GRAUPNER MC-22S Скачать руководство пользователя страница 140

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140

»MIX-only channel« (page 108)

M I X O N L Y C H A N N E L

M I X o n l y

n o r m a l

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

… so that the associated servo is not also operated
by the elevator stick!

Many years ago the author operated a model delta
with the mc-20, programmed exactly in this way, with
a butterfl y (crow) system as landing aid, exploiting the
“Brake

5 aileron” and “Brake

6 fl aps” wing mi-

xers to provide complete compensation for pitch trim
changes. In this case the term “ailerons” means the
outboard wing control surfaces, and “fl aps” the in-
board pair of control surfaces. To achieve the same
effect with the mc-22s, move back to the menu …

»Wing mixers« (page 84)

… and enter the values for the up-aileron travel and
the down-fl ap travel in the “Brake

5 aileron” and

“Brake

6 fl aps” lines in such a way that the pitching

moments which occur in fl ight cancel each other out,

Programming examples – Fixed-wing models

i.e. the model’s fl ight attitude remains stable. Howe-
ver, do take care to allow the control surfaces enough
“elbow-room” for the elevator function: this means,
don’t exploit the full servo travel for the butterfl y / crow
system alone.

You can ignore all the other settings in this menu.

A modern sweptback fl ying wing can also be opera-
ted in the same way. Many of these models also fea-
ture inboard and outboard control surfaces: the for-
mer forward of the Centre of Gravity, the latter aft of it.
Defl ecting the inboard control surface(s) down incre-
ases lift and produces an up-elevator effect. Defl ec-
ting them up creates the opposite effect. In contrast,
the outboard ailerons have the reverse effect: a down-
defl ection produces a down-elevator effect, and vice
versa. In this case there are really no limits to what
you can achieve with careful thought and the sophisti-
cated mixers of the mc-22s. This could extend to set-
ting up curve mixers which pass just a small degree
of up / down travel to the outboard pair of control sur-
faces, and only at fairly extreme stick travels. For his
own model this writer uses a curve mixer defi ned by a
total of four reference points, i.e.:

In this example the two reference points 1 and 2 are
set to 0%, the left end-point to +60%, and the right
end-point to -65%; the curve is then rounded by pres-
sing the

ENTER

button.

Please note that you should be extremely careful
when setting differential travel with such a confi gura-
tion, regardless of the type of servo arrangement you
are using. This is because differential travels tend to
produce an asymmetrical elevator effect on a tail-less

model, rather than the desired adverse yaw reduction.
For this reason it is advisable to start with a differenti-
al setting of 0%, at least for the fi rst few fl ights. When
you are familiar with the model and feel the need to
experiment, it may then be feasible under certain cir-
cumstances to try differential settings deviating from
zero.

For larger models it may be advisable to install wing-
lets fi tted with rudders, i.e. small vertical surfaces at
the wingtips. If these are actuated by two separate
servos, the rudder signal can very easily be “split” by
using a mixer in the menu ...

»Dual mixers« (page 110)

… in which case you can also apply “split” or differen-
tial travel, with the second rudder servo connected to
a free receiver output socket. If you have programmed
the “

Delta / fl ying wing

” tail type at an earlier stage,

receiver output “5” should still be free. If you have se-
lected the “normal” tail type, output “3” (ELE) should
still be free; this is the one we will use in the following
example.

Select the »

MIX-only channel

« menu (see above),

or the »

Control adjust

« menu (if the second ser-

vo is connected to one of the outputs 5 … 12), and
de-couple the “wrong” control function from the cont-
rol channel to which you have connected the second
rudder servo.

The differential travel is

necessary

in this case, since

the outside rudder turns through a larger radius than
the inside rudder when the model is fl ying a turn; this
is broadly analogous to the effect of front wheel toe-

A i l e r o n d i f f e r e n c e

+ 0 %

F l a p d i f f e r e n c e

+ 0 %

A i l e r o n s 2 > 4 R u d d e r

+ 0 %

A i l e r o n s 2 > 7 F l a p s

+ 5 0 %

B r a k e

> 3 E l e v a t o r

+ 0 %

B r a k e