HLG01 Page
26
V1.0
© 2007 Stevens AeroModel. All Rights Reserved.
HLG01 Trim Guide
Points to keep in mind when prior to making trim changes.
•
Rudder controls the launch and transition.
•
Stabilizer
tilt
controls
the glide circle diameter.
•
CG (balance) and Incidence (declage) work together to control the models pitch or glide
attitude and air speed. Changes to incidence will often require changes to CG.
Incidence has more of an affect on flight performance as the speed increases. Thus
you’ll change the incidence to solve looping during launch or nose diving after transition.
CG changes more subtly affect the aircrafts flying attitude and will often be made to affect
flight speed.
Problem Cause
Solution
Model loops on full power
launch and stalls often in glide.
Too much incidence
Decrease incidence by turning
adjustment screw clock-wise.
Model pitches up steeply at
launch then nose dives into
ground.
Too little incidence
Increase incidence by turning
adjustment screw counter-
clock-wise.
Model launches high with
good transition but stalls often
in glide.
CG too far back
Add nose-weight until stall
disappears.
Model launches high with
good transition but is fast in
the glide and slightly pitched-
down.
CG too far forward
Remove nose-weight until
slower glide is obtained.
Model glides nicely from level
toss. Launches are high but
model fails to consistently roll
left* into transition.
Not enough left* rudder.
Increase left* rudder by
bending the trailing edge of
the fin left until left* roll out is
obtained at transition.
Model rolls sharply to left on
launch additionally, model
does not launch high.
To much left* rudder.
Decrease left rudder by
bending the trailing edge of
the fin right* until launch is
high and followed by a “flip” or
roll-out transition to the left*
Model launches high and
transitions well but glide circle
is tight (less than 100’ in
diameter).
Too much stabilizer tilt.
Carefully, soften carbon boom
by heating with heat gun and
decrease stab tilt until the
glide circle decreases to about
100’ in diameter.
Model launches high and
transitions well but glide circle
is wide (greater than 100’ in
diameter).
Too little stabilizer tilt.
Carefully, soften carbon boom
by heating with heat gun and
increase stab tilt until the glide
circle increases to about 100’
in diameter.
Model launches high and
transitions web but glide
tightens up into a tight
descending spiral.
Not enough wash-in
Check model for warps and
wing misalignment. Add
additional wash-in wedge till
spiral is reduced.
*Applies to right-handed throwers. Left-handed throwers will typically trim for the opposite direction.