I don't do much research, however I do know a little about the 38L's dive flaps. They were never designed to slow down the plane, only disrupt airflow where it was thought to be the most compressablility occuring so that airflow over the tail could be restored to a point that the plane could pull out of a high speed dive.
There is always the possiblility that I'm wrong, but they don't act any other way in the game either.