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Logo 400 › Logo 400 vibration problem
08-02-2011 06:37 PM  6 years agoPost 1
Maxime30

rrApprentice

Quebec City, Canada

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I'm trying to figure out a possible vibration problem with my friend's Logo 400.

When I spool up, the cyclic servos go crazy.

Here's a picture of the V-Bar vibration analysis, with no main or tail blades attached. Can you help me analyze this graph???

Thank you!

Max

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08-02-2011 06:42 PM  6 years agoPost 2
Ronald Thomas

rrMaster

Gainesville, Fl, USA

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Looks like mains to me. Could be the main blades, main shaft or spindle. Any crashes??? Any chance the sensor is touching the frame other than on the pad???

Team MikadoUSA 480XXTreme, 550SX, 600SX, 700XXTreme, 800XXTreme!!

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08-02-2011 06:47 PM  6 years agoPost 3
Maxime30

rrApprentice

Quebec City, Canada

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Yes I believe the machine was crashed and repaired by my friend.

He changed the main shaft and spindle. I ran this analysis without blades.

Could it be the main shaft bearings?

I'll remove everything above the swashplate and run the analyzer again...

Max

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08-02-2011 06:49 PM  6 years agoPost 4
Ronald Thomas

rrMaster

Gainesville, Fl, USA

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Absolutely....the main shaft bearings could be it as well. Since you did not fix it, check it all

Team MikadoUSA 480XXTreme, 550SX, 600SX, 700XXTreme, 800XXTreme!!

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08-02-2011 07:01 PM  6 years agoPost 5
Maxime30

rrApprentice

Quebec City, Canada

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I just removed the main shaft and I ran the motor unloaded. Here,s a graph of the analysis...

The cyclic servos are still a bit jerky... Much less than before but they still move a bit.

Max

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08-02-2011 07:02 PM  6 years agoPost 6
Ronald Thomas

rrMaster

Gainesville, Fl, USA

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Does it have the static kit???

Team MikadoUSA 480XXTreme, 550SX, 600SX, 700XXTreme, 800XXTreme!!

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08-02-2011 07:19 PM  6 years agoPost 7
Maxime30

rrApprentice

Quebec City, Canada

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I might have found something... The motor shaft seems to be bent a little bit...

My friend will bring me another motor and I'll give it a shot.

Thank you!

Max

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08-02-2011 08:02 PM  6 years agoPost 8
Ronald Thomas

rrMaster

Gainesville, Fl, USA

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That would definitely be a serious vibration issue. Glad you found it

Team MikadoUSA 480XXTreme, 550SX, 600SX, 700XXTreme, 800XXTreme!!

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08-02-2011 08:34 PM  6 years agoPost 9
Paul Gleeson

rrApprentice

Bonn, Germany

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Check the shafts etc for straightness.

2 other big areas to check are gear mesh, and that the boom is absolutley 100% at 90deg to the main shaft.

Use a digital angle gauge if you can get one.
Or a spirit level on the boom, and check against the main gear.

http://www.vstabi.info/forum/read.p...49977#msg-49977

This was my experience

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09-13-2011 07:33 PM  6 years agoPost 10
Maxime30

rrApprentice

Quebec City, Canada

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Just realized I never came back to say what the problem was...

I rebuilt the whole machine, and still had the problem.

Turned out to be a faulty V-Bar, the main module, not the sensor. Possibly a cold solder joint, or maybe some crash damges ( I don't know the full history of this V-Bar)

Thank you!

Max

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09-13-2011 11:45 PM  6 years agoPost 11
ckevin

rrNovice

Santa Clara, CA

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Mine was due to the sensor.
I had a similar problem. My heli oscillated in an aileron axis.
I sent in my vbar to Mikado, and it diagnosed as a faulty sensor(black sensor).

Recently, a friend of mine had the same problem as me and it worked OK after he switched to a new VBAR(blue line). It seems that the black sensor is more prone to vibration. Good luck.

Regards,

Kevin

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