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        Help! all servos acting crazy on throttle up

#1 janmykelg Dec 04, 2012 12:02 AM

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 :D

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 :mad:

what should i do? :confused:

#2 Steve_ Dec 04, 2012 12:54 AM

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 :D

Also, if you have an antenna lead, the antenna touching anything
conductive will make it act crazy like that.

#3 old4570 Dec 04, 2012 02:51 AM

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 .

#4 Hajile Dec 04, 2012 04:05 AM

What's your heli?

#5 Balr14 Dec 04, 2012 08:02 AM

That sounds like voltage compatibility problems. Disconnect the motor and exercise the servos.

#6 janmykelg Dec 04, 2012 10:42 AM

Quote:

Originally Posted by Hajile (Post 23436259)
What's your heli?

copter x black angel FBL

#7 janmykelg Dec 04, 2012 10:43 AM

Quote:

Originally Posted by Balr14 (Post 23437200)
That sounds like voltage compatibility problems. Disconnect the motor and exercise the servos.

okay i will try that

#8 minbari Dec 04, 2012 11:08 AM

Quote:

Originally Posted by janmykelg (Post 23438329)
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.

#9 Balr14 Dec 04, 2012 12:05 PM

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.

#10 janmykelg Dec 04, 2012 03:17 PM

Quote:

Originally Posted by minbari (Post 23438505)
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?

#11 janmykelg Dec 04, 2012 03:19 PM

Quote:

Originally Posted by Balr14 (Post 23438962)
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 :o

but i will try this once i got home :D

#12 minbari Dec 04, 2012 03:48 PM

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

#13 janmykelg Dec 04, 2012 04:46 PM

Quote:

Originally Posted by minbari (Post 23440890)
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?

#14 minbari Dec 04, 2012 04:54 PM

Quote:

Originally Posted by janmykelg (Post 23441435)
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

#15 janmykelg Dec 04, 2012 04:59 PM

Quote:

Originally Posted by minbari (Post 23441500)
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. :eek:

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? :confused:


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