tricopter batbone help


New member
in David's Flite Test - V-Tail Quad - BUILD video, he spend the second 10 mins of the 18 min video showing how to setup the kk2 board. at about 15:45 he does the test showing what you are talking about.

hope this helps.


Junior Member
yes I still have not flashed it yet. I had a guy at a hobby store look at it, he did some changes and got it to hover in the store. he did not do the outside test


Junior Member
it is still trying to do backflips. not as bad though, if i eas it full throttle it goes way up, but if i just full throttle it tries to back flip and will hit the grond and has two more times


Hostage Taker of Quads
Staff member
it should fly on its own without flashing

But it does fly . . . just not well.

The stock ROM on the kk2 is known to be buggy, so you might be chasing a hardware setup issue, or you might be chasing a bug in the firmware. From your description, (get above a certian throttle level some point above hover, the tail cannot keep level) it's a pretty low chance it's a software setup issue -- unelss the throttle level is near WOT, the board should have plenty of play in the control loops to balance the motors.


- Where's your CG? Is it near the center of the motors? (for a tri with 3 matched motors it will be near 1/3 back from the the front motor's centerline to the tail) If the CG is off, it should still work at low-to-mid throttle, but as you near the top end, you'll have trouble with the motors maintaining balance in pitch. CG does matter.

- Have you de-vibed the airframe? Vibration isolation between the contorl board and the frame? Ballanced your props? Any vibrations from the motors/props increase DRAMATICALLY with throttle -- I've had airframes perfectly tuned close-in, then go completly bonkers (dropping a boom while yawing wildly) in fast forward flight. catch it and slow down . . . tame as a kitten. The difference? higher throttle. Balance your props (I do them all at once, shortly after a new box of props arrives -- it's a pain but it will make a difference at high throttle), balance your motors, isolate your control board.


- Adjusting your I gain in pitch upward might help, assuming it doesn't go so high as to induce osscilations of it's own, but I doubt it will solve your problem. I will help reduce *drift* in angle, and what you're describing ain't drift.

- REFLASH. The stock ROMs stink. They're buggy, and they don't take full advanatage of the hardware to give you the best flight envelope. It's enough to test and ensure everything is functional -- mission accomplished: if you can hover, everything works -- but it won't work well under the stock ROM. The modded ROMs avaialble are a great improvement over what comes loaded. Even if one of the hardware fixes sorts this out, it's really worth your time to reflash it anyways.


Faster than a speeding face plant!
I'm with Dan on this one. It sounds like a hardware issue to me.

I'll buy Dan's CG argument but Turnigy Park300s are a VERY small motor for a BatBone. Dan is right about everything he said and you would be wise to take his advice but there are some nuances here that have yet to be understood that may be playing a part in this.

What lipo are you using? Do you have a link?

Are you using rubber bands (O rings) to hold the props in place?

What props are you using? Link?

Including the lipo, what does your copter weigh when it is in the air?

Here are the common causes of tail flip that I see from posts on the forum.
1. CG
2. Vibration
3. Too much stress on the tail motor
4. Too low a C rating on the lipo not providing enough power under stress
5. Rotor slippage

After your copter crashes, is anything hot? Motor, ESC, lipo, test them all for excessive heat. Anything hot is likely where the rubber meets the road on this.

Personally, whether or not we find a hardware issue, I would flash the KK2 before I tried to fly it. The stock ROM is that bad.


Junior Member
just an update. i got it flying and its great, i crashed it a few more time before i got it, even broke some stuff. still did not flash it trying to download usbasp driver anyway thanks


Junior Member
Don't know kw to calibrate esc. I did calibrate the acc. Once ever thing was hook up. I got it flying without flashing the board. I took it to a guy at a hobby store who new what the problem was and he fixed it. It flies great. I'm getting the parts to do the V-tail next. Anyway Mary Christmas and happy new year.


Junior Member
I fixed my problems, I ended up lowering the front motor throttle to 80% an the back at 100%. I have since recked alote do to pilot error of course, You know trying to do tricks.anyway, I ended up crossing the batbone with the HK X900 tricopter frame, legs (which I shortened), the landing gear which I like better and the rudder tilt in the back which is a better.and the batbone framesnice also I have built the v-tail and crashed it the crossed it with the HK X666 + alluminum rear motor mounts it's cool. Any way my question is how to tell if you need bigger esc's? Also I have since flashed my kk2 board with the RC911 firmware, trying to figure out the self-level mixing.
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