Re: What is a "conventional engine"?

>From: "Dreamer" <dreamer@??????.?????.??.uk>
>Subject: Re: [SPELLJAMMER] What is a "conventional engine"?


>SJ physics still gives you the air envelope, you just don't
>get Overdrive.

SJ "physics" do not require you to have any sort of engine to get an air envelope. Any
object in space gets it air envelope because it has mass or size. All helms do is provide
movement. Some people have proposed helms that refresh air but these items are not
official SJ stuff. (I also think that helms that refresh air are not good for game balance
and prefer separate items like the Crown of the Void in Lost Ships.)

By the way, I don't know if physics exists in D&D (unless the gnomes do it). I think that
philosophy and alchemy would be the sort of science practised in those days.

>I'm told that in some cases it is a matter of 'fantasy style',
>and that vehicles move through space, or 'sail', because they look
>as though they ought to. I am not very happy about that as an
>explanation.

Apperance in fanatasy material is often important, but I don't think I've ever seen things
say that something has an ability because it looks like it does.

Isn't it usually the other way around. A dragon has wings because it can fly. It doesn't
fly because it has wings.

The motive force (SR) on spelljammers is provided by the helm. I belive that wings, sails
oars and other devices are usually used to turn the ship (and provide the MC).

>Some people have told me that wings and sails are working on 'the
>ether', and that's in space, though in planetary atmosphere other
>effects over-power it, and it can be quite difficult to even
>detect.

"The ether" does not exist in spelljammer. It is a non-standard add on. While I think it
is a cool idea, SJ movement in normal spheres has nothing to do with it.

Spelljammer ships travel quickly through the void and through The Flow. In the void they
travel through vacuum and are powered only by the helm, not by anything in space itself.

Spelljamming helms power ships at spelljamming speed. "More conventional helms" which I
agree are not documented in enough detail, would not provide the jamming ability and
therefore can't make ships go at spelljamming speed. Most of the other magical helms are
called somethingjammer. If you come up with some conventional helms I think that you
should avoid having "jammer" on the end of the name.

My understanding is that when a spelljamming ship wants to turn (which you would only do
at tactical speed anyway) the sails, oars, rudders or whatever push against the air
envelope of the ship and allow it to turn. I've always thought of ice skaters, who can
spin faster by pulling their arms in. I think the ships with the best MCs would have a
design that allows sails to move very quickly. If you *can* instantly reconfigure the
sails and rudders on a ship you can change the way it pushes on the air and push the air
around the ship very quickly, the ship should then rotate in the other direction slowly.

I also *think* that MC comes in part from the movement of the ship in conjunction with the
turning of the crew. I think that the loss of a helmsman, means the loss of most MC.
However, I'd have to look that up to be sure.

>Some "conventional engines" seem to convert physical (or magical,
>or psionic) effort into movement in space, by a mechanism I am
>not too clear about - a Fly spell that requires flapping wings?

I think that "conventional engine" means an engine that can not achieve spelljammer speed
rather than an engine that uses Earth science (like a rocket or ion drive). The name is a
bit ambigous and it would have been good if several engines (including the ones the elves
use on flitters) were fully documented in the boxed set.

>If you come up with a good explanation, which doesn't involve too
>much magical or metaphysical hand waving (to keep you in the air,
>that is [grin] ), I would certainly like to hear it! [grin]

I think that you could have magic, but it should be more like flying carpet magic that has

a fixed SR and no spelljamming speed.

However, if you want a non magical thing you could use an idea similar to hot air or
helium ballons and create a substance with anti-gravity.

There is a fantasy film called "The First Men in the Moon" (SIC) where an Earth scientist
invents anti-gravity paint which works if exposed to sunlight. He coats a number of blinds
with the paint and controlls the acent and direction of his vehicle by closing and opening
the blinds. The vehicle makes a trip to The Moon and back.

You could even use baloons to bring a groundling ship to the top of an atmosphere and
lower a spelljamming ship down to meet a ship there.

If the fly spell and reverse gravity spell exist, then many similar spells and magical
devices could also exist. However, I would say that all of these things should be
forbidden to travel above tactical speed and should usually give a bad MC.

Maybe we could compile a collection of conventional engines and ask BtM to put the best on
its website.

David "Big Mac" Shepheard
Virtual Eclipse Role Playing Club
http://uk.groups.yahoo.com/group/virtualeclipselrp/links/d20_system_001071937434/Spelljammer_001071430476
http://virtualeclipse.aboho.com/