If you are like me you often make ships that go really fast... straight into asteroids. i had a difficult time learning how thrust measurements work in this game. i finally buckled down and did the math and this is what i got. first the metal used to build only seems to effect the mass involved. second due, i assume, to lack of decimal point precision in the stats, these are not perfect values. i did all my testing with 1X1X1 cubes of iron and trinium.

1X1X1 engine makes a thrust of ~20391.8 / ship mass

1X1X1 directional thruster makes brake thrust of ~ 12745.2 / ship mass

1X1X1 thruster makes brake thrust of ~ 5098.6 / ship mass

also max speed seems to only be effected by the volume of the engines. i don't know the math behind top speed

this suggests a few points towards ship design. first of all max brake thrust is ~ half of forward thrust. thus to equalize forward thrust and brake thrust, like i wish for, you need double the directional thrusters of the engines. this shows that where thrust is involved all that matters is metal mass and the percentage of engine parts to other parts.

thus a ship that is 100% engine has the same thrust no matter it's size. for the record the top thrust an iron ship can have is 784.3 m/s. the lighter the blocks used the higher the max thrust can go. so if there is an acceleration you want or a brake speed you want you can do the following

take the weight of a 1X1X1 cube of your material of choice then divide the number above for the part you want by the weight of the cube. this is your max acceleration for that part. next divide your desired acceleration by that number. this is the percentage of blocks you need to be of the thrust block of the chosen type.

for example you want to use directional thrusters to get a brake speed of ~ 200 m/s using iron. iron is 26 t per 1X1X1 cube. divide 12745.2 by 26 to get 490.2. 200/490 = 0.41 thus 41% of your iron ship must be directional thrusters to get that brake thrust.

well i hope my rambling made sense to some of you. post below for more tips to get that desired speed.