New Octo, very unstable!

M

Muunk

Member
Hi!

Just got my new Octo (allmost) in the air today.

This is my equipment:

8 x MK3638
8 x Detrum 30A ESC
Wookong M
And a frame from altigator, wich is not at their site yet.

My problem is that it is very unstable, and will tilt to one side or another when I try to get it in the air.

I´ve tried to set the roll and pitch gain from 80 % to 400%, but it seems like there i no improvement at all. I even managed to flip the entire octo on its top, and destroyed a motor,AND the ESC when tested after the crash (luckely nothing happened to the frame or gps sitting on its carbon rod (Its strong!!))
View attachment 2067

I have tried with and without expo, but same problem..

Can anyone tell me what I´m doing wrong?

It must be said, that I can control both RC planes and helicopter normally without problems - the octo in the picture is not mine, but from altigator.
 

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quadcopters

quadcopters

Quadcopters.co.uk Drone Specialists
Are you flying in Atti mode ? with the amber light flashing ?
You should be able to get it dialled in with settings ranging from 80-400 Ball park figures for octos are usually in the late 200 mark .

Geoff
 

M

Muunk

Member
quadcopters said:
Are you flying in Atti mode ? with the amber light flashing ?
You should be able to get it dialled in with settings ranging from 80-400 Ball park figures for octos are usually in the late 200 mark .

Geoff
Click to expand...

Hi!

Yes, I´m "flying" in Atti mode (not that it has been flying yet). The LED is flashing yellow - to times, which I can see in manual meens thats sticks a not centeret. But they are, as I can that in the DJI software.
 


quadcopters

quadcopters

Quadcopters.co.uk Drone Specialists
I would check the obvious things like props on the right way .. I once believe it or not had a prop upside down and was flying and couldnt figure out why it was flying crap , sometimes it can be something so simple.
Geoff
 

Gunter

Gunter

Draganflyer X4
Big beast that is at 1000mm m2m!!

It sounds like as Geoff says, you are flying in manual mode.

Also, make sure that the IMU direction is 100% correct in the assistant. If its set the wrong way round the heli will flip very hard. (ask me, been there!) with the damage you have done, I reckon it could be this one!!

Check motor directions compared to the diagram and props are correctly fitted.

Good luck!


Regards,

Gunter.
Sent from my iPhone using Tapatalk
 

BorisS

BorisS

Drone Enthusiast
Hi Muunk,

double check also on the values that you have for IMU placement. First flight I had with the same frame you had i didnt get the z axis right a negative instead of a positive or the other way around dont remember and it was also very shaky( close to props touching ground). Put your gains for basic gains on your radio and the attitude gains ( some slider so you can adjust them) Check in the config tool which values you are reaching once you have them on the radio. Before you take off take you throttle as close to midstick as possible so it doesnt take of and play with the basic gains. Bring them up until you see oscillations which occur on the ground already if the basic gains are to high, than you know where you set point will be. Bring them down a little and keep the attitude gains at 100%. Once in flight you will tend to bring down the attitude gains to 50% because it makes the bird less aggressive to correct itself.

Boris
 

M

Muunk

Member
Hi Guys.

Thank for the answers so far.

This morning I double checked the props again, (Actually I´ve "octo" checked them now I think ;-) ) They are spinning in the right direction...

But, then er checked the Axis, and I didnt put in the right Z Axis - the IMU is about 4-5 cm above CG. Could this be it?

I will absolutely try to do what BorisS says: Should I a put Pitch and Roll on a Y-cable an program them to a knob so I can control those together, and then attitude at the same time on the other knob?, or what would you recommend? I have a Futaba 12FG, so it should be quite easy.
 
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quadcopters

quadcopters

Quadcopters.co.uk Drone Specialists
The COG wont really make it want to tip over . Maybe post a video of your set up inc the TX calibration screen and move the sticks so we can see everything is moving as it should be .
You also need all the TX channels to be green and in the centre . Apart from throttle which should be at the far left .

Geoff
 

mbsteed

mbsteed

aerial video centric
Could it be that you had a bad ESC from the outset? Perhaps the crash had happened because of the bad ESC. ....just another thought.
 

