09/11/2018
RANS S-21 OUTBOUND
TEXT MANUAL
158
Using common door self-adhesive D-shaped door seal to affect a trim tab.
It is easy to use, since you can try different lengths to gauge impact on trim.
Plane Briskly Rolls Ball Moves Out
This is indicative of roll input, and can also have some yaw. To determine the cause,
center the ball and keep on the rudders, and release the stick. If you can center the ball,
but remain in a bank, roll trim is needed. Apply the same rubber trim material used on
the rudder to the bottom of the opposite aileron of the roll direction. The trim bulb will be
more effective on the bottom side due to dynamic pressure. Start with 4 to 5" of bulb
and shorten as required. If not totally corrected with roll trim, try adding rudder trim.
Plane Flies Wing Low Opposite of Yaw, Rolls Ball Moves Out, and either
slowly changes heading or hold heading
The plane is flying crooked. This will be obvious if you are holding opposite rudder and
aileron to keep the ball centered. In flight if you add rudder only to center the ball, the
plane will enter and stay in a turn until release of the rudder. The corrective action is to
add bump trim strips to both the rudder and aileron. Do so one at a time. While flying,
write down where you need to locate the trim bumps. It is easy to install trim bumps
opposite of where needed.
