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the transmitter control does not influence any mixers
on the "Brake settings" sub-menu. Otherwise, the
mixer travel is expanded back to 100 % automatically.
All other mixers in the »Wing mixers« menu have
their neutral point with the control at its center, i. e.
they have no effect at this control position. The value
set is mixed in at full travel.
Mixer functions
The individual options in the »Wing mixers« menu
are discussed below, separately for single-, dual- and
multi-flap models. Before we start, a number of re-
marks on the differentials for ailerons and flaps:
Aile. diff. or Diff.
(Aileron-Differential)
Wing mixers
Brake settings
Aile.diff.
0%
AI
RU
0%
EL
AI
0%
0%
nor mal
AI
+100%
AiI-tr
+100%
Diff.
fl.pos
nor mal
AILE
For aerodynamic reasons, the drag generated on
an aileron oriented downwards is greater than that
generated by the same aileron when it is oriented
upwards by the same amount. One effect of this
unequal distribution of drag produces is a yawing mo-
tion around the vertical axis and, accordingly, a "turn-
ing away" from the intended direction of flight, which
is why this undesirable side effect is also termed
"adverse yaw". This effect is naturally greater on the
comparably long aerofoils possessed by model glid-
ers, compared to e. g. powered aircraft models, which
172 Program description - Wing mixers
generally have relatively short moment arms. For
the former, it must normally be compensated for by
making a simultaneous rudder deflection in the op-
posite direction. However, this rudder deflection also
generates drag and therefore further degrades flight
characteristics.
If, on the other hand, a differential is applied to the
aileron orientations, by giving the aileron oriented
downwards a smaller deflection than the aileron
oriented upwards, the (undesirable) adverse yaw can
be reduced – and possibly entirely negated. However,
the basic precondition for this is that each aileron
must have its own servo present, which can therefore
also be embedded straight into the aerofoils. In addi-
tion, the shorter linkage paths produce an additional
benefit: reproducible aileron configurations that also
exhibit less "play".
–––
–––
0%
0%
Unlike mechanical solutions, which not only common-
ly need to be designed and built in when constructing
the model but also produce a slightly increased "play"
in the control system for strong differentials, the trans-
mitter-based differential typically used today offers
considerable benefits.
The degree of differential can be changed at any
time, for example, and, in extreme circumstances, the
downward deflection of an aileron, in what is termed
a "split" position, can be suppressed entirely. This
approach not only reduces or even suppresses "ad-
verse yaw", but can, in certain circumstances, even
generate a positive yaw: in such cases, an aileron
command will generate a yaw about the vertical axis
in the direction of the turn. For large glider models in
particular, this approach lets such aircraft fly "clean"
turns using just the ailerons, which is not otherwise
possible unaided.
The adjustment range of -100 % to +100 % makes it
possible to set a differential appropriate for each side,
regardless of the direction of rotation of the aileron
servos. While "0 %" corresponds to a normal linkage,
i. e. no differential, "-100 %" or "+100 %" represents the
"split" function.
For aerobatic flying, low absolute values are required
to ensure the model rotates exactly along its longitu-
dinal axis when an aileron command is given. Values
near to the center (-50 % or +50 %) are typical for
facilitating turns in thermals. The split setting (-100 %,
0% (normal)
+100 %) is popular with slope fliers, where ailerons
alone are often used for turning the model.
A simultaneous tap on the or keys of the
50% (differential)
right four-way button (CLEAR) will reset a changed
value in a given active (inverse video) field back to
0 %.
100% (split)
Note:
Negative values are not usually necessary if channels
are assigned properly.
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