Traveller-digest      Tuesday, August 24 1999      Volume 1999 : Number 1008



(R)1996. Traveller is a registered trademark of FarFuture Enterprises.
All rights reserved.

The following topics are covered in this digest:

Re: GURPS Vehicles weapon design question...
RE: Streamlining
RE: The Heritage Trilogy
Re: Thrust effects (was HEPlar lives!)
Re: The Heritage Trilogy
Re: I Need Some Radiation
Re: Thrust effects (was HEPlar lives!)
Re: Thrust effects (was HEPlar lives!)
Re: I Need Some Radiation
Re: Grav Deckplates
Re: Orion Drive Modules
Re: Thrust effects
Re: slightly OT: Looking to locate...
Re: I Need Some Radiation
Re: Thrust effects (was HEPlar lives!)
Re: Thrust effects (was HEPlar lives!)
Long Range Scouts

----------------------------------------------------------------------

Date: Tue, 24 Aug 1999 16:33:30 -0400
From: Juliean Galak <jg42@cornell.edu>
Subject: Re: GURPS Vehicles weapon design question...

At 04:09 PM 8/24/99 +0000, you wrote:
>I'm either missing something here, or there's a problem...
>
>I'm designing my own weapons for a ship I'm building, and then comparing 
>my design to
>the "standard" designs - and mine are coming out quite a bit more 
>powerful. The reason,
>as I see it, is the power requirement.
>
>Pow = kJ * 2.666 * ROF

Not quite.  For normal GT VE2, this is correct, as it allows a battery to 
hold one (normal GURPS combat round=1sec) round worth of fire.  However, in 
GT, the battery holds not one round worth but one _shot_ worth.  That's EPS 
(energy per shot) and is EPS=kJ * 2.666 (for a laser).  Giving you the 
factor of two error you are getting.  Note that despite this, the 360MJ 
laser is slightly broken (as far as mass is concerned)...

If you'd like, I can email you a spreadsheet I designed that does energy 
weapon calculations for GT.  It's not available for public distribution 
yet, but I'm looking for beta testers to shake out the bugs before I submit 
it to SJG.


           -- Juliean Galak (a.k.a. Falcon)

- --
jg42@cornell.edu        "I do not agree with a word you say, but I will
                          defend to the death your right to say it."
                                              -- Francois Marie Voltaire
#include <disclaimer.h> "Imagination is more important than knowledge"
                          			     -- Albert Einstein
for PGP public-key and
more quotes, finger: jg42@gerfalcon.tzo.com
WWW Page: http://www.cadif.cornell.edu/~falcon/                

------------------------------

Date: Tue, 24 Aug 1999 16:40:11 -0400
From: Ian Ferguson <ian@vax2.concordia.ca>
Subject: RE: Streamlining

Juliean Galak writes:
>>         Entering the atmosphere may be possible, though awkward if
>>         the ship must be pointed straight up all the time, but
>>         landing requires more than surviving the atmosphere.  I
>>         have always assumed that "streamlining" includes landing
>>         gear, wilderness refueling equipment, and general design
>>         considerations that allow access to the ship when it is
>>         landed.
>
>well, that's an acceptable solution for small ships, but that still
>doesn't explain why it's "streamlining" that's at stake here.  I can see
>a 5000dt USL freighter slowly settling, nose up, into a prepared berth in
>a downport, where various gantries grab onto it for support, and fuel
>hoses attach to the same nozzles used in orbital refueling.  The ship
>never completely powers down, and takes off, slowly, as soon as it's
>unloaded and re-loaded.

	Sounds like a good system to me.  IMTU, it is easier and
	cheaper to offload "unstreamlined" ships at the highport
	and ferry the goods down in a shuttle, but what you
	suggest sounds doable.

Peez

------------------------------

Date: Tue, 24 Aug 1999 16:40:56 -0400
From: Glenn Myers <glenn.myers@ansys.com>
Subject: RE: The Heritage Trilogy

I like the Honor series but I HATED In Death Ground. The fact that
Weber's name was on the cover convinced me to buy it. I couldn't sell my
copy back to the used bookstore fast enough. It is a book filled with
tedious descriptions of fleet battles between mankind and alien fleets.
While some of the technical ideas were worthwhile, I considered none of
the characters memorable. I also did not realize it was part 1 of a
series until the end.

