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HelicopterMain Discussion › I'm getting better at flying without a tail rotor. Any help?
04-28-2011 10:14 PM  6 years agoPost 1
wjvail

rrKey Veteran

Meridian, Mississippi

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The long story short is that every time I fly my Raptor 50T now, the tail rotor push-rod pops off! It happened again this afternoon for the 3rd flight in a row! I've been flying this heli the same way for 9 years and just under 60 hours and never had a problem before. Now 5 min into every flight, the thing looses tail rotor control!

What I've done (or what it's not):
-- I've sent the BLS 251 into Hobby Services to be inspected. They replaced the pot.
-- I've replaced the tail output shaft and tail rotor hub.
-- I've replaced the ball and link with X-Cell parts.
-- I've replaced everything in the QuickUK grips to include the two radial bearings and thrust bearing.

The only thing I haven't sent in for service in the recently installed GY-701 gyro. I have any number of other gyros I could put in to see if the problem goes away but since I'm using the governor function of the 701 also, it's a pretty big swap to put in a 611 or Spartan instead. More than that, the gyro is really performing well and I don't have reason to doubt it.

I'm hoping someone jumps in to say "Ah! I've seen that before." "It's your ______". Or, "Here is a test you could try".

I don't know how many more spectacular saves I have in me.

Bill

"Well, Nothing bad can happen now."

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04-28-2011 10:23 PM  6 years agoPost 2
MinAirUSA

rrVeteran

Bavaria, Germany

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Is the control rod supported? How about vibration? Have you set the travel limits, is it binding at the end of the sliders travel?

Miniature Aircraft

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04-28-2011 10:48 PM  6 years agoPost 3
wjvail

rrKey Veteran

Meridian, Mississippi

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Is the control rod supported? How about vibration? Have you set the travel limits, is it binding at the end of the sliders travel?
All good questions..
"Is the control rod supported?"
No but... It never has been before. Yes the weight of the control rod is carried by the ball. I didn't mention this in my first post but the first time this happened, there was nothing to prevent the now free rod end from going through the tail rotor. So it did. I assumed the Rocket City link and Thunder Tiger ball had just worn out after what was almost a decade of use and it just came loose. So.. I build up a new push rod using a MA ball and link using new parts. This time I included a very loose fitting zip tie in the unlikely event it happened again. You can see it in the second photo. Thankfully that little zip tie has reduced the damage to zero as well as allowed me to SEE why I lost tail control. Inspection does not suggest why it popped of in the first place.
"How about vibration?"
Well the motor is running rich (OS 55HZ-R) and the tail is working fairly hard but vibration is not that bad.
"Have you set the travel limits... Is it binding...?"
That was the first thing I looked at. I've tried to duplicate it popping off by upping the limits to 150% (usual is around 100%) so I KNOW it's binding (on the ground) trying to get it to pop of. It does bind, the servo buzzes and the bell crank flexes but no popy offie. I've set the limits so there is no binding and done full throw pirouettes right and left for 1/2 a tank and not been able to duplicate the problem. Two minuets latter doing lazy stall turns waiting for a problem, I loose the tail!

"Well, Nothing bad can happen now."

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04-28-2011 11:15 PM  6 years agoPost 4
2LTime

rrKey Veteran

Walworth,NY

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I'm not sure why it's popping off, but when I used to have raptors, we would put a washer on the outside of the ball so even if the link popped off the ball, it would still stay on and in cotrol.

Jeff

If you can't learn to do it well, learn to enjoy doing it badly.

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04-28-2011 11:15 PM  6 years agoPost 5
airdodger

rrElite Veteran

Johnston USA

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Could the link end where the rod threads in be pushed down by the bellcrank along with the vibration and tail load. Looks like the tail axle could use some lube. Blades are going the right direction on the tail? MA links are directional also. The balls can wear out too. What is the grey on the link from?

Chris

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04-28-2011 11:20 PM  6 years agoPost 6
Steff Giguere

rrProfessor

St-Eustache, Quebec, Canada

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You sure the ball and link are not too loose?

Team Synergy, Rail blades, Team Scorpion, V-Team

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04-28-2011 11:44 PM  6 years agoPost 7
johnbs8

rrKey Veteran

roseville michigan

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if the linkage rod is popping off and the servo isn't over driving the slider, id get a new ball and ball link.also TT's ball links are one directional. The stamped TT on the link should always face away from the Helli.

TT X50 Nitro
Warp 360
Logo 550sx
TeaM KicKnWinG

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04-28-2011 11:50 PM  6 years agoPost 8
Gyronut

rrProfessor

Martinsville In.

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Do yourself a big favor and swap out the balls and links of the correct size and support the push rod.

Rick

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04-28-2011 11:54 PM  6 years agoPost 9
Big Edge

rrApprentice

Oldsmar, FL USA

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Is the control rod supported?
If not it should be. Gravity sucks.
I prefer the stock configuration.. never had a problem.

-----------------------------
Don't taze me bro...

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04-29-2011 12:14 AM  6 years agoPost 10
JOLT

rrVeteran

Baltimore, MD

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You may be able to increase the throw/limit to test if it is popping off on the bench, but you can't reproduce the force required to send the tail rod fully against the resistence of the tail blade deflection keeping the tail locked in place.

