Glider
(GLID)
Section
– 81 –
SAILPLANE TRIMMING CHART
©1996-2001 by Don Edberg (all rights reserved)
To test for … Test Procedure Observations Adjustments
1. Model Control Neutrals Fly the model straight
and level
Adjust the transmitter trims for
hands-off straight & level flight, no
camber control.
Change electronic subtrims
and/or adjust clevises to center
transmitter trims.
2. Control Throws
Note: be sure all aileron &
flap horn pairs have
matching angles
Fly the model and apply
full deflection of each
control in turn. Camber
control in neutral (setup
6 & 9).
Check the model’s response to
each control input. Set flaps for as
much down flap as possible in
glide path control (90° is good) <5°
reflex needed.
• Aileron & elevator rates: set
for desired authority
• Rudder: set for max. throw
• Set flap motions in Steps 4, 5,
& 9.
3. Decalage & Center of
Gravity (Note: this is an
iterative procedure,
depends on desired
handling characteristics.
Back CG = less stability
but better performance)
Trim for level glide.
Enter 45° dive (across
wind if any) and release
controls. CAUTION:
beware of airspeed &
flutter.
A. Does the model continue its
dive without pulling out or
diving?
B. Does the model start to pull out
(nose up)?
C. Does the model start to tuck
(dive more nose down)?
A. No adjustment
B. Reduce incidence (add
down elevator) and/or
reduce nose weight
C. Increase incidence (add up
elevator) or add nose
weight)
4. Glide Path Control
Settings — Pitch Trim
Note: be sure all aileron
& flap horn pairs have
matching angles.
Fly the model and slowly
apply full deflection of
glide path control
(airbrake stick).
Observe any pitch
changes.
A. Nose drops, up elevator
required for level flight
B. No pitch change
C. Tail drops, down elevator
required to maintain level flight
A. Several options:
1) more up elevator mix;
2) reduce aileron reflex*;
3) increase flap motion*
B. No adjustment
C. Reverse of A
5. Glide Path Control
Settings — Elevator
Delays
Rapidly apply full glide
path, observe initial
pitching response
A. Nose drops
B. No pitch change
C. Nose rises
A. increase elevator delay %
B. No adjustment
C. Reverse of A
6. Glide Path Control
Settings — Roll
Response
Fly the model and apply
full glide path control.
Observe any roll motion.
A. Model rolls to right when glide
path control (airbrake stick)
activated
B. No roll motion
C. Model rolls to left
A. Mix in less right & more left
aileron reflex with airbrake
motion
B. No adjustment
C. Reverse of A
7. Differential/Coupled
Rudder setting
Fly the model and apply
alternating left & right
aileron commands.
Observe path of fuselage
line.
A. Model yaws to right with left
aileron and vice versa
B. Fuselage traces straight line
C. Model yaws to left with left
aileron and vice versa
A. Increase differential and/or
amount of rudder coupling
B. No adjustment
C. Reduce differential and/or
amount of rudder coupling
8. Camber (full wing aileron
& flap droop or reflex)
setting
Put the model in a
straight glide passing in
front of you. Apply
camber control.
A. Model slows down & stalls or
sinks rapidly
B. Model slows slightly
C. Model speed unchanged
A. Reduce amount of droop
&/or add elevator
compensation
B. No change needed
C. Reverse of A
9. Launch Settings
(Part 1)
Switch to Launch mode.
Launch the model &
observe climb angle and
required control inputs
A. Shallow climb angle; lots of up
elevator required
B. Model climbs steeply with little
control input needed
C. Too steep climb, weaves back
& forth, down elev. required
A. Move towhook rearwards
small amount, increase up
elevator preset a little, or
add camber
B. No adjustment
C. Reverse of A
10. Launch Settings
(Part 2)
Switch to Launch mode.
Launch the model &
observe climb angle and
required control inputs
A. Model banks left on tow
B. Model climbs straight ahead
with no roll input needed
C. Model banks right on tow
D. Model tip stalls to one side
A. Reduce left ail & flap droop
or increase right ail / flap
droop
B. No adjustment
C. Reverse of A above
D. Check droop same on both
sides. Increase aileron or
decrease flap droop
11. Speed Settings Switch to speed mode
(entire TE reflexed
slightly, <1/16”/1 mm)
A. Nose drops
B. No pitch change
C. Tail drops
A. Increase up elevator preset
B. No adjustment
C. Reverse of A
12. Elevator-to-Camber
Coupling Setting
Fly model at high speed,
bank & pull up
A. Model keeps speed and comes
about rapidly
B. Model slows down
A. Increase down flap or leave
alone
B. Reduce amount of down
flap
*Note: Swept wing planform may cause opposite reactions, so experiment until proper behavior is attained.
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