Sooo, now, for the beginning....
For reference, thats how the record sheet for the small basic Hyperion (Theta model) looks like in Babylon 5 Wars.
A lot of thrusters and stuff, thats really hard to translate into Orbiter and most of it related to the damage model, so we can ignore it.
We have three thrusters in the rear, which together offer a maximum of 7 thrust points without overthrusting. That is just the safe limit. You always had been able to shut down weapons and other systems to get more energy and turn it into additional thrust, that can be used to buy more thrust. The engine in the center has an efficiency rating of 4/1, which means, it needs 4 points of additional energy for producing one point of thrust more, and generally produced 7 points of thrust. The maximum power you could get by shutting everything down except the engine is 50, which means 12 points of extra thrust possible, to a maximum of 19.
Now, this isn't the acceleration, thats more like the thrust force rating... there was another conversion since some ships turned better than others for the same amount of thrust, others accelerated or decelerated better, etc.... a lot of options.
The Hyperion had a pretty average acceleration/decelleration cost of 3, which means changing the velocity by one, you need 3 points of thrust per turn. Which means, using all overthrusting possible, the Hyperion would be able to change its speed in one turn by 6 points, which is proportional to the maximum newtonian acceleration possible in Orbiter.
The rest now is defining, what one point of acceleration actually means in Orbiter. In Battletech, its fairly easy, there the definition was 1 point of acceleration = 0.5g. Here things had been left undefined, since there never was any physical definition at all: Neither the duration of a turn, nor the size of a hex field was ever defined. But that also means: Full creative freedom.
If you want things to be agile and fast, make one point of acceleration worth 10 m/s². Then the usual acceleration of 2 of an Hyperion would be equal to about 20 m/s² acceleration. If you want things to be less insane, if fighters and more advanced ships are involved, use 5 m/s², then the ship can still accelerate at about 1g, but get out of the way at 3g, if needed.
For comparison: The more advanced Omega destroyer has 60 points of extra power available when shutting everything down, has a more efficient engine and is capable of turning this into 20 points of extra thrust, to a total of 28. This means, it can get a maximum acceleration of 9 or 50% more than the Hyperion (At "Dreifach wahnsinnige voraus" / "Triple insane ahead", as German submariners would name this mode)
And if you want to compare this to the Sharlin.... don't. You'll think EarthForce vessels are as fast and agile as a pregnant yak.
If you want to get access to the record sheets of all vessels in B5Wars, because your CDROM from the Ships of the Fleet supplement (that you sure all are owning, right) has gone missing, look here: