Order Numbers
F4090 - F4091 - F4092
F4095 - F4096 - F4097
8.5 Delta mixer (ELVN)
This mixer combines the signals of
the ailerons and elevators for use in
model aircraft of the delta or flying
wing configuration.
It works in the same way as the XMIX
mixer (see also Section 7.11), but is
programmed permanently for the aileron and elevator channels.
When you operate the elevator stick, both servos run in the same
direction; move the aileron stick, and they run in opposite
directions.
The travels for the aileron and elevator functions are separately
variable,and aileron differential is also available as standard.
The left aileron servo is connected to
receiver output 1 (Aileron) and the
right servo to channel 2 (Elevator).
- Move to the Wing mixer (WING) menu at the Select level.
- A short press on the 3-D hotkey takes you to the sub-menu
where you can select between the Flaperon (FLPN) and Delta
mixers (ELVN);select ELVN by turning the hotkey to the right.
- Press the "S" button to reach the Setup menu level.
- The screen shows arrows under the numbers,indicating that the
two functions 1 and 2 are mixed.
- The arrow above the numbers and the flashing "SET and %"
indicate that the mixer value for Function 1 (Aileron) can now be
adjusted.
- Rotate the 3-D hotkey to enter the servo travel as a percentage
between -100% and +100%.The default value of 50% can be left
in place for the moment.
- Press the 3-D hotkey for 1 second to revert to the default value
(+50%).
- A further press on the "S" button highlights the Elevator channel
(2).You can now set up the aileron servo travel in exactly the
same way as just described.
Depending on the physical orientation of the servos and the
control surface linkages you may find it necessary to reverse the
direction of servo rotation, or the direction of mixing, so that the
servos move in the same direction for elevator control and in the
"correct" opposite directions for aileron control.
The first step should always be to reverse the servos as required in
order to make the elevator function work correctly.If the mixer then
works in the wrong direction, set the elevator mixer input (2) to -
50%.
You may find it necessary to set different travels for the two
functions.In our experience most models are more sensitive to the
elevator,and therefore require slightly more travel for the ailerons.
When setting the control surface travels, check that the servos
do not strike their mechanical end-stops at full stick travel
when the functions are superimposed.
Aileron differential
- Press the "S" button again to reach the aileron differential menu.
- Set the desired program values using the 3D-hotkey.
- Check that the travel of the
down-going aileron is now
smaller.
If this is not the case,i.e.the travel of the up-going aileron is smaller,
press the "S" button. The "+" prefix now flashes; rotate the 3-D
hotkey to the left, and the prefix changes to "-", which reverses the
differential.
Explanation:
0% No differential
50% Differential by half the maximum travel
100% "Split" mode:only the up-going aileron moves
Note: the ELVN and VTAL mixer functions are mutually exclusive,
i.e. only one of them can be used.They are locked electronically to
prevent this.If you have activated one mixer function, the other
cannot be activated.
8.6 Camber-changing flaps -> elevator mixer (FL>E)
When you deploy the flaps (see also Section 8.4) many models
exhibit a pitch trim change,i.e. nose up or down.The pilot usually
has to compensate for this with an elevator command.
The FX-18 also provides a mixer to solve this problem, i.e. it
automatically provides the corrective elevator movement.
The following example assumes that the ailerons have been
programmed in the WING menu in such a way that they move up
through about 45º in order to act as a landing aid.This generally
requires a down-elevator trim correction of around -10%.
Note: it may be necessary to mix in a little up-elevator (+10%),
depending on the model’s layout and tail moment arm.
30
Channel 1
Channel 2
Aileron deflection
Aileron deflection
Elevator deflection
Elevator Aileron
