
C.P.Simons
UD078317@NDSUVM1.Bitnet  UD078317@vm1.nodak.edu
"With the good Lord above me, and a drill sergeant behind me screaming
and shouting, I can do damn near anything!"
disclaimer: why, everything, of course!
- -------------------------------------------------------------------------

-------- TML Message #1262 --------

Archive-Message-Number: 1262
Date: Thu, 26 Apr 90 23:17:03 PDT
From: gwh%ocf.Berkeley.EDU@lilac.berkeley.edu

>Good reasoning George.  One problem.  We got on this alternate fuel
>stuff by challenging GDW's universe with real universe physics.  You
>then went back to GDW physics to disallow this.  But if we stick to
>real world physics (or chemistry as it turns out)...

Hey, no fair.  It's been two years since i did reaction chem!  [he's
right, however, folks 8-) ]

>From there:
>     Heat the ammonia to 800K
>     It vaporizes and splits into N2 and H2
>     Separate the gases with a grav plate.
>     Dump the N2 into space
>     Send the H2 into the power plant and jump drives
>
>The only other thing you'll need is insulating partitions dividing
>your fuel into jump-1 amounts.  It wouldn't do to vaporize all your
>fuel when all you wanted was a jump-1.

What you're proposing here is just an ammonia-specific purification process.
I would bet that the easy way to do this would be not in the tank, but in a
seperate purifier, which ought to be simpler and smaller than the book ones
since it doesn't have to be able to deal with anything but ammonia.

>From a process-design standpoint, i can guarantee you that doing the above
operation in a continuous flow is easier than in one reaction chamber
[fuel tank].  
Shall we treat it as a smaller purification plant?  Let's say only 25% of
the normal mass due to less required flexibility?
It will probably also need more power...


Ok; revision of my previous posting with better numbers reflecting this:
For the one-hour version; 30% of fuel tank volume in purification plant, 
at 0.4 mass tons and 150kCr per kl of purifier [the same as normal purif
plants.]  Total vol 130% of ammonia tank vol; with the hydrogen density boost
the total volume drops to 68.5% of what the LH2 fuel would take up.  For
a two-hour charge, it's 15% of tank vol in purification plant and total vol 
goes to 115% of fuel vol; corresponding to 60.5% of the corresponding vol
for LH2.  You still have the added cost due to the purif plant and possible
problems from the purifier failing to deal with.


*******************************************************************************
George William Herbert              JOAT For Hire: Anything, Anywhere: My Price
   UCB Naval Architecture undergrad: Engineering with a Bouyant Attitude :-)
- -------------------------------------------------------------------------------
"Who?" the man managed.                    Whip me, Beat Me, Make me learn C...
"The Rastafarian Navy," Case said,         ++++++++++ gwh@ocf.berkeley.edu  OR
"...and all we want is a jack into your    ========== gwh@soda.berkeley.edu OR
custodial system." -neuromancer            """""""" maniac@garnet.berkeley.edu

-------- TML Message #1263 --------

Archive-Message-Number: 1263
Date:     Fri, 27 Apr 90 15:29 EDT
From: SYLVAIN$%DAYTON.BITNET@cornellc.cit.cornell.edu
Subject:  Address & Account Information

This account is going belly up, and I may or may not have an account
this summer. Therefore, oh TML Admin, please stop sending the list here.
As for you PBEMers, send any stuff like moves to the address down below.
I may or may not be able to reply, so don't feel insulted. This is just
so that in the worst case, I still will have more or less complete game
records.

- ---

EPSL has no UUCP address. It has an Internet address. The best address to
use is "cgs@wam.umd.edu" .. the address "cgs@epsl.umd.edu" should only be
used if some problem develops in the WAM Lab mailer (it hasn't happened
yet).

If for some reason only a UUCP address will do, then mail should be forwarded
to cgs@wam from a UUnet "backbone" site --
sample address: "cgs%wam.umd.edu@uunet.uu.net" <- works for UUCP hosts who
subscribe to the UUnet central host. The "bang path" form of the sample
address: "uunet!wam.umd.edu!cgs"
If for some reason the above doesn't work, then forwarding mail through
UMD5 to WAM will work .. in that case:
 "cgs%wam.umd.edu%umd5.umd.edu@uunet.uu.net" or
 "uunet!umd5!wam.umd.edu!cgs"
- --

-------- TML Message #1264 --------

Archive-Message-Number: 1264
Date: Fri, 27 Apr 90 16:38:47 -0400 (EDT)
From: William Dow Rieder <wr0k+@andrew.cmu.edu>
Subject: Re: Alternative Fuel Storage

[I changed the subject line to be more meaningful -- James]

George William Herbert writes:
>Ok, went home and thought about it and cranked some numbers.  Figured out why
>you don't want to use different fuels.
[shows why you need LH2 for jump fuel]

Quite true. I did a similar analysis. I think that in my original
posting it was
stated that the method wouldn't work for jump fuel.

