Traveller-digest     Thursday, August 26 1999     Volume 1999 : Number 1018



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

The following topics are covered in this digest:

Re: 101 Starships
Re: Thrust effects (was HEPlar lives!)
Re: Thrust effects (was HEPlar lives!)
Re: 101 Starships
Re: 101 Starships
Re: Plankwell 
Re: Plankwell 
Re: Thrust effects (was HEPlar lives!)
Re: Thrust effects (was HEPlar lives!)
Re: Thrust effects (was HEPlar lives!)
Re: Thrust effects (was HEPlar lives!)
Re: Thrust effects (was HEPlar lives!)
Re: Another look at aliens [long]

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

Date: Thu, 26 Aug 1999 00:10:26 -0700
From: "Legate Legion" <legate@futureone.com>
Subject: Re: 101 Starships

From: Black ICE <wombat@premier.net>
Subject: Re: 101 Starships


>> The Sharlin class Merchant Tender


    <Snip-Snip>

>> The Tebryn class Merchant Ship


    <Snip-Snip>

>One question:
>
>What would be the economic benefit from building such a ship?


    Well, not all Mega-Corps are going to be able to use Free Traders, Far
Traders, & Sub. Merchants to carry its cargo, so they will need a large ship
to do that, right?  And, why not this one?  If this ship has say, Jump 4, it
could cross the rifts so Sector Trade can be carried out.  This ship should
also beable to carry enough High Passage passengers to turn this ship into a
true luxury liner.
    Also, why are there so few cargos & passengers?  This ship could be one
of the reasons.  Megacorps will not use Free/Far Traders 7 Sub. Merchants to
carry their cargo, would they?

>Admittedly, AuricTech Shipyards will be _more_ than happy to design such
>a ship and build it (using either HG2 or FF&S2).  All you need to do is
>pay us.  (Note:  in TML credits, expressing appreciation for a design is
>considered payment.)


    Either one would be cool, but both would be better.

>Your shareholders/bankers/whoever else is putting up the money to build
>this ship are concerned with one thing:
>
>Will this make me a larger profit than other ways of investing my
>capital?


    Easy, these ships, the Sharlin & Tebryn can cover a sub-sector in about
2 monthes & that means if say, AuricTech Shipyards needed 100,000 tons of
metals, would you rely upon c. 2,000 Free Traders or a few larger ships?
The profit in this ship will be in bulk cargos & passengers, just like the
real world.  *weg*

>Considering that the AuricTech _Electra III_ yacht has Jump-4, 4-G
>performance, at a cost of only MCr 824.07, I would think that most
>nobles who would need to travel to Capital would have ships of similar
>performance, and would not need to hitch a ride on a _Sharlin_.


    True, but then are not nobles, in general, a petty lot?  Always wanting
to show off their wardrobes & finery?  Do they not want to advance their
Houses at the expense of other Noble Houses?  You cannot do that while you
are alone, can you?  A yacht is fine for short range travel, but say you are
on Regina & you have to get to Capital in style, comfort, & you want to one
up your enimes or make allies on the way there.
    "I say, my lord, Auric, did you see Baron Moony's wife last night in the
arms of that young Count Legate?  I hear they spent the night together."
Nobles love to gosip, an party together & the trip to Capital would be a
good time for them to do it.  Without having the bussiness of government get
in the way.  Along the way, fueds could end, start, marriages could be
brokered.  "I say, my lord, Prior, my daughter is 16 years old & I hear that
your son, Micheal, is 17, what would you say in use talking about joining
our two houses?", duels could happen, "Count Legate, you have slept with my
wife for the last time.  I challange you to a duel.", & other fun hijinks.

>Further, were I a noble of such stature that I needed to travel to
>Capital, I would be loathe to expose myself to the hazards you describe
>below....


