I am having trouble correcting some yaw on my aircraft. Tried following the the PRODUCTION ACCEPTANCE PROCEDURES below but dont know the length of the wedge, have tried one about three inches long which is not enough correction. I can't find Fig 15-5 anywhere. Can anyone help
Tony Earle
Directional (yaw) trim:
An off-center skid ball is common for many new airplanes. Small trim adjustments should be
made so that when at cruise speed the airplane flies straight and true in a stick free mode.
To test directional trim, establish and hold level flight. Remove your feet from the rudder pedals.
If the skid ball is does not remain centered, rudder trim will be needed. Apply rudder as
necessary to center the ball and determine whether ?right or left? trim will be needed. Fig. 15-5
shows an effective and attractive method for a fixed trim tab. Unlike tabs which stick out past the
trailing edge, these do not alter the planform profile of the control surface, yet are very effective.
A temporary tab of this type can be made of wood, sawed into a wedge about 3/8'' at the thick
edge and 1 1/4 to 1 1/2'' wide. This can be temporarily taped on to the rudder trailing edge near
bottom and adjusted simply by trimming the length. Attach to the side of the rudder opposite that
of the rudder pedal effort needed to center the ball. It may take several flights to determine the
exact size. Then the temporary wedge can be replaced by a wedge made of machined aluminum,
plastic, or sealed wood, and attached with flush pop rivets.
Tony Earle
Directional (yaw) trim:
An off-center skid ball is common for many new airplanes. Small trim adjustments should be
made so that when at cruise speed the airplane flies straight and true in a stick free mode.
To test directional trim, establish and hold level flight. Remove your feet from the rudder pedals.
If the skid ball is does not remain centered, rudder trim will be needed. Apply rudder as
necessary to center the ball and determine whether ?right or left? trim will be needed. Fig. 15-5
shows an effective and attractive method for a fixed trim tab. Unlike tabs which stick out past the
trailing edge, these do not alter the planform profile of the control surface, yet are very effective.
A temporary tab of this type can be made of wood, sawed into a wedge about 3/8'' at the thick
edge and 1 1/4 to 1 1/2'' wide. This can be temporarily taped on to the rudder trailing edge near
bottom and adjusted simply by trimming the length. Attach to the side of the rudder opposite that
of the rudder pedal effort needed to center the ball. It may take several flights to determine the
exact size. Then the temporary wedge can be replaced by a wedge made of machined aluminum,
plastic, or sealed wood, and attached with flush pop rivets.