Trim Chart - Model Tech Sukhoi SU-31 Assembly Instructions Manual

After you have test-flown and done the initial trim changes to the airplane, use this trimming chart 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 an airplane that tracks straighter and flies truer.
triM feature
Control Centering
Control Throws
Engine Thrust Angle*
Center of Gravity
Yaw**
Lateral Balance**
Aileron Control System
*Engine thrust angle and center of gravity interact. Check both.
**Yaw and lateral balance produce similar symptoms. Note that the fin may be crooked. Right and left references are as if you were in the cockpit.

triM Chart

ManeuVer
F l y g e n e r a l c i r c l e s a n d r a n d o m
maneuvers
Fly random maneuvers
From straight and level flight, quickly
chop the throttle for a short distance
From level flight, roll to a 45º bank and
neutralize the controls
Into the wind, perform inside loops
using only elevator. Repeat test
performing outside loops from an
inverted entry
Into the wind, perform tight inside loops
using only elevator
With the wing level, pull to a vertical
climb and neutralize the controls
Page 
oBSerVation
Try for hands off straight and level
flight
A) Controls are too sensitive or
airplane feels "jerky"
B) Controls are not sensitive enough
or airplane feels "mushy"
A) Air pla ne co nt inu es in a lev el
attitude for a short distance
B) Airplane pitches nose up
C) Airplane pitches nose down
A) Airplane continues in the bank for
a short distance
B) Nose pitches up
C) Nose pitches down
A) Wing is level throughout
B) Airplane yaws to right in both inside
and outside loops
C) Airplane yaws to left in both inside
and outside loops
D) Airplane yaws to the right in inside
lo op s an d yaws t o t he le ft in
outside loops
E) Airplane yaws to the left in inside
loops and yaws to the right in
outside loops
A) Wing is level and airplane falls
to either side
B) A i r p l a n e f a l l s o f f t o t h e l e f t .
Worsens as loops tighten
C) Airplane falls off to the right.
Worsens as loops tighten
A) Climb continues along the same
path
B) Nose tends to go toward an inside
loop
C) N o s e t e n d s t o g o t o w a r d a n
outside loop
CorreCtion
Readjust linkages so the transmitter trim
levers are centered
If A) A d j u s t l i n k a g e s t o r e d u c e
control throws
If B) Adju st linka g e s t o in c r e a s e
control throws
If A) Engine thrust angle is correct
If B) Decrease engine down thrust
If C) Increase engine down thrust
If A) Center of gravity is correct
If B) Add nose weight
If C) Remove nose weight or add tail
weight
If A) Trim settings are 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) Lateral balance is correct
If B) Add weight to right wing tip
If C) Add weight to left wing tip
If A) Trim settings are correct
If B) Raise both ailerons very slightly
If C) Lower both ailerons very slightly