Trim Chart - Model Tech SUKHOI 40 Instructions Manual

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, straighter and better flying airplane.
TRIM FEATURE
Control Centering
Control Throws
Engine Thrust Angle*
Center of Gravity
Longitudinal Balance
Yaw**
Lateral Balance
Aileron Rigging
*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.
MANEUVER
Fly general circles and
random maneuvers.
Fly random maneuvers.
From straight flight,
chop throttle quickly.
From level flight, roll
to 45º bank and
neutralize controls.
Into wind, do inside
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.
OBSERVATION
Try for hands off straight
and level flight.
A) Too sensitive, jerky
controls.
B) Not sufficient control.
A) Airplane continues
level path for short
distance.
B) Airplane pitches nose up.
C) Airplane pitches nose
down.
A) Continues in bank for
moderate distance.
B) Nose pitches up.
C) Nose drops.
A) Wings level throughout.
B) Yaws to right in both
inside and outside loops.
C) Yaws to left in both
inside and outside loops.
D) Yaws to right on inside,
and left on outside loops.
E) Yaws left on inside, and
right on outside loops.
A) Wings are level and
plane falls to either side.
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.
30
CORRECTION
Readjust linkages so Tx
trims are centered.
If A) Change linkages to
reduce throws.
If B) Increase throws.
If A) Thrust is correct.
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.