Rotating a group in max

Hello all
I am constructing a rotating jet engine for an e learning project ,I have made the turbine blades with an array ,my problem comes when i try to rotate the group ,it consists of around 36 fan blades .The animation is not smooth and it reverses. Is there any way of getting a large group of objects in this case nurb surfaces to rotate smoothly.
Thank you all
Peter

What you do is create some key frames hit auto key the select
frame 50 rotate the object 180 and then turn auto key off right
click on the rotating object and select the curve editor there you
see a under the object's name rotation click on y, x or z rotation
until you see a blue line shape then drag a box around the blue line
selecting the 2 vertex type boxes and click on the red button
called set tangents to linear (the straight line) this will turn the
blue line straight (this stops the object from slowing down or
stopping) then click on the parameter curve out-of-range types
button and click on some arrows say both the loop arrows play the
animation and now it will loop forever no matter how many
frames you add to the movie that's it good luck my friend...