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Swash not level bottom stick and top stick. Any ideas.

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  • #1

    Swash not level bottom stick and top stick. Any ideas.

    I have TRex 700 DFC HV with 3GX
    I have set the swash level at mid stick but it is not level at bottom stick and top stick.
    The Aileron and Pitch servos travel more at bottom stick than the elevator.
    The elevator travels more at top stock.

    That seems to suggest that the centre points of each servo are different.

    I have subtrim set on all of them to get swash level at centre stick.

    Aileron +86
    Pitch -36
    Elevator +28

    Do I adjust end points to correct this, though setup says don't adjust end points.

    First time I have ever tried setup using a swash leveller, usually do by eye and blade pitch and always at centre, never checked at top and bottom before.
    Never seemed too important on my small helis, but now I can see it on the 700.
    TRex 500 FBL DFC VBar Pro Blueline, Standard Align Setup.
    TRex 500 Pro DFC 3GX, Standard Align Setup
    mCPX
    Phoenix
    Futaba 10C
    Tags: None
  • #2
    In general (I use SK not 3GX, so I don't know your specifics):

    All the servo adjustments are made on the FBL controller;

    Adjust servo sub-trim &/or link length to get zero pitch & level at mid-stick; [Servo arms should ideally be perpendicular to links.]

    Adjust servo travels &/or swash mix to get max/min collective pitch & level at max/min collective input.

    [Then set cyclic via swash mix.]

    I like these www.soko-heli-tools.com (and his set-up guide is good, IIRC).
    Last edited by scallybert; 10-01-2013, 01:31 PM.
    Yes, it's th@ tw@ Scallyb@...

    Comment

    • #3
      Oh yeah, +86 seems unhealthily high.
      Yes, it's th@ tw@ Scallyb@...

      Comment

      • #4
        Thought the same but still get quite a high value if I move the servo arm around to next notches.

        I have set the subtrim to zero on the 3 cyclic servos and watched the travels.
        Definitely different on each servo.
        Probably the servos are not very accurate but I would have thought better than this the price they are.

        Think I will do the full setup and see what it's like then as the servos are travel full extent at the moment, probably 25 deg pitch.

        If I watch the servo rods as the servos travel from top to bottom they travel in an arc as expected but the aileron one is a straighter travel than the pitch.
        Maybe something slightly out in arm length and servo ball squareness to the arm.


        Originally posted by scallybert View Post
        Oh yeah, +86 seems unhealthily high.
        TRex 500 FBL DFC VBar Pro Blueline, Standard Align Setup.
        TRex 500 Pro DFC 3GX, Standard Align Setup
        mCPX
        Phoenix
        Futaba 10C

        Comment

        • #5
          The Align 3GX instructions says do not adjust end points.

          That device looks nice but just spent out on RC Logger 2. Not using it yet, just standard swash leveler and noticed the travel problems.
          Pity the servos are not programmable, would solve problem.

          Originally posted by scallybert View Post
          In general (I use SK not 3GX, so I don't know your specifics):

          All the servo adjustments are made on the FBL controller;

          Adjust servo sub-trim &/or link length to get zero pitch & level at mid-stick; [Servo arms should ideally be perpendicular to links.]

          Adjust servo travels &/or swash mix to get max/min collective pitch & level at max/min collective input.

          [Then set cyclic via swash mix.]

          I like these www.soko-heli-tools.com (and his set-up guide is good, IIRC).
          TRex 500 FBL DFC VBar Pro Blueline, Standard Align Setup.
          TRex 500 Pro DFC 3GX, Standard Align Setup
          mCPX
          Phoenix
          Futaba 10C

          Comment

          • #6
            I had the same problem with my 700 v2 with 3gx.
            I had to ignore the manual and reduce my elevator travel down to 91% on my dx8 to get it as close as possible. I had no choice and now flies not perfect but good enough. I still get a slight back drift when idle up just below hover. My mid stick in DIR mode the swash is level and slight over shoot top and bottom. Outside DIR mode its slightly more, say 1.2mm off at top and bottom stick.

            It could well be the servos not matching the travels or the mechanical parts not precision enough as Ive doubled and tripled check all my links are measures exactly as per manual!

            Comment

            • #7
              If your using disc type servo horns, you can improve lots on those numbers of subtrim, you only need to worry @ centre stick and leave endpoints @ 100% or will confuse 3gx. Coolice will tell you that I believe shortly.
              Santander Factory Team

              Proud wearer of 5 x EGS

              Comment

              • #8
                Take a look at the "Freddy Can Fly" 3GX setup videos - his 4-part vids go through this setup really well. Off the top of my head, I think the swash levelling bit is in video 2 or 3.

                T

                Align 3gx full setup video 1 (freddy can fly) - YouTube
                Align 3gx full setup video 2 (freddy can fly) - YouTube
                Align 3gx full setup video 3 (freddy can fly) - YouTube
                Align 3gx full setup video 4 (freddy can fly) - YouTube

                ... and yes, +86 is way too much subtrim.
                Tom
                sigpic Synergy E7SE - Kontronic Helijive 120+ ESC, vBar Neo
                SAB Goblin 630 Competition                 - Castle Edge 120HV, vBar Neo
                Blade 700X - Castle Edge 160HV ESC, Mini vBar
                Logo 550SXv2 - Castle 130LV ESC, vBar Neo
                .... and a Gaui X3
                Spektrum DX8 ; Mikado VBC ; RealFlight 7 & neXt sims                 ... and two EGS'



                Comment

                • #9
                  Got the subtrim reduced a little and just carried on.
                  4 flights Friday and a dream.
                  Sensitive to C of G but found best battery position and fine after that.
                  4 minutes moderate sport flying on 3500 Optipower and showed signs of batteries sagging.
                  2 more flights Sunday and great.

                  The 3GX with V3 firmware is a really great flybarless controller now, it fly's and handles beautifully.
                  No moans on that.

                  Added 30% expo and nothing else to do.
                  Ordered some 5000mAh 40C Turnigy Blue Lipo's and should be comfortable 6 minutes for my style of flying.

                  Going to see Coolice as soon as this cold snap is over for a bit of fine tuning help with the 3GX.

                  Not sure if there is a whine from the tail or not. Not heard a large electric close up before.
                  Frightened by the reports of tail failures so ordered the new black tail drive gears and some Rail Tail Blades to see if any change in the noise.

                  Anyone put off by the 3GX then don't be, it is now a very nice controller.
                  Great on my 700 DFC and 500 DFC.
                  TRex 500 FBL DFC VBar Pro Blueline, Standard Align Setup.
                  TRex 500 Pro DFC 3GX, Standard Align Setup
                  mCPX
                  Phoenix
                  Futaba 10C

                  Comment

                  • #10
                    I had the same issues with my F3C - at the top and bottom the swash was not level, not by a lot but it was off. I used the swash mix menu on my radio. Finless Bob did a great video with some fabulous tips over at helifreaks that covers this subject in great, easy to follow detail. Have a look here Heli Skills and Setup 101 - LOOK here first! - HeliFreak
                    Everyone is entitled to my opinion!
                    Trex 7(8)00 F3C, 600 ESP, 550E V2

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