450 One problem leads to another, I have serious vibrations ..i think its the servo gear

[orbi]

Hi again comrades. Sorry for all this, but without you guys ,people like me will give up this sport.

I am very methodical and feel that for every action there is a reaction, ( sounds familiar) but when it comes to helis Ive found this to be so true.

I have serious tail vibes, so I have stripped out and replaced the mainshaft with genuine parts. I have a 450 pro. Spooled it up without the head on and still got the vibes. so..... I checked the tail bar and slider , which all are tight and no play there.......
Then I had brain storm and disconnected the tail servo rod so that I could get a true spool up and bingo..... there was little or no vibrations !!!!!! I have just manually rotated the servo and can hear a click so I suspect there is a damaged gear which is causing a "jump" in that area on spool up.

Could this be it ??? could this teeny weeny click set off a string of vibrations, ? was Einstein right after all lol.

I figured if the vibrations stopped after disconnecting the tail servo rod then the problem lies right there, in that servo somewhere. I would recommend anyone with vibrations to do this check, its quick easy and saves a lot of hassle.

 

[orbi]

Re: One problem leads to another, I have serious vibrations ..i think its the servo g

OK well I dont want to tell your granny how to suck eggs but..... ive done it. ! yep for sure. the tail was vibrating so much that I tried almost everything to fix it. In the end I spooled it up without the head and watched how the tail slider was going mental, I disconnected the servo from the gyro and the vibrations had stopped. So that led me to checking the gears in the tail servo.
When manually turning the servo i could hear a click so I replaced the gears , ( which LOOKED ok under magnifying glass) booted it up with the head on and its perfection personified guys.

I wont forget this one thats for sure.

 

[pvolcko]

Re: One problem leads to another, I have serious vibrations ..i think its the servo g

Good find!

 

[murankar]

Great work. I was going to mention other stuff also. If that was nit the fix I would have suggested other things to check.

Sent from my LG-E980 using Forum Runner

 

[orbi]

Re: One problem leads to another, I have serious vibrations ..i think its the servo g

what other stuff would you try , im keen t know M. ?

 

[Lee]

Re: One problem leads to another, I have serious vibrations ..i think its the servo g

Nice detective work

 

[orbi]

Re: One problem leads to another, I have serious vibrations ..i think its the servo g

Nice detective work

Thanks Lee.

I never knew there was so much in a shake ! One of the problems was a dodgy boom to gear box fix, It kinda was loose from day one, I never could get a real tight fixing there, its a bad design. It could do with a stronger joint there, even a metal insert into the boom to strengthen it might be a better job.!

 

[murankar]

what other stuff would you try , im keen t know M. ?

Improper joints on the boom supports
Free moving push rod
Pitch slider moves under own weight
Blade grips are free moving
Boom installed correctly

Lots of things can cause a tail to vibrate.

Sent from my LG-E980 using Forum Runner

 

[orbi]

Re: One problem leads to another, I have serious vibrations ..i think its the servo g

One more thing to nail it, I noticed that one of the flybar paddles was always lower than the other in spite of exact measurements from mainshaft centre. I simply taped a small metal washer to the other one, and that added to the smoothness somewhat.

 

[murankar]

Re: One problem leads to another, I have serious vibrations ..i think its the servo g

Since you are using a flybar double check the center of the flybar and double check the distance from the flybar cage to the inside edge of the paddles. This is just to make sure everything is center and even.