    You maybe, but what about your enimes?  "Did you hear that Lord Auric is
going on his own yacht this year?"  "No, pity, his fortune must be gone."
    Rumors could start that because a certain lord or lady is not on the
ship, then something is wrong.  Also, again on the upside, alliances can be
made.  "Count Legate, may I talk to you?"  "Of course Lord Auric."  "Well, I
have a dicey problem, it seems Baron Prior has been trying to put me out of
business."  "So, how can I help you?"  "Well, I hear you have the best
household troops in the Ley Sector."  "So, what would it take for you to
'loan' me a battalion or two."  Sort of deal.  Not all nobles will be good
at everything.  So will be good shipbuilders, other will be good warriors.
This way, with them under one roof, so to speak, they will have time to
talk.  *weg*

>>     Durring war-time, these ships are easily turned into Troop carriers
for
>> the Army.  But, there might be a dedicated Troop Carrier, if Rob creates
it.
>
>Such a ship would, at least, be immune from the profit analysis required
>of a purely civilian vessel.  I could see a government providing a
>subsidy for a tender capable of providing wartime services.  However, I
>doubt that such a ship could earn its keep in peacetime, as a merchant
>vessel.


    You never know, do you.  Think bulk cargos.  This should not be
something a Character gets his hands on, but something in the Background.

>I would gladly change my mind, if the economic numbers work out....


    Then work it out.  They did in mine, but then I based it on the real
world.  With Agro Planets selling their grain crop off & this type of ship
transporting it.

Legate Legion
ICQ # 8973001
legate@futureone.com
http://www.futureone.com/~legate/index.htm

"A man may fight for many things; his country, his principles, his friends,
the glistening tear on the cheek of a golden child. But personally, I'd
mudwrestle my own mother for a ton of cash, an amusing clock, and a stack of
French porn." - Edmund Blackadder

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

Date: Thu, 26 Aug 1999 00:24:11 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

> 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

Actually, without special supports, you'd *ruin* the plane. It'd
designed to have "push" applied from the location of the engine(s), as
well as various aerodynamicd streses.

Balance it on its tail, and the tail will crush (it wasn't design to
support the weight of the plane).

>>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....)

Aerodynamic forces occur in locations and directions that result in
*different* stresses than engine thrust does. That's *the* most basic
difference. 

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

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

Date: Thu, 26 Aug 1999 00:28:39 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

> Would they have to be big thrusters? (see my answer to Leonard)  It
> seems to me that the vessels attitude thrusters would be more than
> enough....  Too bad none of the systems describe just how strong
> these are (AFAIK)

They only need to be big enough to turn the ship 180 degrees in a
"reasonable" amount of time. Which doesn't require a lot of power. 

Figuring out how much thrust is required requires know the moment of
inertia of the ship about the axis of rotation. That's a bit beyond my
abilities.

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

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

Date: Thu, 26 Aug 1999 18:08:49 +1000
From: "The Roc" <roc@kewl.com.au>
Subject: Re: 101 Starships

- ----- Original Message -----
From: Legate Legion <legate@futureone.com>
To: <traveller@lists.imagiconline.com>
Sent: Thursday, August 26, 1999 5:10 PM
Subject: Re: 101 Starships


I read this and read this tender thing, and liked the idea greatly.

Benefits?

1)  Ideal for convoys, all vessels in the convoy would be assured of
reaching a given system at the same time.

2)  A non-jump capable merchant would be easier to maintain and cheaper to
purchase... however, the shared cost of the jump capability provided by the
tender *should* be low enough to make it financially feasible (but no
promises there! :)

3)  If the tender had couplings that were universal, that could take on
certain jump-capable vessels, then for a minor cost, a Type a, for example,
could jump via tender, then continue onwards immediately to another system,
thus extending it's capabilities/range?

Just the three that popped into my head of course.  There are probably r/l
economics that factor in to make it unfeasible, but otherwise, it makes
sense to me.

- -- The Roc

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

Date: Thu, 26 Aug 1999 01:20:30 -0700
From: "Legate Legion" <legate@futureone.com>
Subject: Re: 101 Starships

From: The Roc <roc@kewl.com.au>
Subject: Re: 101 Starships

>I read this and read this tender thing, and liked the idea greatly.


    Thank you.

>Benefits?
>
>1)  Ideal for convoys, all vessels in the convoy would be assured of
>reaching a given system at the same time.