>The average starship has much if not most of its fuel volume as jump fuel.

That depends.  A scoutship has jump-2 and, if memory serves, a 864Mw
powerplant.  It needs 202.5 kl of jump fuel, and 311.04 kl to power the
fusion plant for a month.  Storing the power plant fuel as water would
save about 100 kl, which would more than triple the cargo capacity.
	Any ship with a purification plant must have segmented fuel
capacity, so storing some fuel as water and some as LH2 works. (although
you probably want to adjust the temperature in a segment before
switching fuel types :-)

					W. Dow Rieder

 	When the only tool you have is a hammer, all your problems
start to look like nails...

-------- TML Message #1265 --------

Archive-Message-Number: 1265
Date: Fri, 27 Apr 90 17:15:30 -0400 (EDT)
From: William Dow Rieder <wr0k+@andrew.cmu.edu>
Subject: Re: On reactionless drives

Adrian Hurt writes:
>I think what Bertil was trying to say is, what is wrong with turning a ship
>from having X megajoules of energy stored as potential energy, to a ship
>having .9 X megajoules of kinetic energy and .1 X megajoules of waste energy
>(e.g. heat) without having to dump a load of stuff out of the back to satisfy
>Newton?  This doesn't create energy out of nothing, and doesn't violate
>conservation of energy.   ^^^^^^^^^^^^^^^

Yes it does.  I posted a detailed example showing why recently.  Even if you
use Bertil's idea of  (Energy needed for drive = KE added to ship) it doesn't
work because you need a non-accelerating reference frame to measure KE.

Example: Suppose you have your ship between planets A and B, which
are moving with respect to one another.  We now have to choose a frame
of reference, say A.  Say the velocity of B with respect to A is 1e3 m/s.
The KE of ship relative to A is 0, and relative to B is 5e5*M joules.
The ship now accelerates to 1e3 m/s relative to A, in the direction
opposite to B's motion.  Now the KE of the ship relative to A is K1 =
5e5*M joules, where M is the mass of the ship, so we expend
(K1 + waste) joules to power the drive.  However our velocity relative
to B is now 2e3 m/s, giving a KE of K2 = 2e6*M joules, which
is an increase of 1.5e6*M joules, creating 1e6 joules of "free" energy
with respect to B.  With a rocket, that energy wouldn't appear since
is has to spend energy to accelerate the reaction mass and it masses
less afterwards.
	
I worked all out with a friend for fun when we were building MT
perpetual motion machines. (So I'm weird - sue me)

					W. Dow Rieder

 	When the only tool you have is a hammer, all your problems
start to look like nails...

-------- TML Message #1266 --------

Archive-Message-Number: 1266
Date:     Fri, 27 Apr 90 22:28:46 PDT
From: Orcinus orca <jokim@jarthur.claremont.edu>
Subject:  Re: Alternate fuels--Jump fuel too!

I just thought of a way to get around the slow purification plant/
2 hour zucchini (or whatever) crystal limit.  This time, it's all
kosher with the rules.  I don't have MegaT yet so I can't do any
exact calculations (George, you feel up to it?).

Who says you have to purify your fuel "on the fly"?  If you put
in a moveable partition between the refined and unrefined fuel
(like maybe two "bladders" which can expand to fill the entire
fuel tank), you can refine H2O or NH3 before you start your jump.
You wouldn't be able to refine it all, but you could string two small
jumps together to go further than you normally can.

Example:

Since I don't have Mega-T, I'm going to ignore power plant and
maneuver drives.  Their fuel capacity should help out though by
letting you "steal" some of that space to put refined fuel in.

