There is nothing stopping a huge city-size ship from being as nimble and fast as a shuttle sized ship in the absence of friction. The contrary would actually be the case; the large ship with the larger engines would travel faster than the "fighter" with fighter sized engines.

That's reasonable insofar as it goes, but there are some subtleties to be aware of:

• Acceleration is a function of thrust divided by mass. A fighter tends to have a huge proportion of it's mass devoted to engines - it's doubtful that a city-sized spaceship would devote 50% of it's mass to engines - thus the fighter may still be faster.
  
• Even without friction, we still have inertia. The larger ship may be able to accelerate faster, but changing direction is going to take just as long.
  
• A trained fighter pilot can survive about 5 g sustained acceleration. It's doubtful that a city-sized spaceship would have the structural integrity to survive 5 g acceleration - and the humans inside would likely be pulverised by manoeuvres at those types of acceleration.
  

• A trained fighter pilot can survive about 5 g sustained acceleration. It's doubtful that a city-sized spaceship would have the structural integrity to survive 5 g acceleration - and the humans inside would likely be pulverised by manoeuvres at those types of acceleration.
  
  

"Ludicrous speed! Go!" ... (engines start up) ... "Whaa-aaah-ah-aaaaaaaaaaaaah! What's happening?! My brains! Are going into my feet!"

I love that movie.

[quote name='Eiviyn' timestamp='1327722784' post='4906920']
There is nothing stopping a huge city-size ship from being as nimble and fast as a shuttle sized ship in the absence of friction. The contrary would actually be the case; the large ship with the larger engines would travel faster than the "fighter" with fighter sized engines.

That's reasonable insofar as it goes, but there are some subtleties to be aware of:

• Acceleration is a function of thrust divided by mass. A fighter tends to have a huge proportion of it's mass devoted to engines - it's doubtful that a city-sized spaceship would devote 50% of it's mass to engines - thus the fighter may still be faster.
  
• Even without friction, we still have inertia. The larger ship may be able to accelerate faster, but changing direction is going to take just as long.
  
• A trained fighter pilot can survive about 5 g sustained acceleration. It's doubtful that a city-sized spaceship would have the structural integrity to survive 5 g acceleration - and the humans inside would likely be pulverised by manoeuvres at those types of acceleration.
  [/quote]
  
  I feel all these points rely on differences in design, rather than differences in mass.
  
  With that said, bigger engines are always better in a vacuum. If an engine is twice that of a fighter, on a ship 10 times it's size, the large ship will still travel much faster than the small one. Inertia is a factor, but the limiting factor in speed tends to be friction. With friction removed, it's only really limited by the amount of force you can produce, which is higher in larger engines.
  
  Off topic, but why does the forum require you to use "< br />" in order to create a new line?

With that said, bigger engines are always better in a vacuum. If an engine is twice that of a fighter, on a ship 10 times it's size, the large ship will still travel much faster than the small one. Inertia is a factor, but the limiting factor in speed tends to be friction. With friction removed, it's only really limited by the amount of force you can produce, which is higher in larger engines.

Acceleration = force / mass. Double the mass, and you have to double the force (thrust) in order to achieve the same acceleration.

Contrary to popular myth, putting the same engine on a Tie fighter and a Star Destroyer will not result in equivalent rates of acceleration (where does this myth come from, anyway? It seems very pervasive, but I can only tie it back to a misinterpretation of Galileo's "all objects fall at the same rate in a vacuum").

Off topic, but why does the forum require you to use "< br />" in order to create a new line?[/quote]
Are you using the WYSIWYG editor?

[quote name='Eiviyn' timestamp='1327782595' post='4907130']
With that said, bigger engines are always better in a vacuum. If an engine is twice that of a fighter, on a ship 10 times it's size, the large ship will still travel much faster than the small one. Inertia is a factor, but the limiting factor in speed tends to be friction. With friction removed, it's only really limited by the amount of force you can produce, which is higher in larger engines.

Acceleration = force / mass. Double the mass, and you have to double the force (thrust) in order to achieve the same acceleration.
[/quote]

You're absolutely right, I'll edit my posts.

Hey, if you'll need sound effects or music for your game, let me know. At the moment I'm working on an MMORPG and I'm busy, but at a later time I could help. I love scifi games.