GRAUPNER mx-16 ifs, Programming Manual

Page: 75 / 132

75 Program description: wing mixers – fi xed-wing model
fi gures. It is essential to check and adjust this setting at
a safe height.
brak
¼
fl ap (Airbrake
¼
fl ap)
When you operate the brake function (Ch 1 stick), both
fl ap servos move together for the landing approach; the
mixer ratio can be set to any value in the range -150% to
+150%. Down-fl ap is usually selected.
Pressing
CLEAR resets the value to 0%.
At this point you select the value which causes the fl aps
to defl ect down as far as possible when the airbrake
function is deployed. However, please ensure that none
of the servos concerned strikes its mechanical end-
stops (servos stalled).
brak
¼
aile (Airbrake
¼
Aileron)
When you operate the brake function, both aileron
servos move together for the landing approach; the
mixer ratio can be set to any value in the range -150%
to +150%.
Pressing
CLEAR resets the value to 0%.
It can also be useful to defl ect both ailerons up slightly
when the airbrakes are extended.
Combination of the “brak
¼
N.N.*” mixers:
“Crow” or “Butterfl y” setting
If you have set up all three airbrake mixers for your
model, it is then possible to program a special confi gura-
tion known as the “
crow ” or “ butterfl y ” arrangement for
glide path control. In the butterfl y setting both ailerons
are defl ected up by a moderate amount, and both fl aps
down by the maximum possible amount. The third mixer
provides elevator trim to counteract any unwanted pitch
trim change and maintain the model’s airspeed at a
safe level. This is necessary to avoid the danger of the
model slowing up excessively; if the landing approach is
started too soon, and has to be extended by retracting
the airbrakes again, the model could then stall abruptly.
This inter-action between the fl aps, ailerons and elevator
is used to control the glide angle on the landing ap-
proach. Optionally the butterfl y setting can also be used
without the airbrakes or spoilers; nowadays this is very
commonly used for sports and competition aircraft.
Note:
If your model features full-span (strip) ailerons which
also double as camber-changing fl aps, the two mix-
ers “Brake
¼
aileron” and “Brake
¼
elevator” can be
combined for glide path control. In this case up-fl ap is
applied, but the fl aps can still be controlled as ailerons.
Elevator pitch trim compensation is generally required.
If you have programmed aileron differential, the re-
sponse of the ailerons will inevitably be adversely
affected by the extreme “up” defl ection of the ailerons
in the butterfl y setting, because the differential travel
reduces or entirely suppresses the down-aileron de-
fl ection. However, the “up” travel of the ailerons is also
greatly restricted because they are already at or close to
their “up” end-point. The remedy here is to apply “dif-
ferential reduction”, which is explained in its own section
later.
elev
¼
fl ap (Elevator
¼
fl ap)
The fl aps can be used to enhance the effect of the el-
evator in tight turns and aerobatics, and this mixer feeds
part of the elevator signal to the fl ap servos. The mixer
direction must be set so that the fl aps move down when
up-elevator is applied, and vice versa.
Pressing
CLEAR resets the value to 0%.
For this mixer the “usual” settings are in the low two-digit
range.
* N.N. = Nomen Nominandum (name to be stated)