ORIGINAL: gboulton


At any given AOA and airspeed, a wing (and we can presume, from your original question, that both aircraft have identical wings....we'll drop subtle variations due to the build, etc) will produce X amount of lift.

We've got a couple of options to 'solve' this:

If we want to fly both airplanes at the same throttle setting, then the heavier airplane will need a higher AOA...and will thus encounter more drag, and find itself flying slower.

If we want to keep both airplanes at the same AOA, the heavier one will need more airspeed, thus requiring more throttle (and inducing more drag).

In either case, what we wind up with is a "slower" airplane. For any given amount of thrust, the heavier airplane will be slower than the lighter airplane.

AOA's also going to dictate some of the things jetmech mentioned above. Faster sink rate and quicker stalls for example. Again, it's simple a function of drag and lift. "engine off" is still a power setting...so given both airplanes deadsticked, the heavier one will either need to be more nose-down for higher airspeed, OR will need to have a higher AOA, slowing it down more quickly, and bringing it closer to the critical AOA.

Climbing, too, is about AOA. An airplane climbs because of excess power. It has more thrust than is required for level flight. Well...remember...increased AOA (necessary to produce the extra lift, remember) implies more drag too...requiring more power. Thus, if X power is sufficient for level flight in the light airplane, it'll take X+1, for example, for level flight in the heavier aircraft. Thus, at X+1 power, the lighter airplane is climbing, the heavier one is cruising level.