Thrust Required – is the amount of thrust that is required to overcome
drag and can be found on the total drag curve. It is expressed in pounds
Power Required – the rate of doing work. The amount of power that is
required to produce thrust required
Thrust Available – the amount of thrust that the airplane’s engines
are actually producing at a given throttle setting, velocity and density.
Power Available - the amount of power that an airplane’s engine is
actually producing at a given throttle setting, velocity and density
Shaft Horse Power is the output of the engine.
Thrust Horse Power is propeller output or the horsepower that is converted
to thrust by the propeller
Propeller Efficiency is the ability of the propeller to turn engine output
into thrust
The T-34 has a constant-speed, variable-pitch propeller. Propeller
efficiency will decrease as altitude increases. As the air density
decreases, the blade angle will increase so that the prop takes a bigger
bite of air to maintain a constant 2200rpms. This is much more efficient
than a fixed prop
Thrust Excess – occurs if thrust available is greater than thrust
required at a particular velocity