Motors speeding up without throttle input?

[Shroppy]

Firstly thanks to all those that have already helped me over a replacement GPS on this forum.

A little background on my current question.........

I am new to the A2 flight controller and have just completed a new build Y6 Vulcan UAV hexacopter.
After plenty of trial, error and mistakes I had almost got to the stage of the maiden flight.

During my final checks I laid weights on the landing gear to stop it lifting off and noticed some unusual behaviour whilst changing the throttle position.

If I arm the ESCs and slide the throttle to say 50% the motor speed will hold at that level for a few seconds
and then slowly climb to very fast levels.
I can bring the speed back down by lowering the throttle position but the problem repeats after a few more seconds.
So my question BEFORE I fly - Is this normal behaviour for a tethered multitotor with an A2 flight controller
in GPS mode ?

Many thanks,

Nick.

 

[fltundra]

Is this normal behaviour for a tethered multitotor with an A2 flight controller
in GPS mode ?

Yes. Best way to check if motors are right, remove props and switch to manual mode. Check rotating direction correct with each motor, then gently tilt the copter 30 degrees off level with each pair of motors opposite of each other like a seesaw . Motor that's raised should slow down as the other one speeds up. That will tell you if the gyro's are working properly and if motors are plugged into correct outputs.

Edit: Forgot to mention you also can check the RC pitch and roll too in manual mode. IE forward pitch should raise rear motors lower front etc etc.

 

[Shroppy]

Thank you fltundra.

I have just checked all is working as you suggest. And yes, all motors are spinning in the right direction (counter-clockwise
top and clockwise underneath).
And if one side of the aircraft is raised, the raised side motors slow and the opposing motors speed up. So far so good!

But I'm still a little uncertain about the speeding up of all the motors with the throttle at a fixed position.

Is the reason that at 50% throttle the aircraft is 'expecting' to gain altitude and because it can't it tries harder?
To my way of thinking 50% throttle should produce a hover and therefore no motor speed increase.
But I have to confess I don't yet fully understand the way it functions.
I'd very much appreciate your further thoughts.

Nick.

 

[fltundra]

Thank you fltundra.



Is the reason that at 50% throttle the aircraft is 'expecting' to gain altitude and because it can't it tries harder?

Yes

 

[Shroppy]

OK. I'll sleep easy. Or easy-ish!

 

[fltundra]

Post some pics. Others and I might be able to spot potential problems before you maiden.

 

[nivin]

I had the same issues. Once I set the "Throttle Max" parameter from 80 to 1000, I then had to recalibrate the ESC's to recognize the new throttle high/low values. After doing that, the motors would spin up with the throttle inputs. I realize your question is six months old, but it might help someone else. Oracle dba Training in Chennai | Java training in chennai

 

[Shroppy]

I had the same issues. Once I set the "Throttle Max" parameter from 80 to 1000, I then had to recalibrate the ESC's to recognize the new throttle high/low values. After doing that, the motors would spin up with the throttle inputs. I realize your question is six months old, but it might help someone else. Oracle dba Training in Chennai | Java training in chennai

Thank you Nivin.

My post is only eight days old so any help is still great and appreciated.
So far as I understand it my escs can't be calibrated because there is no facilty to do so
- they are Jeti Hicopter 40A Opto escs.

 

[Hoki]

there's some kind of procedure to calibrate the escs like you put your throttle stick up and then plug in the battery and something and something, it shows you on youtube.

 

[Hoki]

I hope I don't get frisky motors