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Advantage Hobby . Revolution Models . CarbonXtreme

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Main Discussion > Lost of tail control.
 
 
T-Rex-Flyer
Key Veteran
Location: Panama City, Fl

Today, I lost control of my tail, it would be working fine then would intermittently jump to a new position (scaring the crap out of me). At first I thought it was a glitch and tried a second flight latter keeping it in a low hover and it did the same thing a couple of time. While just keeping it light on the skids operating the tail rotor we found control was intermittent, sometimes the tail rotor would work then without warning just quit also note we could not get it to fail with the heli just idling or on the tables jiggling the wires. Switching to Rate mode seem to work constantly but I'm not 100% sure now I have time to think back.
The equipment used

Futaba 9c
Futaba 9254
Futaba 401

Any thoughts?
Also I have check all the wire connections and there are all tight.

If the wings are traveling faster than the fuselage, it's probably a helicopter.
08-30-2008 10:24 PM
 
 
MMike
Elite Veteran
Location: Holland,Mi-USA

Belt looks good?
08-30-2008 10:32 PM
HOMEPAGE  
 
 
T-Rex-Flyer
Key Veteran
Location: Panama City, Fl

Yep, Not a belt problem, I try to explain the problem is with the control of the tail rotor as it would intermittently stop functioning. As I had it light on the skids you could see the tail rotor not changing pitch as I operated the rudder stick.

If the wings are traveling faster than the fuselage, it's probably a helicopter.
08-31-2008 03:48 AM
 
 
seflyer
Senior Heliman
Location: Northern California, Redding

bad servo?

sticky servo slider on tail output shaft. seen that once in awhile on my t-rex, disconnect servo and make sure its perfectly smooth with no binding.

My heli is right side up -- the world is upside down
08-31-2008 06:09 AM
 
 
Lomcevek1
Senior Heliman
Location: Eagle River, Alaska

What does come to mind, is what receiver ?? Sometimes belt static can cause problems, A bad servo (Not sure how you would find it) Tight linkage, Improper setup ie rotation.
08-31-2008 08:57 AM
 
 
TrexRookie
Key Veteran
Location: San Francisco, CA

check the solders on your motor leads... give them all a good tug. if they pop off, it may have been your motor intermittently cutting off, causing the tail to twitch. ask me how I know...
08-31-2008 09:11 AM
 
 
T-Rex-Flyer
Key Veteran
Location: Panama City, Fl

Sorry Guys I forgot to say this is on a Raptor Titan with about a gallon and a half of fuel through it.
I'm Thinking bad servo or 401, But I can't get it to fail on the bench so I can't tell with one.

Lomcevek1 I don't understand how the name of the receiver would help to diagnose the problem but here it is, from FMA and in all respect works fine unless there's an intermittent problem only on the ruder Chanel. It's been my experience the when a receiver go it's totally gone but I've been wrong before (once ). Linkage are as smooth as glass.

TrexRookie the tail does not twitch, as I try to explain above the problem is with the control of the tail rotor as it would intermittently stop functioning. As I had it light on the skids you could see the tail rotor not changing pitch as I operated the rudder stick.

Also I put it lite on the skids because I could not get it to fail at lower engine speed or shut down.

If the wings are traveling faster than the fuselage, it's probably a helicopter.
08-31-2008 03:28 PM
 
 
MMike
Elite Veteran
Location: Holland,Mi-USA

Just a thought:

I've read that a 401 mounted too "tight" can cause "jumps".
08-31-2008 03:50 PM
HOMEPAGE  
 
 
Heli 770
Elite Veteran
Location: Lemon Grove, Ca. USA.

Did you fly it in rate mode again with no problems?
08-31-2008 04:00 PM
 
 
Lomcevek1
Senior Heliman
Location: Eagle River, Alaska

Some recievers are prone to static interferance. I on Caliber 5 I have to rub the belt on occasion with an anti static cloth. problem goes away.

