Elevator-Aileron-Rudder Trim Percentage Question
I'm still working off the digital gauge .xml template I've borrowed from someone else, in an effort to make some new gauges for myself.
I'm stuck at the ELV, AIL, and RUD Trim % commands.
I got Elevator Trim Percentage to work using the command line:
(A:Elevator Trim PCT, percentage))%!2d!
However when I tried to apply the same formula for the Aileron & Rudder... using:
(A:Aileron Trim PCT, percentage))%!2d! & (A:Rudder Trim PCT, percentage))%!2d! respectively, the last two wouldn't work. They zeroed out.
(Note that this is just a section of the command line...all other things in the rest of the .xml text are equal to that of the one for Elevator Trim except of course the words Aileron, and Rudder).
I should point out that the plane I'm doing this for is the default b737_400... a safe litmus test to do all this on. Note that on that plane's default panel are switches for all three trim scenarios... so it's not like any of them are missing on the plane.
In the Parameters page of the SDK, it showed "Elevator (or Aileron) (or Rudder) Trim PCT" as valid command lines.
So my question is of the three, why did only the Elevator one work? Has anyone else had a problem with this in their experiences making gauges and manipulating this data?
I did find a work around, but I don't know if it's an accurate representation of "percentage of trim" or not:
For the aileron trim and the rudder trim only, I decided to use the command "Aileron Trim" and "Rudder Trim", which measures the amount of deflection in the surface being trimmed in units of degrees.
So using those parameters in the command line with the unit "degree" I was able to get those gauges to work. However, I don't want the info in degrees of play (which turned out to be +/- 10° for both-- for the aircraft I'm testing this with. I want it in percentage of play (+/- 100%).
So I had the idea of telling it to take the degrees, divide by 10 and then multiply by 100 to give me the degrees of trim play as a percentage instead of an angle. And I might add that it does work, and I get *FULL* aileron & rudder trim values of -100% to the left and +100% to the right... just like I wanted.
But... is the rate of travel in degrees and percent directly linear to one another?
Can I assume that if 10° of 10° total play in one direction is 100%, that 5° is 50%, 2.5° is 25%, etc.? Or is that relationship not that clean-cut, even though I tweaked the measurement and seemed to make it work that way?
My whole reason for doing this is that sometimes when I trim aircraft while I fly, I don't always know where the exact center point of the trim wheel is when I want to return it to neutral... so I thought this gauge might help me... even if it is a bit of a "cheat". I suppose if all I really care about is 0=center or netural... then it really doesn't matter if it's % or degrees, so long as they both zero out as a percentage or a degree.
Last edited by b3burner; 06-24-2012 at 07:34 PM.
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