Originally Posted by Milt
Ignoring smoothness/human effects the initial rotation could be almost instantaneous to rapidly increase the wing lift to fully support the aircraft weight but one should not overlook the total rotational momentum then generated which would inevitably cause some overshoot towards a potential tail strike before adequate development of the second segment.
Unless your aircraft has some degree of intelligence built into its pitch target for rotation, instantaneously achieving the target pitch target is not necessarily going to be a good thing. Under normal circumstances the aircraft is going to start to lift off significantly before that attitude. Also, as the rotation is continued towards 35ft the aircraft is going to be climbing out of ground effect somewhat; therefore some of the further rotation post-liftoff is needed to counteract the loss of GE lift.
Now, if you *know* what the lift-off attitude is you could perhaps argue that could be attained almost instantaneously with little direct adverse effect, though there would still be overrotation concerns.