Currently there is no way to easily scale the torque and thrust output without affecting other aspects of the engine such as the acceleration, power required, etc - and sometimes you will come across an issue where for a given RPM and torque output, the thrust produced is just too high compared to what would be produced in real life.
This can be easily dealt with in jet aircraft through the N1 and Mach on Thrust scalar table, however this table doesn’t have any effect on the thrust produced through the propellor, and so the only way to scale the thrust for a given RPM and torque is to use the blanket properties such as power_scalar and thrust_scalar.
These properties are not effective in the majority of cases however, as often these issues will only affect certain engine speed regions such as while at low thrust. (In my case, the propellor produces so much thrust that the aircraft can accelerate past 30 knots quickly, without any throttle or propellor lever action, which is a base setting of around 67% RPM and 10% torque).