Why still no dive acceleration difference?

[mayshine]

letme show you some clue here

with the speed increased, the back-drag force will increase pronouncely
due to 1, deformation , 2, propeller pitch, 3, propeller tip speed,4, air wave darging force.

with this backward force increased largely.

the heavier aircraft should prevail in the diving.

roughly it is the result I got, and I am quite comfident it is meaningful
and to some extence correct.