OpenTX - Application Note 11
Flaperons and Reflex
Set up a switch to add a variable offset to the aileron channels to create flaperons or reflex.
When an offset lowers both ailerons, the ailerons are referred to as flaperons or camber. When an offset raises both ailerons, this is called reflex. Flaperons are used to provide more lift in a similar way that flaps do. Reflex is used, usually by gliders, to reduce lift and make the aircraft descend more quickly.
For this example, switch SE is used as the selection switch as shown in this table.
Pot S1 is used to control the range of reflex and flaperon selected. The range is limited to 60% so that enough aileron movement remains to control the roll of the aircraft. Audio files announce the aileron mode when the mode is changed.
These features can only be implemented if each aileron is on a separate channel. In this example, aileron left is channel two and aileron right is channel three. On the Mixer screen, one line is added to each of these channels to implement reflex, and another line is added to each channel to implement flaperon. Either flaperon is enabled or reflex is enabled, or neither is enabled. When one of them is enabled, it is added to the aileron channel, so the multiplex function is ‘Add’. Turning on or off reflex or flaperon is slowed down with 4.0 second ‘slow down’ and ‘slow up’ values. Changing the pot value is also slowed by these values. The changes are slowed so that the ailerons do not change quickly and cause sudden movements of the aircraft.
The curve used for both reflex and flaperon converts the –100% to +100% range of the pot S1 to a range of 0% to +100%. Only two points are needed to define the curve. This is the curve.
For this example aircraft, the left aileron is raised when the left channel value is positive. The right aileron, however, is raised when the right channel value is negative. The left aileron is opposite to the right channel. Therefore, with the pot set to 100%, when reflex is switched on, (switch SE↑) the left aileron channel slowly rises to +60% and the right channel slowly falls to –60%. This raises both ailerons. When reflex is switched off, (switch SE-) both channels slowly move back to 0%.
When flaperon is switched on, (switch SE↓) the left aileron channel slowly falls to –60% and the right channel slowly rises to +60%. This lowers both ailerons.
Note that the pot S1 fully clockwise sets the range up to a maximum of 60% reflex or flaperon. Turn the pot down for reduced range. The maximum range can be changed by changing the weights of the reflex and / or the flaperon lines.
Create the audio files which say the aileron modes. Refer to Application Note 4 for the creation of audio files. Transfer the audio files to the [SOUNDS]/[en] folder on the SD card.
Use special functions to play the audio tracks. In this example, SF6, SF7 and SF8 are used.
Start Up Checks
When the model is selected, startup checks are performed. The start up settings are set on the Model Setup screen under the Preflight Checks parameters.
Set the startup check of switch SE to check for the middle position. This is the normal aileron position.
Set the startup check of pot S1 to 100%. This is the maximum reflex and flaperon setting.