Axes of Rotation

Not only used for chopping wood, but axes are helpful in rotating an airplane.

An aircraft can roan on three axis when moving through the sky. These three axis intersect at the center of gravity.

Vertical Axis – This axis goes vertical (think up and down) through the aircraft. In order to get an understanding of this, think of a vertical line running from the top of the aircraft up to the sky and extending to the ground through the aircraft. The aircraft can move side to side on this line. This left and right rotation movement is known as the “yaw” and rudder is used to control this motion.

Lateral Axis – this axis goes horizontal (think side to side) through the wing tips. This axis is best represented by imagining a line extending from wingtip to wingtip and moves the nose and tail up or down. The elevator is used to pitch the aircraft along this axis.

Longitudinal Axis – this axis goes horizontal from the nose to the tail (think front to back) and is essentially what makes the aircraft move (bank) side-to-side. The wings “bank” left or right using the control wheel.

Axis and Turning

When making a turn, all three axis are used.

Medium Banked Turn – To make a medium banked turn to the left, you will need to simultaneously turn the control wheel to the left, while using left rudder pedal and pull back on the control wheel.

Once at bank, bring the controls to neutral position but continue holding back the control wheel for increased lift.

When getting close to the desired heading, apply opposite rudder and ailerons to level the wings and release pressure on the control wheel once the bank decreases where the turn will stop once the wings are level.

Reverse for Medium Banked turn to the right.

Rudder Movement for Turns

Rudder controls the “yaw” which is used to correct for adverse yaw such as the left turning tendency from the propeller. The rudders are also used to steer the aircraft on the ground in the Cessna 172 Skyhawk.

Since the propeller causes the aircraft to have a more left leaning tendency, more right yaw (right rudder) will be needed in high power settings and slow airspeeds and will almost always need some right rudder pressure to keep the aircraft straight takeoff, roll and after lift off while the aircraft is climbing.

To offset adverse yaw, the proper way to use the rudder is to apply rudder pressure simultaneously with control wheel pressure.

The proper amount of rudder can be determined by your body reaction when making a turn and with too much rudder, you may feel yourself being pushed towards the outside of the turn (high wing), which is know as a skid.

Too much rudder or applying the rudder pressure too soon and the aircraft will yaw towards the direction of the turn instead of “rolling” around the longitudinal axis as the bank angle increases.

Too little rudder pressure or applied too late and the aircraft will yaw in the opposite direction of the turn as you roll the aircraft into a bank.

Making a Good Roll-in Turn

The key to making a good roll-in turn is to look straight ahead as you simultaneously apply aileron and rudder while you verify that the airplane is rolling around the longitudinal axis. It should not yaw left or right and the rate of turn will increase as the bank angle increases.

Slip/Skid Indicator

In some aircrafts, the instrument panel will have a slip/skid indicator in which the horizontal line under the tank indicator or a ball in the turn coordinator. This can help verify that you are making a good turn.

If the slip/skid indicator mark is to the left, you will need more left rudder or less right rudder, and if it is to the right, you will need more right rudder or less left rudder.

Ask your skills develop, you want to know the appropriate rudder pressures to apply without relying on the slip/skid indicator so avoid staring at the indicator and rather just glance after you have established the turn to check as you want to develop the habit of keeping your eyes focussed on the outside by using the horizon as a visual indicator as well as by feeling the pressure applied to you in your seat as a physical indicator.