I read somewhere that a computer simulation was used to model the fleet
battles. While I enjoy wargaming, I would never write a book based on a
game. I don't think Weber should have, either.

Again, YMMV. I don't think you could pay me to read part 2. Honestly, I
don't usually rail against SF authors but I considered this book a
special waste of my time. 

There you go, hardly a wishy-washy review! 


>What's the In Death Ground about?  I haven't seen that one yet...
>
>           -- Juliean Galak (a.k.a. Falcon)

------------------------------

Date: Tue, 24 Aug 1999 16:45:48 -0400
From: Juliean Galak <jg42@cornell.edu>
Subject: Re: Thrust effects (was HEPlar lives!)

At 06:52 PM 8/24/99 +0100, you wrote:
> >This brings up an interesting question: why can't an USL ship land in an
> >atmosphere?  Considering the fact that some of them have 6G of thrust, a
> >mere 1G of gravity shouldn't bother them (of course, if it's the AG that
> >provides some of the structural strength, then you'd need to keep that on).
>
>
>I think of it more an issue of internal stiffness and bracing. If, for
>example, we took a current-day aircraft carrier, strapped a huge mother of a
>rocket pack to its belly and lifted it out of the water on our single thrust
>point, it would just plain snap in two. I'm sure we all know why it would do
>that - because it's supposed to have water supporting it along its length.

I don't think that analogy holds.  An aircraft carrier isn't designed to 
take a single point thrust, but a space ship is.  A better analogy would be 
a modern fighter jet, which, given the right birth , could sit on the 
ground on it's tailpipe all day long

>That's the kind of thing that happens when you move something outside of the
>environment for shich it's designed. A spaceship designed never to enter a
>plant's gravity well (except in orbital freefall) would have exactly the
>same problem. Sure, you could redesign an unstreamlined ship to have the
>internal bracings (or distributed thrusters) necessary, but I think that's
>actually the majority of what you pay for when you buy a
>TNE-streamlined/HG-partially-streamlined (as opposed to an
>TNE-airframe/HG-streamlined) ship.

Instinctively, I have to agree with you.  If a vessel isn't designed for 
atmosphere, it shouldn't be able to handle atmosphere.  But I want to know 
_why_.  I'm really looking for specific problems the ship would 
experience.  I don't think that internal bracing is an issue, as it's 
already in place to survive the multi-G thrust of the ship.  (a ship rated 
for .01G OTOH, _would_ get torn apart by a planet....)

           -- Juliean Galak (a.k.a. Falcon)

- --
jg42@cornell.edu        "I do not agree with a word you say, but I will
                          defend to the death your right to say it."
                                              -- Francois Marie Voltaire
#include <disclaimer.h> "Imagination is more important than knowledge"
                          			     -- Albert Einstein
for PGP public-key and
more quotes, finger: jg42@gerfalcon.tzo.com
WWW Page: http://www.cadif.cornell.edu/~falcon/                

------------------------------

Date: Tue, 24 Aug 1999 16:55:13 -0400
From: "Jory Earl" <j-man@iname.com>
Subject: Re: The Heritage Trilogy

"In Death Ground" is written in the same 'universe' as Insurrection and
Crusade.  Basically there's an enemy out there who can attack with what
seems to be unlimited amounts of ships.  And they pick up new tech and
tactics pretty quick.
___________________________________________________________
 J-Man
 ICQ# 2843475
 New Hampshire - U.S.A.
 Email : j-man@iname.com
 Home Page : http://www.geocities.com/~jman037/
___________________________________________________________

------------------------------

Date: Tue, 24 Aug 1999 16:52:58 -0600
From: "David J. Golden" <goldendj@pcisys.net>
Subject: Re: I Need Some Radiation

At 08:13 PM 8/23/99 -0500, you wrote:
>Wondering about my close encounter with starships coming up....
>
>I've got a PC hanging by the handgrip of the airlock ON THE OUTSIDE
of
>the bad guy ship.
>
>The bad guy ship just slammed on full thrust.  It's moving from an
>all-stop position to 3G acceleration.
>
>So, my questions are--
>
>1)  Inertia.
>
>There are no inertial dampers outside the bad guy ship.  What will
>happen to the PC as he holds onto the bar?  Can he withstand the
force
>of the ship moving and ride on the outside of the thing?  Or will
the
>ship leave him floating in its wake?

