adjusting pitch on TREX 450 PRO with dx8

[sendittokeith]

edit: This is a 3GX flybarless heli

so i am setting up my heli again to try to get everything as close to 100% perfect as possible. i am a little confused about setting the pitch though, let me explain...

1.) I got a perfectly level swash plate (used tool to verify) when throttle is at 0, 50, 100
2.) I got the pitch while at mid stick almost perfect zero (is .1 off) using only mechanical adjustments and measured with a digital pitch gauage - its within .1 all the way around

Now, i am trying to set my pitch +/- 12 degrees and this is where i am a little confused...

so (for example) my positive pitch measures 13.2 while my negative pitch measures 22.6 -- if however i adjust the settings in the SWASH PLATE menu and set the negative to 12, then the positive becomes something like 7.2

thus, i am not sure what i should be adjusting to get perfect +/- 12 -- endpoints?? could someone please tell me how i get a perfect pitch on both pos/neg.

thanks so much..

[bstanley72]

Do you have your servo arms at 90 degrees when you are at mid stick? Most likely your problem is you have your servo to swash links either too long or too short.

[sendittokeith]

yes, i put the servo arms at 90 degress at mid stick, i did however have to adjust sub trim in order to accomplish this.

so if i have more positive than negative pitch, do i shorten or lengthen?

.. and so your saying i shouldnt need to adjust travel or anything else to have perfect pitch?

[positive charge]

I have been very challenged with this helicopter myself, I pondered for a long time when I had different pitches positive and negative. I set mine at mid stick in the dir mode and adjusted the swash pitch menu until I got the right pitch, I have 8 degrees both positive and negative now plus or minus .003. what are your numbers for the swash mix mine are +63 +63 and +35. still got some more inspections and adjustment before it fires up but well on my way.

[bstanley72]

You didn't mention that it was flybarless, if not are you using a flybar lock? If the flybar is moving around while you're changing pitch you could get some weird numbers like you're posting.

[sendittokeith]

@Positive Charge
I am starting over from scratch so im not sure what my settings were at :-( Thank you for sharing yours, i'll post mine when my setup is complete

[sendittokeith]

Originally Posted by bstanley72

You didn't mention that it was flybarless, if not are you using a flybar lock? If the flybar is moving around while you're changing pitch you could get some weird numbers like you're posting.

Oh good point, its the 3GX flybarless - i'll update my post also

[bstanley72]

Where you are adjusting the swash plate menu? Are you doing this in the radio? I’m not familiar with the 3GX but I believe with all FBL controllers (definitely with the Skookum that I use) you set your servo type to 1 servo in the radio and then will do your swash plate adjustments in the FBL controller software.

Here are a couple of other things to consider:

Do you have a linear pitch curve (0-100) in your radio? Again I’m not familiar with the 3GX; does it have any curves that you program into it? Or some way that limits the travel of the swash plate?

When you get to the ends of the pitch range is the swash binding on the frame (negative pitch) or washout block (positive pitch)? If not then your links aren’t the problem.

I’m guessing you have something set wrong in the software or you don’t have a linear curve in your radio.