Take a jump-3 trader.  The captain gets a hot tip that would
let him make a hefty profit on his latest cargo.  Unfortunately,
the destination is 4 parsecs away.  Never fear.  The captain
fills 77.5% of his tanks with ammonia.  This is enough hydrogen
for a jump-4.  He purifies enough to make a jump-1 (19.4%).
This LH2 occupies 33% of the fuel tank, while the leftover
ammonia takes up 58.1% (77.5%-19.4%).  So everything fits.
After the jump-1, the captain purifies the rest of the ammonia
until his tanks are filled.  He then makes his jump-3 and is
promptly killed by pirates because he has no maneuver drives. :-)

If William Dow Rieder's scout ship numbers are right, let's see...
202.5 kl of Jump fuel, 311.04 kl of power plant fuel...
Total fuel capacity = 513.54 kl.  Since the purification plant
can keep up with the power plant, store the power plant fuel as
ammonia.  This cuts down its volume from 311.04 kl to 180.84 kl.
You now have 513.54-180.84 = 332.7 kl left for jump fuel.
Even if you go with straight LH2, you have enough space for
three parsecs worth of fuel (101.25 kl Lh2 for one parsec).
If you go with ammonia, you can put in 235.48 kl (four parsecs)
in.  Purify half of that to leave 117.74 kl of ammonia and
202.50 kl of LH2.  They total 320.24 kl so it all fits.  Do
your first jump-2, then you still have enough methane left
(er, ammonia, sorry) for another jump-2.  

In fact, you're just 4.03 kl short of being able to do a jump-1,
jump-2, jump-2.  If you really wanted to go five parsecs, you'd
only have to give up 4 cubic meters of cargo or power plant fuel
space.
- --
John H. Kim
jokim@jarthur.claremont.edu
uunet!jarthur!jokim

-------- TML Message #1267 --------

Archive-Message-Number: 1267
Subject: Noisy weapons ..
Date: Wed, 25 Apr 90 13:31:34 +0100
From: Jim Cheetham <is_a063%ux.kingston.ac.uk@nsfnet-relay.ac.uk>


>From Mark F. Cook
>  Sorry, but I have to side with Adrian.  Speaking as an experienced hunter
>  and rabid firearms enthusiast, I can guarantee you that a 4mm supersonic
>  gauss needle makes a very noticable noise and a subsonic needle might not
>  even go through a thick leather jacket.
>  ...
>  While the magnetic acceleration process of the gauss weapon may be ABSOLUTELY
>  silent (and I have my doubts about this also), anyone within several hundred
>  meters of the weapon will be treated to the staccato crack of gauss needles
>  punching holes in the air.

	OK, well, nothing like the voice of experience to blow a theory!
	You're right - I hadn't thought it all through properly ...
	I'm still siding with the idea that the acceleration/launching
	process should be silent though ... The only noise I can think
	of would be charging capacitors, and with a bit of TL application
	I would have thought that that could be easily cured ...

	So what about sculpting the needles so that the air-flow around
	then is radically different - ie it generates sound of a frequency
	that is too high for the ears to pick up ? Obviously horribly
	expensive to produce, but would it work ? Subsonic only, I expect ...
- ------------------------------------------------------------------------------
     _____               (JANET) jcheetham@uk.ac.kingston
    (__ __) O  ______    (local) is_a063@ux.king
   (____)  (_)(_)()(_)   (voice) (+44) 1 549 1366 x2690
   Jim Cheetham, ISD Kingston Polytechnic.
   "... nuke the site from orbit. It's the only way to be sure."
- ------------------------------------------------------------------------------


-------- TML Message #1268 --------

Archive-Message-Number: 1268
Date: Mon, 30 Apr 90 13:45:49 BST
From: Jo Jaquinta <jaymin@maths.tcd.ie>
Subject: The Temperature of Space

	What with all that talk of fuel tanks freezing over people out there
seem to have this idea that space is cold. Only objects have temperature, space
is a vaccuum and thus has no definitive temperature at all.
	Remember your thermos flasks? A vaccuum is a very good insulator. If
anything you ship will be too hot. When half the solar panels were ripped off
Skylab when it first went up the team had to contend with temperatures over
100oF at times. A spaceship adsorbs all radient energy, raising the 
temperature. The life support system radiates this back into space.  That's
why they're all bright and shiny. Remember how important Albedo was in the
old Scout's book?
	In my own campaign the engines can process their fuel at a variety of
temperatures (certain are more optimal of course). The life support then uses
the fuel mass as a heat sink. Before jump the fuel is cooled (possibly using
outgassing/evaporation). During jump the ship can't radiate energy and so the
heat is pumped into the fuel tanks too keep the place livable. After exiting 
from  jump the heat is then pumped outside.
	My players are crewing an old standard Scout ship. We all already know
the problems that design has with life support. And they are manning eight
people! The jump starts OK but as the days lengthen the temperature raises,
the smell gets worse, and people get narky. The crew nearly mutinied when they
had to jump twice without flushing the air system.
	Other thoughts:
	If your maneuver drives work better with preheated fuel, you can get one
hell of a boost coming out of jump.
	Assuming skimming heats you up, a quick skimm followed by a quick jump
means one hot trip.
	Mold and mildew can be a problem when your life support goes slightly
wonky. They are in Mir. Hot humid air... it's no wonder Scout ships smell.
	Misjumps that cause you to stay in jump longer are real headaches. The
heat exhaustion will probably get you before the 4D-madness.