	Gather concrete blocks equal to twice your weight. Do a chinup on a
steel bar and have a friend tie the blocks to your ankles. Now have
your friend drop the blocks ...

	Hanging on by hand I'd doubt. If he had a place where he could brace
himself feet and hands (and preferably other body parts as well),
maybe ... until you start doing evasive maneuvers at 3G.

>2)  Radiation.
>
>If the PC is left floating (or if he lets go and does not travel
with
>the ship), what happens when a person in a vacc suit veers too close
to
>the wrong end of a T-plate?  Those things glow blue with the
ionization
>(I use the DGP style of T-plates in my campaign).  Will that
radiation
>fry anyone who comes to close to it?

	This one is, I think, entirely your call ... at least until Glenn
makes a better report on his sighting near Area 51 and we find out
just what thruster plates are. Blue light, by itself, isn't a
penetrating radiation hazard. It may be bright enough to burn through
a faceplate, or even fry. What other radiation accompanies it is up
to you.

>If so, how close does one have to get to the T-plates in order to
take
>damage?

	How close do you want to get?

>What kind of damage (how many D) would you put on a PC in that kind
of
>raditiation?

	Well, since it's a PC, I'd probably do no more than a few D6 if I
wanted to teach him a lesson about stupid tricks.
- -- ------------------------------------------------------------ --
   Dave Golden                  http://www.pcisys.net/~goldendj 

   Rome did not create a great empire by having meetings, they 
   did it by killing all those who opposed them.

------------------------------

Date: Mon, 23 Aug 1999 23:59:38 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

>  "Nick Bradbeer" <nickb@ndirect.co.uk> writes:
>>Well, every single ship in Brilliant Lances (that's all the classic designs)
>>has contra grav, except for the Lab Ship, Donosev, Chrysanthemum and Aurora.
>>All those four are unstreamlined, and thus not atmosphere-capable.
>
> A USL ship can land in an atmosphere with CG, provided the bracings are
> adequate (ie it is stressed to take local gravity). In most cases this is
> probably the case as the ship can take accn from the drives.
>
> CG means it can float down real slow.

Only if it's a dead calm all the way down. USL means that it is *not*
staticly *or* dynamicly stable under the combination of thrust loading
and wind loading. 

The usual result of such lack of stability is *wild* tumbling in even a
breeze. 

And trying to weasle out by saying "but the computer will compensate"
requires that the computer have been programmed *in advance* with the
aerodynamic properties of the ship. Which, since *by definition* USL
ships are never intended to land seems more than a little unlikely.

:-)

- -- 
Leonard Erickson (aka Shadow)
 shadow@krypton.rain.com        <--preferred
leonard@qiclab.scn.rain.com     <--last resort

------------------------------

Date: Tue, 24 Aug 1999 00:07:12 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

> This brings up an interesting question: why can't an USL ship land in an 
> atmosphere?  Considering the fact that some of them have 6G of thrust, a 
> mere 1G of gravity shouldn't bother them (of course, if it's the AG that 
> provides some of the structural strength, then you'd need to keep that on).

> As for the atmosphere itself, that's only an issue if you do a fast, TL7 
> spacecraft style landing.  Given either CG or Thruster Plates/Reactionless 
> thrusters, it should be possible for a ship to take a few hours to _slowly_ 
> come down through the atmosphere and land gently.  Same on takeoff.

The problem is *wind*. USL is "unstable" in a wind. I won't go into
details, just note that the wind forces act thru a point *other* than
the center of mass. And where the point is depends on the angle. Thus,
in the presence of even a *light* wind, the vehicle will tumble
wildly. 

> Am I overlooking something?  Is this in a faq somewhere?  Or is this an 
> acknowledged hole in Traveller?

It's a frequently debated question. 

Having had to design objects that were aerodynamicly stable at low
speeds, I can assure you that it will be a major problem.

Engine thrust is fixed with respect to the hull. And any "deflections"
are figure with respect to the hull, not with respect to the outside
world. 

Thus, when a light gust of wind exerts more force on one side of the CG
than the other, the ship will turn in the direction of the excess wind
load. But the thrust *also* turns (until someone tells the system to
change it). 

So now the ship is moving in a *different* direction relative to the
wind. Which means the wind forces are form a different direction, and
since (by definition) this ship is not even rudimentarily streamlined, 
the wind will now turn it in a *different* direction. 

