fuel saving on a320 with CG

[benftima]

hy ,
i have a question on fuel saving on a320 family
on the getting to grips with fuel economy
page 11

the diagram shows that only the a320 family has a negligible fuel burn increase with more for more forward CG

why and for what it is due ???? why just the a320 family??

[bfisk]

Most aircraft will have a higher fuel burn with forward centre of gravity. More nose-heavy requires more tail-down-force, and the total required lift on the wings is increased, increasing drag, increasing the need for thrust... which burns your fuel faster.

Should be PPL-level theory?

[benftima]

hello ,but for a320 family the effect is negligible why.....its due to some aerodynamic due...what are they.....