# Skidding Starships?

#### cerebrolator

##### Mongoose
I don't claim to be a physicists (though, as a psychologist, I do have physics envy) but I can't imagine that a spacecraft would skid. Slide might not apply completely either. In space, the speed wouldn't drop would it? Is the drop in speed supposed to reflect changes in the craft's vector? Please help me to understand how these rules would apply to spacecraft.

The drop in speed is supposed to reflect thrust-whether through use of reaction mass or gravitics or whatever-in a direction equal to your current vector. Put simply, you thrust in the opposite direction that you want to go; that's why the main engines are on the back so it will push forward more. Anyway, it is the use of thrust that decreases speed.

However, you are right in thinking that a ship would skid in space, but the rules used in the D20 system are very abstracted for simplification. Don't compare it to real physics, you'll give yourself a headache.

Are you guys talking about rules from the Core Book, or the new ACTA rules?

My ears pricked up because I've actually studied spaceflight mechanics at university, and worked for the European Space Agency for a time. Just be careful about using the words speed and velocity, you can change velocity without changing your speed but not vice versa. Speed is the absolute magnitude of your velocity vector.

As for what to call it, in one of the old Wing Commander games they called it a "Shelton Slide" when you yawed round without changing your velocity. I always refer to the bit when the flying wedge of WhiteStars does an about face when battling the Shadow-fied Advanced Ommegas "a handbrake skid in space". Whatever it's called it looks cool.

Just chipping in.

LBH

Thanks for the help. It's always good to have help from those who know the mechanics. Thinking about it in terms of physics does give me a headache; I'll stick with the d20 abstractions.

lastbesthope said:
Are you guys talking about rules from the Core Book, or the new ACTA rules?

My ears pricked up because I've actually studied spaceflight mechanics at university, and worked for the European Space Agency for a time. Just be careful about using the words speed and velocity, you can change velocity without changing your speed but not vice versa. Speed is the absolute magnitude of your velocity vector.

As for what to call it, in one of the old Wing Commander games they called it a "Shelton Slide" when you yawed round without changing your velocity. I always refer to the bit when the flying wedge of WhiteStars does an about face when battling the Shadow-fied Advanced Ommegas "a handbrake skid in space". Whatever it's called it looks cool.

Just chipping in.

LBH

I like to think about it in terms of facing, vector, and speed. The terms may not be so accurate, but it keeps things understandable for me. So everyone knows what I'm talking about:

facing=which way the ship is pointing
vector=direction in which you are traveling
speed=the actual velocity you are traveling down the vector

As for "jinking", I have always considered "jinking" to be maneuvers made while maintianing the same vector. Makes it hard to hit you without having to spend significant amounts of energy changing your vector.

As for what I call it when you change your facing without making any other maneuvers; 'spinning the top', 'changing your point of aim', or 'bootlegger'. :wink:

I remember in the first season two dogfights.

The first had a Starfury being chased by a Delta. The Fury continued straight ahead and rotated 180 degrees so it could fire on the Delta.

"That is how space combat should be", I thought.

The next episode had a similar situation but the Fury fired its thrusters so its velocity had a +Z (up) component. As the Fury continues ahead and up it rotated 180 and pivoted down so it could fire on the Delta and not be in the Delta's line of fire.

"Perfect! They finally got it perfect!" I thought.

I don't know how you can do three dimension space combat on a two dimension board. You really need a computer to do it right.

Today, we can have a fun board game to represent space combat but it won't be realistic until we can incorporate computers into the mix.

Sidney

In my games, we have been doing three dimensions for a long time, Star Trek Tactical Simulator, Champions, etc. We use those cool little plastic things that the pizza deliveries have to keep the box from squishing the pizza. They are about the size of a square/hex, and elevate the piece about one hex as well. The cool bit? You can write on them with the same markers you use on the battle map to specify how far off the plane they are. Keep a calculator handy for determining ranges (a^2+b^2=c^2).

"He's quite intelligent, but not experienced. His pattern indicates two dimensional thinking."

Pottsbr said:
We use those cool little plastic things that the pizza deliveries have to keep the box from squishing the pizza.
Clever, Pottsbr, quite clever indeed... 8)
Might as well just try it some day, just to add a little zest.

You guys seem to be getting the idea.

I really hate it ehen fil/TV get space physics wrong, which let's face it is most of the time. The prime offender is the movie Armageddon, it gets almost everything wrong (Just don't get me started!)

Dag'nabbit,
To compkletely represent the situation, you need facing, vector and speed as you rightly point out. Also you might need weapon direction if you're firing arcs are not fixed. To be perfect you would also need to know your current acceleration rate (unless you accelerate in discrete bursts).
Obviously all of these would be needed in 2 or 3 dimensions, however many you're working in.

El Cid,
I'm going to be really picky but traditionally in aircraft, and missile, technology. Forward is +x axis, positive yaw is a turn to the right (or starboard) and so motion to the right is usually considered +y axis. Therefore to maintain a right handed axis set, +z would be 'down'. The number of times in my work I have to remember higher altitude is a bigger negative number, it can make you go spare, it really can!

And as for our guest, Pottsbr, I like the quote, which is from Star Trek II, and is one of only a handful of occassions when ST universe uses 3-dimensionality of space, and besides that it's the best of the movies.

Here endeth the lesson

LBH

Replies
17
Views
1K
Replies
65
Views
30K
Replies
18
Views
5K
Replies
25
Views
6K
Replies
9
Views
3K