Originally Posted by
safetypee
For powered aircraft the engines are the source of energy.
Wings convert energy to lift.
The elevators distribute the lift.
Trim balances residual force in the elevator control system.
The way I think of it is, the elevator (AOA) routes the energy toward speed vs. climb angle. (And this is true for powered and glider alike.)
A more complete picture is that you're always getting energy from the engines and losing it to drag, but any leftover amount (excess thrust) goes to the routing control mentioned above. In a glider, that is a negative amount and you still have to choose what to do with it the same way.