    Correct.

>2)  A non-jump capable merchant would be easier to maintain and cheaper to
>purchase... however, the shared cost of the jump capability provided by the
>tender *should* be low enough to make it financially feasible (but no
>promises there! :)


    Well, I tend to build a J-4 "Tender" & J-1 or J-2 "Riders".  So that the
"Tender" can move along on the main route & the "Riders" can vist systems
off the main route.

>3)  If the tender had couplings that were universal, that could take on
>certain jump-capable vessels, then for a minor cost, a Type a, for example,
>could jump via tender, then continue onwards immediately to another system,
>thus extending it's capabilities/range?


    True, or it could carry a few Scouts or X-Boats for communications.

>Just the three that popped into my head of course.  There are probably r/l
>economics that factor in to make it unfeasible, but otherwise, it makes
>sense to me.


    Correct, why not use the Battle-Rider & Battle-Tender idea for mechant
shipping?  Heck I can even see building a J-1 Tender & several non-jump
capaible Riders to go along with it.  Why not?  The Tender in this example
could be an open structure & it could carry 6 riders & in war-time, one of
those riders could be a true Battle-Rider.  Think about a commerce raider
who runs into a Battle Rider.  *weg*

Legate Legion
ICQ # 8973001
legate@futureone.com
http://www.futureone.com/~legate/index.htm

"A man may fight for many things; his country, his principles, his friends,
the glistening tear on the cheek of a golden child. But personally, I'd
mudwrestle my own mother for a ton of cash, an amusing clock, and a stack of
French porn." - Edmund Blackadder

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

Date: Thu, 26 Aug 1999 05:03:39 -0400
From: "Keven R. Pittsinger" <jamstar@accesstoledo.com>
Subject: Re: Plankwell 

>  "Legate Legion" <legate@futureone.com> writes:l
> 
> >Well, Jesse, it is from High Guard, & you know what Kevin says, don't
> >you?  "There is only one Traveller & High Guard is its product."
> 
> Comrade Hudson, the plot is working. Your slogan for the revolution has
> been adopted by the unknowing and has permeated the consiousness of the
> TML. At last we can have revenge, at last we can reveal ourselves to the
> Templars.... Keven is subverted, and soon Legate will be too.

Recheck your T.O., comrade.  I'm up near the top.

And it looks like our plot to suborn the Leader is successful; he's talking about rereleasing the Good Old Stuff.  Success, comrades, success!!

Keven

- -- 
tc++ tm+ tn t4- to ru++ ge+ 3i c+ jt au st- ls pi+ ta+ he+ so- vi zh sy
- ------------------------------------------------------------------------------
                                                     Science-Fiction Adventure
                                                     In Reavers' Deep

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

Date: Thu, 26 Aug 1999 03:21:45 -0700
From: "Legate Legion" <legate@futureone.com>
Subject: Re: Plankwell 

From: Keven R. Pittsinger <jamstar@accesstoledo.com>
Subject: Re: Plankwell


>Recheck your T.O., comrade.  I'm up near the top.


    Well, I am a heritic, so I am way down at the bottom.  *weg*  Starcraft,
anyone?

>And it looks like our plot to suborn the Leader is successful; he's talking
about rereleasing the Good Old Stuff.  Success, comrades, success!!


    Truly a day for much rejoicing.

>Keven


Legate Legion
ICQ # 8973001
legate@futureone.com
http://www.futureone.com/~legate/index.htm

"A man may fight for many things; his country, his principles, his friends,
the glistening tear on the cheek of a golden child. But personally, I'd
mudwrestle my own mother for a ton of cash, an amusing clock, and a stack of
French porn." - Edmund Blackadder

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

Date: Thu, 26 Aug 1999 01:12:27 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

>> No, it *is* true. Manuevering thrusters *can* turn the ship. But the
>> main drive thrust is fixed. There's no real advantage in making the
>> main drive "steerable" that way, and lots of disadvantages. 
>
> If ships are capable of evasive action, there's a damn good point to making 
> the main thrusters steerable in exactly this way; even a 5 degree slew would 
> be enough.

