Weird vibration on 6S 450L Dominator

[SpringerKing]

I made sure all the gears were pushed in tight, still got a vibe. Replaced the tail set of gears and still have a vibe. Testing last night I stripped the front umbrella gears.

Not really sure where to look next, but I need to replace the gears first...

[alyon187]

You stripped the new set of gears you just installed?

[SpringerKing]

Yes, but it was my fault for putting it down to fast.

[alyon187]

Well the vibration I bet is from your gears not being centered, all their gears are like this, so you can slide the drive shaft out and rotate it a quarter turn and then slide it back in. You can do this with both umbrella gears til you get a match that produces the least amount of vibes. Also off set your tt bearings like mentioned above, they should be spaced unevenly throughout.

[SpringerKing]

Thanks, I will give those a shot and see if i can find a lower vibration that i can deal with.

I appreciate all the input.

[AlvaSpeed]

https://www.helifreak.com/showthread.php?t=624846

[SpringerKing]

Thanks for the link. It sounds very similar to what i have going on. I have been all through the Tail section on this heli and cant find a problem...

I didnt notice any scarring to the TT like that thread mentions, but i have added 1 extra bearing and i will try adding a 3rd. I also think there is something up with my main shaft or Auto rotation gear.

I do not get any binding or friction spots out side of the heli, but as soon as i install the tail box there is a higher friction point when rotating it by hand.

I got the bird in the air with managable vibes by doing everything suggested thus far and loosening the frame bolts and re-squaring it all up.

Thanks for all of the help.

[Acid Junkie]

hi guys i have the same almost issue...its the 2nd time i bought the 450L....this time after 3 weeks in the box and reading and watchin some videos i was so sure i ll make it perfect.....but with no stock parts as the servos i use mks ds95 and esc (cause to the previous one it was broke down and got on fire while i was flying)...the story with a few words...9 months in the hobby...my 1st heli was a 450 plus rtf with flybar...i changed it with beastx 4 pro these days first came out....and with a dfc head i managed to make it perfect and using the attitude control i was crash free anymore..that heli costed me 1800 euros....guess what...the 2nd day after i was relieved...i lost it.....searched it for 15 days..earth swallowed it...! bought the 450L 6s ....i assembled it alone as the manual says and my shopper said me just dont fix nothing at the tail part...so i did ( i hadnt the experience back then that all the screws were loosen)...so for 1 month i had no probs only some wagging times by times...anyway....the heli had bad tail vibes after some flights till the stock ESC got broke down on the air and got fire....i kept the frame and anything saved and bought a new one again.....and here we go...took me 3 days to assebly it as perfect as possible....1 by 1 screw to avoid strips like the previous i had always probs....!! i finish it 3 days before....with beastx 4pro and mks servos and for esc i got the hobbywing pro platinum v3 50a bec 7A.....!!! i cross my hands i put it down with only back blades.......and ....PFFFFFFFFFFFFFFF.......vibes on the tail......the more rpm the more stronger vibes.... ! i was going crazy....i had a spare second TT bearing...so i pooled out the TT and put it at the back of the TT between the other one and the end of the TT......a very noticable reduce..almost no vibes at all this time......but my luck....will i had in on the floor testing it....a carbage bag came from nowhere in the house cause of the air from opened windows...and went straight to the back blades.....! i got socked.....my nightmare....to change the front umbrellas.....this type they made it..its too hard to remove the case of the boom with these hexagons on the white parts of frame....anyway....i had a spare of new umbrellas and changed them almost easy ....cause i was too carefull with the screws this time so i had not stripped or something like that to give me hell changing it...! at the time i thought to try one suggestion i heard ....to pull out the tail boom just 1mm from the case so the TT have some space and not bent in high or low rpm and cause vibes if its touching both end at the front and rear side exactly the idea was that maybe that was causing it to bent .....but no....i had again vibes and maybe a little more than before.....so i m in a desperate position too....in 9 months i have spent more than 5000euros for 3 helis 450 ...1st lost when it was perfect...2nd lasted one month till issues with tail started and only one time found the problem by mistake i dont know what i did and the tail was like dead even from 0 to 100% throttle.....like unplugged from battery...but my luck....i didnt get hapiness for more than 3 seconds....while i found that prob then....the plastic thing between the fin who goes to the back hole of the boom stripped ..a back blade hit the ground...and all my efforts gone...i was almost near to break down....! anyway that heli finaly on idle up the esc broke on the air and it was flying alone for 1 minute almost at 100% till it got crashed badly.....! then it was i decided to try buy a 2nd one and keep that for parts what is saved...! and yes this is it..right now i have a totaly new out of the box heli with mks servos ...hobbywing v3 platinum and beastx 4pro....2 bearing on the TT and small vibes at 45% flat for governor mode....but on idle up with flat like....the more rpm...the more vibes.....i dont know what to do anymore.....sell it? fly it till i smash it and give up the hobby? i dont know.....i m really disssapointed