				Jo Jaquinta
				jaymin@maths.tcd.ie


-------- TML Message #1269 --------

Archive-Message-Number: 1269
From: Adrian Hurt <adrian%cs.heriot-watt.ac.uk@nsfnet-relay.ac.uk>
Subject: Re: Reactionless drives
Date: Tue, 1 May 90 12:57:13 BST

William Dow Rieder <wr0k+@andrew.cmu.edu> writes:
> Adrian Hurt writes:
> >I think what Bertil was trying to say is, what is wrong with turning a ship
> >from having X megajoules of energy stored as potential energy, to a ship
> >having .9 X megajoules of kinetic energy and .1 X megajoules of waste energy
> >(e.g. heat) without having to dump a load of stuff out of the back to satisfy
> >Newton?

>								   Even if you
> use Bertil's idea of  (Energy needed for drive = KE added to ship) it doesn't
> work because you need a non-accelerating reference frame to measure KE.

Oh, *@!~.  Relativity strikes again. :-)

After reading this, I did a bit of working out on some scrap paper myself,
which started out with conservation of energy and ended up with conservation
of momentum.  If you really want a long, boring load of ASCII, I can post it
here.  Suffice to say, I was right to leave all those exhaust nozzles on my
model ships!

There is one possible loophole, which someone on rec.arts.sf-lovers suggested.
So-called "reactionless" drives are nothing of the sort; they use the rest of
the universe as a reaction mass.  Someone else can figure out how, or if, this
can be done.  I'm sticking with rockets - they make the models look better.

> I worked all out with a friend for fun when we were building MT
> perpetual motion machines. (So I'm weird - sue me)

You want perpetual motion machines?  Try assuming that a black globe absorbs
gravitons and see what happens.

- -- 
 "Keyboard?  How quaint!" - M. Scott

 Adrian Hurt			     |	JANET:  adrian@uk.ac.hw.cs
 UUCP: ..!ukc!cs.hw.ac.uk!adrian     |  ARPA:   adrian@cs.hw.ac.uk

-------- TML Message #1270 --------

Archive-Message-Number: 1270
Date: Tue, 1 May 90 11:19:07 PDT
From: "Kelly St.Clair" <kstclair@jacobs.cs.orst.edu>
Subject: Fool, er, Fuel Discussion

I've been reading the postings on fuel storage, and decided to post this
  song.  If nothing else, it offers an idea on the subject of emergency
  fuel supply...

FOOL TO FEED THE DRIVE


A hundred parsecs out, on a ship quite second rate
The engineer, McQuillin, sent the word up to the mate:
"Our engine's out of steam," he said, "and soon our ship will die,
If we can't find a planet with fuel to feed the drive."

Now, our ship's a noble lady, and our captain, she is, too,
But our engineer is none too bright; the dimwit of our crew.
The captain said,  "I thought you filled the tanks on Vega Five."
McQuillin just looked sheepish.  He forgot to feed the drive.

Can curses stir the gods of space who dwell beyond the stars?
If so, they surely woke up then, for we used up most of ours.
We thought we'd drift forever, lost between the stars we'd die,
And all because McQuillin bought no fuel to feed the drive!

But then the captain's eyes grew bright.  She said,  "It seems to me
That a fusion drive burns H2O."  McQuillin turned to flee.
"Grab him, boys, and hold him.  He's no good to us alive,
But two hundred pounds of water will feed our dyin' drive!"

So once again we fly through space, avoiding all the stars.
Who knows what ruin will take us, what evil fate is ours?
We didn't find our planet, but we'll all but one survive.
As long as we are granted some fool to feed the drive!

                            --Jordin Kare
                              Filk to "Fuel to Feed the Drive" 
                              by Cynthia McQuillin and Phillip Wayne

-------- TML Message #1271 --------

Archive-Message-Number: 1271
Date: Wed, 2 May 90 09:11:20 EDT
From: Fiver Toadflax <09nilles%cuavax.dnet@netcon.cua.edu>
Subject: Silencers

>  While the magnetic acceleration process of the gauss weapon may be ABSOLUTELY
>  silent (and I have my doubts about this also), anyone within several hundred
>  meters of the weapon will be treated to the staccato crack of gauss needles
>  punching holes in the air.
     
