RunRyder RC
 3  Topic Subscribe
WATCH
 1 page 718 views
Scorpion Power Scorpion Power
HelicopterHIROBOOther › X Spec tail vibration
08-08-2007 12:59 AM  10 years agoPost 1
bobbyhill4x4

rrApprentice

Watertown NY

My Posts: All  Forum  Topic

I have been chasing a tail vibration in my X-Spec for over a year. I have removed and balanced the engine and fan, replaced tail blades, replaced tail shaft and check for missing screws. The problem was reduced after changing the tail shalft but have returned. Is this a common problem with the X-spec.

Thanks
Robert

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 02:09 AM  10 years agoPost 2
RICH.L

rrKey Veteran

east springfield​p.a.

My Posts: All  Forum  Topic

are you talking about an actual vibration or a buzz form the fins?

my evo 90 gets a terrible buzz in the horizontal fin in idle up.

rich

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 02:36 AM  10 years agoPost 3
Turkana

rrKey Veteran

Montreal,Quebec ,​Canada

My Posts: All  Forum  Topic

Hi

Well some time back I talked to a advanced 3 D Pilot who was flying Freya in the World cup and he told ma that Tailvibration can be caused whan the Tailpully is screwed on and whan that screw is tightend to much, it will actually make the Tailshaft bend, belive it or not and you will not be able to see the bend.HE said just lossen the screw fully and put it back with locktight and just not as tight and mostly the Tailvibrations would go.!
Well you could try, and if it works it would be nice to get an update on that!

Regards Pete

PM  EMAIL  Attn:RR  Quote
08-08-2007 01:01 PM  10 years agoPost 4
Big Edge

rrApprentice

Oldsmar, FL USA

My Posts: All  Forum  Topic

I had the same problem...
I copied this from the thread where I found the fix.
WOO HOO, that annoying vibe has GONE . It was a fin buzz on both the vertical (top bit) and the horizontal fins. I took out the play on the tail rotor mast and hey presto. So if you get a fin buzz that varies with RPM, ie going to ID1 it buzz's, then check the play in the tail bearings. I added a couple of shims to take out the play, my tail mast doesn't move at all now. To see if yours needs a shim, hold the tail boom, and try and push the tail rotor head towards the nose of the heli. If there is a small amount of play then that could be the reason for your fin buzz.
Thought I would bring this back to the top....
After re-dialing fan and clutch, new main shaft and new headblock, I still had the vertical fin vibs above 1600 head speed.
I shimed the tail rotor shaft and replaced the pitch lever boss, it had some slope in it. Vibs are now gone...

The X-Spec is silky smooth now....

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 01:06 PM  10 years agoPost 5
z11355

rrMaster

New England

My Posts: All  Forum  Topic

you almost always need 1 (if not 2) of the tail shaft shims. I think
they now include them in the kit. You MUST tighten down the
tailcase clamshell screws (dont overtighten, I use 2.5 or 2.6 locknuts
and SHCS) in order to guage 'slop'.

There is no screw that holds the pulley on the shaft, it's a compression roll pin that gets pressed into place.

It is moderately easy to ever so slightly bend the tail hub via
'hanger rash' so be careful of that.

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 05:35 PM  10 years agoPost 6
RICH.L

rrKey Veteran

east springfield​p.a.

My Posts: All  Forum  Topic

one other search that I found said to move the tailboom supports to the lower part of the frame,on my evo I have them up too high and I am going to try moving them down to see if the buzz goes away.
(not sure if the x-spec has the supports already on the bottom of the frame?)

I noticed in your gallery the boom supports are up high,is there and holes in the c/f frames to attach the supports lower?

as you can see I have mine way up on the evo 90,I am going to try it this weekend lower and see what happens.
rich

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 06:15 PM  10 years agoPost 7
Big Edge

rrApprentice

Oldsmar, FL USA

My Posts: All  Forum  Topic

one other search that I found said to move the tailboom supports to the lower part of the frame,on my evo I have them up too high and I am going to try moving them down to see if the buzz goes away.
(not sure if the x-spec has the supports already on the bottom of the frame?)
Yeah I tried that to, didn't work.

Good luck...

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 08:08 PM  10 years agoPost 8
kcass518

rrVeteran

Manhasset, NY - USA

My Posts: All  Forum  Topic

"Over a year" - Holy Cow! I've been going through it on a 50 for a couple of months and was ready to run it into a tree. I hope we hear from you again when the cause is found.

