d&tm wrote:

Are there any single engine airplanes out there that really can go outside
the envelope by burning fuel? ( I am only interested in the normal
ategory - not utility). Perhaps the training is just to prepare you for
heavy aircraft?

I believe Bonanzas can have this problem in certain configurations.

It depends on which where the CG is. If you've got an aft CG
and burning fuel drives it more aft, you've got problems.

In my plane, we typically sit on the forward CG limit with
the tanks full. Since the envelope is sloped on the forward
CG side (the limit moves aft as you go up in gross weight),
even as the CG moves forward with fuel burn, you're also
getting lighter so the CG limit is moving forward faster.