1. Where can I see how many turns a launched AI spaceship has remaining? Also on normal speed how do I calculate how long it takes in general? I know a completed ship is 10 turns, but nothing about how a missing engine affects the turn count.
2. If a vassal or a colony refuses to trade me techs ("becoming too advanced") this is a bug right?
1) I think all the information is in the Victory Conditions Tab.
Regarding the logic of the victory delay (aka spaceship travel time):
The base # of turns is
10 when all the parts are done.
The travel is inflated by a percentage of the missing components of the spaceship over the total.
Code:
iExtraDelayPercent = (iVictoryThreshold - iCount) * igetVictoryDelayPercent /iVictoryThreshold
iVictoryThreshold: It is the maximum of a type of spaceship component that has to be built to be allowed to launch. Info readily available in-game. For instance, 5 SS Casings.
igetVictoryDelayPercent: A modifier for two exclusive parts of the spaceship. The value is 50 for a thruster. 100 for an engine. Other parts get 0 as value. It increases their value regarding travel speed compared to other components. Makes sense.
iCount: The actual number of a particular type of spaceship parts built in the game.
iVictoryThreshold: The minimum threshold needed to be able to launch the spaceship. For instance, one engine minimum to launch. Info readily available in-game.
Code:
TravelTimeDelay=[COLOR="DarkGreen"][B] 10[/B][/COLOR] * (100 + iExtraDelayPercent)) / 100;
Afterwards, the first formula result is entered in the second formula above to get the final TravelTimeDelay.
2) It depends of which version of Civ4. That is why people in IT always repeat the asker to display their condition to allow the responder to answer as precisely as possible.
If you play Vanilla or Warlords versions, then you'll meet this problem. In BTS, it was discarded for free tech trade from a vassal. If you play a mod, perhaps the modder has implemented new restrictions.