The result is a wild tumble. And to attempt to compensate for it would
require that the ship's computer be programmed with a lot of
aerodynamic data about the ship. Which is hard to justify in a ship
that (again, *by definition*) isn't intended to enter atmosphere.

And even if you use this sort of computer aided stability, these wind
forces impose a *lot* of strain on the hull. And in directions that
manuevers in space *won't* impose stress.

Now consider the fact that speed relative to the ground and speed
relative to the atmosphere aren't the same thing. Not even close in far
too many cases. Things like clear air turbulence and wind shear (the
boundary between two masses of air moving in different directions at
*very* different speeds) regularly destroy airliners that run into
them. And being slow is a *dis*advantage, because it means you are
dragged or tossed around for that much longer. 

Heck, look at hot air ballons. They are streamlined (really!) and move
slowly. And even then, sudden updrafts and downdrafts are a danger. 

So, essentially, the answer is that a ship has to be *designed* to
enter atmosphere.

- -- 
Leonard Erickson (aka Shadow)
 shadow@krypton.rain.com        <--preferred
leonard@qiclab.scn.rain.com     <--last resort

------------------------------

Date: Tue, 24 Aug 1999 00:34:17 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: I Need Some Radiation

In mail you write:

> Wondering about my close encounter with starships coming up....
>
> I've got a PC hanging by the handgrip of the airlock ON THE OUTSIDE of
> the bad guy ship.
>
> The bad guy ship just slammed on full thrust.  It's moving from an
> all-stop position to 3G acceleration.
>
> So, my questions are--
>
> 1)  Inertia.
>
> There are no inertial dampers outside the bad guy ship.  What will
> happen to the PC as he holds onto the bar?  Can he withstand the force
> of the ship moving and ride on the outside of the thing?  Or will the
> ship leave him floating in its wake?

Probably leave him floating. Picture yourself holding onto a similar
grip attached to a rope going over a pulley. Your feet are *securely*
fastened to the floor. 

At the start, the grip is pulling upwards gently (say there are a
couple of pounds on the end of the rope. (zero G). When they
hit 3g of thrust, it is pulling upwards with *three times your weight*.
(ie someone just *dropped* weights equal to 3 times your weight into
the "basket on the end of the rope).

I doubt that anybody could hold onto it. 

> 2)  Radiation.
>
> If the PC is left floating (or if he lets go and does not travel with
> the ship), what happens when a person in a vacc suit veers too close to
> the wrong end of a T-plate?  Those things glow blue with the ionization
> (I use the DGP style of T-plates in my campaign).  Will that radiation
> fry anyone who comes to close to it?

> If so, how close does one have to get to the T-plates in order to take
> damage?
>
> What kind of damage (how many D) would you put on a PC in that kind of
> raditiation?

The tyupe of radiation involved has never been stated. You'll have to
wing it.

- -- 
Leonard Erickson (aka Shadow)
 shadow@krypton.rain.com        <--preferred
leonard@qiclab.scn.rain.com     <--last resort

------------------------------

Date: Tue, 24 Aug 1999 00:42:28 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Grav Deckplates

In mail you write:

>> Experiments show that spin gravity is only practical with a radius of
>> say 50 meters or larger. Preferably a *lot* more. Like several hundred
>> meters. All because of human physiological limits.
>
> I would prefer to utilize a lot of spin grav constructs IMTU, as I think of
> gravitics as being way ultratech. Do you have any further ideas on this? As
> in what diameter would be ideal, overkill, unfeasible, etc.? The results of
> smaller diameters and how to compensate? Perhaps alternate shifts, nobody
> living on the station?

Check out some of (Gerald?) O'Neil's stuff on designs for L5 colonies.
It's old but it should have references to the actual research. 

Basicly, you can get away with the classic "wheel" type staion. And
with *big* cylinders like the proposed L5 colonies. 

For ships, such as some designs for Mars expeditions, you seperate the
living quaters and drive section leaving them connected by a strong
tether. Then you spin them about their common center of gravity. This
also helps minimize shielding requirements. 

And the ship "decks" can continue to treat the "nose" as the top (or
any other orienation that is convenient).

