MD11Nut From , joined Dec 1969, posts, RR: Reply 1, posted (11 years 7 months 2 days 16 hours ago) and read 2991 times:
Not too sure if this is what you're looking for... For cruise, the answer perhaps lies the Breguet range equation? Range is maximized at flight conditions which maximize M*L/D. With a constant Mach M, that means max L/D which means constant CL which means flying at a constant W/delta which means you continue to climb in cruise as fuel is burned off (follow optimum W/delta). I believe this is your L/D and Range/altitude relationship. If this is not what you have in mind, perhaps take a look at the equations of motion for climb/descent...One can deduce the relationship...maybe. I haven't touched the aero books in years.