Nope. Check my other message, where I point out that far *less* than a
g of thrust can turn a ship 180 in a very few seconds. Pivoting the
main drive *won't* change your COURSE any faster. And changing your
*heading* (facing) without changing your course is moderately pointless
as far as evasion goes. 

And by *not* pivoting the drive, you avoid some *very* massive
bearings, making various feed and control circuitry runs "flexible",
and you get to keep everything but the exhuast nozzle (if any) *inside*
the ship, where the engineers don't have to suit up to work on them.

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

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

Date: Thu, 26 Aug 1999 01:19:12 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

>> But I'm sure there are dodges that can be used. The one I'd look into
>> is similar to the stunt they do with jet engines in some applications.
>> "High bypass turbofans" for example. 
>> 
>> Have a "shroud" around the HEPlaR unit. The exhaust of the HEPlaR, even
>> at *really* low power will create a partial vacuum behind the shroud.
>> This wil suck air into the shroud and out the back. This provides a lot
>> of extra thrust without increase full needs to much. And it provides a
>> "sheath" of air around the HEPlaR exhaust. 

> Actually, it will superheat the air, creating in effect a fusion-powered jet 
> effect.  That _would_ work, though it would require somewhat special design 
> for the drives.

Check out some of Willy Ley's stuff. I recall a book I had as a kid
(and wish I still had, I *loved* the illos) that had a ground to orbit
shuttle using jets, then ramjets, then "ram-rockets", and finally pure
rockets on the way up.

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

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

Date: Thu, 26 Aug 1999 01:21:19 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

> oops, I accidently sent this message before I finished it... Disregard 
> previous post...
>
> At 12:44 AM 8/25/99 -0800, you wrote:
>>In mail you write:
>>
>> > 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.
>>
>>Oh? I suggest you ask the skipper of a supertanker about how
>>"ignorable" the way off center "sail" area of his superstructure is.
>>Luckily, it's at the *tail* of the vessel, so it helps keep the ship
>>pointed into the wind. It's a royal pain if you *don't* want the ship
>>pointed into the wind. And this is with much of the ship immersed in a
>>medium (water) that helps *damp* the effects.
>>
>>Remember that a "200 ton" ship is 200 *displacement* tons. It doesn't
>>*mass* 200 tons.
>>
>>The force exerted by the wind is:
>>
>>P = 0.5 D V^2 cos^2 A,
>>
>>P = Pressure, N/m^2 (multiply by 0.000146 for psi)
>>D = Density, kg/m^3 (=1.225 for sea-level air on Earth)
>>V = Velocity, m/s (multiply by 2.24 for miles per hour)
>>A = Angle from perpendicular
>>
>>So, let's try perpendicular impact at 35 mph, in sea-level air.
>>
>>P = 0.5*1.225*2.24*35
>>P =  48.02
>>
>>That's 48 newtons per square meter. Assume the ship has 100 meters of
>>cross sectional area in the plane of the wind (it likely has *more*).
>>That gives 4800 newtons of thrust.
>>
>>Assuming the ship really *does* weigh 200 tons...
>
>>F = m*A
>>4800 = 200,000*A
>>A = 0.024
>>
>>That's 10 *times* the thrust you guessed. And if the ship has a cross
>>sectional area of 1000 m^3, the thrust is 0.24.
>
> Err... the ship weighs a _lot_ more than a 200 tons.  so the acceleration 
> is even less... but even if it did weight 200 tons, .024m/s2 is only .002G, 
> nothing compared to the multi-G drives of Traveller ships.  Remember that 
> the supertanker can do much, much less than a G of acceleration...
>
> Again, it comes down to how strong the attitude jets are...

See my other message where I show that for a 200 meter long ship, it
takes 0.07 g to turn the ship 180 in 30 seconds. Plug the proper radius
(half length) into the formula and come up with your own figure. 

You *don't* use the main drive to turn.

