I think a lot of the posters who are saying the Parasitic Drag... increases... have forgotten one thing... The Axis of the fuselage is not the axis of the mean chord line. Airplane designers ( model or full size.) include about 3 degrees difference in these two axis.
So it might just be that the fuselage will align more into the prevailing airstream at an increased weight, if the airplane was initially flying somewhat nose-down. There should only be one speed where the fuselage is level, at all other speeds it is either Plus or Minus.
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