BorisS

BorisS

Drone Enthusiast
quadcopters said:
The COG wont really make it want to tip over . Maybe post a video of your set up inc the TX calibration screen and move the sticks so we can see everything is moving as it should be .
You also need all the TX channels to be green and in the centre . Apart from throttle which should be at the far left .

Geoff
Click to expand...

Geoff is right. In my case I guess it only flipped because the COG was far off my gains were far off and the landing gear caught itself in the ground for a sec. If possibe give us as much info as possible pic of the setup placement of the the components. Some config screen and if you ever flimed the bird fly that also.

But having the gains on knobs on your radio is a good ideas. Even if you find the perfect gains for one day they will probably need adjustment for the next do to changed conditions payload etc.

Boris
 

M

Muunk

Member
Hi Guys.

Just came home from batminton, thanks again for your answers.

Tomorrow I will make a video an take some pics of the bird ! I really hope that you can help me when you see it, as it did cost a lot of money. And using it as a paperweight would be stupid :shame:
 

I

Icarus

Member
Sounds exactly like an issue we were having.

Make sure that the right orientation is designated in the software for where your arrow on the IMU is pointing. Forward, backwards, left, right. Note that this has nothing to do with the CofG.

Hopefully it solves your problem.

Gunter said:
Big beast that is at 1000mm m2m!!

It sounds like as Geoff says, you are flying in manual mode.

Also, make sure that the IMU direction is 100% correct in the assistant. If its set the wrong way round the heli will flip very hard. (ask me, been there!) with the damage you have done, I reckon it could be this one!!

Check motor directions compared to the diagram and props are correctly fitted.

Good luck!


Regards,

Gunter.
Sent from my iPhone using Tapatalk
Click to expand...
 

DucktileMedia

DucktileMedia

Drone Enthusiast
I assume you know this but just in case.... all heli's have ground effect. You are really better giving it a strong jump off the ground and then backing off the throttle. If you try to take off any heli super slow they just act weird. At least this has been my experience.
 

Siteline

Siteline

Member
Make sure IMU arrow is pointing in right direction before you give a big throttle thrust to escape ground effect. :)
 

M

Muunk

Member
IrisAerial said:
I assume you know this but just in case.... all heli's have ground effect. You are really better giving it a strong jump off the ground and then backing off the throttle. If you try to take off any heli super slow they just act weird. At least this has been my experience.
Click to expand...

Hi!

I work at a hobbyshop where I test costumers helicopters allmost everyday, (Its a service we have, so its trimmed in when they come home). So I should mean that I know what groundeffekt is, damnit I didn´t get a video when I tried to fly the octo. The lady in the house, meant it was to cold to go out and start filming me and my octo ( By the way, now I´m thinking, could +5 degrees celsius make the problem?)

I´ve also checked this morning about the arrow pointing the right way, and regarding to the software it should be where it is, argh!! I just hoped it could be the problem....!

Never the less, I´ll make a video and take some pictures when I get home from work, I really want that bird to fly :highly_amused:
 


BorisS

BorisS

Drone Enthusiast
munk just post everything you can give us.

Pcis on the components places on the centerplate !

Screen shots of your configs at the moment.

Otherwise all tried to help you will continue to be a guessing game !

Boris
 

M

Muunk

Member
View attachment 2108View attachment 2109View attachment 2110View attachment 2111View attachment 2112View attachment 2113View attachment 2114View attachment 2115View attachment 2116View attachment 2117View attachment 2118View attachment 2119View attachment 2120View attachment 2121View attachment 2122View attachment 2123Hi again!

Here some pictures of my setup and two videos aswell. The reason for I´m using the higher channels on the rx are that I want to use to lover ones for my 3 axis cameramount.

And the videos http://youtu.be/cbaZON-GS0g and http://youtu.be/ZLDJsz2t1o0

I really hope you can help me :)
 

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Stevey

Stevey

Member
Do you think maybe the GPS antenna is mounted to close to the main electronics & is picking up interference it would be better mounted out on one of the arms, I did have the same problem with flipping myself, moving the antenna sorted it.
Just a thought.
 

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