Q-My Tricopter Always flip at launch

[Chamika]

Hi everyone

I built the david's tricopter and when I increase the throttle 3rd motor ( motor arm with servo) Always come up and flip the tricopter. also sometimes the yaw servo wont come to its default position when i let go the rudder.This is not always the same and this happens in varying directions at varying angle at different times.I think this is due to my kk 2.1 settings and I am really grateful if someone can help me with this. I have updated the kk with the latest firmware in the KKflash tool.I think its 1.9

This is my first multirotor and not enjoying this at all.

 

[cranialrectosis]

Instaflip as I call it is usually the result of swapped motor servo wires.

Double check your connections to the KK2. Does the esc servo wire for motor 1 go to M1 on the KK2, servo wire for motor 2 go to M2 servo wire for motor 3 to M3 and the tail servo go to M4?

Usually this issue is caused when the esc servo wire from motor 3 is connected to M1 and M1 is connected to M3 or something similar.

If that is not the issue, we can dive into subtrims and reversed channels, but start there.

Two last items of note.
1. PLEASE post video. I am making assumptions here. Video will make this all MUCH simpler.
2. Welcome to FliteTest. You have chosen to do something hard because it is hard. Here at FT you will find LOTS of folks willing to help you turn this around (instead of flipping it over ) and have a good time.

 

[Mustang7302]

Check motor rotation and prop direction.

Motor 1 should spin clock wise (right) and should be using a R prop.
Motor 2 should spin counter clock wise (left) and should be using a normal prop.
Motor 3 should spin clock wise (right) and should be using a R prop.

 

[xuzme720]

Prop direction isn't as critical on a tri, as long as the motor is spinning the props you have installed in the right direction. Tri's use the tail tilt for yaw control and using the CW/CCW props just help mitigate adverse yaw, but aren't necessary for good results. Cranial has already covered the primary cause of flips and the rudder servo action is common on the ground. That usually goes away once the tri is airborne and the accelerometers/gyros have inputs to sense and correct.

 

[Chamika]

Thank you Thank you Thank You!!!!!!!!! EVERY ONE

it flies. The problem was the lock nut was not tight enough and prop was slipping.Now its clearing the ground without a problem,

BUT!!!!
Then begins a another problem It rotates on its own and drift automatically.First it drift to the forward and i increase the pitch settings in the " self leveling setting" In kk and now its rotating at z axis and drift to side. this is not by small amounts .also what should be the PI settings for yaw and Ailerons to start with.
PLease help Guys........

 

[Mustang7302]

If you did not calibrate the KK2's accelerometer on a level surface, you're going to have drifting issues, assuming you are flying in self level mode. A properly built and calibrated craft should need very little trim, if at all.

 

[Chamika]

Yes That was the problem now there is much less drift.. Now i need to learn to fly it's not like the simulator at all Broke 3 props and 20+ zip ties THank you all for your support. Love flight test
Now need to order a box of props and few hundred zip ties.

Also If fellow beginners interested I found this on RCgroups It has great info about tricopter tuning

 

[xuzme720]

This is my favorite video for tuning the gains as it shows the types of oscillation you get when either is too high...

 

[cranialrectosis]

Great! Glad to hear you are in the air. I will have to remember rotor slippage as a possible cause of instaflip.

Got any video of your flight or photos of your copter? We love video here.

 

[Chamika]

Great! Glad to hear you are in the air. I will have to remember rotor slippage as a possible cause of instaflip.

Got any video of your flight or photos of your copter? We love video here.

Thanks cranial .Will upload a one soon .It will be a short video and a definite crash at end