Tutorials : Automatic rate switching for aerobatics

Harry Curzon 3 August 2002, addendum by Sam Johnson 7 March 2005

Pattern power aerobatics use very soft control responses. This means that when you need big movement for flicks/spins you have to switch rates, which is not good during an avalanche or coming out of an inverted flat spin at low altitude.

The 4000 can be made to recognise the need for high rates by assuming that full, or almost full, rudder travel means that high elevator rate is required.

We start by using two type 'C' switches on the rudder, one for right rudder and one for left rudder. Trigger points are say 95% control stick movement. Now go to the logical (type 'L') switches and create an OR switch with the 'C' switches as inputs. Now whenever the rudder stick passes 95%, this will trigger the relevant C switch switch and hence the L switch.

The elevator rate switch can now be assigned to the logical switch, use low rate as the normal and high rate whenever the logical switch is triggered.

What this means in flight is that the plane behaves gently but as soon as lots of rudder is input the spins or flicks are superb.

7 March 2005 - Thanks to Sam Johnson's for his step-by-step description

I fly mode 2 so A is Rudder.
Right rudder is positive servo percentage
Left is negative.
Assigned Servomix to Rudder servo. (Servo 3 in my case.)

Assign Switches 
     Control SW: 1
         From Control A
         1pt: Max -95%
     Control SW: 2
         From Control A
         1pt:  Max +95%
     Logical Switches
         Logical switch: Log 1
             Input 1  C1-A  with up arrow.
             "or" is set
             Input 2  C2-A with down arrow
             "or" is set
     Assign Servo
         Servo 3  Rudder
 Menu 1    Adjustments
     Control: Elevator
         Dual Rate - Switch Log 1