Is there a problem with jump engines, or is it me missing something. I designed a ship say 3000 Tons then I designed a jump engine to cover ship weight plus itself. Say jump enging is 1500 tons then spend time researching said jump engine. Total of final ship weight should be 4500 . but it is always over. I have done this a few times with different ships wasted days of game time researching jump engines that are to small for final ship
You most likely forgot that Jump Engine has crew and they need crew quarters, that are automatically added to the ship and that of course increases size of ship.
I would advice to use Prototypes if you are not sure how big the final design will be.
Oh I thought it might have been that. But I assumed it would of been included. How do you work out weight of extra crew? Thanks for info on using prototypes. I didn't realise I could.
I'm not aware of what the formula is for crew weight, but it will depend on the deployment time you select (ie a ship with 3 month deployment needs less than 12 month deployment).
One other thing is that adding a component will cause the armour to increase, because it needs to cover a larger internal volume. I am also not aware of the formula is for armour weight.
Personally I add stuff like engines and jump engines first, then design the rest of the ship around that.
I have yet to figure how to use prototypes, shame on me.
Prototypes is nearly the same as SM instant mode, just without being cheaty. Just make sure you have the "show prototypes" checkbox in class design turned on.