Add On aircrafts

Hello again guys
Well you see.....i've downloaded some aircrafts (add ons), but i've noticed that they are a little difficult to manuever, not as smooth as the default aircraft in MS2002.
Is it just me? or is this normal? and if so, what can i do to improve their performance.
Thanks again
JC.
Well you see.....i've downloaded some aircrafts (add ons), but i've noticed that they are a little difficult to manuever, not as smooth as the default aircraft in MS2002.
Is it just me? or is this normal? and if so, what can i do to improve their performance.
Thanks again
JC.