GRAUPNER mx-16 ifs Programming Manual Download Page 73

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Program description: wing mixers – fi xed-wing model

nates the danger of errors when a fl ap command is
given.

The basic programming procedure

Hold the rotary cylinder pressed in to select the de-

sired mixer.
The bottom line of the screen will now display

SEL

on its own, or with the

symbol.

Use the rotary cylinder to select one of these two

fi elds.
Press the rotary cylinder: the appropriate input fi eld

is now highlighted.
Set the desired value using the rotary cylinder, and

assign a switch if required.
Negative and positive parameter values are possible;
this may be necessary to obtain the correct direction
of servo rotation (control surface defl ection).
Pressing

CLEAR

in the inverse fi eld resets an altered

value to the default value.
Press the rotary cylinder to conclude the input proc-

ess.

Mixer neutral point

(offset)

The neutral point of the mixers
Aileron

N.N.*

Elevator

N.N.*

Flap

N.N.*

is by default the zero point of the transmitter control,
i. e. that is the point at which they have no effect. At the
end-point of the transmitter control the full mixer value is
applied.
The default neutral point (“offset”) of the mixers
Airbrake

N.N.*

at which the airbrakes are

always

retracted, is the

forward position of the Ch 1 stick (throttle / airbrakes) if
you select “no” in the “Motor at Ch 1” line of the »

base

sett.

« menu, and is the back position of the Ch 1 stick if

you select “no/inv”.

diff aile.

(differential aileron travel)

Aileron differential compensates for an unwanted side-
effect which occurs when ailerons are defl ected: the
problem known as “adverse yaw”. When ailerons are
defl ected, the drag generated by the down-going aileron
is greater than that produced by the up-going aileron.
The differential drag causes a yawing motion around the
vertical axis in the opposite direction to the desired turn.
This effect is much more pronounced in model gliders
with high aspect ratio wings than in power models with
their much shorter moment arms, and usually has to be
countered by giving a simultaneous rudder defl ection in
the opposite direction to the yaw. However, this in turns
causes additional drag and reduces the aircraft’s ef-
fi ciency even further.
Aileron differential reduces the angular travel of the
down-going aileron relative to the up-going aileron, and
this reduces the drag and therefore the adverse yaw.
However, electronic differential can only be applied
if each aileron is actuated by its own servo, usually
mounted in the wings themselves. The shorter pushrods
also result in virtually slop-free aileron linkages with
reliable centring.
Mechanical solutions are also possible, but they usually
have to be “designed in” when the model is built, and the
degree of differential cannot be altered subsequently.
In any case signifi cant mechanical differential tends to
cause additional slop in the control system. Electronic
differential offers the following important advantages:

0% (normal)

50% (differential)

100% (split)

It is easily possible to vary the degree of differential
without affecting the travel of the up-going aileron. At
one extreme it is possible to suppress the down-aileron
defl ection completely, i. e. only the up-going aileron
moves at all, and this arrangement is sometimes called
the “split” setting. Split ailerons not only tend to suppress
adverse yaw, but can even generate positive yaw, which
means that the model yaws in the direction of the turn
when an aileron command is given. In the case of large
model gliders, smooth turns can then be fl own using
ailerons alone, which with most models of this type is
usually by no means the case.
The adjustment range of -100% to +100% makes it pos-
sible to set the correct direction of differential regardless
of the direction of rotation of the aileron servos. “0%”
corresponds to a normal linkage, i. e. no differential,
while “-100%” or “+100%” represents the “split” function.
For aerobatic fl ying it is necessary to set low absolute
differential values, to ensure that the model rotates
exactly along its longitudinal axis when an aileron
command is given. Moderate values around -50% or
+50% are typical for making thermal turns easier to fl y.
The split setting (-100%, +100%) is popular with slope