super cheap tricopter

[eagle4]

that's the problem, as soon as i take off it continues spinning, at quite an alarming rate too. it would do a complete revolution in about a second

 

[xuzme720]

Has it ever flown stable? If not it could be that the servo is correcting in the wrong direction...

 

[eagle4]

nah it hasnt ever flown correctly. i am pretty sure i have the motor tilting in the right direction, i do get control over it, but its really only when i push the sticks all the way to the side, as its gotta counteract the massive spinning that it wants to do

this is my first tricopter, and my first time playing with a kk2 board, so there is a chance i am overlooking something simple, so i really appreciate your input

 

[eagle4]

WOOHOO!!!

I worked it out. and by my guess this is a huge problem with the kk2 board which is undocumented. I had the rear servo moving in the correct direction, however the kk2 is not bright enough... let me explain.

I had to set the servo's mix on the kk2 board to -100 (it was originally 100) I then reversed the input that was coming from my tranismitter, this way it was still moving in the correct direction, but now the kk2 actually keeps its level. For some reason it thought it was going the wrong way. This explains how it kept spinning like crazy, the kk2 noticed it was spinning and wanted to counter act it by making it spin more... silly kk2 ;p

I fired it up after changing this setting and it flew like a dream. Took off with 0 yaw in each direction. Absolutely smooth take off. the rest of my flight it was a bit iffy as I'm not a good multi pilot just yet. But yeah. super simple

Just set the servo mix to -100 (it was set to 100 before that) and reverse the channel on your radio and everything will work great.
I hope anyone else who has a problem with a tricopter who's rear servo isn't centering can find this and get it sorted out. There was a lot of trial and error in this for me, I'm really surprised this isnt documented somewhere (it could be somewhere, just after a couple of hours of searching i was unable to find it.)

 

[Nathan_116]

Could you make a list of the parts you used so that others could duplicate this project, like me. Lol! Also could you post a picture of your yaw mechanism?

 

[eagle4]

Motors: These are horribly out of balance. be sure to balance the motors even before you put the props on. Also they are hard to attach to my frame as the holes are in random locations it means i can only attach it with 2 screws, i couldnt use zip ties as the holes are so small
http://www.hobbyking.com/hobbyking/...T_700kv_Park_Fly_Indoor_Motor.html&aff=604742
$7.65

ESCs:
http://www.hobbyking.com/hobbyking/...d_Controller_SimonK_Firmware_.html&aff=604742
12:49

Controller board: I used the KK2.1, but its now been replaced by the KK2.1.5
http://www.hobbyking.com/hobbyking/..._With_6050MPU_And_Atmel_644PA.html&aff=604742
$29.99

Servo:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=14459&aff=604742
$5.45

I made my own power distribution cable from scraps of wire i had laying around, and some bullet connectors i already had. but you can buy one thats premade
http://www.hobbyking.com/hobbyking/...star_ESC_Power_Breakout_Cable.html&aff=604742
$2.88

I already had a bunch of 10x4 props for my quadcopter, so i didnt buy any more. same with my battery. this flies great on my 1300mah and my 2200mah batteries. both are 3s.

I built the frame from wood i got from the hardware store, so nice and cheap. (about $1.50 for the wood for the arms)


I ended up putting some LED lights onto my tricopter, but thats just for me, if you're wanting it to be super cheap, forget about the lights (eventhough they werent that expesive)
http://www.dx.com/p/waterproof-14w-...p-strip-white-100cm-dc12v-178061#.U6mouPldV8E
$5.35CA

I also used zip ties for landing gear, these were also super cheap from the hardware store, it was like $1.50 for 10 giant ones or something awesome like that.

For my Yaw mechanism I used the middle design in my 3D image (back on page 2 of this thread)

 

[Nathan_116]

Okay I think I'm gonna get the ESC's from RTFQ because they come in both 10 and 20 amp preflashed for only $10. Also, he sells the KK2 board for $20 so that will shave some money. Also, I I wanted to use smaller props, like 8045, should I go with a higher kv motor? I want to build a quad or small tri, something easy to carry around, and be able to fly indoors, in a decent sized room, and outdoors. I was thinking the FC 2812 1200kv motors, basically equivalent to the "beef size motor but a little smaller (its what I use as it is only like $7 not $15 plus the accessory pack for the NTM and I don need servos) and it will keep the price down.

 

[eagle4]

for cheapness i chose a tricopter cause i realised that the cost of a servo was less than the cost of another motor and propeller

 

[Nathan_116]

True, I might do the same, just depends.