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Archive for January, 2017
Posted by Miami Mike | Jan 15, 2017 @ 12:11 PM | 17,684 Views
Adding V-Tail Differential to Mike Shellim's F3J/TD Setup, Version 2 or 3

Last updated on January 16, 2017.

If your V-tail glider changes pitch when you apply left or right rudder, the cure is to add V-tail differential. Here's a mod for Mike Shellim's F3J/TD Setup for the Taranis, Version 2 or 3, that not only adds that capability but also provides convenient in-flight adjustment!

There are other radio brands that have V-tail differential capability but I'm not aware of any that provide a way to adjust it in flight. The usual method is to try a setting, land, tweak the setting, launch, and try again. This modification features a way to avoid having to make several test flights and landings. Instead, you'll be able to adjust differential in flight with the throttle trim switch (TrmT).

To add this feature you'll need to free up a global variable (specifically GV6) that's currently used to set reverse differential, which is a setting that applies when both ailerons are raised during Landing mode (known as "crow"). After you've found the best V-tail differential setting you'll have a choice of several options, including restoring GV6 to its original use.
  • Free global variable GV6
    The first step is to free up GV6. Currently it's read by the two aileron channels, CH01 and CH02, and can have any value from 0% to 100%. Personally, a reverse differential setting of 100% seems fine to me, and the setting won't even matter unless you have crow enabled in
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Posted by Miami Mike | Jan 02, 2017 @ 11:33 AM | 18,049 Views
Here are some examples of experiments you can do to determine the order in which data is processed by the OpenTX Inputs and Mixes pages:

Experimental Testing of OpenTX Data Flow
  • Set up a new model memory for testing.
    1. Create a single input on the Inputs page.
      [I1] Ail Weight(+100%)
    2. Create a single mix on the Mixes page.
      [I1]Ail Weight (+100%)
    3. On the Outputs page, ensure that all channels are set to the defaults of
      • Subtrim = 0.0%
      • Min = -100%
      • Max = +100%
      • Direction = ---
      • Curve = ---
    4. Test the basic setup.
      • Start Companion simulator and move the aileron stick left and right. Observe that the CH01 indicator moves left and right from -100% to +100%.
      • Exit the simulator.
    5. Create a special test curve.
      • On the Curves page, create a 7-level, 12-point, stair-step curve.
        • Select Curve 1.
        • Select 12 points.
        • Select Custom X.
        • Enter these values:

  • You are now set up to perform experiments to determine the order in which data are processed in the Inputs and Mixes pages by OpenTX.
  • Testing the Data Flow in Mixes
    1. Experiment #1: In Mixes, which is processed first, Weight or Curve?
      • On the Mixes page, copy the mix from CH01 to CH02.
      • Add Curve 1 to the CH02 mix:
        CH02 [I1]Ail Weight(+100%) Curve(1)
      • Start Companion simulator and move the aileron stick left and right. Observe how the CH02 indicator steps through a range of 7 discrete levels as it moves left and right from -100% to +100%.
      • Exit the simulator.
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