- -- 
Leonard Erickson (aka Shadow)
 shadow@krypton.rain.com        <--preferred
leonard@qiclab.scn.rain.com     <--last resort

------------------------------

Date: Tue, 24 Aug 1999 00:52:54 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Orion Drive Modules

In mail you write:

>> >In mail you write:
>> >
>> >> Orion engines are rarely encountered in the Traveller universe, because 
> of
>> >> the early advent of reactionless thrusters. However, they can provide
>> >> low-tech planets with a nasty surprise for intruders: the bombs 
> themselves
>> >> are dangerous at close range, while they can also be used to trigger
>> >> nuclear-pumped x-ray lasers. The effective thrust of an Orion drive is
>> >> dependent on two factors: the yield of the propellant bombs, and the 
> pulse
>> >> rate (the number of bombs exploded per second).
>> >
>> >They also need cooling for the baseplate. And in the process they
>> >provide *enormous* amounts of high temp steam for generating power, use
>> >as thrusters, or direct use in "catapults" for launching ordinance.
>> 
>> That makes sense. Which means that they'd also need water tanks, but that
>> you could use the steam to produce electrical power if you wanted.
>
> Why would you use *water* for this purpose?  Why not freon?  And besides, 
> wouldn't the graphite 'blast shield' deflect the heat away from the plate?

Because water has *the* highest heat capacity of any common substance.
That is, it takes more energy to raise the temp of a given amount than
it does for other substances. 

The graphite is to provide protection from the high temp plasma. It has
the highest "melting point" of anything. But the baseplate has to
*absorb* a lot of neutrons and the like to protect the crew. They wind
up as heat. 

>> If you can improve the modules, I'd welcome the input. (And if you don't
>> have a Pyramid subscription, I'll pass it along to the GURPS Space folks
>> for you, so that you have a chance of getting it used in GURPS Space 3rd
>> edition. Assuming that you don't mind, of course.)
>
> Still, it would be interesting to see a group of PCs' faces when they see an 
> Orion launch into orbit and park next to them.  <grin>

An Orion could possibly out accelerate a lot of ships. And the sheer
*size* has to count for something. Remember, one of the early
suggestions was using one to establish a lunar colony. By launching the
entire colony as a unit!

- -- 
Leonard Erickson (aka Shadow)
 shadow@krypton.rain.com        <--preferred
leonard@qiclab.scn.rain.com     <--last resort

------------------------------

Date: Tue, 24 Aug 1999 16:15:22 -0500
From: Eris reddoch <eris@pcola.gulf.net>
Subject: Re: Thrust effects

> > >This brings up an interesting question: why can't an USL ship land in an
> > >atmosphere?  Considering the fact that some of them have 6G of thrust, a
> > >mere 1G of gravity shouldn't bother them (of course, if it's the AG that
> > >provides some of the structural strength, then you'd need to keep that >on).
> > >
> > >As for the atmosphere itself, that's only an issue if you do a fast, TL7
> > >spacecraft style landing.  Given either CG or Thruster
> > >Plates/Reactionless thrusters, it should be possible for a ship to take a
> > >few hours to _slowly_ come down through the atmosphere and land gently.
> > >Same on takeoff.

It all comes down to what you want in YTU.  

I *like* the picture of *huge* battleships slowly drifting down
through the atmosphere on their CG's, occasional puffs of flame from
their maneuvering thrusters keeping her in balance. Pilots having to
keep an eye out for sudden downdrafts and wind gusts that might
unbalance the waddling ship and snap her into.  And heaven help them
all if their CG goes out...

There was a story a few years ago with that very image. A
multi-million ton ship suddenly losing CG at a few thousand meters,
breaking up, and plunging into the ocean. I can't remember the story,
but the image has stuck with me.

Eris
ps. For my players....no, I'm not planning on dumping you into the
drink if/when you bring the /Mae Lee/ down to the surface for
repairs...I'm not *planning* for that to happen. Really! ;-J

------------------------------

Date: Tue, 24 Aug 1999 17:12:14 -0600
From: "David J. Golden" <goldendj@pcisys.net>
Subject: Re: slightly OT: Looking to locate...

>I thought the archive would be DOA now and I'd have to recreate it
somewhere,
>but it's still there...
>	ftp://ftp.ocf.berkeley.edu/pub/Traveller/TNE-pocket

	Is it just me, or is the site refusing to give a directory to
*anybody*? I can log on, but then I sit there until the cows come
home waiting for the directory listing ...
- -- ------------------------------------------------------------ --
   Dave Golden                  http://www.pcisys.net/~goldendj 

   Rome did not create a great empire by having meetings, they 
   did it by killing all those who opposed them.