[alyon187]

Are you sure the vibes are coming from the tail? There are quite a few areas you can check that maybe suspect. First is to make sure you have all your umbrella gears pushed all the way in and that the mesh between isnt too stiff. Sometimes it feels like you've got them pushed in and their not. Put a good amount of force behind your push. I sometimes here a click when the rear ones are all the way in.

Another area to make sure you have right is the gear mesh between the motor pinion and main gear. Ive used the paper method and that seems to work well. Basically you put a regular piece of paper in front of the main gear and slide the motor pinion to the main gear w the paper between them. Make sure the gears are lined up and start to tighten down the bolts. One secured, spin rhe gear to remove the paper. Spin the gear around a few times to make sure there are not tight spots other wise this can also cause vibes, wags, and hotter than normal esc and motor temps. While the gear is still you should be able to move the main gear back and forth a tiny bit without actually rotating the gear and motor. (If that makes sense)

The umbrella gears are almost always not centered to well so what most do is what you have done as well as try to rotate the tt a quarter turn then 'reinsert and see if the vibes get better. You can do this on both ends of the tt.

Make sure your tt bearing is not in the center of the drive shaft. It should be off center 8 to 10 mm (I believe). If you add another bearing then make sure it is also set so that it divides the tt shaft into unequal sections, so that no one section of the tt is equal to another.

Any binding in your tail slider or any part of your tail will cause tail wag. Your tail should slide smoothly with very little effort. Ive got mine to where if I fold the tail blades onto each other and disconnect the tail rod and give a pretty hard blow against the blades that they will move. Its gotta be smooth as glass.

The last thing I can think of off the top of my head is to check how tight are you running your blades? You should be able to pick up your heli with the blades parallel to the boom (like your about to fly), turn it on its side, and give a quick downward thrust and both blades should fall the same amount (I usually try for 15 to 20 degrees, just a guess though) if they dont move at all they are too tight and if they fall all the way down to where they touch or come within a few inches of eachother then they are too loose.

That's all ive got at the moment, I couldn't really make out your actual question too well so im just giving ya some areas ive checked, and have read, that can cause vibes at higher rpms as well as tail wag.

Chasing these vibes and getting your heli to fly like you want it is all part of the hobby. But once you start to do this, and see improvements in how your heli performs then you'll start to get better at fixing, setting up, and troubleshooting issues like this. Its just a part of the learning process that EVERYONE goes through before it starts to become easier. You've got a good heli and pretty good electronics for a beginner so my guess is that its def something from the build that wasn't setup right, over tightened, or not meshing correctly that's causing your issue. These helis are picky about how they want/need to be built.

[SpringerKing]

I agree with everything thing said above. This thread helped me tremendously in troubleshooting my vibe issue.

It is not completely resolved, but greatly improved and I believe I know what I need to do next.

I found with my 450L after 3-5 flights I had a vibe, tore down, replaced all tail gears, played with the gear mesh etc. no binding in the tail assy. outside of the heli. As soon as I re-installed, I had a tight spot when rotating which I believe is either a bent main shaft, or the autorotation tail drive gear being out of round.

So I would check above an beyond the tail assy. the square ness of the frame, and check for binding/friction coming from the main drive assy. as well.

[Pascandrea]

I finished to make my 450L, and badly during a test the blade touched the boom tube, so i bend the tube and the shaft + broke the servo, i changed the boom + shaft, add new kst servos and try again ...
Before today i did the test only in 4S and i had no vibration at all, today I bought some 6S and now i have some bad vibration, the setting on the radio is the same in 4S or 6S ...
I really don t know what is the problem ...
Someone could help me to resolve this ?