Mikrokopter MK Mikrokopter ACC Calibration

[Copterman]

Hello everyone!

I made this new thread to clear out one thing and thats about calibrationg the ACC of the mikrokopter.
The manual says and all the threads i have read about that says that acc needs to be calibrated only once! But in reality that doesn't work. Me and my friends have 4-5 MK controlled octokopters and that doesn't work. What i mean by that: if you calibrate it and do it correctly check that all are level then you can fly that kopter very smooth on that day. But in next day if you go fly the kopter is drifting away. Sometimes to left somethimes to right. That can be fixed if you calibrate the acc again (pushing throttel up and right). Allso if you check MK tool's 3d simulation then the next day if you put kopter to100% level position then the 3d simulation shows that copter is not level again that can be fixed by calibrating the ACC. Is that normal or why do we possibly have that kind of problem? That is really not cool to calibrate it before every flight.

T.

 

[krleas]

Hello everyone!

I made this new thread to clear out one thing and thats about calibrationg the ACC of the mikrokopter.
The manual says and all the threads i have read about that says that acc needs to be calibrated only once! But in reality that doesn't work. Me and my friends have 4-5 MK controlled octokopters and that doesn't work. What i mean by that: if you calibrate it and do it correctly check that all are level then you can fly that kopter very smooth on that day. But in next day if you go fly the kopter is drifting away. Sometimes to left somethimes to right. That can be fixed if you calibrate the acc again (pushing throttel up and right). Allso if you check MK tool's 3d simulation then the next day if you put kopter to100% level position then the 3d simulation shows that copter is not level again that can be fixed by calibrating the ACC. Is that normal or why do we possibly have that kind of problem? That is really not cool to calibrate it before every flight.

T.

As in my experience i never do that. Calibration up and right is only 1 time and helicopter must be perfeclty leved, after that i always do ACC calibration up and left. Mk will always drift a little specialy depende on wind.
just use mikrotrims then to level it.

 

[Bartman]

but trims will mess up the GPS if it's in dynamic mode.

I've seen where I couldn't get the motors on a working, reliable heli to start unless I redid the ACC calibration before the flight. I never could figure out why it was doing it but it would happen from time to time.

If you do the ACC calibration and the heli doesn't fly perfectly, try this;

Put it on a level surface near a place where you can fly it, mark the spot and then do the ACC calibration.
Fly it with the trims centered and note if it is drifting. WInd will make it drift so try to separate what the heli is doing from what the wind is doing.
If it is drifting left (nose away from you), it is because the left side was a little low when the ACC cal. was done. The same logic goes for whichever way it is drifting.
Put the heli back in the spot where the ACC Cal. was done but shim the left side up a little (I use stacks of business cards).
Redo the ACC Cal with the helicopter on the shims and then fly again.
Keep doing this until it's perfect.
After this you shouldn't have to do the ACC Calibration again and it should continue to fly perfect but will always drift a little in wind. This all assumes the FC and the frame were put together properly and that there are no major alignment issues with the build.

Bart

 

[Copterman]

Thank you for answering. I calibrated it and at the moment everything seems to work. Lets see how it goes!
T.

 

[Macsgrafs]

but trims will mess up the GPS if it's in dynamic mode.

I've seen where I couldn't get the motors on a working, reliable heli to start unless I redid the ACC calibration before the flight. I never could figure out why it was doing it but it would happen from time to time.

If you do the ACC calibration and the heli doesn't fly perfectly, try this;

Put it on a level surface near a place where you can fly it, mark the spot and then do the ACC calibration.
Fly it with the trims centered and note if it is drifting. WInd will make it drift so try to separate what the heli is doing from what the wind is doing.
If it is drifting left (nose away from you), it is because the left side was a little low when the ACC cal. was done. The same logic goes for whichever way it is drifting.
Put the heli back in the spot where the ACC Cal. was done but shim the left side up a little (I use stacks of business cards).
Redo the ACC Cal with the helicopter on the shims and then fly again.
Keep doing this until it's perfect.
After this you shouldn't have to do the ACC Calibration again and it should continue to fly perfect but will always drift a little in wind. This all assumes the FC and the frame were put together properly and that there are no major alignment issues with the build.