>>No, it *is* true. Manuevering thrusters *can* turn the ship. But the
>>main drive thrust is fixed. There's no real advantage in making the
>>main drive "steerable" that way, and lots of disadvantages.
>
> Well, at least in GT, _all_ ship drives are assumed to be vectored 
> thrust.  In fact, a ship built without would suffer massive penalties... 
> But even disregarding GT...

And the only time vectored thrust is "needed" is for landing these
silly ships with decks parallel to the thrust axis. 

>>And I *wouldn't* count on thrusters intended for changing heading in
>>vacuum being able to overcome any sort of significant wind forces in an
>>atmosphere.
>>
>>As I recall, we worked out some time ago that a ship didn't need to be
>>able to use even .1 g for manuevering thrusters. They'd actually whip
>>the ship around so fast that it could *cause* problems.
>>
>>But it won't take a lot of wind to generate more force than the
>>manuevering thrusters.
> even .1g is still 10-100 times more than the wind effects above.

And I've just shown today that the manuevering thrusters need *less*
than that. *much* less.

> And that's the crux of the matter, IMHO.  Just how strong are those 
> maneuvering/attitude thrusters?  (I'm going to use GT as that's all I have 
> handy right now...)  A 5,000 ton Young Assault Tender (GT:SM, p73) is 
> approximately 101 meters long (it's about 27-7-7 proportions according to 
> the book illustrations.  It's actually longer, but this should be close 
> enough)   and 27 meters across.  It's loaded mass is 24,180 tons or about 
> 29,000 metric tons.

<snip>

> so, assuming my math is correct, the thruster only needs to put out 
> .0000009G.  That means that, in fact, wind is a huge factor, and will 
> tumble the ship out of control.
>
> Would someone double check my math please?  This doesn't look right, and I 
> don't have my good calculator handy....

I derived similar results by working from the equation for the
acceleration *induced* by rotating at a given radius with a given
period: 

a = 4*pi*2*r/t^2

So with your figures:

a = 4*pi*2*50.5/1200^2
a = pi*404/1.44e6
a = ~8.8e-4
a=~0.00088g

I get a much higher value for acceleration, but still far too little
for significant help against wind forces.

Another point. You can turn faster and with less stress on the hull by
using *paired* thrusters. The fire in opposite directions and are
either placed equally distant from the CG of the ship and are the same
strength, or, if the ship's CG is noticeably off center, they may be
placed as far as practical from the CG, and have their thrusts set to
provide equal "moment arms" (thrust * distance from CG). 

These will have problems compensating for wind force, because the wind
forces *aren't symettrical about the CG. :-)

BTW, so far we've been considering *rotational* thrusters (yaw, pitch &
roll). Translational thrusters are what you use for making small
movements "up", "down", "right", "left", "forwards" and "backwards". 

Since these will be used for things like the final stages of docking to
a station or another shiupo, you want them to be inducing very *low*
velocities. Just consider what a multi-thousand ton mass ship can do
when it impacts at a "mere" meter per second. Ouch!

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

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

Date: Thu, 26 Aug 1999 01:44:22 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

> However, a vectored thrust ship in GT can dodge, with a bonus based
> on its Gs.  According to GURPS Vehicles, dodging requires a 15
> degree/second change in direction (though the ship itself doesn't
> turn that fast, that's why you have vectored thrust).  That's roughly
> 1/4 of the directional Gs of the ship, and is plenty for overcoming
> air resistance.

15 degrees is 1/24th of a rotation. Therefore we get a 24 second period
of rotation. Great. We now have a figure for the acell provided by the
thrusters.

a = acceleration (m/s)
r = radius of rotation (m)
t = period of rotation (s) 

You've just "fixed" t at 24.

a = 4*pi*2*r/t^2

becomes

a = pi*r/72

So if the ship is 20 meters long, you need 0.04g of acceleration from
your thrusters to meet the turning specs for dodging.

> Basically, any ship capable of evasion needs _substantial_ turning ability, 
> or substantial vectored thrust effects.  I'm not terribly familiar with all 
> of the starship combat rules in Traveller, but certainly in High Guard ships 
> could dodge.

