How does increasing the horsepower/torque to a piston engine in an airplane increase top speed if the propeller size and rpm stay the same?

Question

How does increasing the horsepower/torque to a piston engine in an airplane increase top speed if the propeller size and rpm stay the same?

In: 16

Answer 1

In an aircraft with a constant speed prop you increase thrust by taking bigger “bites” of air by changing the angle of the blades relative to the airflow. So when you increase the engine power the blades take bigger bites which keeps the RPM the same since the bigger bites increase drag on the prop.