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Adjusting the throttle on my Graupner mx20 for more gradual movements

Discussion in 'Cinestar 8' started by David N Atkisson, Jan 15, 2013.

  1. David N Atkisson

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    I have noticed that when I am flying my CS8 that my throttle control feels way to sensitive. In order to hover I am having to constantly having to make very minute adjustments to keep the CS8 at the elevation I choose. It's always possible to get it where I want and then turn on Altitude Hold but I would like to be able to hold stable with out always having to resort to Alt Hold. Is there a way to adjust the throttle so I don't have to make such minuscule adjustments all the time. I was thinking there has to be a setting on the Graupner to help me with this. Also how do experienced pilots do gradual ascends and descends, It looks better on the video if I slow the ascend and descends down a little but I find it hard to be consistent when I fly. It may be I just need to keep practicing. I can accept that but if any of you experienced pilots have any tips then I would love to listen and learn from you experience.
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    David:
    The things I did were:

    1. Learn to fly with fingers and thumbs, not just thumbs on the top.
    2. Treat the stick tips like a delicate part of anatomy....don't go white knuckle grip on them.
    3. Make sure that the spring resistance on the throttle is set low -- you can adjust that on the MX-20 (I presume you removed the centering spring on the throttle? If not, do that too!) See the manual page 18, 19 for how to do all of this.
    4. Adjust the sticks so they are at they're maximum length -- then you have maximum leverage, but it significantly reduces the sensitivity. (See the manual page 17 for this).
    5. Check out the Channel 1 curve on page 116 et seq. in the manual. I've not done this because I found the above to be sufficient.

    Hope this helps.
    Andy
     
  3. Chris Babiana

    Chris Babiana Member

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    Possibly change "dynamic stability" in MK Tools. Watch this video


    And if you want to soften up the stick inputs so the copter doesn't react so quickly, change nick/roll P & D. I did this and really like the softer flights.

    Chris.
     
  4. Dave King

    Dave King Well-Known Member

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    HI David

    Like yourself, I am still learning my way around my copter. While I am inexperienced, I have done a ton of research on these copters and I believe its a combination of different things. For one thing I truly believe that no copters are the same, so the settings are not optmal for everyone. I think they can be close from one to another provided they are exactly the same. I think adjusting the PID and stick settings are for a more experienced flyer and not for a beginner though. Stick inputs are important like Chris mentioned as well, but I would hesitate to put slower values in because of you are inexperienced and your not used to how your copter reacts you may not react fast enough. Over reacting though can also be bad but I would stay with the stock settings until you get other thngs in place first. I believe the balance of the copter also can play a large role in how your copter responds. Being a drag racer for 20 years I kind of compare a Cinestar 8 to a race car. If you never drove before its hard to jump into a 600 horsepower car and learn to drive. Thats the way I feel for me at least how it is learning to fly a rotorcopter with a C8.

    One recommendation I think you should give serious consideration too is for you is to purchase thet aerosim software. It's really worth $100, probably the best $100 I spent on the copter. It really simulates a 8 blade octocopter really well and the training exercises are outstanding. I'm still not done with the training. It starts you out working the gas and then the controls. It gives you lots of training exercises that I think you will find worth the time. Right now I'm trying to do the exercises for hovering in a circle with boom #1 at the 9 oclock position. I think once you get flight time in you that the sensitivity of the sticks wont be so much an issue.

    Hope this helps.
     
  5. Gary Haynes

    Gary Haynes Administrator
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    I did the stick adjustment and was pretty happy with the results. Roll P: 4 Roll D: 6 Yaw P: 4
     
  6. Sedric "Zellevision" Sari

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    And expo, I have some expo and hover point, and that helps alot.
     
  7. mathewfarrell

    mathewfarrell Member

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    He Sedric. What do you mean by hover point? and I presume by Expo you mean you've changed the exponential curve of your stick inputs on the transmitter?
     
