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550 Class Electric Helicopters 550 Class Electric Helicopters manufactured by Align, Tarot, SYMA, Airhog, Chaos, HK and similar.


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Old 05-03-2012, 02:22 AM   #1
Mikka_
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I'm sure there's many posts on this topic but I can't find what I'm looking for and want to ask fellow 550 owners. I am having a problem with excessive vibrations. My 550e V2 is new and never crashed. It's not very bad vibration and it does not seem to affect flight but it does seem to vibe more then it should. I can see the vertical tail fin dancing around the whole time. I want to try reduce vibration as much as possible in order to strap a camera to her. I dont know where to start. What process would you recommend and what are the most common causes of excessive vibes?
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Old 05-03-2012, 02:51 AM   #2
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Bearing in the tail tube that 'holds' your TT would be the first thing I checked. Also, how far up is the rubber pushed through the tail tube?

Could be a few other things.
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Old 05-03-2012, 04:26 AM   #3
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Its a new bearing and I have it at the exact distance specified in the manual. It does seem like a likely source of vibration but I'm am rather certain it's in good shape
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Old 05-03-2012, 04:28 AM   #4
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You would be surprised how many overlook it thinking it is ok.

Does your tail slider move smoothly through the entire length of shaft?

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Old 05-03-2012, 04:32 AM   #5
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Also remove your main blades and tail rotor and see if you experience same issue.

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Old 05-03-2012, 05:24 AM   #6
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Quote:
Originally Posted by msedhom View Post
You would be surprised how many overlook it thinking it is ok.

Does your tail slider move smoothly through the entire length of shaft?

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Tail slider?? Not sure what you mean by this. I will pull the tail apart an check that the glue holding the TT bearing in place hasn't come loose and check it is all still as it should be but I don't think this is my problem. I have spun it up with the head off and I still get vibes. Main shaft appears the be completely stationary as far as its axis goes. Haven't tied removing tail blades. Will try that next. Thanks for the ideas. Keep em coming
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Old 05-03-2012, 05:32 AM   #7
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Its a well known issue. Im not sure if there has been a one fits all solve for this issue. There has been reports from the motor vibe, torque tube etc. Its kind of hard to tell if your heli has an "actual" vib issue unless you have a vbar with the spectrum analyzer running on it. Even then the vbar was happy enough with the vibes when the tail fin was shaking. I noticed it at the start & the fix was just to mask it by putting a thicker tail fin on it off a 600 or 700. You don't see it after you have put the thicker ones on. So just dont look at it haha.
Having said that, i have put the 550 tail fin back on to lighten it up. I never thought to look at the tail fin so ill have a look this weekend.
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Old 05-03-2012, 06:29 AM   #8
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Yeah I have read a lot of people say that the flimsy 550 fin does show al lot of vibration for most people. Mine seems to show more then I think is normal. Shaky camera footage is my main motive for reducing vibration though.
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Old 05-03-2012, 06:31 AM   #9
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Torque Tube probably has a slight bend in it. Adding an additional bearing in the boom fixed it for me. You might also want to try to straighten the torque tube.

Yes, brand new torque tubes come bent. It doesn't take much. If it's not perfectly straight...vibration.
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Old 05-03-2012, 07:07 AM   #10
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Quote:
Originally Posted by Rototerrier View Post
Torque Tube probably has a slight bend in it. Adding an additional bearing in the boom fixed it for me. You might also want to try to straighten the torque tube.

Yes, brand new torque tubes come bent. It doesn't take much. If it's not perfectly straight...vibration.
How can u tell if your TT is slightly bent. Especially once the bearing has been glued in place. I am starting to believe it is a torque tube related problem.
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Old 05-03-2012, 07:18 AM   #11
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Prior to installing the bearing I would have suggested rolling it on a flat surface or holding it up to a light.

With the bearing, you might try one of the following:

1) Put it on a DuoBro Tru Spin balancer or some other spinning balancer and check for wobble.

2) Remove the tail assembly from the end of the boom. Spin the gear and see if you can notice any wobble in the torque tube at the end of the boom. Should spin dead center within the boom. If it's wobbliing off center then it's bent.

Problem with method number 2 is that it could be bent forward of the bearing. In which case you would need ot rever the process and pull the boom from the block. Then spin the tail blades and see if the TT is wobbling in the front of the boom.

In electrics, there really isn't a whole lot of things that are going to cause a tail vibration. If it were a gasser or nitro, you could certainly spend more time tracking it down. The Electric motor really doesn't produce that much vibration...not enough to really make the fin dance all the way down the boom. The boom itself is typically the only suspect for this problem.
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Old 05-03-2012, 08:07 AM   #12
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I've seen this issue so many times and I really think it all comes down to careful preparation and assembly of the TT. I have built many 550's and have never used more than one bearing and they all run great. I don't like the idea of adding more bearing to this assembly because this can cause ither issues that I really don't have time to explain right now. The single bearing will give you the compliance that you need to deal with small amounts of error and with careful assembly will run flawlessly. Here are a few observations and tips:
  • The 1.6mm fin is weak and will shake on just about any 550 built. Go out and get yourself a 2mm fin such as a Tarot or just get a 600 tail fin (this has already been stated in other posts).
  • In assembling the TT bearing I do not use CA but actually secure the bering with Loctite 680 (Thick Green Loctite). I measure the location, put a piece of blue painters tape around the TT, clean the ID of the bearing and the TT with rubbing alchohol, apply a smooth coat of loctite to the TT with a small brush, Install the bearing onto the TT being careful not to get any loctite in the bearing, carefully adjust the bearing so that it is rotation true to the TT axis of rotation (this is critical since there is a bit of slop in the fit and you can rock the bearing back and fourth on the TT), and carefully set this aside to dry overnight.
  • In assembling the TT put the boom on the machine, assemble the TT into the boom, look at the position of the TT relative to the center axis of the tail boom, and record this position on a piece of paper. Now, pull the TT back out of the gear, rotate it 90 degrees, reinsert this into the TT gear, and record the position like the first time. Repeat this procedure 2 more times and then look at the recorded exit position on the TT relative to the tail boom and set the TT to the one that puts the TT closest to centerline. Install the tail box and you should be good to go.
Hope this helps...
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Old 05-03-2012, 09:51 AM   #13
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Take the tail grip/hub assembly off the tail shaft and see how that feels. Then convert to a belt tail (the tail shafts are much straighter)
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Old 05-05-2012, 09:06 AM   #14
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Ok I checked my TT and bearing and everything looks good I then noticed the front TT gear seemed to have a slight resistance in one spot as I turned it by hand. I think it was slightly bent. So I replaced it. I also replaced the vertical fin with a 700 fin and now she stays still. I still notice some unwanted vibration when I attach a camera but I think it is now in the normal vibration spectrum.
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Old 05-05-2012, 03:47 PM   #15
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Mine shakes a bit on the ground, but once airborn it goes away, bird fly fine. I'm pretty sure with mine it's the flimsy vertical tail
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