85
SAILPLANE TRIMMING CHART
©1995 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.
Aft CG = less
stability but better
performance)
Trim for level glide.
Enter 45° dive (across
wind if any). Release
controls when model
vertical. 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 in
(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. Butterfly Glide
Path Control
Settings
(Part 1)
Note: be sure all
aileron & flap
horn pairs have
matching angles.
Fly the model and apply
full deflection of glide
path control (usually
throttle 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 mixing;
2) reduce aileron reflex*;
3) increase flap motion*
B. No adjustment
C. Reverse of A
4. Butterfly Glide
Path Control
Settings
(Part 2)
Fly the model and apply
full glide path control.
Observe any roll motion.
A. Model rolls to right when glide
path control (throttle stick)
activated
B. No roll motion
C. Model rolls to left
A. Mix in less right & more left
aileron reflex with throttle
motion
B. No adjustment
C. Reverse of A
5.
Differential/Coupl
ed Rudder setting
Fly the model and apply
alternating left & right
aileron commands.
Observe path of fuselage
line (p. 51).
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
6. 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
B. No change needed
C. Increase droop amount
7. 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 elevator required
A. Move towhook rearwards small
amount, increase up elevator
preset a little
B. No adjustment
C. Move towhook forward,
increase down elevator preset
8. 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. Be sure droop same on both
sides. Increase aileron droop
or decrease flap droop (no typo)
9. Speed Settings
Switch to speed mode
(entire TE reflexed
slightly
, no more than
1/16” or 1.5 mm)
A. Nose drops
B. No pitch change
C. Tail drops
A. Increase up elevator preset
B. No adjustment
C. Reverse of A
10. Elevator-to-Flap
Coupling Setting
Fly model at high speed,
bank & pull up
A. Model keeps speed
B. Model slows down
A. Increase down flap
B. Decrease down flap
*Note: Swept wing planform may cause opposite reactions, so experiment until proper behavior is attained
.
