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Need more throttle/thrust!

Posted by Kristian on October 3, 2011 at 10:19am

With Ardupirates code my quad had lots of thrust available to carry camera. It was unstable if giving full thrust, so I had to turn down the thrust to about 75% by adjusting throttle Endpoint(EPA) on my transmitter.

 

With AC2.0.46 my quad just barely manages to lift the camera. I have 100% EPA on transmitter, and have calibrated the ESC's. Is the throttle being reduced by the code to make sure the quad have enough power to handle correctly? Is there any way to change this? I just need a LITTLE more power.. :-)

 

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Replies

  • Nicolas February 27, 2014 at 2:49pm

    hi,

    i build a quad with 470kv and 17 inches prop, running on 4s, alltogether 4 kg.

    i have a throttle issue, on the log i put throttle up but my motors stay at the same rate and i still loose altitude.

    could it be an esc issue, and i have a great difference between thrin and out at hover (60% of throttle on radio).

    i tried calibrating esc one by one without apm.

    i tried putting a higher value on param thr_max but it only increase the thr_in

    i tried tricking apm calibration of my radio by playing with trim.

    i really dont know what is the cause of not taking care of my throttle input up.

    3701672219?profile=original

    2014-02-27 16-52.log

    2014-02-27 16-52.log.gpx

    2014-02-27 16-52.kmz

    • Kristian > Nicolas February 27, 2014 at 3:03pm

      This thread is about a setup from 2011. You should probably start a new thread. there is a new generations hw and sw now...  :)

      • Nicolas > Kristian February 28, 2014 at 6:26am

        you re right, i will start a new thread

  • Bryan Schwartz December 16, 2012 at 11:47am

    So I realize I'm reviving and old dead thread, but after much searching I couldn't find an answer to this problem that suited me. I understand the need for headroom for stabilization, but in my case there was way too much being reserved, even though without the arducopter I can normally hover at about 65% stick I could just barely lift off the ground in stabilization or Acro mode. I initially tried to trick it by trying to set the throttle range on the ESCs so that what the ESCs would think were max stick was actually 2/3rds stick. Long story short that didn't work, but I found something that did. My next step was to calibrate the controller with the mission planner, and only move the stick 2/3rds up when calibrating the throttle. This had the opposite effect that I was trying to achieve, actually lowering the maximum thrust I got at max stick. So counter my intuition I calibrated the throttle movement with more movement than I would possibly have normally by moving the sub-trim full max and stick full max (the low end was more complicated as I needed to keep some room at the bottom for fail-safe but you should be getting the picture). End result: IT WORKED! I now have PLENTY of power to take off and counter a fast decent.

    Does anyone have any insight as to why, during calibration, increasing the total throttle range the Arducopter "sees" increases my maximum available throttle even when after calibration the throttle never comes close to the calibrated maximum?

    Using a Spektrum Dx6i - v2.5 of rcexplorer.se tricopter (10.47 blades, 750kv, total weight with battery ~950g)

  • David Karim December 18, 2011 at 7:03am
    So I never figured out a parameter that helps increase thrust. Maybe there isn't one. But I did figure out my problem. I had at least one weak propeller. I switched out a couple of the regular 10X45 propellers and all of a sudden I am taking off at around 65% throttle. So now I am wondering if there is any good way of knowing how efficiently your props are working. When I look at the blades I changed out, there is nothing I can see that would seem they are bad. I balanced all of them also. Is there a way to test how much air the props are blowing?
  • David Karim December 10, 2011 at 7:02am

    Kristian, did you ever find out what the TRIM_THROTTLE is for? I am having lift issues on my new copter also. I have a standard 3DR frame with the 850 kV motors and 3S Lipos and it gets to a point (at full throttle) where it just barely wants to lift off the ground but doesn't quite make it. I had that TRIM_THROTTLE value at 503 (not sure why since I had never touched it). I changed it to 740 but I didn't see any change in behavior. Isn't there a place where these values are explained?

  • CyberCrash October 4, 2011 at 3:49am

    I am using 4S Lipos. With these you get a lot more power out of your motors.

     

    The only downside: You cannot use the next bigger props  (e.g. you are using 12" instead of 10") with higher voltage. I've seen tests in my Mikrokopter times. Using 4S with 12" props is not as effective as 10"   (e.g. when using Roxxy 2827-34 or some AXI)

     

    Maybe you should switch to 4S.

     

    I am using cheap ebay 4S Lipo: 30C , 3200mAh

     

    I get around 23-26min with my Roxxy 2827-34 and 10x4.7 APC.

     

    My 1.3kg copter has lift off at 50% throttle and there is much more power left in the next 50%.

  • CyberCrash October 3, 2011 at 2:22pm

    You should check your lipo. I had loss of power once and after checking and checking I tried a new lipo and suddenly the power was back.

  • Developer
    Jason Short October 3, 2011 at 10:23am

    The thrust is limited from the Radio at 80% by default to give you the headroom needed for stabilization.

    What is the throttle hover value TRIM_THROTTLE in the planner?

    Jason

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