Graupner Hendheld RC 2.4 GHz No. of channels: 8 33116 Data Sheet

Product codes
33116
Page of 200
164 Programming example - fixed-wing model
mx-16 HoTT programming techniques
Preparation, using a fixed-wing model aircraft as an example
Programming model data into an 
mx-16 HoTT …
… is easier than it might appear at first sight.
There is one basic rule which applies equally to all pro-
grammable radio control transmitters, and not just to the 
mx-16 HoTT: if the programming is to go “smoothly” 
and the systems work as expected, the receiving sys-
tem components must first be installed correctly in the 
model, i. e. the mechanical systems must be first-rate. 
This means: ensure that each servo is at its correct 
neutral position when you fit the output lever or disc 
and connect the linkage to it. If you find this is not the 
case, correct it! Remove the output arm, rotate it by one 
or more splines and secure it again. If you use a servo 
tester, e. g. the RC-Tester, Order No. 
2894.12, to centre 
the servos, you will find it very easy to find the “correct” 
position.
Virtually all modern transmitters offer facilities for offset-
ting the neutral position of servos, but this is no substi-
tute for a correct mechanical installation; this function is 
only intended for fine tuning. Any substantial deviation 
from the “0” position may result in additional asymmetry 
when the signal undergoes further processing in the 
transmitter. Think of it this way: if the chassis of a car 
is distorted, you may be able to force the vehicle to run 
straight by holding the steering wheel away from centre, 
but it does not make the chassis any less bent, and the 
basic problem remains.
Another important point is to set up the correct control 
travels wherever possible by using the appropriate link-
age points in the mechanical system; this is much more 
efficient than making major changes to the travel set-
tings at the transmitter. The same rule applies: electronic 
travel adjustment facilities are designed primarily to 
compensate for minor manufacturing tolerances in the 
servos and for fine adjustment, and not to compensate 
for poor-quality construction and defective installation 
methods.
If two separate aileron servos are installed in a fixed-
wing model aircraft, the ailerons can also be employed 
as flaps by deflecting both of them down, and as air-
brakes by deflecting both of them up - simply by setting 
up a suitable mixer (see the section starting on the next 
double page). Such systems are generally more often 
used in gliders and electric gliders than in power models.
In such cases the servo output arms should be offset 
forward by one spline relative to the neutral point, i. e. 
towards the leading edge of the wing, and fitted on the 
servo output shaft in that position.
The mechanical differential achieved by this asym-
metrical installation takes into account the fact that the 
braking effect of the up-going ailerons increases with 
their angle of deflection, and this means that much less 
travel is usually required in the down-direction than the 
up-direction.
Similar reasoning applies to the installation of the flap 
linkage when separately actuated flap servos are in-
stalled, designed to be used in a butterfly (crow) system. 
Here again an asymmetrical linkage point is useful. The 
braking effect of the crow system is provided primarily 
by the down-movement of the flaps rather than the 
up-movement of the ailerons, so in this case the servo 
output arms should be angled aft, i. e. offset towards the 
trailing edge of the wing, as this makes greater travel 
available for the down-movement. When this combina-
tion of lowered flaps and raised ailerons is used, the 
ailerons should only be raised by a moderate extent, as 
their primary purpose in this configuration is to stabilise 
and control the model rather than act as brakes.
You can “see” the difference in terms of braking effect by 
deploying the crow system, then looking over and under 
the wing from the front: the larger the projected area of 
the deflected control surfaces, the greater the braking 
effect.
Outboard ailerons
Inboard camber-changing flaps
(This type of asymmetrical installation of the servo 
output arms can also make sense when you are setting 
up split flaps or landing flaps on a power model.)
Once you have completed your model and set up the 
mechanical systems accurately in this way, you are 
ready to start programming the transmitter. The instruc-
tions in this section are intended to reflect standard 
practice by describing the basic model settings first, and 
then refining and specialising them to complete the set-
up. After the initial test-flight, and in the course of con-
tinued test-flying, you may need to adjust one or other