How to "dial in" the CS8?

Discussion in 'Cinestar 8' started by Dan Walker, May 18, 2014.

  1. Dan Walker

    Dan Walker Member

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    Good evening everyone!

    I just finished my CS8 Heavy Lift from QC build recently (MK stack). I decided to do a couple test flights in a bare bones configuration (just frame, motors, PDB, ESCs, and Flight Control).

    The first flight was 20 seconds of sheer terror. Barely got her back on the ground without crashing.. but managed.
    The craft kept wobbling all over the place. My thought was that without a payload the craft was overpowered and top-heavy, as the battery mounts to the top. So I zip-tied a 10lb bar-bell weight to the bottom center plate.

    The second flight (with the weight) was much more controlled and lasted about 2 minutes. It was a fight to keep it hovering in one spot though. If I let the pitch/roll stick center itself the craft wanted to pitch forward at a rather alarming rate.

    As I said, there's nothing but the bare bones on it right now. Everything is centered. I tested the balance by placing a finger under opposite booms - everything looks pretty well balanced.

    So I'm guessing this pitch issue can be corrected by adjusting the pitch trim on the Tx (MC-32). But I'm concerned that this is just addressing a symptom and not the cause. All axis' trim are set to 0 (centered). Should I be looking for a cause that is unrelated to trim?

    Thanks everyone!
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Dan:
    Ah, yes, one of those flights during which you discover adrenalin is brown. :rolleyes: Been there. Done that. My first Cinestar flight was "colorful."

    Have you:
    1. Calibrated the ACC with the flight control board completely level?
    2. Calibrated the compass?
    3. Verified with MK Tool that you have Parameter Set 3 selected (look at the bottom of the MK Tool screen to the right of the exclamation mark in the red triangle -- you should see 3 there).
    4. Made sure that all of the motors are completely level, turning the correct way, and you have the props on the right way up.

    Also, what's your flight experience to date -- have you put any time in on a simulator like AeroSIMRC (which does have a Cinestar 8 simulation that is pretty realistic)?

    Andy.
     
  3. Dan Walker

    Dan Walker Member

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    Thanks Andy.

    1. I'll recallibrate the ACC.
    2. My understanding was that the Navi board held the compass. I have not installed the Navi board yet. Based on that assumption I have not performed the compass calibration procedure yet.
    3. I will verify the proper parameter set is loaded.
    4. I made sure all the motor mounts were level before mounting the motors. I will verify that they remained level though.

    One more quick question. I've got the quad2xl-cool PDB/ESC board. For the Flight control mount I placed nylon standoffs into the frame holes, then stacked the vibration dampeners on top of those. I did not want the flight control sitting on the exposed aluminum of the dampeners, so I added shorty nylon standoffs to the top of the dampeners, with the flight control board on those. This puts the flight control board within a few millimeters of the battery plate. Will this close proximity to the battery be an issue?

    -Dan
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hard to say whether the proximity of the FC to the batteries will be an issue, Dan. It's one of those issues where you just have to try it and be prepared to move the FC further away. Can you post an image of the general set up you have?

    Thanks
    Andy.
     

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