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HelicopterThunder TigerOther › R90SE Vibes
05-08-2005 04:08 PM  12 years agoPost 1
Will B

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Bicester, Near Oxford, UK.

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HELP!

I've recently built an R90SE and althogh it flies great the thing vibrates like a bitch. This shows up in the tail realy bad with about a 1cm hi frequency vibration. Today the vibration cracked a boom support....not good. The carbon boom is MEGA bendy and the boom supposts are just as bendy too.

So, I'm wondering wether this vibration could be caused by the head dampening? I am running red rubbers with 2 shims, all well greased. The vibration tends to come and go when at hover rpm but its noticeable when I flick on the Governor in idle up and it locks into 15000 on the YS91. The manual says that an osscilation can occur at 1600. As I'm not sure what gear ratio the 90SE uses I'm not at all sure if my headspeed is close to that. I've also heard people here say that the manual is wrong and that this osscilation occurs at a higher headspeed. True? I have checked over the head and flybar for balance, i dont think its a really high freq vibration liek out of balance fan, which leaves the tail out of balance or this sodding osscillation thing.

Have others found their 90SE booms to start shaking when at the "wrong headspeed" (whatever that is!!) ??

Cheers, Will.

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05-08-2005 06:19 PM  12 years agoPost 2
drdot

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So. California, Orange County.

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My two cents..

I'd suspect an out of balance head..HIgh point the head if possible, check the main blades and tail blades for balance...This heli should be like buttah!

John.

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05-08-2005 06:28 PM  12 years agoPost 3
col

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U.K. Ipswich.

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thats a vibe.

Not a headspeed nodding load of old bollox.

that headspeed nodding thing can sometimes occur BUT it won't be there all the time. Only just after a control Input.

First take out the shims, UNLESS u have end float without them.

Next Try softer blue dampers.

U do not need to balance anything on a raptor.

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05-08-2005 06:30 PM  12 years agoPost 4
col

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U.K. Ipswich.

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P.S.

i feel ur pain mate. mine did it..

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05-08-2005 08:04 PM  12 years agoPost 5
Will B

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Bicester, Near Oxford, UK.

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Col, I know what your saying by telling me to remove the Red dampeners but I dont want to use the Blue dampeners! I surely shouldnt have to compromise flying performance to get a heli that flies without vibes, no??!!?!

I think I may try and balance the head next, then the tail rotor as it seems thats where all this rattle is coming from. Never had to do it before on a new heli so this will be a first!!

Still a little disappointed about the flex in the tailboom and boom supports...kinda lets down an otherwise superb helicopter!!

Cheers, Will.

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05-08-2005 08:26 PM  12 years agoPost 6
stevengerrard

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Wigan NW of England

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hi Will B
has it just started doing this or has it always done??

dont remove the reds......i run 2 SE's.
it should not do as you describe...there is a problem some were....

i use the red dampners in the wrong way to make them even stiffer and use 1 thick and all 3 thin shimms on each side of my heads and dont get any wobble...at any head speed ....

check the spindle is greased well....

did you put the tail drive rod in tight up as far as it goes?? if it is pushed in hard if becomes very stiff.....you should put the drive shaft into the boom then push the drive shaft as far in as it will go ..then back it of about 2mm...

not sure why your carbon boom is bendy....mine are stiff..

also check that the alloy ends on the boom supports are glued on well...i had 1 of mine come loose and the tail would shake badly.....undo them and give them a firm pull and twist to see if they are loose....

also i find it better to move the strutts lower down the frames ....see pics....


also check the one way auto unit....i no when mine locked up about 3 weeks ago it started shaking.....

let us no what you find....hope this info helps...its just what i have found flying these fine helis....

Regards

Steven Gerrard

CarbonXtreme
AvantRC
V Blades
Magnum Fuel
Align
Spektrum
Thunder Power

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05-08-2005 09:51 PM  12 years agoPost 7
C-DOG

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SunShineState

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Steve is absolutely correct

about the struts.Move them down.Also look into the arrow shaft mod for the tail.Assuming that you have balanced your clutch and fan,If not this will also cause the tail to shake violently.Also check your tail drive- shaft guides are spaced properly.

Good Luck Corey I PAY-PAL

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05-09-2005 11:08 AM  12 years agoPost 8
Will B

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Bicester, Near Oxford, UK.

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OK guys. I didnt back the boom out a couple 2mm but will try that next. Will also check the tube drive spacing and also move the boom supports downwards towards the skids.

I'll let you know how it goes!!

Cheers, Will.

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05-12-2005 11:09 PM  12 years agoPost 9
flytech

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Sunland, CA

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engine/clutch alignment

i'm new to 90se tuning but i wondered if this could be mis-alignment between the engine and the clutch bell... couldn't that cause vibes if not aligned properly? i would think so anyways...

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05-12-2005 11:40 PM  12 years agoPost 10
frankg11

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Bellevue, WA

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I also have head nodding on my 90SE.

Running Blue Dampers, No head float, no shims needed, well greased spindle.

I am going to put in a set of Carbon Extreme Dampers tomorrow and flyi it on Sat to see if prob still exists.

If so will be back for more help.

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05-13-2005 03:24 PM  12 years agoPost 11
Qrrambero

rrKey Veteran

San Francisco / Bay Area

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Something that may help.
Check tracking. Sometimes we do not see it. Ask your friend to check it for you while you hover.
Also, many of the vibration come from the engine. If it not set right the heli flys like a dog. Open the neddles few clicks and see if you see any different. Start with the mid r.
Good luck
Ae

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05-13-2005 05:50 PM  12 years agoPost 12
RCtaz

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Leander, TX

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use a run out guage and check your tail output shaft. Mine was 20 thousanthes out of true and was causing the same prob on a rappy 50. you could not see it with the naked eye. took a run out gauge to find it and prob sovled! Would not hurt to try it. Hope that helps.

Mike

~Texas Renegade Rotorz~

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04-17-2006 02:39 AM  11 years agoPost 13
TAZZY

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Westfield,MA

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dial indicate the crankshaft and fan, i know others who ran the metal fans and they had lots of runout when dial indicated. if you are running a metal fan, change it to a plastic one to see if it is your problem.

GDay

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05-09-2006 04:17 AM  11 years agoPost 14
smartguy

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Corona, CA

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did u solve the problem? my new 90 SE having the same problem

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05-09-2006 05:15 AM  11 years agoPost 15
flytech

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Sunland, CA

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most of the new birds I've dealt with have been due to dampeners needing lube or head linkages being too tight (needing reaming). although there's a small chance of manufacturer flaws, you can reserve checking the various shaft straightness once you've dealt with the what could be the most obviously wrong in a new setup.

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05-09-2006 05:27 AM  11 years agoPost 16
smartguy

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Corona, CA

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do the dampners need lube in the inner hole or the outter part? and does lithuium grease work?

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