Blockade Runner uses (mostly) Newtonian Physics with its ship movement, speed, ect.
So when the dampers are off and the thrusters also, the ship will keep it's velocity.
You start spinning and the ship will never stop spinning until you use the thrusters, or the dampers to stop the spinning.Controls
The game gives you full 6DoF. That means you have 3 axis for movement (Up/Down,Left/Right,Forward/Backward) and rotation around this axis.
When perfect balance is on, the controls always work how they should and your ship is just flying into the direction you press the key for.
Just that this perfect balance will have some drawbacks in later game and a balanced ship will be advantageous.
So it's important to know how the game calculates the movement based on the thrusters.Thrusters
The thruster produce force and this force leads to acceleration. But the force will also produce a turning moment when not directed at the mass center. The center of mass is a represantation of your ship. Your ship as a whole basically behaves the same as this one point where all the mass of the ship is concentrated.
The Thruster fires upwards but it's 3 blocks away from the center of mass and this leads to a rotation.
The acceleration of this rotation depends on how far away the thruster is.
Double the space -> double accerelation.
A second example:
Now we have 2 Thrusters firing into the same direction. Both produce the same amount of turning moment but into opposit directions. That means there is no turning moment in the system and it flys straight up.
Here is another example:
Now you got double the engines. But to fly straight up the thrusters on the left would have to reduce their thrust.
Perfect balance would just shift the mass center but with real balance this "ship" will fly up and rotate.
The thruster on postion 5 alone would produce at full power nearly double the amount of the turning moment the thruster on position 3 on the right side produces.
What the examples showed for 2 dimension happens ingame in 3d.
What does that mean for ship building?
It's easy. If you want a ship that flys even without perfect balance good and suffers less from it's future drawabacks then you have to place your thrusters right.
Thrusters far away from the mass center let you spin faster, just take care they won't do to much unintended rotation around the other axis.
If you want fly straight then place your thrusters so that they produce no rotation while moving forward.