as the heading sais, i would like to know if the initial motor start up speed can be reduced once armed ?

ivetried softstart with th esc but still starts motors very fast, i would like them to be as slow as possible when giving throttle. any ideas? 

mikrokopter for example have the props spinup as you arm, really niceand slow, can we do this if needed?

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Yes, I can do this.

I've got a couple things I've been working on floating around already, waiting to be tested by other people, which is happening very slowly.  So I am going to wait until I have a quad flying to continue working on some of this stuff.  It's frustrating to be coding but not being able to test it myself, because I don't have any feedback on what works or doesn't.

But just so I know, what is the reason or desire for this feature?

Hi again. Reason is mainly because the motors feel to spin up to fast, and more often than not prop spins the wrong way, I then need to drop throttle wait for them to stop and try again, if motors start up slow they always tend to start in the correct direction. When I say they turn the wrong way, they don't really turn, they just kinda get 'stuck', I believe this is very normal as it does it with every build I've done with many different motors/escs

Could you/anyone point me to the code where I can just drop the startup speed / min throttle ??

Motors getting stuck or jerking when starting usually means the ESC timing is wrong (brushless motor design, makes it hard starting from standstill), or a bad connection on one of the motor phase wires. Are you running standard firmwares? Most ESC's like the Turnigy brand etc. have slow, medium fast timing and some high-end ones can be adjusted in actual timing degrees. Try changing that. The Turnigy TY-P1 ESC's I am using now had a hard time starting a 15" prop when using a 4S battery and original firmware. But after flashing the SimonK firmware they started just fine.

I've re-calibrated all ESCs to LOW timing as I've read before that for low KV motors low is better, correct ? I'm using T-Motor 2814-11 which are 710kv, I would asume LOW timing would be best. The seem to spin up more gently now.

I would still LOVE to know where I can adjust start up speed, or even have motors already spin up when armed like MK. Anyone ?

Compile with arduino and put


in apm_conf.h

Standard is 200 (20% throttle) in arducopter 2.6.  I have mine always at 100 (10% throttle), you might try even lower values.




I asume that when this value is on 0 it will startup motors as I arm ?

This will affect the flight control, though won't it?  Duran, I wouldn't use 0, because I believe what that means is if you drop the stick to the bottom, the motors will full stop, and your copter will drop.  Been there, done that with my helicopter.  You don't want that.

Duran, if I give you a piece of code to patch in, do you think you can compile it and test?

Regardless of all the other pros/cons of this request, I think it's a good idea for safety if the props start a little slower.  If you have an unintentional spin-up, it gives a person just a little time to get out of the way. I'm thinking maybe a 3-5 second spin-up?

yeah sure, pass on the code I can give it a go, I've not lowered the #define MINIMUM_THROTTLE to 20, and seems nice and slow startup, thanks. Did try 0, but had no effect I could see.

What code do you want me to try ?

I still cant get the motors to spin up as soon as I arm, any advice ??


# define CUT_MOTORS 0 // do we cut the motors with no throttle?

in apm_config.h.

Then motors will start to spin at min_throttle as soon as you arm and will only stop when you disarm.

Be carefull with it though !

Lowering the min_throttle will indeed influence the stick hoover point a bit and throttle control might be a little coarser.  

Also, if you're gonna do this, make sure that your motors still have enough power at MIN_THROTTLE to keep from stalling in the air (eg with fast descends).  If the stall, they won't restart unless you disarm-arm and your copter will probably crash before you can do that.

Have a look through config.h file in the source code if you wanna know all the possible options you can configure :-)

I'm confused here by what you're saying.  You want them to spin up as soon as you arm?  I thought it was already doing that, and you wanted to make it spin up slowly?

I would like the motors to start spinning as soon as you ARM, like mikrokopter, they sipn up as you arm, currently deafualt for Arducopter is that when you arm your motors, you need to push throttle to 20% (200) before they spin up, I would like to play around with them starting up as soon you arm.

Thanks u4eake, will try that.

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