>>	So what about sculpting the needles so that the air-flow around
>>	then is radically different - ie it generates sound of a frequency
>>	that is too high for the ears to pick up ? Obviously horribly
>>	expensive to produce, but would it work ? Subsonic only, I expect ...

It is also worthy to point out that a simple pillow when held against the
muzzle of a gun, be it supersonic or subsonic, quiets the sound to the point
that a person 20 feet or so away cann't hear it clearly.  Admittedly we
are talking about a single shot.  But there are TWO things that cause the
noise of gun fire.  First and obviously, the expanding gasses of the burning
gun powder, are easily quieted.  Second is the bullet passing the sound
barrior.  Another easily solved problem.  The only real hard part is making
the silenecer have enough space to allow the compression wave to be absorbed
and still have something that is small and light weight.  That is why you will
notice the larger/faster the round, the bigger the silencer.  It would also
be theoretically possible to silence a 155mm Howizer but not practicle.

                 Dave

+-----------------------------------------+
|          09nilles@cua.bitnet            | Nuke 'um Till They Glow
|  09nilles%cuavax.dnet@netcon.cua.edu    |     Then Shoot Them in the Dark
| uunet!cua.bitnet!09nilles@uunet.UU.NET  |
| Fiver.Toadflax@f329.n109.z1.FIDONET.ORG | Peace through superior firepower
+-----------------------------------------+


-------- TML Message #1272 --------

Archive-Message-Number: 1272
Date: Wed, 2 May 90 17:08:24 -0700
From: "Ted Kim (Random Dude" <tek@lanai.cs.ucla.edu>
Subject: undigestifier

TML submission:

A while back, I asked if anyone had pointers to an undigestifier
program, so that I could be more selective when saving articles from
this mailing list. While better mail programs (mh, mush, etc.) have
them builtin, I did not want to switch just to read this mailing list.
Well, after receiving no suggestions and turning up nothing at uunet,
I wrote my own. 

I make no claim it works for anything in particular or in general at all.
<add legalistic disclaimer mumbo-jumbo here> 

The program is specific to the formatting used in the TML Nightly and
probably dependent on the BSD UNIX way of doing mail. (James, please
don't change the format, or my fragile program will break!) 

Basically, Berkeley mail users can just pipe the TML Nightly into this
program and get the inidividual articles mailed to themselves. Due to
the way TML is formatted, they generally show up with the correct
author and date. (Some articles have no "from" line, and show you as
the author!). Of course, the actual delivery history will show you
mailed to yourself.

- -ted

Ted Kim                           
UCLA Computer Science Department  Internet: tek@penzance.cs.ucla.edu
3804C Boelter Hall                UUCP:    ...!{uunet|ucbvax}!cs.ucla.edu!tek
Los Angeles, CA 90024		  Phone:   (213) 206-8696
====================================cut here====================================
/*
 * udt: undigestifier for TML Nightly
 * by tek@cs.ucla.edu
 */

#include <stdio.h>

extern char *getenv();
extern void get_line();
extern void peek_line();
extern void put_line();
extern void write_marker();
extern void write_repeated();

#define BUFLEN (1024)
#define HEADER_DASHES (60)
#define ARTICLE_DASHES (30)
#define END_MARKER "End of TML Nightly\n"
#define TMP_FILENAME "/tmp/udXXXXXX"

#define WRITE_EMPTY putc('\n', fp)
#define CLEAR_BUF peeked = 0

main()
{
  register int cont;
  int article, peeked = 0;
  char buf[BUFLEN];

  char filename[256];
  int fd;
  FILE *fp;

  char cmd[BUFLEN];
  char *user = getenv("USER");

  /* header */
  for (cont = 1; cont; ) {
    do get_line(buf, BUFLEN, &peeked); /* anything, blank line */
      while (strlen(buf) > 1);
    peek_line(buf, BUFLEN, &peeked); /* dashes */
    if (!check_repeated(buf, '-', HEADER_DASHES)) 
      continue;
    CLEAR_BUF;
    get_line(buf, BUFLEN, &peeked); /* blank line */
    if (strlen(buf) == 1)		
      cont = 0;
  }
  printf("header removed\n");

