On the ground with motor disconnected, check that the elevator compensates in the correct direction
(down). If not, invert the weight to minus 5. (i.e., just highlight the number and press both the RIGHT
and LEFT keys simultaneously).
Leave offset at the default zero. We don’t want to shift the point where the mix operates.
Next to edit is the switch field, where we select GEA to serve as the throttle switch.
The 'multpx' field determines how mixes interact. By default it is set to 'add', which in our case is
what we want to do, i.e., add this small elevator servo movement to whatever inputs come from the
elevator stick.
Those are the standard mix elements. Now for something a little more sophisticated.
Consider the behavior of the model when you apply throttle. Even with the motor switched to full
throttle, the model will take time to accelerate and make the wings generate much extra lift. So we
need to delay the application of lift compensation (down elevator), let’s say by one second. So we
enter 1 into the 'delay up' field. 'Up' refers to the increasing input to the motor, not to elevator
movement. But the model will not achieve full speed until sometime later, say 3.5 seconds. To apply
the elevator correction gradually, therefore, we enter 3.5 in the 'slow up' field. The result is that when
the throttle switch is activated, the motor starts immediately, but the down elevator lift compensation
does not start for 1 second, and then takes 3.5 seconds for full deployment.
Now consider what happens at the top of the climb. The throttle switch instantly cuts the power. The
model will be going fast so down elevator is still required to prevent the model from pitching
upwards. We need to delay the return of the elevator to zero by let’s say 2 seconds to allow the
model to slow down. Enter 2.0 in the ‘delay down’ field. To avoid an abrupt change in the aircraft’s
attitude we can also slow the elevator movement so it takes say 1 second to return to neutral for the
glide. Insert 1.0 in the 'slow down' field.
Here’s what the mix screen looks like with these changes:
We now have a mix line in the elevator channel, using the throttle switch as the source, which gives
5% down to compensate for the extra lift generated under power. We have a 1 second delay before
the elevator compensation starts and a 3.5 second period for it to reach full deployment. At throttle
off, we have a delay of 2 seconds while the model slows and then a 1 second period during which
the elevator resumes the neutral position for the glide.
Now we test the model by flying it to see if the settings are correct and change them as necessary to
give a straight climb trajectory and smooth transition to the glide.
Ersky9x Explained – version 1
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