Arming & throttle issue with 250 Pro

Discussion in 'Walkera Help!' started by whoop, Oct 7, 2017.

  1. whoop
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    whoop New Member

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    Got my 250 PRO (RTF) with the Devo 7 today and I haven't been able to successfully arm and fly it.

    I turned on the controller, connected the battery to the quad but didn't get any clear sign (as I've seen on youtube videos). I tried arming (unlocking) it which started the motors running in idle but after a short while they cut out and I have to re-arm it for the motors to start again. When they're actually running and I'm moving the throttle stick it is sort of either all or nothing, up to 50% nothing happens, after that the motors starts to build of revs quickly for each percentage. Lowering the throttle results in that the motors drop revs quickly and not at the same amount as I'm moving the stick.

    Also if I arm the quad and leave the throttle between 25-50% it will stay in idle, any lower than 25% it will cut out and needs to be re-armed.

    I've also used the controller with FPV Freerider and DLR Simulator without issues. When I tried Mr Drone (from Walkera) I couldn't get the drone started cause the throttle couldn't reach 0% as the lowest level (seen in the simulator settings) was 19%.

    I've tried resetting the controller, applying the settings described in the 250 manual and also cleaning the the 250 itself.

    Not sure if it's the quad or the controller... Anyone have an idea?

    Thanks!
     
  2. bjr981s
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    bjr981s Moderator Staff Member

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    This is normal behaviour.

    You need to apply more than 50% throttle to get it to lift off.

    By not applying > 50% throttle and it still being on the ground it does an auto prop disarm as it assumes you have either just landed or are aborting the takeoff.

    Apply > 50% throttle before it auto disarms.

    Cheers Brian
     
  3. whoop
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    whoop New Member

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    Well this is embarrassing :p I sort of figured it out in the end.... I should say that this is my first experience with a quad so bear with me :D Thanks in any case Brian, much appreciated!

    Having tested it in proper flight I've noticed that it's drifting a bit (forward-left), this was also the case when I did a calibration in the Mr Done simulator. For the drone part I suppose it could be fixed by doing a compass calibration, right? I tried doing a calibration by following the manual but when turning it 360 degrees horizontally the lights doesn't change, I've tried multiple rotations, left/right, but no change. I also tried adjusting the transmitter using the trim buttons but it's not enough.

    I also stumbled upon the 250 (R) manual where it described gyro calibration along with compass calibration, that is however not described in the 250 Pro manual, is that automated in the Pro and thereby not necessary? Just curious.
     
  4. bjr981s
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    bjr981s Moderator Staff Member

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    No compass calibration is not required. Compass is there for GPS mode return to home. It has no other effect / use. Tail hold is accomplished by the IMU gyros and accelerometers. Also compass is also not accurate enough to do a tail hold.

    Do not use the trim buttons. It will effect GPS flight mode. Reset them back to zero.

    What does this mean?

    This is normal on all non GPS flight modes for all drones. They will drift.

    The degree of drift is related to the location of the battery. You must balance the drone with the battery installed every flight. There are location tabs on the main frame for you to hold to assist the balance check. Check the manual.

    The 250(R) has a completely different flight controller. None of the references in the 250(R) manual is relevant to the 250 Pro.

    The gyro on all Walkera models is zero calibrated once the accelerometers show 0 movement after power on. ( that means that if you plug the battery in while you are holding the drone it will not zero the Gyros. It will wait until you place on the ground and stabilises before calibration.)

    The upshot of this is that if you place on non level ground the gyros will be offset. Make sure you only power on, on absolutely level ground.

    Cheers Brian
     
  5. whoop
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    whoop New Member

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    Got it!

    Before flying in the simulator you need to calibrate the transmitter. For example push all the sticks to their outer most position, throttle to max, yaw to max etc so the simulator knows the which stick is which and what position it's in. And after having done that you get a preview of the drones position which, when all sticks are zero, will tilt the drone forward-left and the throttle is 19% even though the stick is at its lowest position.

    It seems like the transmitter is by default sending out a signal which is not totally zero but slightly forward-left. It could certainly be something with the software on the PC but I'm curious what's causing this.
     
  6. bjr981s
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    bjr981s Moderator Staff Member

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    Go to the System menu and do a Sticks calibration.

    Make sure trims are at 0.

    When you start make sure all sticks are in the centre position including the throttle and the Aux 2 knob.

    Cheers
     
  7. whoop
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    whoop New Member

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    Finally got around to test all of the above and it made a change, the drone is more balanced (not drifting that much). Didn't manage to test with the simulator though as I only got the free version which was 60 minutes flight only.

    Anyway, thanks a ton Brian!
     
  8. bjr981s
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    bjr981s Moderator Staff Member

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    You are most welcome. :)
     

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