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Roger1950 Roger1950's icon
 2008-03-30 19:16:53
I have been out flying my TREX 450 today, it is fitted with aLogitech LGT2100T Gyro. One minute it is fine and rock steady the next it does like a piroette spins around and I have a job to control it. Also when leaving the floor most times I lift off into a perfect hover three or for feet off the ground no problems. The next time I try lifting off my TREX just wants to spin around and needs a lot of imput into the rudder to prevent this.I am definitely in the head lock mode as I can switch this on and off useing my gear switch on the Spektrum DX7. Once or twice now I have been in a steady hover at around 15 or 20 feet in front of me tail in and then she wants to just spin around, I had this problem once before and I found the tail gear was lose on the shaft letting it spin, this is not the case now as I have fitted a complete new tail assembley. Is it just me or do others have similar problems.
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Phil Phil's icon
 2008-03-30 22:56:22
buy a better gyro
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Alvin Alvin's icon
 2008-03-30 23:39:50
i've had this fault before,on a csm 420,it was the tail linkage rod set with far too much tail pitch one way causing the problem,the gyro was pirouetting a short while every time the stick was centered, trying to correct the tail position due to having too much blade pitch at center stick.make sure the mechanical set up is only need to nudge the rudder a little bit and the gyro will go back to that wrong blade pitch a center stick,then it will pirouette a while until the gyro forces the blade pitch to the correct setting for no movement.

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Helidude Helidude's icon
 2008-03-31 00:44:51
That is a good idea!. Can you turn off heading lock on that gyro? If you can, have you hovered the helicopter with standard non heading lock to see if the mechanical link is set correctly? Check all connections. What servo is it using and if it is digital, does the gyro have a speed and pulse rate setting that could be wrong? Could that servo be faulty? New servos can be faulty but rare. I do not think that logitech make a gyro that does not work. Is the control rod free moving? Take the ball link off the servo horn and move it with your fingers. Is it free or stiff? If it is stiff, that could be another reason. All logical things. If not these, then the servo or gyro is faulty I think.
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Roger1950 Roger1950's icon
 2008-03-31 18:21:46
Hi Guys
Thanks for all the info you have given. I will try adjusting the rod length to the tail. I thought it was correct because when I hover in the not headlock mode she stays pretty well tail into me without any need to correct any spin.

Will let you know.
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Crasherman Crasherman's icon
 2008-04-01 04:34:23
(Quote)I thought it was correct because when I hover in the not headlock mode she stays pretty well tail into me(/Quote)If you have done what you have written, then it is not the link.
If you hover the helicopter in non heading lock mode and it stays pointing in the same direction with no rudder input from you, then this is all you can do and is correct. So if it is ok one minute and then turns the next, I would think that it is an radio fault, like the servo or gyro. Check all the connections. Can you try a different tail servo? Check the bearings in the blade grips. If they have thrust races in them, make sure they are the correct way round, because if not, they can lock up under centrifical force.
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