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KK2.0 throttle limits

#1
Thanks for taking the time to read this. I want to confirm my thinking. The throttle limits on the KK2.0. If I set the limit to say, 70%, the KK2 or ESCs will limit the motors output to 70% of its maxim power, is that right?
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#2
Throttle limit on the radio? Don't do it there. Look instead at stick scaling on the board. Stick scaling will take the throttle input and give you a percentage output -- 100% throttle from the radio with 70% scaling => 70% output to the motors.

The reason this is better is the throttle limit reduces range the radio can command, whereas doing it in stick scaling the radio sends the full range (and you keep full resolution in control) and the board interprets your wishes through it's setup -- the clearer your wishes are, the better the board can do it's job.

To answer your question directly . . . no. stick scaling won't hard limit the ESCs either -- The problem is in the mixing. The instantaneous speed for any one motor depends on a lot of factors, not just the master throttle output. It also depends on the any roll/pitch/yaw command which will increase or decrease the motors speed above the master throttle to accomplish the maneuver. If that's not enough, the correction loops (gyro's P&I loops and accelerometer's P loop) can add even more throttle on top of this. The correction loops can be limited with their P & I "Limits" setting, but this is kinda hard to convert to a "limit of 50 means X points of throttle".

If you're worried about overstressing the motors and ESCs (I'm assuming it's why you're using a "magic number" of x%), it'll be hard to predict -- better to test it out. Fly briefly with a 70% scaling and see if the motors or ESC get hot. Not warm. Hot. It's the heat that kills these guys, so a brief small burst above the limit won't break it.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#5
Gotcha Mike.

Throttle actually won't be the channel that can get away from you, but a modest amount of stick scaling on the board (70-80) will help learning the feel of holding altitude on hover.

I'd also recommend strongly scaling back the pitch/roll (30-50) -- those will get away from you if you're not careful.

If rudder is a little too snappy, it won't hurt there too, but it's usually not as bad.

As you get more comfortable, slowly move up these scalings until you feel you've got full control and as much response as you car to have.

Good luck with it Mike! Let us know how it's treating you :)
 

xuzme720

Dedicated foam bender
Mentor
#6
Also, one thing that might help is that you are not anywhere near full power when you are hovering. It sounds like you are worried that you are too close to the limits of your motors or ESC's...? If so, and you don't have a wattmeter to test actual current draw, hover for a minute or two, land and immediately check the heat of the motor cans and the ESC's. If your response to grabbing a motor can or ESC is to yank away newly blistered fingertips while yelling obscenities, then you will probably want to do some shopping for other motor's or ESC's, depending on what caused the burning sensation. If, on the other hand, you can hold your fingers to them for a few seconds without blistering, you should be fine with running what you have now. Once you learn more and start doing more serious maneuvering, you'll want to perform the heat check again to be sure you are still not over-stressing anything.
 

4props

Junior Member
#7
When I was learning to fly I set the stick scaling to 30% and on the radio dual rates of about 50% with a 20% expo. This made it quite docile and not scary. I spent days flying away from me and then back again (going backwards), then I would practice moving left and right. Then I stood in a large field and flew away, yawed to face me and then slowly flew towards me. Then turn and back again. All very boring stuff but the core needed to learn to fly a quad.

The other thing I found helped was lights, white and red (but only facing in one direction rather than wrapped around the arms, if it was wrapped it all blurred and didn't help). I would then fly early evening, the lights helped instil confidence with orientation. This eventually rubbed off into day time flying. I still have "Oh bugger" moments but they are few and far between :)

I now have the stick scaling up at 100 ish and this is enough for flips etc... The only thing left dialled in is the expo.

Good luck
 
#8
OK.set the stick scaling to 30%on kk2, and on the radio dual rates of about 20% expo, 50% wait . now it will not arme...


Thinking about buying some hydrogen and fill two garbage bags with it and tie to the tri and load the 12 gage for target practice, at least it would go out with a boom……..
 
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4props

Junior Member
#9
OK.set the stick scaling to 30%on kk2, and on the radio dual rates of about 20% expo, 50% wait . now it will not arme...
Make sure dual rates are not set when arming. To be honest I never worried about yaw with dual rates, I preferred 100%. Pitch and roll were another matter :)

You will get there!