The Rudder and Airmanship

In this photo the pilot is executing a climbing turn to the left. P-factor yaw is assisting the turn, so little is any rudder is required in most airplanes. Viewed from the cockpit, this climbing turn to the left will be stable with constant bank, pitch and rate of turn. Viewed from the cockpit, a climbing turn to the right will be much different. Without rudder properly used to control P-factor yaw, the turn will be unstable: the wing will want to drop, the nose will fall, rate of turn will be very slow – the pilot might over-control or significantly reduce rate of climb to achieve an effective turn; instead, the pilot should apply right rudder pressure to control yaw.
In this photo the pilot is executing a climbing turn to the left. P-factor yaw is assisting the turn, so little is any rudder is required in most airplanes. Viewed from the cockpit, this climbing turn to the left will be stable with constant bank, pitch and rate of turn. Viewed from the cockpit, a climbing turn to the right will be much different. Without rudder properly used to control P-factor yaw, the turn will be unstable: the wing will want to drop, the nose will fall, rate of turn will be very slow – the pilot might over-control or significantly reduce rate of climb to achieve an effective turn; instead, the pilot should apply right rudder pressure to control yaw.
What does the rudder do? What is it good for? Airplanes are stable with reference to pitch and roll; with proper settings for power and trim (pitch) they maintain constant AOA and bank. On the other hand, airplanes are not stable on the vertical axis. Good airmanship requires a pilot to control yaw with timely use of rudder pressure. Yaw results from four forces:
Adverse yaw is caused by deflection of ailerons. That action creates lift, and drag. Drag is the force that rotates the airplane on its vertical axis.
P-factor yaw is a force generated by differential lift between ascending and descending blades of a propeller. When climbing, airplanes yaw (turn) left. When descending airplanes yaw (turn) right. P-factor yaw adversely affects climbing turns to right by reducing rate of turn. During descending turns to the right, P-factor yaw will cause the airplane to seek a dangerous descending spiral.
Gyroscopic yaw is very powerful force well known to pilots flying tailwheel aircraft and when performing aerobatics. A spinning propeller is a very strong gyroscope. If you push the nose down an airplane turns (yaws) left. Pull back on the stick and the airplane will yaw right.
Pilot induced yaw is all too common. A pilot’s misuse, untimely and inadvertent use of rudder will cause the airplane to yaw.

To control yaw, whatever the cause, a pilot must apply rudder pressure when needed and only as much as needed. Too much rudder pressure can be as ineffective as too little. Rudder pressure too late or too soon is also ineffective. Many pilots are taught to step on the ball to control yaw. That advice is not helpful. When the ball is off center the airplane has already yawed.

Do you fly by the seat of your pants? Watch pilots fly through a turn. Typically they are leaning – their butt is uncomfortable and the situation is ameliorated with a hefty lean out of the turn. Better to use rudder and control yaw.

Key point: A fundamental of stick and rudder skill is to monitor and interpret the sight picture to recognize yaw. If you do not see yaw, you cannot control yaw.

If you want to learn more, please watch this month’s featured video: Adverse Yaw – A Stick and Rudder Fundamental. click here

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