  /* articles */
  for (;;) {

    /* open tmp file */
    strcpy(filename, TMP_FILENAME); 
    fd = mkstemp(filename);
    fp = fdopen(fd, "w");

    for (;;) {
      get_line(buf, BUFLEN, &peeked);

      /* check for end of article */
      if (strlen(buf) == 1) {	/* blank line */
	peek_line(buf, BUFLEN, &peeked); /* dashes */
	if (!check_repeated(buf, '-', ARTICLE_DASHES)) {
	  WRITE_EMPTY;
	  continue;
	}
	peek_line(buf, BUFLEN, &peeked); /* blank line */
	if (strlen(buf) > 1) {
	  WRITE_EMPTY;
	  write_repeated(fp, '-', ARTICLE_DASHES);
	  continue;
	}
	CLEAR_BUF;
	fclose(fp);		/* mail article */
	sprintf(cmd, "/bin/mail %s < %s\n", user, filename);
	system(cmd);
	unlink(filename);
	printf("sent article %d\n", ++article);
	break;
      }

      /* check for end of digest */
      else if (strcmp(buf, END_MARKER) == 0) { /* end marker */
	peek_line(buf, BUFLEN, &peeked); /* stars */
	if (!check_repeated(buf, '*', strlen(END_MARKER) - 1 )) { /* no nl */
	  write_marker(fp);
	  continue;
	}
	peek_line(buf, BUFLEN, &peeked); /* blank line */
	if (strlen(buf) > 1) {
	  write_marker(fp);
	  write_repeated(fp, '*', strlen(END_MARKER) - 1);	  
	  continue;
	}
	fclose(fp);		/* exit */
	unlink(filename);
	printf("end of digest\n");
	exit(0);
      }
      
      else
	put_line(buf, fp, &peeked);
    }
  }
}

void
get_line(buf, len, pp)
     char *buf;
     int len, *pp;
{
  if (*pp) 
    *pp = 0;
  else 
    fgets(buf, len, stdin);  
}     

void
peek_line(buf, len, pp)
     char *buf;
     int len, *pp;
{
  fgets(buf, len, stdin);  
  *pp = 1;
}     

void
put_line(buf, fp, pp)
     char *buf;
     FILE *fp;
     int *pp;
{
   fputs(buf, fp);
   *pp = 0;
}

void 
write_marker(fp)
     FILE *fp;
{
  fputs(END_MARKER, fp);
  WRITE_EMPTY;
}

int
check_repeated(buf, c, len)
     char *buf;
     register char c;
     register int len;
{
  register int i;
  register char *cp;
  
  for (i = 1, cp = buf; i < len; i++, cp++) /* check all but the newline */
    if (*cp != c)
      return 0;
  return 1;
}

void
write_repeated(fp, c, len)
     FILE *fp;
     char c;
     register int len;
{
  register int i;

  for (i = 0; i < len; i++)
    putc(c, fp);
  WRITE_EMPTY;
}
====================================cut here====================================

-------- TML Message #1273 --------

Archive-Message-Number: 1273
From: "Mark F. Cook" <markc@hpcvss.cv.hp.COM>
Subject: Pillows as silencers
Date: Thu, 3 May 90 11:21:53 PDT

In TML note 1271 "Silencers" <09nilles%cuavax.dnet@netcon.cua.edu> writes:

>>>While the magnetic acceleration process of the gauss weapon may be ABSOLUTELY
>>>silent (and I have my doubts about this also), anyone within several hundred
>>>meters of the weapon will be treated to the staccato crack of gauss needles
>>>punching holes in the air.
>>     
>>  So what about sculpting the needles so that the air-flow around
>>  then is radically different - ie it generates sound of a frequency
>>  that is too high for the ears to pick up ? Obviously horribly
>>  expensive to produce, but would it work ? Subsonic only, I expect ...
>
>It is also worthy to point out that a simple pillow when held against the
>muzzle of a gun, be it supersonic or subsonic, quiets the sound to the point
>that a person 20 feet or so away cann't hear it clearly.  Admittedly we
>are talking about a single shot.  But there are TWO things that cause the
>noise of gun fire.  First and obviously, the expanding gasses of the burning
>gun powder, are easily quieted.  Second is the bullet passing the sound
>barrior.  Another easily solved problem.  The only real hard part is making
>the silenecer have enough space to allow the compression wave to be absorbed
>and still have something that is small and light weight.  That is why you will
>notice the larger/faster the round, the bigger the silencer.  It would also
>be theoretically possible to silence a 155mm Howizer but not practicle.

