heli vibration problem need help

[bioactive23]

i hav an erazor 450 and i hav replaced the flybar main shaft main gear pinion nd fethering shaft and i still seem to hav a vibration from something and im pretty much lost i cant figure it out doesn anybody have any ideas whats causeing it help help help

[salrica]

Have you check your blades pitch?
Dampeners?
Servo links?
Main rotor head?

[srt4tom]

Dose it vibrate with the blades off?

[Dylan Hudock]

have you replaced the tail shaft? I had a really bad vibration a couple days ago and then i noticed that the tail shaft was bent considerably, enought to see it with the whole tail assembly on the tail shaft. You should replace the tail shaft if you havent already.Spool up with out the main and tail blades on too because might be unbalanced blades.

[srt4tom]

Originally Posted by Dylan Hudock

have you replaced the tail shaft? I had a really bad vibration a couple days ago and then i noticed that the tail shaft was bent considerably, enought to see it with the whole tail assembly on the tail shaft. You should replace the tail shaft if you havent already.Spool up with out the main and tail blades on too because might be unbalanced blades.

Dude!! that's just not right, telling someone to replace something that you haven't even determind that's it's the problem.

[Dylan Hudock]

The tail shaft was the only thing that he didnt list that he had checked. I only told him he maybe should replace the tail shaft or atleast check it because that was causing me a bad vibration other day and that could maybe fix his vibration problem.

[Michael bacon]

Sounded reasonable to me!!!

[alyon187]

Good luck finding parts for that thing...

[lainchy]

My Hughes 500 Vibrated like crazy when I spooled it up the other day. I've stripped it and checked... knackered bearings on the tail, so I replaced them... just spun it up on the bench, checked all again... knackered bearings in the tail box again!

I had a glass of port last night, and while tinkering, I spooled up, blades off, under fluorescent light... I got a bent tail shaft! Need to change that at the very least and then maybe it'll stop eating bearings!!

Another thing though, is that the motor doesn't spin up the same every time??? I have no idea what that is yet... almost like it only spins to 75% one time... shut down and re-spool gives 100%

Think this one is a Friday afternoon built heli! All sorts of bits changed and I haven't flown it in anger yet either.

Getting there slowly though

[macdad]

There is also plenty of opportunity for binding in a Flybar head. Make sure you don't have any binding anywhere in the head.

Since you replaced the feathering shaft, I would probably start by checking the main blade grips.

Also, since you changed the main shaft, you should make sure everything is level at mid stick and the endpoints.

I also agree that you should check the tail rotor shaft. I have bent these from a rough landing on skids. No tip over or anything and the tail rotor bent.

[pctomlin]

Being a flybar head the flybar needs to be exactly centered in the cage and the paddles need to be the same distance from the cage or you will have vibes. A slightly bent tail shaft will also induce vibes that can be hard to locate unless you are looking specifically for this cause.
When chasing the illusive vibe diagnose on the bench with no blades and start removing rotating parts until you find the culprit, just remember it could be the bearing this part is turning on.

[Highspeed1964]

One other thing that often gets overlooked in troubleshooting vibrations is the pinion to main gear adjustment. If it's too tight it could also lead to vibrations. Too loose and you could strip the gear. Check that the clearance between the two gears is sufficient to pull a piece of paper through without binding.

Highspeed