Table of Contents
Advertisement
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:
Aileron differential
W I N G
M I X E R S
Brake settings
Aileron differential
2
4
Aileron
rudder
Elevator
3
5
aileron
0%
Normal
AI
+100%
Ail-tr
+100%
Diff.
0%
0%
0%
Fl-Pos.
+100%
0%
+100%
FL
0% +100%
+100%
Normal
AILE
FLAP
Note:
The upper display corresponds to the choice
of "2AIL" in the line "Aileron. / Flaps" of the
"Model type" menu and the bottom of a
choice of "2/4 AIL 1/2/4 FL".
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 un-
equal distribution of drag produces is a yawing motion
around the vertical axis and, accordingly, a "turning
away" from the intended direction of flight, which is
why this undesirable side effect is also termed "ad-
verse yaw".
174 Program description - Wing mixers
This effect is naturally greater on the comparably long
aerofoils possessed by model gliders, compared to
e. g. powered aircraft models, which generally have
relatively short moment arms. For the former, it must
normally be compensated for by making a simultane-
ous rudder deflection in the opposite direction. How-
ever, 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
0%
oriented upwards, the (undesirable) adverse yaw can
0%
–––
be reduced – and possibly entirely negated. However,
0%
–––
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
0%
0%
benefit: reproducible aileron configurations that also
0%
0%
exhibit less "play".
0%
0%
0%
+100%
0%
WK2
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 centre (-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
right touch pad (CLEAR) will reset a changed value
50% (differential)
in a given active (inverse video) field back to 0 %.
Note:
100% (Split)
Negative values are not usually necessary if
channels are assigned properly.
Advertisement
Table of Contents