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 11:33 PM  10 years agoPost 9
Helinutnz

rrElite Veteran

below 42 South

My Posts: All  Forum  Topic

Plenty of posts on this. do a search. I did the same. The best I got it was to do this.......I did the same that hirobo did on the evo 90. I slowed the tail down. There was an article done by Rob Landry on the evo 90. There was a sentence in the write up that hirobo designers have reduced the tail ratio to help reduce vibration at the tail. The x-spec has one of the highest tail speeds of all 90's.
I put the evo 90 tail drive delrin gear in to reduce the rpms at the tail. Still an incredibly powerful tail.

. Too many people have experienced this for it to be an anomaly. I replaced almost everything to rid myself of the dredded tail buzz but to no avail. I tried everything in these forum pages. I even replaced the engine and tried a different one!!!!!!!!
Funny thing is the heli operates super smooth everywhere else...tank nice and still, skids are never vibing, head looks still. Boom looks great, canopy as still as......but the vertical fin would set up a heli destroying buzz like you wouldn't believe. At least 10 mils side to side. Now I build my helis slop free so don't go thinking that the tightening up of the tail shaft will help much. Perhaps there is some truth in the bending of the hub or shaft but I replaced and tried SEVERAL shafts and hubs. Never has this heli had hangar rash or been in a crash.

Look at the tail. This drove me nuts and it sounded like a chainsaw.
I cut the fin off at the top I was so annoyed with it.

This is what I think it is.....a design fault
1. The fins are too weak and need to be stiffer.
2. The tail spins very fast
3. This may cause a harmonic imbalance set up within the fins and getting out of that rpm range changes this and causes the buzz to stop. Why did hirobo reduce the speed of the tail in the evo 90?

By putting the smaller tail drive gear on I got my freya out of the rpm range in the tail that causes this imbalance. I did not want to simply replace the fins to a harder thicker material as the underlying vibe may still have been there damaging things (or the vibe may have simply been a fin issue???? I dont know)
That lets me run an 1850 head speed without the buzz.....yep thats where it happens doesn't it????
Some have never had this happen......others like me haven't been so lucky with this machine. When it's behaving.....there is no other machine that rolls like it.....it flies on rails and is so smooth.

GODD LUCK!

PM  EMAIL  GALLERY  Attn:RR  Quote
08-08-2007 11:38 PM  10 years agoPost 10
Helinutnz

rrElite Veteran

below 42 South

My Posts: All  Forum  Topic

A full res photo you can see the nice stable heli with the top of the fin going to town. (nz term for going nuts!)

Oh well that didn't work...sorry. If you want the full res photo....send me a pm.

PM  EMAIL  GALLERY  Attn:RR  Quote
08-09-2007 12:32 AM  10 years agoPost 11
RICH.L

rrKey Veteran

east springfield​p.a.

My Posts: All  Forum  Topic

anyone ever try putting something in between the fin and the tailcase?(like a small piece of foam or maybe some nylon washers)

I always thought mine was the horizontal fin but maybe it actually is the vertical fin.

I have tried the plastic tailblades,95 mm c/f tailblades and 105 v-tailblades and doesn't change.

that is the one and only thing on my evo 90 I cannot stop,doesn't seem to affect the way it flies and never had a problem but is annoying especially with the gearing for an os91szh and I need to fly 1950 to stay in the power band.

sorry bobbyhill4x4 I am not trying to steal the post,just trying to help see if there is something that can be done to stop that buzz,if that is even what you are talking about?
rich

PM  EMAIL  GALLERY  Attn:RR  Quote
08-09-2007 06:34 AM  10 years agoPost 12
bobbyhill4x4

rrApprentice

Watertown NY

My Posts: All  Forum  Topic

Thanks everyone, I will give the subjestions a try and post results later.

PM  EMAIL  GALLERY  Attn:RR  Quote
WATCH
 1 page 718 views
Scorpion Power Scorpion Power
HelicopterHIROBOOther › X Spec tail vibration
 Print TOPIC  Make Suggestion 

 3  Topic Subscribe

Saturday, November 18 - 6:28 am - Copyright © 2000-2017 RunRyder   EMAILEnable Cookies

Login Here
 New Subscriptions 
 Buddies Online