I have a PDM reciever in my Titan and have not had a problem.
08-31-2008 07:49 PM
 
 
Rogue123
Key Veteran
Location: Phoenix AZ

http://runryder.com/helicopter/t286...ght=9254+failed

http://runryder.com/helicopter/t325...ght=9254+failed

http://runryder.com/helicopter/t431...ght=9254+failed

I thought they fix this issue, but could of gotten an oldy.



I had one fail ( 9254 a long time ago.), also you might want to check you pwr system. Also connections
08-31-2008 08:20 PM
 
 
Jeff polisena
Veteran
Location: westpalmbeachflorida usa

Check clutch and auto hub .

I dont know how to fly just how to not crash !!!!!
08-31-2008 08:26 PM
 
 
Blade_Master1
Key Veteran
Location: Canada

I had the same prob with my throttle servo turned out it was the servo

try tapping your finger on the servo and other electronics

recheck your tail linkage all the way to the slider it could be a faulty bearing in the slider



JM2C's :)
08-31-2008 08:34 PM
 
 
T-Rex-Flyer
Key Veteran
Location: Panama City, Fl

Heli 770 Weather to crappy to get out and try it today so I can't tell you if it was ok in rate mode.

MMike Not jumping as stated earlier, more like intermittent control or lack there of.

Jeff polisena "I don't know how to fly just how to not crash !!!!!" With that comment I believe you. Did you read the post?

Blade_Master1 Tried that but can't get it to fail on the bench.
Quote 
recheck your tail linkage all the way to the slider it could be a faulty bearing in the slider
As stated before it's all smooth as glass.

If the wings are traveling faster than the fuselage, it's probably a helicopter.
08-31-2008 11:11 PM
 
 
tchavei
rrProfessor
Location: Portugal

two 9254 failed on me recently and I had exactly the behaviour you described. Sudden loss of tail for a second or so, tail overshooting target during piro stuff etc.

Dump that servo ASAP. Its not worth keeping to fly with it and trying to diagnose the problem.

Of course it could be something else (I don't believe it though) but dump that servo before it dies for good.

Both my servos had between 150 and 200 flights.

Tony


--------------------
"Perfection and patience usually walk side by side..."
08-31-2008 11:20 PM
HOMEPAGE  
 
 
legoman67
Elite Veteran
Location: Nanoose Bay B.C, Canada

im assuming you tried reinitalizing it, power on and dont touch any controls until you hear the servo twitch. ive gone to fast and lifted off to find my tail acting up, a quick cycle of power and it was all good.

Matt M.
http://www.filepile.ca
09-01-2008 12:39 AM
HOMEPAGE  
 
 
Blade_Master1
Key Veteran
Location: Canada

If won't fail on the bench and it has to be in motion for it to happen then it has to be mechanical.

then there is something your not seeing, And there isn't any slop ?

just wierd








JM2C's :)
09-01-2008 01:06 AM
 
 
tchavei
rrProfessor
Location: Portugal

^^^

Just because you can't make it fail on the bench doesn't mean its not the servo. on my second bad 9254 I thoroughly tested it on the bench and everything was fine until I stressed it for 6 minutes (holding my finger on the arm simulating load while moving the stick a little right and left) then, as the servo got warm, the arm suddently shot full right then full left and then back to center position.

Tony


--------------------
"Perfection and patience usually walk side by side..."
09-01-2008 02:03 AM
HOMEPAGE  
 
 
Blade_Master1
Key Veteran
Location: Canada

^^^^
but you got it to fail on the bench ???

JM2C's :)
09-01-2008 03:08 AM
 
 
tchavei
rrProfessor
Location: Portugal

^^^

after believing 100% it was the servo.

If I hadn't been so convinced, I wouldn't had stress the servo to the point of it getting hot and reproducing actual flight conditions. Have you purposely tortured an apparently good servo for 6 minutes until the point it got hot? I only did it because I thought "hey, the servo is wacked, I'm not ever going to use it again, lets see how it actually fails in flight". I wouldn't ever to that to a servo I thought that was working ok.

TOny


--------------------
"Perfection and patience usually walk side by side..."
09-01-2008 04:13 AM
HOMEPAGE  
 
 
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