Anyone has an idea why the gross weight does not affect the glide performance?
If we're taking about a modern jet (this is Prune), then Warped Wings is on the money. Heavy goes much further. I assume Nitpicker is not thinking of his A330 now...
The extra weight contributes more to the "thrust" vector, so the down angle doens't need to be as much.
If you're descending at best glide speed, different story. Same distance, different time.