My guess, is that you are getting a SURGE from static build up running that belt. It goes into brown out and then resumes with a full punch of throw popping the link off the ball in flight.

God bless you for flying the same heli for so long!

I think the problem is either static or the gyro going nuts in the air. I don't think I would count on the gyro to be reliable if you are having a problem like this.

I would definitly swap out the gyro for future flights. You may have already used up your nine lives...

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04-29-2011 12:43 AM  6 years agoPost 11
jschenckrrProfessor - La Vista, NE. - My Posts: All  Forum  Topic

http://www.raptortechnique.com/tips.htm
3-23-2006 This is a safety tip I came up with last year. In the picture you see a brass eyelet that comes with a servo has been cut in half and placed between the ball link and the head of the screw. Some have installed a washer between the two but I found that limited the pivoting range of the link. This is why I used the brass servo eyelet. As you see <here> the ball is worn out yet the link cannot come off. You do need a longer 2mm screw.

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04-29-2011 02:04 AM  6 years agoPost 12
bopshi

rrApprentice

greenport ny

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Maybe hub is binding on shaft near center and ball end is popping off? Hold it at center with your hand move rudder stick full travel both directions see if it pops. Just a thought Dave

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04-29-2011 02:07 AM  6 years agoPost 13
Ladymagic

rrKey Veteran

South Korea

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Don't mean to over simplify the solution, but it sounds like you just need to replace the ball and the link...they sound like they are just worn or improperly sized. I always give my links a good pull before each flight so I don't have to deal with an untamed heli. And know you said you did check your end points, but it sounds like that's what is most likely causing the issue. If your servo is over extending the slider then that can theoretically cause your link and ball to wear prematurely.

I would replace the ball, the link, and add an extra control rod support and I think your problem will go away. Adding a collet or a washer is also a great suggestion to prevent total loss of tail control if the link does manage to pop off again.

Good luck and I have a feeling that your problem will quickly be resolved based on the suggestions that have already been given.

Mellisa

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04-29-2011 02:39 AM  6 years agoPost 14
dkshema

rrMaster

Cedar Rapids, IA

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Got a slightly bent tail rotor shaft, out of balance tail rotor assembly, or perhaps a bearing or two in the TR gearbox that's shot allowing a lot of vibration in the tail boom?

Bearing in the pitch slider gone south? Mount for the TR bellcrank loose or bending?

If it's been OK till now, and then starts doing it all the time, something's changed. Find it, fix it, fly it.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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04-29-2011 05:13 AM  6 years agoPost 15
RCHSF

rrKey Veteran

NC

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My guess is worn out ball. The plastic can wear down the steel ball. And then vibrations on top of this will do it.

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04-29-2011 05:32 AM  6 years agoPost 16
dkshema

rrMaster

Cedar Rapids, IA

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Note from the original post:
-- I've replaced the ball and link with X-Cell parts.
I don't think the ball and link are worn anymore. They are NEW parts.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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04-29-2011 05:53 AM  6 years agoPost 17
wjvail

rrKey Veteran

Meridian, Mississippi

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I don't think the ball and link are worn anymore. They are NEW parts.
Yea.. That's the thing. The first time it happened, the end of the control rod went through the blades and is somewhere in outer space now (That was a beauty save by the way, even if I say so myself ). I, like others that have posted help, thought the ball or link had just gotten old and had fallen off. Of course since the control rod was shattered (along with the blades + a bent T/R output shaft) so I built a new control rod with new links and replaced the ball on the T/R bell crank with NIP MA parts. And its now happened on the next two flights.

All these parts are new:
T/R output shaft
T/R hub
T/R control rod
T/R control rod links
T/R bell crank ball
T/R Blades (V-Blades)
4 grip radial bearings
2 grip thrust bearings

Items not replaced:
T/R yoke
Gyro

For those that suggested putting a washer under the ball or supporting the control rod, that would work and I'll do that but I have to question why and wonder if I not masking a larger problem. As I said, I've flown this heli for 9 years with it set up the way it is. Why is this link popping of NOW?

"Well, Nothing bad can happen now."

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04-29-2011 07:03 AM  6 years agoPost 18
The man

rrVeteran

at home

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1. Binding somewhere in the tail.
2. Vibration causing resonance on the control rod.

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04-29-2011 06:29 PM  6 years agoPost 19
ThumbBumper

rrVeteran

A little to the right and down!

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^ +1 on the vibration. That can cause some strange things to happen.

If it ain't broke, go fly some more!
http://facebook.com/groups/TORCHS/

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04-30-2011 02:36 AM  6 years agoPost 20
swoop_g

rrApprentice

Lake Charles, LA USA

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Just because a part is New in Box doesn't mean it fits with proper tolerance, especially with a press-fit part like ball links. Check to see how easy it is to take the link off of the ball and I would be willing to bet it is too loose for proper operation. Also this is happening for a reason. You must be getting binding when everything is at full speed in the air and spinning. You add binding to a ball link that is a little too loose and POP! off it goes. Of course I can't be certain without physically inspecting the tail but with the given facts this is the only thing I can think of. For a ball to pop off there is too much force or a force acting in an improper direction. I hope you figure it out before something bad happens. Good luck bro.

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HelicopterMain Discussion › I'm getting better at flying without a tail rotor. Any help?
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