Hk 250 clone with mini kbar problems - RC Groups
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Jul 15, 2017, 12:20 PM
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Hk 250 clone with mini kbar problems


I have a HK gt 250 clone with an upgraded fbl head and a mini kbar, I adjusted it to my radio, and it flew but had excessive wobble, so I tried to set it up again, using the trex 250 settings. It spooled up fine, as I added pitch it got light on the skids, then banked hard left, I hit th immediately, but not before shattering a few blades, feathering shaft, and destroying a main gear. I am tearing into the mechanicals today, but was hoping to find someone with experience setting these up to offer any advice regarding commonly overlooked issues or recommendations. It was a gift from a generous individual in a nearby town who did quite a few upgrades on it, but never got it working quite right. It is also my first attempt with anything other than small bnf micros (hcp100, hcp80, k1110) and a v370d05. (read as a first flight controller setup) I really want to make it fly, and fly correctly. Just not quite sure where to go after setting up the swash and pitch mechanically. I am currently using an upgraded fw (10 channel) fs-i6 with a 4 in 1 to bind to a dsm2 satellite. vr1 is on ch 5, linked to gyro adjustment, the kbar is mounted on the side of the frame. the servos are the stock HK ones, and it has a turnigy plush 20a sc. I was thinking about putting the fb head back on it to see if the issues are head related, but I'd rather get it working with the fbl unit.
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Jul 15, 2017, 01:55 PM
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So far I found a bad lower main shaft bearing, not sure if it was the cause or if it was taken out during the crash. (is it even really a crash if it happens before lift off?) guess I will change both bearings and the main shaft, just to be sure...
Jul 17, 2017, 11:47 AM
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tipovers are usually either vibration or gyro direction wrong.

hook it up to pc with vbar software and remove both mains and tail blades. spool it up watching the vibration anylisis. with no blades you should be pretty low around 300ish in the current reading (not peak)

With blades on ive managed to get around 1000 when its been in top contidion, still complains about raised vibes but flies fine.


If its wobbly around, i had that issue and it wasnt until i changed the swash plate it finally went away. I replaced every bit until it was all align and that was the last thing i changed.

I started of with a copterx 250 FBL which had copterx 3x200 gyro, switched to kbar and it would just wobbly around. Changed more bits, changed servos to faster servos, still wobbled, changed to even better servos that were digital (turnigy 213c) was better but still wobbled. then changed the swash plate. perfect.

I cant say what exactly was the wobble issue but i guess the vbar/kbar does not like certain servos . not sure what the deal was with the copterx swash it looked pretty similar to align one
Jul 17, 2017, 03:18 PM
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could be a lot of things but sounds a little like maybe gyro direction
could be pitch curve
could be a radio setting
could be voltage/battery
could be gyro setting

I will have to look at that
I have a Gaui 200 FBL i built from parts flies great CX1000
I have a Trex 250 DFC Pro flies pretty good XG3
Flown mulit rotor 3 and 5 bladed
But my Copter X 250 FBL does not fly well out all its pretty much out of control no matter what I do.
I also have ZYX and mini bars I swapping out the CX1000 for a ZYX to see if it changes now but its still in a great many pieces.

I have noticed clones vs the real deal the set ups are always a little different. link lengths and servo set up etc as well as sometimes significantly different radio pitch curves and such.

If you look at them Trex vs Clone close which i have done there are actually a good number of subtle differences between the two.
Jul 17, 2017, 04:43 PM
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ael


"I've done that, man!"

I would bet that the direction of the correction is wrong for roll.

I have 2@ HK250GTs with CC3D / Libre pilot controllers. I put my finger under a servo arm to feel the correction as I roll the heli. If it pinches your finger as you roll away from that side it is correct. I can't see it well enough because it bounces back a bit but I can feel the correction well.
Jul 17, 2017, 05:53 PM
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kbar doesnt allow changing individual axis. you tell it what way the gyro is mounted and everything shyould be good.

wobbling is another issue. i did have that issue and it took multiple changes before it was fully fixed, but the strange thin was it flew great stock
Aug 03, 2017, 01:21 AM
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I have some parts on the way for it, I think the 2 biggest issues were the belt rubbing on the ever so slightly bent tail boom, and the sloppy tail shaft bearings. the swash does move correctly, as does the tail. thanks for the input
Aug 03, 2017, 09:45 AM
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vibes


'sloppy tail shaft bearings' happen just before tail explodes -- balance tail blades --the poor things spin at over 15,000rpm.

