Tricopter issues

[1387]

Yes thanks Ace2317,

what I meant was exactly that: plug your servo into the rudder port on your (somehow powered) reciever. Then try with the transmitter rudder stick if you get the servo to move. If it doesn't (and your reciever is correctly binded) the servo is faulty.

On a normal RC plane wich has no flight controller, you plug all your ESCs and Servos directly into your reciever. That's why your transmitter probably has so much mixing features and such. For RC planes, the transmitter is the "smart" device, for multirotors your flightcontroller has to be "smart" and you shouldn't use most of the features of your transmitter, to get a clean signal to the flight control board (e.g. don't use throttle curves or mixing).

Hope I didn't confuse you, if so, you can ignore the last part. Let us know if you need more help.

-1387

 

[Top shelf]

Appreciate it guys. Damn I think my servo is toast. Is it common for these to be bad out of the box? If the reciever test on the board is recognizing signals from my Tx that means I'm binded correctly right? I'm going to order another servo from hobby king and see if that works I guess. The waiting game is terrible.

 

[Top shelf]

Should I stick to this servo? Or do you guys reccomend another?

 

[1387]

I don't think it is too common that parts aren't working out of the box.
If you plugged everything correctly like I tried to explain and the servo doesn't work, it is as you said toast. If you aren't 100% sure about your test setup, you can always post a picture of it and let us see if we find any errors. I do not want to insult your intelligence, but as you said everybody hates the waiting game and I want to take out any other errors, that could occur.

I don't know wich servo you chose, but it is recommended to get a digital servo with metal bearings if possible. The torque needed depends on the size of the tri you want to build. For my rcexplorer style tri, I went with a 4.1kg torque servo, wich is probably plenty. I remember that David even recommended servos in the 2 kh-ish zone, but I'm not exactly sure.
If you can afford it, you shoud probably buy 2 to have one spare. This helps when one is toast right out of the box, but it helps too, if you crash. I already destroyed one of mine in a bad crash...

-1387

 

[Top shelf]

Ok so my replacement came and the tail servo works now. The old one was a dud. I'm going to see if I can send it back.

I notice another issue now. When I swing the servo to the right it has a long travel but it returns slowly to center. Left will have a short travel but snap back to center.

I attached a youtube video to illustrate.

Also is it normal for the servo to be making a faint buzzing noise when the copter isn't armed?

 

[makattack]

I'm not familiar with the KK2 board, but I suspect that might be normal, because the KK2 is seeing your yaw input, but not registering any yawing on your tricopter, so when you center the stick, it's not going to give you direct 1:1 output.

Try keeping your sticks centered, then pick up the tricopter, and yaw it around. You should see the tail move somewhat proportionally the opposite direction to compensate for the yaw. So, if you yaw to the left, the tail will go to the left to give you more right yaw, and vice, versa.

I use multiwii, setup for a tricopter, I don't need to run up the motors, and can use the rudder/yaw stick to run the tail servo around and it will respond accordingly. I'm assuming the KK2 doesn't do the same, which is why you're running up the motors.

 

[1387]

You can change a setting called "servo on arm" or something (can't check, my KK2 is broken and I have to wait for replacement). This would give you the same behavior like makattack suggested.
Try the servo movement when flying. If it does that then aswell, something is wrong.

The buzzing noise probably comes from the servo who tries to push/pull the tilt mechanism around against its physical borders. Make sure the linkage to your servo is not too tight, putting force on the servo, or it will try to counteract that constantly, wich will increase the chance of it getting broken in a crash and lessen the overall lifetime.

-1387

 

[Top shelf]

Strange the buzzing goes away when the servo is on and the copter is armed. Anyways I'll post results after the maiden flight sometime this week. Wish me luck and much thanks again for all the help and suggestions 1387 & others!!!

 

[Ace2317]

Is there any friction anywhere when the servo moves? Mine doesn't usually take that long to return to center. You might want to check for resistance. I had to bend my wires a bit to make them line up well. Servo arms don't like pushing a load at an angle so if you can bend them a bit to where the rods come in parallel to the arm, you'll have much better response from your servo.

It could also be that your control horns are tightened too much. I'm bad about overtightening those. I usually go back off 1/2 turn and it improves greatly.

One other thing to check was to make sure you used the right screw when mounting the servo arm. Sometimes this can cause resistance too. One screw should be different from the other two that came with it.

Also, after all that, my servo has no resistance, but it does still buzz. I think that tail pivot just isn't the best position for a servo, probably part of the reason for the tough tilt design that's coming soon.

 

[1387]

Don't worry about some light buzzing. Especially for digital servos, I heard it is normal. My tail servo buzzes aswell sometimes.
It is good to get your pivot servo as smooth as it can get - without friction, but without slop aswell. I for my part didn't care so much about that, but I think the motor wires being pushed around by the pivoting put more stress on the servos than the friction on my pivot mechanism. So I should be fine one that part.

Hope everything goes as well as my maiden! Good luck, let us know when we can help.
-1387

 

[PhoenixFlight77]

How did you arm the kk2 board I'm having th same problem?

 

[1387]

The KK2 is being armed when putting the throttle stick in the bottom right corner.
When this doesn't work, then it could be a number of problems:

Your transmitter trims are way off
You connected the reciever to the KK2 wrong. Make sure you have throttle on reciever connected with throttle; aileron -> aileron and so on...
Does the KK2 show "Error" on the screen? If so, you can't arm it and you have to get rid of the error first (ACC calibration e.g.?)

Most errors can be found by going into the KK2 reciever test menu. Move the sticks of your transmitter. If the corresponding sliders on the KK2 screen don't move, move in the wrong direction or the wrong slider moves, something is wrong (e.g. reversing channels on your transmitter; wrong connection between KK2 & reciever; etc...)

Ask, if you need help.
-1387