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View Full Version : Servo Chattering mean Gyro issue????


Chris Corbett
12-16-2007, 05:18 AM
Hello

OK here goes....I have just finished building my 600N and just when I thought everything had gone to plan, I come across the following problem.
I am using 9255 on cyclics and 401/9254 on tail. After setting up head I moved to the tail/gyro etc but found when I turned on the tail servo was jittery and even seen to be creeping. (I should point out at the this stage the 9255 have always been very noisy!!).
At first I thought 9254 was faulty so I plugged in other servos (without going through Gyro and they were fine). So I thought it was gyro and set about elimating any chattering. As I am mounting gyro at front, it is righ on top of the two cyclic servos so I suddenly thought it might the the servos chattering that is making the 401 do wierd things.
So I then disconnected all cyclic linkages to check if they were correct length ie not pulling on servo and making them strain.One was a little tight so i corrected it but still noisy.
I then realised my head (Kasama) is quite tight but guess this is no problem for the powerful 9255's. I also noticed when building that no much how I lube it the tail slider is fairly tight.
Could any of these end up affecting the tail servo? It is fair to say it's better than it was but still have one very noisy chattering heli, which I hate!!

OHIOBOWHUNTER
12-16-2007, 05:34 AM
I had the same issue when I finished mine 401/9253 ,i had to turn the gain down in the transmitter ( 9chp) alot ,its at 45 % in hh. maybe could go more ? I don't know I've only got 8 tanks through it so far (winter got here )
good luck :thumbup:

Chris Corbett
12-16-2007, 05:53 AM
THats interesting, thanks for that. I have only hovered a couple of feet of the ground for two tanks so yet to start playing around with gain but that may be it. I have noticed a slight tail stepping in hover but think this may ne down to slow head speed and new engine vibration.

jpolidore
12-16-2007, 10:27 AM
Chris do you have the Gyro mount? I had the same exact thing with the 401/9254. I do not have the front mount from Align yet so I moved the Gyro to the back and it solved my problem. I was told by LHS guy people were mounting the gyro right on the servos, I feel this is not the case and if you look at the pics posted in this thread I think you will feel the same:

http://www.helifreak.com/showthread.php?t=53638

Chris Corbett
12-16-2007, 12:11 PM
Hello.

Yes my gyro is at front and I must admit that I thought this might be the problem, being so close to the servos.
Looked at the thread with interest and may try putting metal plate between pads like the 611.

mporlier
12-17-2007, 03:54 PM
Digital servos will always be noisy. Even the smallest movement will have the gyro issue a correction to the servo emitting some noise.

rototiller
12-17-2007, 05:01 PM
How are you powering your radio? If your over 5V your 9254 will chatter some.

I had my 401 right on my cyclic servos for one tank. Tail shutter bad. After I moved it to the radio plate up front I have had no issues.

DK