Vibes, vibes, vibes!
Aug 04, 2017, 02:47 AM
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there are several issues with the copterx. main one being bearings that are either wrong out the box or just dont last.

I wish tarot still did the 250 as the tarot parts are dirt cheap and much better. I refuse to replace my align swash because its the same price as the 450 swash! but wont use a copterx swash as it doesnt work for some odd reason with my kbar
Aug 12, 2017, 03:02 PM
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It's a HK with align bearings... looks like I will be going after the tail belt drive gear bearings next... with bearings replaced, (main,feathering, and tail, whole shaft not just bearings) with align parts, it's giving me 2k vibs on the kbar AAARGGH!!! I want to fly this thing, it just became a personal challenge to get it nailed down.

Maybe I should pull the head and swash... if it stops it's swash, if not, tail drive?
Aug 13, 2017, 08:09 AM
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mount the gyro on the gyro tray or on the bottom plastic frame. the sides gve more vibes although it does work.

if you go with on the bottom plate you will need to use spacers to spread out the frame a little otherwise it wont fit.

Use a thin mounting tape. vbars/kbars dont like jelly mountings they dont fly well unless mounted stiff. im using the grey 3mm stuff now on all helis, too thick and the gyro wobbles.\\\


remove your main and tail blades, spooll it up and watch the vibe analisis, that will give you clues to were the problems are. without blades you should be around 300 or less if its super smooth. with baldes i was getting around 1100 its its smoothest although before its last crash it was around 1800 but still flying fine.

the peak vibe number cane be confusing, it can spike during spoolup.


If you put blades on and the vibes are a mess you know you have a balance issue with the blades.
Aug 13, 2017, 11:00 AM
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Latest info... It flies! I missed the swash bearings. seems they may have rusted during it's shelf time, or got some debris in there. vibes are still way higher than I would expect, but once it spools up to 80% they drop to around 1200. not great, but it flies (At least, it hovered for about 3-5 seconds before my excitement got too much to fly and I set it back down, LOL) I am still a little shaky, going to calm down a bit and then go do a proper flight. I can't call it a maiden, unless you consider that most of the aircraft is now new, LOL

just hovering a few inches off the ground it sounds MEAN, nervous, excited, jittery, WOW! hehe I have never had this feeling with a few exceptions... the first time I broke into 11's in the 1/4 mile. the first time I hit 140mph. The first ride on a 500cc dirt bike.

I don't like the way it fits (or doesn't ) on the plate... I test fit another kbar (that one lives on my 450 now) on that tray, maybe the HK has a slightly smaller one, but it just seems to hang out too far for my liking. Not to mention there is a bit of movement in the tray itself, because the mounting tabs fit loosely in the frame
Last edited by Wayne Moyer; Aug 13, 2017 at 11:19 AM.
Aug 14, 2017, 11:42 AM
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Quote:
Originally Posted by Wayne Moyer
Latest info... It flies! I missed the swash bearings. seems they may have rusted during it's shelf time, or got some debris in there. vibes are still way higher than I would expect, but once it spools up to 80% they drop to around 1200. not great, but it flies (At least, it hovered for about 3-5 seconds before my excitement got too much to fly and I set it back down, LOL) I am still a little shaky, going to calm down a bit and then go do a proper flight. I can't call it a maiden, unless you consider that most of the aircraft is now new, LOL

just hovering a few inches off the ground it sounds MEAN, nervous, excited, jittery, WOW! hehe I have never had this feeling with a few exceptions... the first time I broke into 11's in the 1/4 mile. the first time I hit 140mph. The first ride on a 500cc dirt bike.

I don't like the way it fits (or doesn't ) on the plate... I test fit another kbar (that one lives on my 450 now) on that tray, maybe the HK has a slightly smaller one, but it just seems to hang out too far for my liking. Not to mention there is a bit of movement in the tray itself, because the mounting tabs fit loosely in the frame
I forgot to mention that the tray needs to be secured (CA works and is easily to break if work neeeds done) or even better is on the bottom plate. As i mentioned beforeyou need to widen the frame to make it fit. or.... sand down the sides of the unit until it fits in. its possible to shave enough of the kbar case to leave 1mm clearance between the case and frame sides..

dont spend much time trying to chase down vibes on a 250. fly it, if its flying fine ignore the vibe warnings. unless its suddenly kicking or the tails drifting it should be fine. there are people out htere flying with the logs doing nothing but extreme vibration warnings.

if your getting around 1200 during a hover that should be pretty good.


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