Tricopter wont hover. Drifts away. Yaw issue?

[freedom]

Tricopter electro hub
kk2.15 ver 1.6
DT750s
20 amp afro esc

Hi everybody. This is a second attempt at resolving my tricopter issues. I built this thing a year ago and was never able to get it to fly smoothly. Long story short I shelved this project and forgot about it until a few days ago in hopes of enjoying this hobby. Here is a video I made last year of what goes on after take off. I broke off the delrin landing gear during the making of this video : (

I also noticed that the yaw mechanism does not want to center after yawing towards left. If I yaw to the right it will go back to center position. Video to illustrate.

Any input is appreciated. Thank you

 

[rockyboy]

Not sure of the answer you're looking for, but I have most all the parts you used in a box on my bench and intend to start assembling my tri-copter in a couple weeks. Very interested to see if someone is able to help you solve this as I just might run into the same challenge.

Good luck!

 

[cranialrectosis]

Rip the delrin landing gear off and replace with zip ties or thin rings of <> 3" PVC.

I would guess your tail servo isn't centering correctly. I can fix this on a Naze by setting the servo limits. My tricopter yaws a little to the left naturally due to not having 4 props counter rotating. So, the center of my servo is a touch left. Instead of center at 1500, it is at 1450.

Once I pop the copter up, the flight controller won't try to center the tail servo, it will try to keep the copter at the attitude I told it. I wouldn't expect the tail servo to pop back to center every time.

What is the firmware version on your KK2?

Did you center your subtrims?

What is your yaw I gain set to?

I haven't used a KK2 since 2012. Hopefully Dan will chime in here as he still uses the oldies.

 

[freedom]

Good call on the pvc landing gear. 1.6 is the firmware I'm using. I adjusted sub trims on Tx until the receiver test showed 0s for everything. Yaw I gain is 80. Sorry the extra pics are rotated. It's uploading strangely from my iPhone.

 

[RGJameson]

Because there is only one rear arm there has to be compensation for the motor torque which is the tilt you are seeing. When just hovering the servo will tilt, the direction of the tilt will depend on the motor's rotation.

It's hard to tell by your pic, but you want to choose airplane in your radio, not heli. There's good chance that there is some channel mixing going that you don't want.

 

[freedom]

Because there is only one rear arm there has to be compensation for the motor torque which is the tilt you are seeing. When just hovering the servo will tilt, the direction of the tilt will depend on the motor's rotation.

It's hard to tell by your pic, but you want to choose airplane in your radio, not heli. There's good chance that there is some channel mixing going that you don't want.

Thanks switched to plane mode.

I also notice when I have the tri on the ground with low throttle the front left motor will just start gaining speed to full throttle. I can imagine that's why it was causing the random drifting away. Not sure what's causing this

 

[makattack]

That motor running up on its own might be due to the flight controller software thinking it should be adjusting for flight but because you're still on the ground gets confused. I wouldn't keep low throttle idle with props mounted on any multirotor unless the software specifically handles it. An example where the software does that is with those where the armed state includes a motor on at lowest spin.

I think you solved the problem you were having by switching to airplane mode on your TX. Heli mode is for collective pitch helicopters.

I would still double check everything and make sure the rear servo is setup correctly to counter/correct opposite spin. You might test that by removing there props, arming, spinning up the motors to half throttle and hold the tricopter in the air. Then rotate/yaw it back and forth while observing the tail servo/motor assembly to make sure it goes the opposite to try and counter the yaw.

 

[oOFutteOo]

Have you zeroede your gyros. David W explaind it in his video on the kk2 board you can finde it on his youtube chanal rcexplore there is also sugestede values to a lot of motor, prop and battery combinations i the video. I just folowed his instruktions and my coptor flew first go i had to adjust my gain up bye 5 to get it to flye better and be a bit more locked in as he say. An other dirt simpel problem can be your prop balance if your props are out of balance the coptor dose wirede stuff. I put a new unbalanced prop on my coptor after a crash and it just freekede out an was uncontrolebel a bit like yours.

