Julian Scarfe wrote:

The data there indicates an L/D of 51 at higher weights, 49 at lower (about
50%).

But given that the original poster was most probably talking of
airplanes with noisemakers, I suspect that for him, best glide gets
dramatically worse at higher speeds. As I always say: Airplanes don't
*have* airbrakes because the whole plane *is* just one huge airbrake.

Stefan