Turboprop Torque as power indication????

[Tu.114]

Not untrue, but mind the engine limitations in this process. Looking at a free turbine engine here.

Consider what the power and condition levers do to the engine - the power lever basically governs the gas generator speeds (type dependent, it normally has direct control on propeller pitch in beta mode as well), while the condition lever sets the RPM the propeller is attempting to maintain (again, type dependent, it usually also governs the fuel shutoff valve for starting and shutting down the engine).

And these two are very much interdependent. Remember the formula "Power = Torque * RPM" - this time let me change it to Torque = Power / RPM to hopefully make it clearer. Now let the gas generator run at constant 96% Nh and pull back the condition lever - as the power provided from the gas generator is constant but the propeller is spinning at a lower RPM, You will see the torque value skyrocket, likely exceeding the engines torque limitation. Also, You will find the exhaust gas temperature (whatever it may be named in Your engine) to have risen - when the power turbine is spinning slower, it will exert a greater drag on the gas flow, causing the temperatures to rise. One might simplify it and say that the ability of the prop to digest the engines power is dependent on its RPM - the higher the RPM, the more power it can accept from the gas generator.

So normally, reducing the propeller RPM will entail also reducing the gas generator speed in order not to overtorque the engine. On the DH8-300, setting climb power was normally done using both hands, one on the power and one on the condition levers, as just pulling back the condition lever with the engines delivering normal takeoff power at 1200rpm and 95% torque would immediately have overtorqued them.