Bart

Bart, how do you align the motors vertical with the arm?

Ross

 

[Bartman]

Ross, up until now I've used a small scale in between the wires and the motor mount to eyeball the motors to level. When I get my new motor mounts injection molded I intend to add a hairline marker to each piece so, with a straight line penned on the arms, you can just set the arms to the marks in the boom mounts and the motor mounts to the marks on the booms and it will all be in alignment. that probably made no sense but I've just spent two hours in the basement soldering so I'm a little blotto at the moment.

i can try again in the morning.

 

[Macsgrafs]

no worries Bart, I understand how you acheive vertical now

Ross

 

[Bartman]

no worries Bart, I understand how you acheive vertical now

Ross

View attachment 9554

i was able to do this with my old motor mounts. everything's changed though and so i don't know if i can do it with the new ones as i haven't fully assembled any yet. when the mold is made there will be a mark to use for alignment and it will be very simple and accurate.

 

[Macsgrafs]

Thats basically as I done mine, used a straight edge & eyes it up with the centre plates as best as I could

 

[RTRyder]

Here's my method, I cut a piece of G10 the size of the flight controller board drilled to the same mounting hole spacing and I mount it on standoffs above the F/C. Put a small bubble level on it and use old business cards or pieces of thin cardboard under the landing gear to get the bubble level centered, then do the Acc calibration. This assumes that the flight controller is sitting fairly square to the frame of course, and if it isn't you should probably fix that before trying to do the calibration. The closer to parallel the F/C is to the frame the better it will be for overall stability and the easier it will be for the board to keep things level, one of the little MK quirks I've learned over the last few years of flying them. A good way to check the F/C to frame is to use the bubble level as close to the center of the top frame plate as possible to get the frame level, then put the bare G10 on the standoffs the F/C will sit on. Use shims to get the G10 level then install the F/C in its place and do the rest of the setup with the G10 on standoffs above the F/C just to make sure everything has stayed level...

Ken

 

[Macsgrafs]

Great idea Ken, but I'm to lazy to do all that

Ross

 

[ghaynes]

Sorry Ross just can't resist. Your method is what results in straight and level flight looking like your Avatar. ig:

Seriously only kidding.....

But I saw a great idea from a friend today. Take a round bubble level, mount a motor nut to the bottom with epoxy. Make sure as it sets that you keep it leveled. Screw onto the top of the motor shaft and you do eight pretty quick.

 

[Bartman]

that's a good idea Gary. i've tried ken's method as well but since it's all relative with the FC and motors I just get it close then tune with a few flights in between and it's done.

more than one way to skin a cat here, do what makes you feel like you've done a good job and if it flies well (unlike Ross' avatar), you're good to go.

 

[Macsgrafs]

Sorry Ross just can't resist. Your method is what results in straight and level flight looking like your Avatar. ig:

Seriously only kidding.....

But I saw a great idea from a friend today. Take a round bubble level, mount a motor nut to the bottom with epoxy. Make sure as it sets that you keep it leveled. Screw onto the top of the motor shaft and you do eight pretty quick.

My avatar is great its a foamie flying at 01:30 in the morning...I call the 30 second exposure "Lovers"

Your idea seems great to me, might have to try that & see what results I get...trouble is I have a home made trike undercart for my octo (retractable)...yes it goes up ok, but they don't come down...thank god for the mrs being there to catch it as it lands anyway I digress...the trike undercart maens nothing is level to start with!!!! Have to balance the arms on the back of chairs & try the nut & spirit level version as stated above.

Ross

 

[DKTek]

I can't help but think that these variations are due to temp, humidity, etc. Maybe some day, Holger will do something similar to DJI to account for this in the hardware. But, gotta love Holgers firmware updates!