rtn9105

My Feedback: (35)

I'm still in the newbie learning stage of helicopters. I put about 8 tanks through my Raptor before I crashed it and had to replace some parts. Since then it has had a vibration just after lift off that shakes it violently enough to bend both ends of the flybar up.
To date I've replaced the following:
Flybar (several times)
Flybar paddles (checked, rechecked, and double rechecked the alignment)
Main rotor shaft
Feathering spindle
Tail rotor shaft
Tail rotor blades
Tail pitch slider
Main blades (rebalanced several times) (also tried carbon blades from a friends V2 and still had the shaking)
Starter shaft
Clutch
Clutch bell and liner
I've checked the bearings associated with all these parts and all seem to be fine. I'm to the point that I don't know of any other parts to replace to get rid of this shaking and the heli has spent about 10x more time on the bench than it has at the field. Any other suggestions are welcome.

ShempHoward

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Are you using training gear? If so sometimes that can generate very serious vibration problems.

kmbeers

It looks like you have changed almost everything that could be the problem. First I would try and balance the flybar/paddle assembly becayse they could be the source of the problem. Just pull out the main bolt below the main gear, disconnect the linkage from the swash, remove the main blades, and lift out the entire head assembly. Using a high point balancer balance the entire assembly. The other thing i would check is the Fan assembly to be sure it is running true. This is done with a dial indicator. I hope this helps....
kmbeers

bl092599

My Feedback: (1)

Hey there!
I once had a similar problem with my raptor 30 v1 and what i found was that the bolts were to tight on the swash plate bearings and on the seesaw bearings, what I did was popped the links and moved the applicable arm to see if there was resistance or if they moved freely. if they were tight i loosened the bolt 1/8 turn or so at a time till the lever moved freely on the bearing. I hope this helps and good luck

rtn9105

My Feedback: (35)

Well I've just about had it with this thing. I tried flying it again today and got the same results, got it about 2 feet off the ground and the shaking started. By the time I got it back on the ground, it had bent both ends of the flybar up so the flybar looked like a big U.

ShempHoward: yes I'm using training gear but I've tried 3 different sets that work just fine on other helis and still get the vibration. So I'm pretty sure that's not the cause.

Bl092599: I checked all the bolts and bearings that you mentioned, all seemed to move just fine.

Kmbeers: I checked the fan when I changed the clutch, all seemed fine with it. I don't have a high point balancer so I can't do the main shaft assembly right now.
Besides I'm at the point that I don't really want to stick any more money into this thing. I've already bought allot of replacement parts just to find out that they weren't the cause of the vibration to begin with. Plus replaced allot of parts that keep getting bent from the vibration. I think the shelf is looking pretty good for it right about now.

Thanks for trying to help anyway

pilot77

is the engine running okay, i gather that can cause vibration if its misfiring. and not set right.

rtn9105

My Feedback: (35)

Engine runs great.
I had wondered about a bent crank causing the vibration but I would think it would shake all the time then, not just after it gets in the air.

rtn9105

My Feedback: (35)

Does anyone know the phone number for Thunder Tiger's tech support? I looked through the manual but found nothing.

Helirat

Rtn you can go to thunder tiger main page and get the phone #
here is the link
http://www.acehobby.com/acehobby/

green river rc

My Feedback: (2)

Any chance you have your paddles on backwards?

rtn9105

My Feedback: (35)

Helirat, thanks for the info on TT. I'll give them a call to see if they have any ideas.
Green River, Checked just to make sure (at this point I'll try anything) but they are on the correct way.

After spending the entire day thinking about what could be the cause of this vibration, I have come up with one other thing that I haven't addressed yet. This vibration all started after I had a mild tail boom strike. I didn't have the blades tight enough and I set it down pretty hard. One blade hit the tail boom just hard enough to chip the tip of one of my carbon blades and to put a small dent in the top of the boom. I've changed all of the parts listed in my first post since this happened, but I haven't changed out the tail boom. The dent didn't seem big enough to cause any problems. My question is this. Is the dent in the attached pic large enough to cause this vibration? Could the belt miss the dent at low RPM's but stretch enough at higher RPM's (hovering RPM) to hit the dent and cause the vibration? This would maybe explain why it's fine on the ground but 5 or 6 seconds into a hover it starts to vibrate and shake. I don't know if this is possible or not, what do you all think?

Nakz

Ask some experienced guy to fly your heli without trainning gear, different helis have different ressonant frequencies.

rtn9105

My Feedback: (35)

Thanks, I can give that a try. If the training gear is causing all of this, I still have a question. When I first got heli it flew fine with the training gear, no shaking at all. Does the resonance frequency change the more the heli is flown to cause the shaking to start after a few flights?

raptor_dude

Probably too low of an rpm. When the rpm gets too low the spindle felxes up so much that the dampers loose effect and the heli will shake.

Colin

Nakz

In fact same happened to me, because of the flexibility of some gear's legs there's an up and down movement (air pressure forcing it to down and then the leg recovering itself) that starts low and increase after a few seconds into a hover (resonance), this vibration is transfered to the heli. Try to short the training gear's legs and/or tighten it, this will modify the resonance frequency. With so, ask someone to fly it without training gear, at least, u will check if the problem doesn't come from the gear.I hope this helps :-)

randy41

Well: If this heli was fine before the crash then it has to be
either you done something wrong when installing parts.
Maybe got something out of adjustment/alighnment/balance
or you got a bad part from the factory. I would recheck the
spindle/main mast for straightness. Recheck all adjustment/
alignment and balance. The tail boom dent dont appear to be
bad enough by the pic to cause you any problems.But I my self
would replace it cause i couldnt stand the thought of that dent
in the tail boom. LOL

frugalflyer

If the vibration is so bad that your bending the flybar then it may be more radical than an out of balance problem. It is unlikely that a dented boom is the culprit. I fly with booms in a worse shape than that. I even made a tool for pushing out the bad dents.
I went through a period of severe shakes - more like violent up and down movements, that I got over by flipping the blades so that the links lead the blades. There's some 'how to' pics on my page http://geocities.com/wisebrit. This is an old problem that was much discussed in the past. There were lots of theories - but whatever caused the problem flipping the blades solved it.
Do try it - it is quite an easy to do

scouse

How about posting some pics of the heli, maybe uve just got something set up wrong with the head or something. Got to be worth a look b4 u shelve it

rtn9105

My Feedback: (35)

Well first of all I'd like to just say thanks to everyone for all the help. I flew it today and all the vibration is gone.
The only thing that I've changed is putting the stock muffler back on it and I don't think that would make a difference, but it doesn't shake anymore so I guess I'll keep it.
Again thanks for all the help

Mikee-RCU

My Feedback: (2)

It's about time ya let us know what was happening with it. Glad to hear it's flying for you. Were your ears ringing on Sunday?
Mikee

rtn9105

My Feedback: (35)

Hey Mikee

Were you guys talking about me again?