On Dec 15, 11:14*pm, Andy wrote:
On Dec 15, 10:56*am, jimboffin wrote:

Are you sure you are reading the manual right?

Don't need to read it. *The allowable mass/cg envelope is depicted
graphically on page 5.10 of the flight handbook. *I only have the
German version on hand, the English translation is in the glider. The
graph shows an aft limit of 345mm from 300Kg to 380kg, then reducing
linearly to 322 mm at about 460 kg then linearly to about 306 mm at
525 kg max gross.

The envelope also shows that the forward limit moves forward above
380kg but the shift is much smaller than for the aft limit. *It also
clearly shows that the aft end of the recommended cg range of
300-310mm falls outside the aft cg limit at max gross.

Hank - what is on page 5.10 of your 28 flight handbook? *If it is a
mass/cg envelope what is the allowable CG at 525kg? *I'm surprised
that 2 28's both with tail tanks would have different limits. *Mine is
serial 28048.

Andy (GY)

OK oops- I have to admit not paying large amount of attention to
variable CG since I don't remember the last time I flew above about
480kg. Easterner ya know. I suspect this limitation relates to Waibel
trying to ensure not going out the back if mains dump and tail
doesn't. Gotta admit it doesn't interest me enough to do the math.
Review does show that empirically through flight experience, I've
pretty much confirmed that the factory suggested range works well.
UH