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Other › L400 Wobble
08-06-2011 05:21 PM  6 years agoPost 1
helinutz

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Bournemouth, Dorset, UK

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Getting to the end of my tether trying to track down a fault on my logo 400.
It has recently (and without any obvious reason) developed a sort of circular wobble on the cyclic when flying.
I started off by checking the vib log, which showed quite high motor vibes, so I replaced that.
No difference so I went through the following, flying the heli after each change to see if it made a difference:-

Replaced V-Bar sensor with new one.
Replaced all rotor head bearings including thrust.
Replaced damper O Rings
Replaced each individual servo (one at a time then fly)
Reset V-Bar and did new setup.
Reduced cyclic gain right down to 45

Its still doing it, and its driving me mad, cause I dont know what else to try.
Headspeed about 2400
Please help

>>>>>I'm so broke, I cant even pay attention!<<<<<

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08-06-2011 05:44 PM  6 years agoPost 2
Paul Gleeson

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Bonn, Germany

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Which serovs are you using?

I had exactly the same issue using Savox SH-1350s after several flights.
Put in a set of Futaba S9650s and the wobble was gone.
Good centering, quality servos make a big difference.

Also, hold the servo arm and a blade grip. Can you feel any slop at all?
If yes, then check your ball links etc.

Hope this helps.

These may also help
http://www.vstabi.info/forum/read.p...49944#msg-49944

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08-06-2011 07:20 PM  6 years agoPost 3
helinutz

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Bournemouth, Dorset, UK

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Cheers Paul
I dont think it is the servos, as its still there even after replacing all 3 cylics.
Servo's are Align DS510
All 3 are now brand new and there is no slop in the system.

>>>>>I'm so broke, I cant even pay attention!<<<<<

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08-06-2011 07:32 PM  6 years agoPost 4
3D-ALEX

rrApprentice

Daytona Beach, FL

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Did you try replacing your mainshaft and spindle? I know that can cause a wobble. It has happened to me on a few helis. It can get bent by transportation or hard flight. It happens.

Hope this helps,
Alex

Alex Morley
Logo 6003D

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08-06-2011 07:45 PM  6 years agoPost 5
Ronald Thomas

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Gainesville, Fl, USA

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Was this after a crash???

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

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08-06-2011 09:31 PM  6 years agoPost 6
helinutz

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Bournemouth, Dorset, UK

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Havnt replaced any shafts as I havnt crashed or damaged it.
1 flight it was fine, next outing it had a wobble.
Theres no obvious vibration, and the vib analasys on the v-bar is pretty low across the spectrum.

>>>>>I'm so broke, I cant even pay attention!<<<<<

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08-06-2011 09:39 PM  6 years agoPost 7
Ronald Thomas

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Gainesville, Fl, USA

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Increase your HS to about 2600.....LMK if that solves it

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

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08-07-2011 12:55 AM  6 years agoPost 8
gorn

rrElite Veteran

Western Australia

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^^^ what he said
I think its a low headspeed wobble.
Kind of a low frequency circular wobble.

2400 is very very low for a L400.

For the love of the hobby

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08-07-2011 10:35 AM  6 years agoPost 9
helinutz

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Bournemouth, Dorset, UK

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Will double check later today, but pretty certain it just gets more pronounced the higher the headspeed, and it seems strange that the wobble just appeared when nothing had changed (including headspeed)

>>>>>I'm so broke, I cant even pay attention!<<<<<

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08-07-2011 12:14 PM  6 years agoPost 10
Paul Gleeson

rrApprentice

Bonn, Germany

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Before I stretched my 400 to a 400SE, I was running about 2100rpm with stock dampers, and no wobble.

After I changed Savox/Align servos to Futaba 9650. My servos were also new, I even changed the gear set as well.

So a Logo 400 can run low head speeds without issues.

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08-08-2011 10:24 AM  6 years agoPost 11
Roger Salmon

rrNovice

Prenton UK

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Helinutz

I tried Align 510's once and got the same problem. Went away once they were replaced with 9650's

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08-08-2011 11:26 PM  6 years agoPost 12
helinutz

rrVeteran

Bournemouth, Dorset, UK

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OK, tried higher headspeeds and the oscilation just gets quicker the faster it goes.
Decided to swap out the maingear for a mod 0.7 one as it was in the pipeline to do it anyway.
New Kontronik pyro 600-11 motor and 17 tooth pinion and tried again.
Wobble still there
If I crank it up to 2700, it does seem better, but I just think the wobble is increasing in speed to the point where its becoming less pronounced.
Went back through with the vib log, and without mains it was a maximum of 274, with mains 467, so dont think its a vibration issue.
I hear what a few of you are saying re- DS510 servos, and if I can pick up some different ones, I will give it a go, but again, it doesnt make sense that it would go from fine one flight to wobbling the next, and then not cure it (even for a short time) with brand new, slop free servos.
Will keep digging, but starting to really frustrate me now.

>>>>>I'm so broke, I cant even pay attention!<<<<<

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08-11-2011 05:55 PM  6 years agoPost 13
HeliFisher

rrVeteran

Verdi , Nevadafornia

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I would suggest checking the bearings in your taildrive gear. I've seen that one cause some different problems that would seem unrelated. It's worth a look whilst your checking everthing else....

Good luck!

The less a man makes a clarative statement, the less likely he is to look like a fool in retrospect.

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08-11-2011 07:19 PM  6 years agoPost 14
helinutz

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Bournemouth, Dorset, UK

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Will do ta

>>>>>I'm so broke, I cant even pay attention!<<<<<

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