In flapped ships, the speed is controlled by moving the flaps......down and the ship slows down.......up and she speeds up, this happens when the CG is aft at 85 to 100% of the allowable range. Will Schueman wrote about this in his modications to the H-301 Libelle. I first noticed it in my Nimbus-3, on the first flight after adding tail weight to put her at 100% of allowable CG range, I realized after an hour and a half, that I hadn't touched the trim! I have observed the same thing in non-flapped ships, I can slow down my Genesis-2 to thermal speed without the need to apply aft trim (CG @90%)........still needs forward trim to go faster than 65 knots, but she will slow to 45 with a little back pressure and thermal with no back trim required (trim neutral).
Does that make sense?
JJ