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Old Dec 04, 2012, 12:02 AM
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Help!
all servos acting crazy on throttle up

i had to replace one servo because it was stripped.

had to upgrade it to metal gear servos

since i bought 3 servos, i thought y not change all the 3 servos to metal gear. i used the tower pro mg90s.

there were no problems not until after the repair.

all servos has it's own life on throttle up. the swashplate seems to dance back and forth, left and right, including the tail

what should i do?
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Old Dec 04, 2012, 12:54 AM
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I'm new to heli's but been into RC for 20 years.
Sure sounds like an interference problem, or possibly
an internal intermittent short in one of the servos.
Will your radio still initialize if a servo is unplugged?
Some will not (maybe all), so that might not work.

Is there a way to test them individually?
With an old radio and RX perhaps?

Also, look for pinched servo leads.

If the rest of the old servos were good, start swapping them out
one at a time

Also, if you have an antenna lead, the antenna touching anything
conductive will make it act crazy like that.
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Old Dec 04, 2012, 02:51 AM
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Hmmm , Hardware incompatibility ?

Are the servos plugged in correctly ?

If everything is Good plug in wise ! disconnect the gyro and see if the problem goes away .

Components dont always play nice with each other .
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Old Dec 04, 2012, 04:05 AM
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What's your heli?
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Old Dec 04, 2012, 08:02 AM
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That sounds like voltage compatibility problems. Disconnect the motor and exercise the servos.
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Old Dec 04, 2012, 10:42 AM
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Originally Posted by Hajile View Post
What's your heli?
copter x black angel FBL
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Old Dec 04, 2012, 10:43 AM
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That sounds like voltage compatibility problems. Disconnect the motor and exercise the servos.
okay i will try that
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Old Dec 04, 2012, 11:08 AM
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Originally Posted by janmykelg View Post
copter x black angel FBL
I bet they dont have enough torque. I have those for my heli and they work ok for a flybar heli, but they only have about 1kg of torque. for an FBL heli, I bet that is the issue. (I assume that the swash is behaving correctly on the bench, for direction)

on my tail, wouldnt work AT ALL. on the bench it worked fine, but once you spun up the heli and tried to law the tail it would just seize up or go to one direction and couldnt pull it back.

replaced the tail servo with a 3kg servo and all problems went away.
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Old Dec 04, 2012, 12:05 PM
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An excellent observation, minbari. The servos have to work really hard on a flybarless heli. If they don't show any problems with the motor disconnected you probably nailed it. 3kg force on all servos is probably a good idea.
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Old Dec 04, 2012, 03:17 PM
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Originally Posted by minbari View Post
I bet they dont have enough torque. I have those for my heli and they work ok for a flybar heli, but they only have about 1kg of torque. for an FBL heli, I bet that is the issue. (I assume that the swash is behaving correctly on the bench, for direction)

on my tail, wouldnt work AT ALL. on the bench it worked fine, but once you spun up the heli and tried to law the tail it would just seize up or go to one direction and couldnt pull it back.

replaced the tail servo with a 3kg servo and all problems went away.
Yes, the servos are behaving correctly on throttle hold.

what exact brand do you recommend for a 3kg tail servo that goes well with those towerpro MG90s?
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Old Dec 04, 2012, 03:19 PM
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Originally Posted by Balr14 View Post
An excellent observation, minbari. The servos have to work really hard on a flybarless heli. If they don't show any problems with the motor disconnected you probably nailed it. 3kg force on all servos is probably a good idea.
i haven't tried this yet, i'm still at the office for my work

but i will try this once i got home
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Old Dec 04, 2012, 03:48 PM
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The ones I have are the Turnigy tgy306g. $22 but have impressed me so far. I plan on replacing the tower pros with these after Christmas for the cyclics as well

Friend of mine said they look like mks made them
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Old Dec 04, 2012, 04:46 PM
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The ones I have are the Turnigy tgy306g. $22 but have impressed me so far. I plan on replacing the tower pros with these after Christmas for the cyclics as well

Friend of mine said they look like mks made them
the one i'm using right now are the stock tail servo (Fusonic (MG-D-9257-V2) 9257 25g Metal Gear High Speed Mini Digital Servo).

so what i'll do i'll just replace that tail servo with the Turnigy tgy306g and it should work fine then?
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Old Dec 04, 2012, 04:54 PM
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Originally Posted by janmykelg View Post
the one i'm using right now are the stock tail servo (Fusonic (MG-D-9257-V2) 9257 25g Metal Gear High Speed Mini Digital Servo).

so what i'll do i'll just replace that tail servo with the Turnigy tgy306g and it should work fine then?
If your cyclic servos are the problem, then replacing the tail won't solve that. If tail control is the problem, then yes.

I thought you said that cyclic and collective control was the problem
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Old Dec 04, 2012, 04:59 PM
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Originally Posted by minbari View Post
If your cyclic servos are the problem, then replacing the tail won't solve that. If tail control is the problem, then yes.

I thought you said that cyclic and collective control was the problem
my bad. sorry. it's the cyclic and the tail servos are the problem.i have no idea what to do.

a friend of mine said that it might be the esc or the flybarless gyro that causing that problem, do u think he might be correct?
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