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Old Nov 20, 2012, 02:06 AM
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United States, NY, New York
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Wow...you need to get rid of that vibrations the gyro is detecting in your tail section. Seems that it also is seeing some problems from the mains as well. Fix that problem first before you increase the gains.
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Old Nov 20, 2012, 07:21 AM
Team Mulikow 3D
Oxfordshire, UK
Joined Jan 2007
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Quote:
Originally Posted by scribble007 View Post
Tried turning them up a bit. And got severe wobbles. So Turn them down a bit and it flies reasonably well. I blame my unbalance-able blades for the tail getting the shakes every once and a while.

How do you lower gains for the tail to stop the osculations ? Is it the Acc?

And on a second note. First successful flight with the 600 can attest to the vibration resistance this thing has. It flew like a champ!!
Scribble,

As R_R said you're probably not going to get the tail to work well until you sort out the vibes, lots of gyros and FBL units suffer from drift or other maladies if the heli has noticeable vibes.

Good luck,
Mike
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Old Nov 20, 2012, 10:26 AM
RobirdUSA.com
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United States, CA, San Diego
Joined May 2012
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Originally Posted by MikeHRC View Post
Scribble,

As R_R said you're probably not going to get the tail to work well until you sort out the vibes, lots of gyros and FBL units suffer from drift or other maladies if the heli has noticeable vibes.

Good luck,
Mike
Regarding the vibration that the G31 log is showing: The G31 will show some natural vibration that occurs when you're doing certain 3D maneuvers. For example, if you're doing tic-toc maneuvers there will be some vibration as the blades rapidly change their pitch.

On the other hand, if all you were doing was hovering or some forward flight and the G31 detected a large amount of vibration then there is a more serious problem.

You need to take a look at your Vibration Analysis log and consider what you were doing at the time that the G31 detected the excessive vibration. That's the reason why the vibration analysis is conducted along a time line. Take a look at the whole picture, not just that one red bar.
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Old Nov 20, 2012, 12:02 PM
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United States, CA, Yosemite Lakes
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That was on the 600
Mostly just forward flight. But a couple very poor tick tocks.
As a whole, it had bad vib issues
But the 450 is much better having normal vibs in the sub 300 range. But It's having the tail issues. The 600 is acting solid much to my surprise
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Old Nov 20, 2012, 12:48 PM
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Scribble: My 450 did the same thing. It turned out to be bearings in the tail. I allso had to fiddle around with the gain settings in the transmitter to get rid of a minor tail wag. This gyro works really well, but mechanical setup still has to be pretty close. Good luck. Ed
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Old Nov 20, 2012, 02:29 PM
just gotta mess with it!
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North West Louisiana
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Another thing that can go unnoticed is the end fitting working loose on the carbon boom braces, might be worth checking them.
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Old Nov 20, 2012, 04:22 PM
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United States, WA, Issaquah
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Originally Posted by 2Doggs View Post
Another thing that can go unnoticed is the end fitting working loose on the carbon boom braces, might be worth checking them.
+1
particularly if you have them epoxied. Many complain about CA not being as strong in this application, but I find that CA, being a bit more flexible, stands up to vibration much better than the tougher epoxies. I've actually done a test on my Protos by mounting one of the boom braces into the end fittings with JB Weld and the other with thick CA from hobbyking. It took about 100 flights and the epoxied boom brace worked itself loose from the end cap (at the aft side), while the CA is still holding strong. I've since removed the epoxied boom brace ends and CA'd them in place too.
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Old Nov 20, 2012, 09:30 PM
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Originally Posted by Dr.M View Post
+1
particularly if you have them epoxied. Many complain about CA not being as strong in this application, but I find that CA, being a bit more flexible, stands up to vibration much better than the tougher epoxies. I've actually done a test on my Protos by mounting one of the boom braces into the end fittings with JB Weld and the other with thick CA from hobbyking. It took about 100 flights and the epoxied boom brace worked itself loose from the end cap (at the aft side), while the CA is still holding strong. I've since removed the epoxied boom brace ends and CA'd them in place too.
i had the opposite experience....CA broke loose but the JB Weld held like a bleep.
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Old Nov 20, 2012, 09:43 PM
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United States, CA, Yosemite Lakes
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Thanks for the tips. I will try all that.
My blades seem to still be balanced on the 600. I got new tail blades to try, New main shaft, Has anyone ever experienced the swash plate bearing being out of round? It seems like its got a small wobble in it. But I don't have a blade balancer for helis. Just the dubro one.
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Old Nov 21, 2012, 01:11 PM
just gotta mess with it!
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North West Louisiana
Joined Nov 2009
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I had a clone 450 swash that was a bit eccentric. I think it was caused by the ball wearing in the socket rather than it being manufactured off centre. Check for up and down play in the ball in the socket.

