The danger of assumption

"Jay Honeck" wrote:
Here I had assumed that she was holding it down too long before rotation --
but it had now become apparent that she (and I) were in fact rotating
prematurely. Wind conditions were calm, temperatures were in the 80s,
humidity was very high, and a ground fog was developing as we landed.
Otherwise, everything was done according to Hoyle, with 2 notches of flaps
set for take-off.

Usually the plane just "flies itself off" the runway in this
configuration -- but not that night. Conditions of flight were fairly
unusual, for us -- the back seat was empty, no wind, high humidity, fairly
light on fuel -- so I suppose it was just pilot error.

Is there a reason why you *shouldn't* rotate at the published rotation
speed? ... more precisely, is there a reason why continuing the takeoff
roll beyond the published rotation speed before lifting off is not safe
(assuming you have enough runway ahead of you)?

In the C152, rotating at the published rotation speed nearly always
produced nice, smooth takeoffs. I recently bought a Shinn/Varga (low
wing, tandem, stick, trike), and in early flights, rotating at the
published rotation speed often produced a couple of seconds of "can't
decide if I'm really ready to take off and start climbing" hesitancy on
the part of the airplane (and yes, everything checked out during run-up).

We then tried letting it continue the takeoff roll beyond published
rotation speed, not really "rotating", but pulling back just enough to
take the weight off the nosewheel and letting it lift off in its own
time. Presto, all the takeoffs have been nice and smooth ever since, and
once it lifts off, there is NO hesitation to begin the climb. How far
beyond published rotation speed it lifts off, using this technique,
varies depending on temp, humidity and weight.

Other than runway length concerns, is there a reason why this technique
would not be preferable to abruptly rotating at the published rotation
speed?