I don't think I'd go so far to call the problem "easily solved", Dave,  The
pillow idea (or any other means) still boils down to the same simple truth:
if you want a silent round, reduce it's velocity until it's subsonic.  This
is not as easy as it seems (and for large, powerful rounds, like a .44 Magnum,
a pillow is not nearly enough).

A typical .357 Magnum round (w/ a 200 grain slug, which is roughly 12.9 gm.)
will have a muzzle-energy of 590 ft./lbs. (800 Joules), and a muzzel-velocity
of 1,158 ft./sec. (or 353 M./sec.), which is slightly above the speed of sound
(1,120 ft./sec. at sea level).  Now, 2 simple formulas involving energy, mass,
and velocity (using the metric system) are:
                (((E(j) * 21,630) / M(g))^0.5) / 3.28 = V(m/s)
        - and - ((V(m/s) * 3.28)^2 * M(g)) / 21,630 = E(j)
where E(j) is energy (in Joules), M(g) is Mass (in grams), and V(m/w) is
Velocity (in Meters/Second).  Given these formulas, and the fact that the
mass of the .357 Mag. slug doesn't change, then it follows that to make
the round's velocity drop below supersonic, we must reduce the total energy
of the round by 53.9 Joules (work it out for yourself).  Since this equals
only about 2/3 the muzzle-energy of a .22 short, a thick pillow MIGHT do
the trick, but for more powerful rounds (anything in the high-powered rifle
catagory), forget it.  And you still have the leaky cylinder to contend with.

Leaky cylinder?  I'm glad you asked.  Revolvers cannot be effectively silenced,
since a significant portion of the blast from the powder burning leaks out
at the interface between the cylinder and the barrel.  Semi-auto pistols
don't have this problem, but the slide itself is extremely noisy as it works
(let the slide on an empty pistol slam forward and you'll see what I mean).
I guarantee you that it CAN be heard more than 20 feet away.  Most silenced
weapons (both military and covert ops.) are single-shot pistols, firing
subsonic rounds.  To be effective, they must be employed at close range
(less than 10 meters), and must be acccurately aimed at an un-armored part
of the victim.  Sniper weapons (long range by definition) are never silenced,
as physical laws prevent the design of a weapon that is both silent AND
effective.

(Note: You can get the muzzle-energy/muzzle-velocity/slug mass data from
any Reloaders Handbook.  Most sporting goods store carry them.)

Later,

        "Look.  All of this talking is getting us nowhere!  I think we
         should try a more direct approach."

        "MY GOD!!  THAT'S A HAND GRENADE!!"

        "Right.  It's faster than Imperial arbitration, and it hurts less."

Mark F. Cook

USMail: User Interface Technical Support
        Hewlett-Packard - Interface Technology Operation
        1000 NE Circle Blvd.  Corvallis, OR 97330

INTERNET: markc@hpcvss.cv.hp.com
UUCP:     {cmcl2, harpo, hplabs, rice, tektronix}!hp-pcd!markc

-------- TML Message #1274 --------

Archive-Message-Number: 1274
From: Bart Massey <bart@fatal.tv.TEK.COM>
Subject: Undigestifier patch, comments (Re: (1272) undigestifier)
Date: Thu, 03 May 90 12:12:30 PDT

Sorry I didn't respond sooner, but I assumed others would e-mail you.
My *strong* recommendation is to use mh-mail.  Its "burst" command
does exactly what you want -- try 'burst -inplace -verbose'.

Below is a patch to the posted undigestifier for older Berkeley
systems which don't have mkstemp() .  Note that this generates
a race condition, but since the result of mkstemp() wasn't being
checked anyhow...

Also note that the define for END_MARKER needs to be changed for
those of you receiving the bi-weekly digests -- otherwise the code
loops forever consuming disk...

					Bart Massey
					..tektronix!videovax.tv.tek.com!bart
					..tektronix!reed.bitnet!bart

- ------
*** tml_undigest.c.orig	Thu May  3 12:06:08 1990
- --- tml_undigest.c	Thu May  3 11:45:45 1990
***************
*** 4,9 ****
- --- 4,12 ----
   */
  
  #include <stdio.h>
+ #ifndef HAS_MKSTEMP
+ #include <sys/file.h>
+ #endif
  
  extern char *getenv();
  extern void get_line();
***************
*** 53,59 ****
- --- 56,67 ----
  