Actually, as shown above, the requirements aren't all that
"substantial". 

ps. In actuality, moment of inertia (which depends *strongly* on shape,
and is a bear to calculate) will be required to determine the actual
*thrusts* involved. But the figures I've given are correct for the
*acceleration*. 

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

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

Date: Thu, 26 Aug 1999 01:56:47 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Thrust effects (was HEPlar lives!)

In mail you write:

>>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.
>
> Isn't this a bit of a circular argument. If you intend a USL ship to
> land you must surly have programmed the computer.

Nope. It has to have been programmed in advance by people considerably
different from the captain and crew of the ship. The required
programming requires info and calculations that the crew *won't* have. 

The equivalent of a bunch of wind tunnel tests, and control loop
calculations. Or detailed info on aerodynamics, the shape of the ship
(down to the millimeter level) and some really *massive* numerical
intergration.

Producing such a program is gonna get *expernsive*, and it'll be one of
the things involved in the cost of producing "streamlined" ships.
Another will be covering and securing all the pipes, conduits, control
runs, etc that could otherwise be left open to space. 

> Not that I would like to be in a USL ship attempting to land in
> either case. Maybe we should compare the risk of landing USL ships
> with the (rigid) Zeppelins of the 30is and 40is. Usually safe but not
> a good idea under some (most) conditions.

Actually, the reason zeppelins and dirigibles went away isn't because
they were hard land. It's because they were *inherently* too flimsy to
withstand weather conditions that they weren't fast enough to outrun.
Read up on the Akron and the Shenendoah. They got ripped into large
pieces by the same sort of winds that throw jetliners out of the sky. 

Jetliners can be built stronger because they don't have to average out
lighter than air. 

> </serious>
> Clearly this outrageous practise of operation of unsafe starships
> must be a flagrant breach of the Imperial Safety Regulation on the
> Operation of Atmospheric Craft. (or ISRotOoAC for short)
> <serious>

> Maybe we should split streamlining into two steps.
> 1. USL, SL or AF.
> 2. Landing or no landing.

I think the real problem is that when you have things broken down into
USL, SL, and AF people are *reading* USL, but *picturing* SL. For
example, a *brick* is SL! It's got a regular shape and relatively
smooth surface.

Basicly, any building or "vehicle" that can survive medium to strong
winds without having to be tied down qualifies as "SL",

Stuff that gets flipped end over end or gets the odd shaped bits (or
exposed bits) ripped off is USL. 

It's *possible* to build an "SL" open structure (but far from easy!). 

In short:

AF	can *use* aerodynamic forces for steering or even lift
SL	won't be adversely affected by aerodynamic forces
USL	will be adversely affected by aerodynamic forces

And for ships that aren't *too* weirdly shaped, software may be able to
make an USL into an SL. But it ain't the sort of programming that
anybody but professionals can write. Well paid, experienced
professionals. 

It'd take an awful lot of skill levels of various sorts (and "pilot"
*isn't* one of them!) before I'd consider a program written by anyone
on the ship's crew to give any sort of chance of getting an USL ship
down safely. And it'd have to be "borderline" USL.

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

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

Date: Thu, 26 Aug 1999 02:17:32 PST
From: shadow@krypton.rain.com (Leonard Erickson)
Subject: Re: Another look at aliens [long]

In mail you write:

> On Tue, 24 Aug 1999, Bruce Johnson wrote:
>> 
>> One thing that is missed in all the Ttraveller discussions, is that
>> people who actually _leave_ their homeworlds regularly are a minority;
>> Travellers are rare.
>
>         In my TNEC game, I actually note what generation "spacer" the
> character is...  professional spacers are considered a bit odd by
> dirt-siders...  who'd want to work and live somewhere that death was just
> a bad seal away?  Or the myriad other unpleasant things that can happen?

There's an old Heinlein short story from the 40s that applies. "It's
Great to Be Back". Also check out "Columbus Was a Dope." I can't recall
what collection either is in, but they *should* be tracked down. They
both give *excellent* examples of how perceptions of "normal" are
likely to change. 

After reading them players may have a better grasp on how their
*characters* might feel about things.

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

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

End of Traveller-digest V1999 #1018
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