Airplanes tires are small diameter [generally] and the
rotation speed creates high forces. Jets and a few light
twins sit on the ground at a negative angle of attack. A
positive rotation is needed to lift-off, but most light
aircraft want to lift-off just past stall speed.

There is no good reason to keep any airplane on the ground
at a speed higher than Vr or Vmc+5 and the nicest take-offs
are the ones where you rotated 4° up 10 knots below stall
speed and fly off the runway just above minimum stall speed.

The Beechjet 400 is flown to Vr and given a firm pull to 15°
nose up to hit the target V2 speed. It isn't very suave.


Dudley knows this, I just said it for the others out there.



"Dudley Henriques" wrote in message
...
|
| "Jim Macklin" wrote
in message
| ...
| Real world flying, tires have speed limits, extra speed
| burns the tires up and the stop gets very expensive.
|
| You can say THAT again! Not in the GA venue of course, but
the tire pressure
| on a T38's mains is 250psi. When you blow these suckers,
you'll think you've
| been shot!
| The T38 rotates at 160, max tire speed is 220, and gear
speed is 240kts. In
| this airplane, you are accelerating so fast on takeoff
that rotation, and
| gear retraction are practically one fluid motion....and
indeed they HAVE to
| be, to meet the Vle parameters.
| Of course, GA airplanes are a bit tamer!! :-)
| Dudley Henriques
|
|