Bruce Wayne's batsuit is hardly a batsuit without a cape, but physicists at the University of Leicester have determined that the Dark Knight's memory cloth cape — which snaps into a rigid form when exposed to an electric current — is pretty much a one-time-use accessory. Not because it would break or anything, but because Batman would probably be dead.
After accounting for the drag and lift forces acting on Bruce Wayne in flight, the doomed trajectory was calculated. The 15.4-foot wingspan is just half that of an ordinary hang glider and, when launching off an 492-foot-high Gotham city skyscraper and gliding (successfully, the team predicted) for around 1,150 feet, Batman's velocity would peak at 68 mph before levelling off at a life-threatening 50 mph descent.
Also included in the paper is this excellent diagram, which shows the Caped Crusader "gliding at a constant angle with respect to his direction of travel," not unlike a skydiver. If only all studies on trajectory could include Batman diagrams, the world would be a much better place.
For more super-hero-themed pedantry, check this guide to the physics of the Hulk's jumps.