------------------------------

Date: Tue, 24 Aug 1999 14:19:05 -0700 (PDT)
From: Anthony Jackson <ajackson@molly.iii.com>
Subject: Re: I Need Some Radiation

David J. Golden writes:
> 
>      This one is, I think, entirely your call ... at least until Glenn
> makes a better report on his sighting near Area 51 and we find out
> just what thruster plates are. Blue light, by itself, isn't a
> penetrating radiation hazard. It may be bright enough to burn through
> a faceplate, or even fry. What other radiation accompanies it is up
> to you.

Presumably 'blue light' was chosen to resemble cerenkov radiation, in which case I guess you're being affected by a wave of tachyons, since nothing else will produce cerenkov radiation in vacuum.

------------------------------

Date: Tue, 24 Aug 1999 16:26:23 -0500
From: Chris Olson <chris@pdaguy.com>
Subject: Re: Thrust effects (was HEPlar lives!)

Juliean Galak wrote:

> At 06:52 PM 8/24/99 +0100, you wrote:
> > >This brings up an interesting question: why can't an USL ship land in an
> > >atmosphere?  Considering the fact that some of them have 6G of thrust, a
> > >mere 1G of gravity shouldn't bother them (of course, if it's the AG that
> > >provides some of the structural strength, then you'd need to keep that on).
> >
> >
>

[SLASHED FOR BREVITY]

>
> Instinctively, I have to agree with you.  If a vessel isn't designed for
> atmosphere, it shouldn't be able to handle atmosphere.  But I want to know
> _why_.  I'm really looking for specific problems the ship would
> experience.  I don't think that internal bracing is an issue, as it's
> already in place to survive the multi-G thrust of the ship.  (a ship rated
> for .01G OTOH, _would_ get torn apart by a planet....)
>
>            -- Juliean Galak (a.k.a. Falcon)
>

[MORE KNIFE WORK]

Speaking as someone who builds and flies model rockets, the major problem you are
going to have with landing an unstreamlined ship in an atmosphere is control.

Unless the exposed surfaces are balance with respect to the centers of pressure
and the center of mass, and the axis of thrust passes through the center of both
points, the ship will be /negatively/ stable.  Unless the control software is
prepared to handle this, and control surfaces or sterring jets available to
control the effects the instant they begin to occur, the ship will tumble out of
control at the first gust of wind or application of thrust.

*WHEW*

Here's an ASCII diagram of a rocket showing the locations of the points:


 _
| \
|  \________________________________
|                                   \
|            +   +                   )  ---- Axis of thrust
|   ________________________________/
|  /
|_/          |   |
         Center  |
           of    |
        Pressure |
                 |
               Center
                 of
                Mass

Now, the fun parts.  The center of pressure is the point here the air forces along
the hull are balanced.  The pressure of the wind flowing along the hull can be
simulated by applying pressure at this point.  As speed increases, the point tends
to slip
back non-linearly based on the geometry of the fins.

The center of mass is the point at which the rocket is balanced.

If the center of pressure is behind the center of gravity, the wind will tend to
autocorrect the orientation of the rocket.  The further back the center of
pressure is, the more stable the rocket is.

If the thrust is out of alignment with any of these two points, the rockt will
tend to rotate about that point.

Since the USL ships can thrust at all, we can assume the axis of thrust passes
through the center of mass, else they would spin out o control in all cases.  One
of the things that streamlining does is to assure that the center of pressure is
properly located.  USL ships have to reason to assure this, and in  many cases it
is difficult and awkward to assure this is so.

Before anyone mentions gyro-stabilization, the forces we are talking about are
immense on large graft, more than sufficient to rend steel at not unreasonable
speeds.  Gyros could be used to detect sheearing, but you would have to rely on
some pretty honking thrusters or control surfaces.

Chris Olson
chris@pdaguy.com

PS.  Negatively stable craft do fly, but they are not very unstable, only
relatvely unstable.  To far out of stability and there is no hope of reacting
swiftly enough, or of being able to apply enough force to correct it.

------------------------------

Date: Tue, 24 Aug 1999 14:27:03 -0700 (PDT)
From: Anthony Jackson <ajackson@molly.iii.com>
Subject: Re: Thrust effects (was HEPlar lives!)