 

[freedom]

Have you zeroede your gyros. David W explaind it in his video on the kk2 board you can finde it on his youtube chanal rcexplore there is also sugestede values to a lot of motor, prop and battery combinations i the video. I just folowed his instruktions and my coptor flew first go i had to adjust my gain up bye 5 to get it to flye better and be a bit more locked in as he say. An other dirt simpel problem can be your prop balance if your props are out of balance the coptor dose wirede stuff. I put a new unbalanced prop on my coptor after a crash and it just freekede out an was uncontrolebel a bit like yours.

If it's the video that I'm thinking then I'm pretty sure I followed his instructions when first assembling this thing. Since I'm out of options I'll go through the process again.

I currently don't have a prop balancer. I didn't think I would need one just to get up in the air. : /

 

[earthsciteach]

Tricopter? KK2? Well, there's your problem!

I have to state up front that I am not a fan of either tricopters or KK boards. Plenty of people love them. Tricopters have an inherent disadvantage compared to copters with more motors. Long story short, its a matter of symmetry. When that tail rotor tilts off axis, things get wonky and it is up to the fc board to deal with that as best it can.

To me, it looks like the board isn't correcting for the servo being off center. Have you checked to see that the servo is good? Could it have a stripped gear? You definitely need metal gear servos for tricopters. But, many of the cheap MGs have a nylon gear inside that strips easily.

 

[freedom]

Tricopter? KK2? Well, there's your problem!

I have to state up front that I am not a fan of either tricopters or KK boards. Plenty of people love them. Tricopters have an inherent disadvantage compared to copters with more motors. Long story short, its a matter of symmetry. When that tail rotor tilts off axis, things get wonky and it is up to the fc board to deal with that as best it can.

To me, it looks like the board isn't correcting for the servo being off center. Have you checked to see that the servo is good? Could it have a stripped gear? You definitely need metal gear servos for tricopters. But, many of the cheap MGs have a nylon gear inside that strips easily.

I agree tricopters suck lol I just bought another motor and esc as a means to build a quad in the case I can't get this flying. I have tried three metal gear servos thinking it was a hardware issue. Currently using bluebird 210D

 

[oOFutteOo]

im not imparcial, im a big fan of david and i love my tri coptor
one thing i did not mention is rember to to hold the coptor still when coneckting the battery. if i move my coptor around when i coneckt the battery it will drift and and yar. another thing is do you use sability mode if not try to turn it on this will make the coptor level when you let go of the sticks. if it is turned off the coptor will keep the the orintation it is in when the you let go of the stiks and it will drift a lot and keep yaring.

 

[cranialrectosis]

Earthsciteach is absolutely accurate. Tricopters are for madmen and evil geniuses. They are a mix of physics and witchcraft.

I love mine!

That said, I thought this was resolved when the transmitter got flipped to plane mode...

If you have mechanically centered your servo and you know you have full range of left and right you can tweak center with the subtrims. Start by zeroing the trims on your transmitter. Then, in the KK2 receiver menu, tilt the tail rotor a bit toward the direction of the unwanted yaw. If the copter yaws right, tipping the tail to the right a bit in subtrims will push the nose of the copter left.

Next time you fly, 'pop' the copter up at least 24" off the deck to get it out of it's own rotor wash. You will have some drift. Tune out the drift that happens in clean air with I gain.

My tricopters have always lifted off with a bit of right yaw and always yaw a little right when I am within <> 8" of the ground. In clean air it flies straight and true until I break teeth off the servo by hitting the fence or the cherry tree.

 

[oOFutteOo]

i think i fall into the catgory mad men, were as im pritty shure David is a evil genius
https://www.youtube.com/watch?v=n-4G9tzZLfs

sorry could not resist

 

[cranialrectosis]

i think i fall into the catgory mad men, were as im pritty shure David is a evil genius
https://www.youtube.com/watch?v=n-4G9tzZLfs

sorry could not resist

GHOD I miss David!

 

[hunterisbest18]

its the aliens that mess up our drones

 

[RGJameson]

Tricopter? KK2? Well, there's your problem!

I have to state up front that I am not a fan of either tricopters or KK boards. Plenty of people love them. Tricopters have an inherent disadvantage compared to copters with more motors. Long story short, its a matter of symmetry. When that tail rotor tilts off axis, things get wonky and it is up to the fc board to deal with that as best it can.

The super yaw authority is what makes tris great.

Well this dude, a great pilot seems to do well with his KK2s and rather rude and crude builds.

https://youtu.be/miD9iwDPssg

BTW he doesn't like quadcopters,