RunRyder - HBK2 - How much tail vibration is normal?

rrTV-PHOTO

New HD TV

HOME rrTV-PHOTO GALLERIES MY GALLERY HELP-FAQ

myHOME PM pmRR MEMBERS 320 ONLINE 19 EVENTS SEARCH REGISTER START HERE

2 pages [ << < ( 1 ) 2 NEXT >> ]

276 views

POST REPLY

CanoMod	.	Futaba-RC	.	A Main Hobbies
	.		.

e-E-Sky Honey Bee- Lama- Belt CP- E-Smart > HBK2 - How much tail vibration is normal?

Gregor99
Elite Veteran
Location: Western Wa

I've mentioned this before, but I've got a tail vibration causing a small amount of visible shake on the tail. Its been this way since its was new. Lots of parts have already been replaced and the vibration is still there. The vibration is visible in the tail and you can feel it if you hold the tail box. Its not so bad that the heli doesn't fly. But the gyro is giving a little wag at all but the lowest gain settings.

Before I go any further, I was wondering how much tail vibration is normal for the HBK2? Can you see it? How much can you feel if you hold the tail box while spinning up?

Here's what's been done so far.

The tail blades have been balanced.
Tail bearings replaced.
Tail box upgraded to purple.
Tail shaft replaced
Main bearings replaced.
Main shaft replades
Main gear and pinion replaced.
Feathering shaft replaced
Main blades replaced and balanced.
Belt replaced
Pully replaced
Flybar paddles centered.

01-13-2008 02:10 AM

jwhitacre
Key Veteran
Location: Tarentum,PA- US

Mine has a little bit of vibration in the tail. My brother in laws has about the same amount also.

Depleting the world of parts, one crash at a time!!

01-13-2008 02:13 AM

Gyronut
Elite Veteran
Location: Martinsville In.

Mine has some also.

Rick

01-13-2008 02:14 AM

tryan02
rrProfessor
Location: Canton, Missouri

holding it mine shakes like my wifes nightstand for some odd reason her nightstand has a high frequency vibration. But with my heli I get a little bobble up and down on spoolup to 1/4 stick till the blades plane out then there is no visible vibration at all. Especially now that I have a fuse on it.

But seriously by half throttle there is no visible signs of vibration.

Canton MO backyard flying club
Club President
Team No funds left.

01-13-2008 02:19 AM

HOMEPAGE

Sgt Heli
Veteran
Location: Remlap, Al USA

Any mechanical thing has a natural vibration frequency. This is called the 1st order. Your heli tail will pass through this natural freq. as it speeds up. I would think some vibration at this speed (whatever it is) would be unavoidable. If you have a vibration and it goes away as you gain speed then that might just be your tail passing through this 1x speed.

01-13-2008 02:36 AM

tryan02
rrProfessor
Location: Canton, Missouri

I think Im gonna take the counterbalacer off my harley and mock one up for my heli.

Canton MO backyard flying club
Club President
Team No funds left.

01-13-2008 02:41 AM

HOMEPAGE

Gregor99
Elite Veteran
Location: Western Wa

Yes, there's definitely a lot vibration from 1/4 to midstick. By midstick, most of them have smoothed out. The vibration in the tail is still there and just changes frequency as the headspeed increases. So it seems with the exception of Tryan's King, some amount of vibration is normal, for tails and nightstands

For those with vibrations, does this affect your gyro? Are you wagging? For everyone, any other suggestions for reducing tail vibrations. I was thinking about trying the K&B tail blades. I've read some posts that even balanced tail blades can cause vibrations.

01-13-2008 04:28 AM

slider46
rrProfessor
Location: Gloversville, NY

Are your blades too tight???? How about your gyro gain setting is it too high??? Headspeed is too low???

Tom..... No "D" flying....

01-13-2008 04:34 AM

Gregor99
Elite Veteran
Location: Western Wa

Are your blades too tight????
I've tried tight and loose. No change. What's the recommended tightness for tail blades? I've heard that loose blades can introduce slop in the tail which results in a bounce when piro comes to stop.

How about your gyro gain setting is it too high???
I've tried high and low. Wagging occurs for both. Much over 75% and the tail starts the real gyro pshyco wag. Under 65% and the tail becomes very sloppy and the wag persists.

Headspeed is too low???
Any higher and my blades will not track. I'm currently on a 9t with a 3800.

Next?

01-13-2008 04:41 AM

vortechZ230
Elite Veteran
Location: Michigan, U.S.A.

I have the King V1 drive shaft, and mine is the same way also!, I think it is due to less than "Pristine" parts used on the HB King, It is a mild high frequency "Buzzing" vibration!, everything is working well, and Im just living with it

01-13-2008 01:02 PM

HOMEPAGE

shizack
Key Veteran
Location: Augusta, GA USA

How is your gyro attached? Thick servo tape? Thin servo tape? double-sided Scotch tape? Just zip-tied (yes I've seen that)? Is it physically stuck (taped) to the back of the servos? If too much heli vibe gets transerred to the gyro, it can get wacky.

Quote
tryan02: for some odd reason her nightstand has a high frequency vibration.

You'd better tell her to fix that thing's "off" switch. Otherwise she's gonna raid your "AA" battery collection while you're out flying or tweaking (she'll be working on her own tail twitch).

