Just for general clarification, Section 4.5.6 of my
Nimbus 4T flight manual says:

“Note:

In order to achieve a high maneuverability, a favourable
c/g position (when using the fin tank) and a maximum
in ground clearance of the wing tips on take-off and
landing, it is always recommended to fill the inboard
water tanks first.”

I know it is the opposite for the Nimbus 3, I assume
the wings are just that much stronger on the 4. In
my experience it does make take off less fraught and
handling a bit nicer on the 4 than the 3.

Mike


At 18:30 11 July 2005, Roy Bourgeois wrote:
I think what Bert says is technically correct (wing
load doesn't change
when you open the air brakes) - but the distribution
does change a lot -
especially on a ship like the N3 & N4 where the brakes
are located inboard
on the inner panels. Stated differently, when the
brakes are opened the
outer panels are being asked to do more work supporting
the fuselage (and
non flying portions or the inner panels) than before
the dive brakes were
opened. The Nimbus 3 and 4 are placarded against
carrying water ballast
in the inner panel tanks with the outer panel tanks
empty for structural
reasons. You also must dump the inner tanks first.
The same structural
problem occurs when the dive brakes are open and that
part of the inner
panel becomes 'dead weight'. So - while the brakes
should be used to
prevent the glider getting to extreme speeds - we need
to be cautious about
suggesting that nothing bad is going to happen if you
open them at extreme
speeds.

Roy B. (Nimbus 3 # 65)