Overview
The easiest way to figure out how much gravity drive your ship needs for how fast you want it to accelerate. Nothing could be easier.
Gravity Drive Basics
Gravity drives are super simple to make and even easier to understand. But in order to get that super massive star destroyer to maneauvre like the Millenium Falcon, the whole system has to be perfect.
A Gravity Drive is made by pairing an artifical mass block with gravity.
The force is generated by the gravity acting on the mass of the artificial mass.
Here’s how to build a super simple gravity drive.
Place one artifical mass block.
Put a Gravity Generator on the side of it.
The configuration will move (by default) in the same direction as the gravity – by default that is the DOWN orientation of the gravity generator. i.e. towards the base of the generator.
Give it power, watch it zoom away.
How the math works
The math behind a gravity drive is so simple that 8 year olds can understand it.
Not kidding, I taught this to an 8 year old.
You have to understand THREE things before we start.
FIRST:
Acceleration is loosely defined as the amount of velocity that is added to something every second.
So an accelaration of 3 metres per second would increase the velocity of the object by 3 metres per second, every second.
at 0 seconds = 0m/s velocity
at 1 seconds = 3m/s velocity
at 2 seconds = 6m/s velocity
at 3 seconds = 9m/s velocity
at 4 seconds = 12m/s velocity
And the pattern continues for an acceleration of 3.
Now the important thing – ONE g (like a gravity generator makes) is 9.8 metres per second per second of acceleration.
Second:
FORCE = MASS x ACCELERATION
aka
f=m*a
Third:
Force is measured in NEWTONS
One NEWTON (one ‘N’) is the amount of force it takes to ACCELERATE 1kg by 1 metre per second, per second.
THEREFORE applying a force of ONE NEWTON to a ONE KILOGRAM object would give it an acceleration of 1 metre per second per second.
So from all of that we can say that
N (newton) = 1kilogram x 1m/s/s
OR, assuming we’re working off the gravity drives
9.8N = 1kg x 1g
That’s all the basic info.
The math is easy.
One gravity generator working on one artificial mass block makes force like this…
N = m * a
N = 50,000 kg * 1g
N = 50,000kg * 9.8(acceleration of gravity)
N = 490,000
What’s the point of all that?
It means that one gravity generator, and one mass block, can accelerate 490,000kg at 1m/s/s
But it increases in a special way.
TWO gravity generators working on TWO mass blocks is this… (I’ve used brackets for visualisation)
N = (m*a) * 2
N = 2m * 2a
N = (2 * 50,000kg) * (2*1g)
N = (100,000kg) * (2*9.8)
N = 100,000kg * 19.6
N = 1,960,000
That means that TWO gravs working on TWO masses can move 1.9 million kilos at 1m/s/s
If you factor in the mass of your ship, it’s easy to see that you want the N to be working that well on EVERY KILO
Therefore you MULTIPLY the N by the TOTAL MASS OF THE SHIP to give you the desired NEWTONS
Now, the working backwards part.
Applying the Formula
If our desired acceleration is 20m/s
Then for a 13,000,000 kilo ship (yep, she’s a big un)
we need 13,000,000 * 20 Newtons.
Or 290,000,000 N
To make that much force we need
290,000,000 / 490,000 Artifical mass blocks and one grav generator
Or
591.8 mass blocks one gravity generator.
But that’s a lot of mass blocks and not much gravity. Let’s even it out.
So we make more grav generators instead and try and cut down mass blocks.
So lets DOUBLE the grav gens, then we only need HALF the mass blocks. Assuming the grav field covers them all.
Then it’s 592/2 mass blocks and 2gs
or 296 mass blocks.
Still too many.
Lets double the grav again.
296/2 and 4gs = 148 mass blocks
and again
148/2 and 8gs = 74 mass blocks
and again
37 and 16gs
getting closers , lets not double it, just increase by 50%
37/1.5 and 16*1.5 = 24.666 mass blocks and 24 g
Just round it up, cos it’s fun to go faster.
25 mass blocks, 25 grav generators for a 13,000,000 kilo ship to accelerate at (a tiny bit faster) than 20m/s, which should get us to top speed in 5 seconds.
Optimal placement
So you know how many you need of both gravity generators and mass blocks.
But you gotta put them somewhere.
This is the part some people miss – you MUST put the MASS BLOCKS in the CENTRE OF GRAVITY on your ship.
AND
They must be evenly space around the FORWARD DIRECTION OF TRAVEL
Basically, start from the exact centre of gravity (or the multiple blocks that overlap it) and put mass block.
Then work your way toward the front and back of the ship, and expanding around those blocks exactly evenly.
The reason for this is that if the mass blocks aren’t perfectly centred, they will apply a twisting action to the ship.
Think of pushing a tissue box along a table by pushing your finger on the corner instead of the exact centre.
Other than that, enjoy your super accelleration and the immediate redundency of forward (and even reverse) thrusters.