With the clone swashes, the top and bottom halves can often be joined a bit loosely. It's sometimes possible to take out the slack by judicious use of a hammer, peening the bottom edge of the top part. You'll probably see five or more flat indents where it's been pressed together.

Even if the swash was running a bit off centre, I don't think it would give you big vibrations though.

If you continue to suffer bad vibes, you might have to resort to taking off the main and tail rotors, and even the swash, checking for vibes, then adding parts back on incrementally, checking for vibes each time.

On my 450, I feel the tail fin by hand with the heli spooled up. Obviously not a risk-free procedure, even more so for a large heli, but you can immediately feel lower frequency vibes from the main rotor and higher frequency ones from the tail. You could certainly do that safely without the blades on, though.

Good luck!
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Old Nov 21, 2012, 04:13 PM
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Quote:
Originally Posted by 2Doggs View Post
I had a clone 450 swash that was a bit eccentric. I think it was caused by the ball wearing in the socket rather than it being manufactured off centre. Check for up and down play in the ball in the socket.

With the clone swashes, the top and bottom halves can often be joined a bit loosely. It's sometimes possible to take out the slack by judicious use of a hammer, peening the bottom edge of the top part. You'll probably see five or more flat indents where it's been pressed together.

Even if the swash was running a bit off centre, I don't think it would give you big vibrations though.

If you continue to suffer bad vibes, you might have to resort to taking off the main and tail rotors, and even the swash, checking for vibes, then adding parts back on incrementally, checking for vibes each time.

On my 450, I feel the tail fin by hand with the heli spooled up. Obviously not a risk-free procedure, even more so for a large heli, but you can immediately feel lower frequency vibes from the main rotor and higher frequency ones from the tail. You could certainly do that safely without the blades on, though.

Good luck!
I had the tail blades on my 450 shear off the rubber duck antenna on a radio once. I have no doubt they could do the same to fingers.
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Old Nov 21, 2012, 04:56 PM
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United States, CA, Yosemite Lakes
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lol
Try at your own rick type situation.
My bearings seem a bit off center. Ill have to post a video of what I'm talking about cause its hard to explain.
But with only the blades off. If I slowly rotate the head by hand. You can see the swash holding level but rocking back and fourth going straight back toward the tail by 1-1.5mm and then forward again.
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Old Nov 21, 2012, 07:14 PM
just gotta mess with it!
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North West Louisiana
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Quote:
Originally Posted by scribble007 View Post
lol
Try at your own rick type situation.
My bearings seem a bit off center. Ill have to post a video of what I'm talking about cause its hard to explain.
But with only the blades off. If I slowly rotate the head by hand. You can see the swash holding level but rocking back and fourth going straight back toward the tail by 1-1.5mm and then forward again.
Wow, that's a lot! Normally, you might see a fraction of a mm.
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Old Nov 22, 2012, 02:14 AM
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United States, CA, Yosemite Lakes
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It's enough to see movement in the swash slowly turning by hand. But the main shaft is perfectly straight
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Old Nov 25, 2012, 12:33 AM
Retired Old Guy
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United States, IL, New Lenox
Joined Jan 2012
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RJX FBL Head Arrived

My RJX FBL Head finally arrived today. I ordered it from Hobby King on Oct 23 and it arrived today. My Robird G31 controller that I ordered from http://www.tarot-rc-heli.com/ has also shipped. I should have it on Tuesday or Wednesday of next week. I hope to have the heli in the air (weather permitting) on Saturday. It has been cold so I hope it warms up a bit and the wind calms down.

RWW
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