In a typical trainer airplane, smooth power application is approximately 3 seconds to bring in full throttle. The FAA says: "An abrupt application of power may cause the airplane to yaw sharply to the left because of the torque effects of the engine and propeller. This is most apparent in high horsepower engines." > [!note] From Jack > I've also heard this can cause engine roughness from an incorrect mixture, but I haven't tested the theory. ***Source***: [[AFH Ch6]] #todo :: Find out more about engine issues from advancing too quickly.