  8. Steve Maller

    Steve Maller UAV Grief Counselor

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    3 year old thread exhumed! @Matthew, I'm not sure you're going to get an answer from Sedric.
     
  9. mathewfarrell

    mathewfarrell Member

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    Perhaps not, it is a bid old. Anyone else is welcome to answer if they think they know...
     
  10. Steve Maller

    Steve Maller UAV Grief Counselor

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    Can you be more specific in your question?
     
  11. mathewfarrell

    mathewfarrell Member

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    Sure. The original question is about softening up throttle response. There are some good responses which talk about adjusting the P&D settings for the Stick response. Sedric also talked about Hover Point and adding some Expo. I'm trying to figure out what he meant by these, especially since I'm in the same boat at David, the OP and want a less responsive throttle control
     
  12. Steve Maller

    Steve Maller UAV Grief Counselor

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    Oh, sorry, I'll have to beg off. Not using the mx20 anymore.
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Check the Manual and look for "Channel 1 Curve." It allows you to adjust the effective throttle the transmitter sends with respect to the physical stick position. On my PDF it's on page 116 -- remember the ALTA is a "winged model." (Yeah, I know, it should be a helicopter, but it lacks the swash plate etc.)

    You can therefore adjust so that, in the middle range of the throttle, the output values are relatively small -- thus desensitizing the throttle.

    This is effectively the same as "Expo" (see page 108), but applied to the throttle channel.

    The key mental model to have in mind is that you can "map" how the physical placement of a control stick causes a change in the transmitter's signal for that radio channel -- so you are adjusting the stick's physical movement to the "effective" change in what the transmitter actually sends to the receiver.

    Hope that helps.
    Andy
     
  14. mathewfarrell

    mathewfarrell Member

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    Thanks Steve and Andy. Since asking, I did discover the Channel 1 curve, as well as the expo settings for the other channels. I wasn't sure if this was what Sedric meant or not. I'll have a play with the curve and see if I can improve things.
    From what I've seen messing about with expo, if you soften the centre response of the curves you loose the extremities. I think I've seen you talking about the danger of this elsewhere, Andy, whereby you can no longer start/stop engines since you don't have full rudder range.

    Besides Channel 1 curve, does anyone know another way to apply 'expo' without interfering with the extremities? I know this can be accomplished with the PID settings in MK tool (as described above), but I'm looking for a way to do this via a dual-rate switch on the transmitter. I have an expo dual rate switch set up, but the lack of extremities makes it too slow to shut down the engines in a crash (so I've heard...)
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Matthew:
    There really is no way to soften the response curve of the throttle (or any of the other sticks), without altering what happens at the extremities, I'm afraid. And, as you say, in extreme cases you may lose the ability to deflect the sticks far enough to effect the "gesture based commands" like motor start/stop.

    One thing I do is make sure that the top of the control sticks is unscrewed and then locked so the the sticks are as long as possible -- this creates the effective of lower sensitivity because you have to move the tip of the stick further to achieve a given angular deflection.

    Have you experimented with that?

    Andy
     
  16. mathewfarrell

    mathewfarrell Member

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    Thanks Andy, I appreciated the thoughts.

    I haven't experimented with the stick length. In fact, I have the sticks as short as possible so I get a good thumb contact on sticks and have other controls (such as side paddles) in comfortable operating reach of my fingers.

    I guess other ways to achieve similar these things are lower pitched props, heavier payload, etc. Many factors to experiment with...
     
  17. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Well, there is an argument for longer sticks and using the "thumb/forefinger pinch" method of holding the sticks. That increased leverage certainly makes a big difference and would solve the problem you're trying to solve -- reduced sensitivity across the entire range of motion. Just a thought! :)

    Andy.
     
  18. mathewfarrell

    mathewfarrell Member

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    Yes, I'll certainly be giving it a go. I accidentally sent my last reply before saying as much. Cheers
     

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