Trim Chart - Model Tech Yak 54 Assembly Instructions Manual

After you have test-flown and done the initial trim changes to the aircraft, use this trim chart to begin trimming your aircraft. 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 aircraft that tracks straighter and flies truer.
TriM fEaTurE
Control Centreing
Control Throws
Engine Thrust Angle*
Centre 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. Make certain both elevator halves are even with each other
and that they both produce the same amount of control deflection throughout the entire deflection range. Right and left references are as if you were
sitting 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
maneuvres
Fly random maneuvres
From straight and level flight, quickly
chop the throttle for a short distance
From level flight, roll to a 45º bank and
neutralise 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 neutralise the controls
obsErvaTioN
Try for hands off straight and level
flight
A) Controls are too sensitive or
aircraft feels 'jerky'
B) Controls are not sensitive enough
or aircraft feels 'mushy'
A) Aircr aft continues in a level
attitude for a short distance
B) Aircraft pitches nose up
C) Aircraft pitches nose down
A) Aircraft continues in the bank for
a short distance
B) Nose pitches up
C) Nose pitches down
A) Wing is level throughout
B) Aircraft yaws to right in both inside
and outside loops
C) Aircraft yaws to left in both inside
and outside loops
D) Aircraft yaws to the right in inside
loops and yaws to the left in
outside loops
E) Aircraft yaws to the left in inside
loops and yaws to the right in
outside loops
A) Wing is level and aircraft falls
to either side
B) A i r craft f a l l s o f f t o t h e l e f t .
Worsens as loops tighten
C) Aircraft 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
Page 4
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 or use exponential
If B) Adjust linkages 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