Global Ultimate - Trim Chart; Control Centering; Center of Gravity Longitudinal Balance; Lateral Balance

27
TRIM CHART
After you have test flown and done the initial trim changes to the aircraft, use the Trim Chart below to
begin trimming your airplane. Following and adhering to this chart will result in the ability to diagnose
trim problems and correct those problems using the simple adjustments shown below. Making these
observations and related corrections will result in a truer, better flying airplane.
TRIM FEATURE MANUEVER OBSERVATION CORRECTION
Control Centering Fly general circles and Try for hands off straight Readjust linkages so Tx
random maneuvers. and level flight. trims are centered.
Control Throws Fly random maneuvers. A) Too sensitive, jerky If A) Change linkages to
controls. reduce throws.
B) Not sufficient control. If B) Increase throws.
Engine Thrust Angle* From straight flight, A) Airplane continues If A) Thrust is correct.
chop throttle quickly. level path for short
distance.
B) Airplane pitches nose up. If B) Decrease downthrust.
C) Airplane pitches nose If C) Increase downthrust.
down.
Center of Gravity From level flight, roll A) Continues in bank for If A) Trim is good.
Longitudinal Balance to 45º bank and moderate distance.
neutralize controls. B) Nose pitches up. If B) Add nose weight.
C) Nose drops. If C) Remove nose weight.
Yaw** Into wind, do inside A) Wings level throughout. If A) Trim is correct.
loops using only elevator. B) Yaws to right in both If B) Add left rudder trim.
Repeat tests doing inside and outside loops.
outside loops from C) Yaws to left in both If C) Add right rudder trim.
inverted entry. inside and outside loops.
D) Yaws to right on inside, If D) Add left aileron trim.
and left on outside loops.
E) Yaws left on inside, and If E) Add right aileron trim.
right on outside loops.
Lateral Balance Into wind, do tight A) Wings are level and If A) Trim is correct.
inside loops. plane falls to either side.
B) Falls off to left in loops. If B) Add weight to right
Worsens as loops tighten. wing tip.
C) Falls off to right in loops. If C) Add weight to left
Worsens as loops tighten. wing tip.
Aileron Rigging With wings level, pull A) Climb continues along If A) Trim is correct.
to vertical climb and same path.
neutralize controls. B) Nose tends to go to If B) Raise both ailerons
inside loop. very slightly.
C) Nose tends to go to If C) Lower both ailerons
outside loop. very slightly.
*Engine thrust angle and C.G. interact. Check both.
**Yaw and lateral balance produce similar symptoms. Note that the fin may be crooked. Make certain both elevator
halves are even with each other and produce the same amount of control throw. Right and left references are from the
rear of the plane, as if you were in the cockpit.