Futaba 8UHFS, 8UHPS - Manual (Page 60)

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CH 7 (left) aileron:
Left aileron up travel Left aileron down travel
12. Set up the butterfly (also referred to as
“crow”) function for glide path control and precise
spot landings. The ailerons go up and the flaps
drop with movement of the throttle stick. Turn
on the BFLY function (p. 59) by pressing the Plus
(+)
KEY. The ‘ ’ display will be
flashing unless switch A is up, then OFF will flash.
First set the Butterfly function activation point.
Hit the Left (<)
key one time to get to
the BFLY offset setting menu. Now move the
throttle stick to where you want the function to
begin. (we recommend having the throttle stick
all the way up for normal flight, and have the
BFLY function “kick in” about 3 clicks from top.
This way, if you accidentally jog the throttle stick
a bit, you won't activate the butterfly function.)
Enter your position by pressing the two
keys simultaneously.
Next, hit the right (>) button until the AIL setting
menu appears. Input a 25% value for the
ailerons. Move the throttle stick and be sure the
ailerons go UP with butterfly (see figure below).
If they don’t, change the sign of the number
you’ve chosen (this may depend on servo
orientation). You'll probably want 1/4 to 1/3 of
aileron travel so you'll have plenty of roll authority
while on approach in full butterfly command.
Notice that you set the throw for both ailerons at
the same time: this is the reason to have identical
control arm lengths and neutral positions.
Hit the (>) CURSOR key once and input the
throw for the flaps. Move the throttle stick and
be sure the flaps DROP with butterfly. If they
don’t, change the sign (this again may depend on
servo orientation). You want as much flap
motion as possible — 90° is great if you can get it.
Like the ailerons, you set both flap offsets at the
same time.
Use zero or very little elevator compensation until
you fly and determine what is needed: if the
model pitches up with butterfly, add down
elevator compensation and vice versa. Make
only small changes in compensation because it
has a big effect on trim. Refer to the sailplane
trimming chart for more details.
13. Set up the START (launch, p.62) preset for
high launches so that the flaps drop slightly lower
than the ailerons to reduce tip-stalling tendencies.
Recommended settings are 30%, 0%, 40%, 40%,
30%. Increase the up-elevator preset in small
increments until the plane launches as steeply as
you like; add down elevator if the model weaves
back and forth or is hard to control (remember to
use the rudder stick, or rudder coupling, during the
launch). A well-trimmed model may actually
have some down elevator mixed in for launching.
Remember that to get the START function to turn
on, you have to flip the START/SPEED switch
(Switch C, over the right-hand stick) to its lower
position.
ON or OFF
indicates
Start-Speed
switch
position.
OFF
ON
Switch G
14. You may also set up the speed mode presets
(SPEED, p. 63) for high-speed cruise between
thermals. Reflex (raise) the entire trailing edge
no more than 1/16" (1.5 mm), or you'll gain more
drag than penetration ability. Use no more than 5
or 10% for initial setup.