27
TRIM FEATURE
MANEUVERS
OBSERVATIONS
CORRECTIONS
CONTROL
CENTERING
CONTROL
THROWS
ENGINE
THRUST
ANGLE
1
CENTER OF
GRAVITY
LONGITUDINAL
BALANCE
YAW
2
LATERAL
BALANCE
AILERON
RIGGING
Fly general circles and
random maneuvers.
Random maneuvers
From straight flight,
chop throttle quickly.
From level flight roll to
45º bank and
neutralize controls.
Into wind, do open loops,
using only elevator.
Repeat tests doing
outside loops from
inverted entry.
Into wind, do tight inside
loops.
With wings level, pull
to vertical climb and
neutralize controls.
Try for hands off straight
and level flight.
A. Too sensitive, jerky
controls.
B. Not sufficient control.
A. Aircraft continues level
path for short distance.
B. Plane pitches nose up.
C. Plane pitches nose
down.
A. Continues in bank for
moderate distance.
B. Nose pitches up.
C. Nose drops.
A. Wings are level
throughout.
B. Yaws to right in both
inside and outside
loops.
C. Yaws to left in both
inside and outside
loops.
D. Yaws right on insides,
and left on outside
loops.
E. Yaws left in insides,
and right on outside
loops.
A. Wings are level and
plane falls to either side
randomly.
B. Falls off to left in loops.
Worsens as loops
tighten.
C. Falls off to right in
loops. Worsens as
loops tighten.
A. Climb continues along
same path.
B. Nose tends to go to
inside loop.
C. Nose tends to go to
outside loop.
Readjust linkages so that
Tx trims are centered.
If A, change linkages to
reduce throws.
If B, increase throws.
If A, trim is okay.
If B, decrease
downthrust.
If C, increase downthrust.
If A, trim is good.
If B, add nose weight.
If C, remove nose weight.
If A, trim is correct.
If B, add left rudder trim.
If C, add right rudder trim.
If D, add left aileron trim.
If E, add right aileron trim.
If A, trim is correct.
If B, add weight to right
wing tip.
If C, add weight to left
wing tip.
If A, trim is correct.
If B, raise both ailerons
very slightly.
If C, lower both ailerons
very slightly.
1. Engine thrust angle and C.G. interact. Check both.
2. Yaw and lateral balance produce similar symptoms. Note that fin may be crooked. Right and left references are from the plane’s vantage point.