      /* open tmp file */
      strcpy(filename, TMP_FILENAME); 
+ #ifndef HAS_MKSTEMP
+     mktemp( filename );
+     fd = open( filename, O_CREAT | O_RDWR | O_EXCL, 0644 );
+ #else    
      fd = mkstemp(filename);
+ #endif    
      fp = fdopen(fd, "w");
  
      for (;;) {


-------- TML Message #1275 --------

Archive-Message-Number: 1275
Date: Fri, 4 May 90 02:08:31 -0500
From: Mark Gellis <f3w@mentor.cc.purdue.edu>
Subject: Lasers are silent


I have been following the discussion of silenced weapons with some interest.
Without wishing to rain on anyone's parade, I thought it might be worthwhile
to note that in the Traveller universe (and any game universe set more than
one hundred years in the future, if it's high tech), the question is moot.
Lasers are probably going to be VERY silent, compared to slug throwers, and
will not have to deal with the problems of reduced power.  If I were an
assassin, 3,000 years in the future, and I wanted to make a quiet attack, and
had to use a firearm to do it, I would use a laser.  I would suspect that
for any future game universe, a person needing to use a firearm in a stealthy
manner would rely on one of two methods:

   1) A laser, since it is quiet, and does not lose power by being quiet 
(I do not know if it is silent; I imagine there is a soft crackling noise
from the laser superheating the air as the beam passes through it, but this
cannot be any louder than the noise released by contemporary silencers).

  2) A low calibre pistol at point blank range.  (I understand this is how
many assassinations are done today.)  It takes real balls to do this, but
what you do is to walk up behind someone, put a .22 or .25 to the back of
their neck or head, pull the trigger, AND THEN JUST WALK AWAY AS IF YOU 
WERE JOE AVERAGE AND HAD NEVER DONE ANYTHING WRONG IN YOUR LIFE.  The guy
you have just snuffed will fall.  On a busy street, it will be several
seconds before anyone realizes that the guy has anything more wrong with
him than stumbling on a cracked sidewalk.  By this time, you're gone.

For the second method, I recommend soft-nosed, explosive, hollow-point, or
glaser safety rounds.  Against an unarmored target, they will do more damage.
If you're using a .22 or .25 (both 5-6 mm.) pistol rounds, you need all the
help you can get.  

By the way, while we are on the subject of assassinations, I would like to
mention that no one seems to be talking about the possible applications of
microrobotics in Traveller, for assassinations or other enterprises.  What
do you people think about wasp-sized robots, with VX nerve toxin in the
stingers, homing in on people based on their individual chemical signatures?
(Users would need a skill like Robotics or Remote Controls--I call it 
Remotes in my game--to use the robots.)  They fly about as fast as angry
hornets, hardly ever miss, and if the victim does not get medical attention
in about one minute, they are dead, dead, dead.

Any other interesting ideas?

Mark

-------- TML Message #1276 --------

Archive-Message-Number: 1276
Date: Fri, 4 May 90 11:31:47 -0500
From: tey@sage.cc.purdue.edu
Subject: PBEM, Silencers, and other stuff...


Well, it's the end of the year here at dear old Pud U., and I've a few
things to say before I head out. First, and most unfortunately, I haven't
yet found out if my friend back home will have an account I can borrow
for this mailing list, so Dr. Morser may be effectively silenced until
next semester. If you just _have_ to get in contact with me about something,
I can be found via snail-mail at:
		3927 Elmwood Ave.
		Louisville, Ky.  40207

Secondly, my final action before going into low storage(or whatever), is
to ask if any of the Social or Generalist teams would care to work on
a somewhat more flexible translator program. I have the computer skill, but
no linguistics, and there's no telling what kind of stuff that probe's going to shak
going to shake loose.

Thirdly, I'm very sorry for the last-minute nature of this message(I'm leaving
this afternoon)...I really should have given more warning, but I've been 
in a real crush this week for finals. 

And finally, on the subject of silencers...Actually, there _is_ a good
reason for putting silencers on military-type sniper weapons; You see,
a silenced weapon doesn't necessarily mean the sound of the round going
through the sound barrier is quiet(as has already been explained by a
number of people), but it does mean that that the sound of the actual 
explosion of gunpowder is quiet(if a halfway decent silencer). Now while
that may not sound terribly useful to you, it means that there's no way
to tell(by sound, anyway) _where_ the shot was fired from...And let's
face it, as soon as some poor fool's head explodes for no apparent
reason, somebody's gonna guess that there's a sniper somewhere anyway...

				Hasta la bye-bye, guys
				Craig Waylan

-------- End of TML Messages --------