Leonard Erickson writes:

> The problem is *wind*. USL is "unstable" in a wind. I won't go into
> details, just note that the wind forces act thru a point *other* than
> the center of mass. And where the point is depends on the angle. Thus,
> in the presence of even a *light* wind, the vehicle will tumble
> wildly. 

No, its much too heavy for that.  Your average 200-ton unstreamlined ship has
a terminal velocity in air of somewhere around 700 mph, a typical heavy wind
(say, 35 mph) will accelerate it at .002 Gs or so.  Assuming the ship can turn
moderately quickly, this is flatly ignorable.

> 
> Engine thrust is fixed with respect to the hull. And any "deflections"
> are figure with respect to the hull, not with respect to the outside
> world. 

Given that ships can turn, this simply isn't true.  Manuevering thrusters are
plenty to overcome wind effects.

> Heck, look at hot air ballons. They are streamlined (really!) and move
> slowly. And even then, sudden updrafts and downdrafts are a danger. 

They're also 3 orders of magnitude lower density than a spaceship.

------------------------------

Date: Tue, 24 Aug 1999 17:27:03 -0400 (EDT)
From: "William F. Hostman" <aramis@gci.net>
Subject: Long Range Scouts

>I haven't seen a truly LONG range scout yet.  Jump-6 with a long endurance.
>The ones in CT are Jump-4.  The Book 2 rules allow for a Jump-6 100dT scout,
>but none of the later rules make it possible.  Perhaps one with a new
>silhouette?
>

It's doable under MT...

Presenting the Xen Class FarScout

Xen class Scout (type SF)
100Td C=1 SL A=40G TL14
927.9MW Total from a Fusion PP
1J6 Fuel, 3G
BEnv, BLS, ELS, AG,IC, Airlocks x2 (Fwd, Aft)
Computers 3x6, HoloLink Panels x103, HoloHUD x1
Radio: SystemRadio-14
Laser: SystemLaser-14
Maser: SystemMaser-14
AEMS Array	FO-AEMS-14
PEMS Array	IS-PEMS-14
EMS Jammer	FO-EMSJ-14
HP Densitometer	250m HP Dens
Neutrino Sensor	10kw
NAS	Long
1x BLaser13 (or 14) in turret (xx1)
Cb x1, Ce x1, Cm x0, Cg x0, Cc x0, Cs x0, Cd x0
1 Large Stateroom, shared.

Fuel 28 days PP Fuel at full up   346.416 kl, costing Cr12,124.56
Jump Fuel:  472.5 KL costing Cr16,537.5, good for 1j6
Cargo: 5.8 KL

No subcraft. Fuel Scoops can grab 270 kl/hour, but no purifier is installed.

Mass:  1,115.986 Tm Dry,  1,149.342 62 Tm Fully loaded
Cost: MCr89.746 556 4  excluding fuel, MCr89.775 218 46 List including fuel
Free Power 15.572 MW, agility 0 (0.075)

The Xen class is a long range 2 man scout craft. It lacks comfort. It lacks
space to move about in. But it has a full sensor kit, and it can move. It
is also hard to distinguish from the ubiquitous Sulieman class Type S
scout/courier. The minimal cargo space is usually food or urgent messages.
As an adjuct to scout HQ, as a courier it has sufficient computer power for
internal use. The problems are the dirves maintenance and the same (low
bid) life support system as the Sulieman class scout; the life support
problem is compounded slightly by having far less habitable volume.

William F. Hostman  |  "Smith & Wesson: THe original Point and Click
interface!"
Aramis 0602 C55A364-C S kk+ as+ hi+ dr+ va++(--) so+ zh++ vi+ da++ sy- ge-
533
Mailto:aramis@gci.net http://home.gci.net/~aramis http://www.alaska.net/~mhaa
ICQ:14640742          AIM:AKAramis	ARM 1.0: 3 R H++ P+
IMTU 1.0: tc tm++ tn- t4-- tt+ to- tg-- ru+ ge 3i+ c+ jt-() au+ st- ls
pi+() ta+ he+(-) kk+ as+ hi+ dr+ va++(--) so+ zh++ vi+ da++ sy- ge- pi+

------------------------------

End of Traveller-digest V1999 #1008
***********************************

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