Pumping your fist and yelling, "COME ON!!!" does not increase battery charge rate.

01-13-2008 01:22 PM

HOMEPAGE

Gregor99
Elite Veteran
Location: Western Wa

How is your gyro attached?

The gyro is attached using the double-side foam included with the 2100t package. It is placed on the frame behind the servos with the label facing the sky. No part of the gyro is touching anything else on the heli. The wire coming from the gyro has a small amount of slack and can flex.

As an experiment, I tried running a zip tie over the top of the gyro and around the bottom of the frame. I've seen this done in a number of pics and thought it might be fun to see what the differnce was. The results were not good. The tail would hold in hover but wasn't very predictable when any rudder input was applied.

Next?

01-13-2008 07:09 PM

DougsRC
Elite Veteran
Location: MA

Gregor, When you grab the tailblade between your forfinger and thumb while still attached to the heli, is there slop or movement. Also is there any side to side slop or play in the tail belt shaft??

01-13-2008 07:25 PM

Blusaber
Senior Heliman
Location: Ca

Hi Gregor99

I know this doesn't help but just took a vid of my tail with the 2100t

http://www.youtube.com/watch?v=PpSftnB1KZw

I key off the vert fin no vibes visable. my only thought (and it's way out there) since you have replaced all of the givens is it possible your bearings are going bad in the motor itself? That would cause vibes. Have you ever lubed them? This is really a stumper hope you can find the cause

Gary

01-13-2008 07:26 PM

Gregor99
Elite Veteran
Location: Western Wa

Quote
When you grab the tailblade between your forfinger and thumb while still attached to the heli, is there slop or movement?

Yes, in two places. First place: Unless the tail blade grips are tightened down to the point that they are hard to move in the grip they have a lot of side to side slop. This didn't seem right to me so I tried cranking the grips down so there is no slide to slide slop. This is in contradiction to what I have read regarding other helis, where the grip tightness should similar to the main blade tightness, loose, but not to loose. Regardless, loose or tight the vibes are still there. I haven't tried new blades yet but the current blades balance out perfectly.

The second place I see the slop is in the bearings that attach the blade grip to the tail shaft. They've been like this since day one and both sides are the same. It didn't seem right to me so I took them apart, cleaned and lubed them. Re-assembled with locktite. There is still some side to side play. I figured this was normal but kept it the back of my head as a reason to switch to the metal parts.

Quote
Also is there any side to side slop or play in the tail belt shaft??

Nope. Checked that thoroughly when I put the CNC tail box on. Checked and double checked. And for good measure I checked again, just last night when I replaced the belt. I thought I saw something odd on the belt so I put on a fresh one just to see if made any differnece. It didn't.

Quote
I know this doesn't help but just took a vid of my tail with the 2100t

Thanks for taking this video. I was wondering if it would be possible to see the state of the tailbox on YouTube. If you had a vibration, I don't think I could have seen it. One thing that did come through was the lack of wagging.

Quote
I key off the vert fin no vibes visable

.
Now that you mention it, I'm not able to see many vibes on either tail fin. But its clearly visible at the tail box.

Quote
is it possible your bearings are going bad in the motor itself?

I can't say for sure, but I don't think so. The vibes started on day 1 when the motor was fresh. I've been thinking about getting a second motor and speed control just to test it out. But that seems a bit extreem.

Before I do that, I was thinking about trying the following:

New tail blades
CNC tail grips and new bearings
CNC head (I never got the plastic head to run right at high speed so there may some issue still there)

01-13-2008 10:57 PM

ut_neon
Key Veteran
Location: Coimbra, Portugal

what does mean: "tight the belt tension of a helicopter"? first of all what is the belt?

01-13-2008 11:16 PM

DougsRC
Elite Veteran
Location: MA

ut-neon, Is this some kind of JOKE ??? You have the Belt cp-- You have the manual for it--Take a look at the manual.

01-13-2008 11:48 PM

ut_neon
Key Veteran
Location: Coimbra, Portugal

i don't have it yet... i will bring it tomorrow from the post office=DDD i'm getting much info as possible so i don't make mistakes when i have it=)

the only experience i have is with a lamav3 =<

01-13-2008 11:51 PM

tryan02
rrProfessor
Location: Canton, Missouri

Thats no excuse read the dang manual instead of wasting peoples time with dumb questions.

http://www.twf-sz.com/english/downl...nual/Beltcp.pdf

Canton MO backyard flying club
Club President
Team No funds left.

01-14-2008 12:01 AM

HOMEPAGE

DougsRC
Elite Veteran
Location: MA

Gregor, This is a real long shot and you may or may not to try this, but until you find the source of the vibration you could try using peel and stick velcro to attach your gyro. It seems to transmit a little less vibration from the frame to the gyro. It sounds like your gyro is getting false signals from the vibration causing your tail to wag. After that I'm out of ideas outside of replacing every single part on the heli essentially making it a brandy new heli again.

01-14-2008 12:02 AM

2 pages [ << < ( 1 ) 2 NEXT >> ]

276 views

POST REPLY

Boca Bearings	.	Modefo's RC Helicopters	.	XHELI.COM
	.		.

e-E-Sky Honey Bee- Lama- Belt CP- E-Smart > HBK2 - How much tail vibration is normal?

PRINT TOPIC

Advertisers

Subscribe to This Topic