Hi Guys,
I wonder if you can help. Karma, a friend of mine in New Delhi asked me how he could stop juddering/ rapid vibration on servo arms.

I experienced this on 35mhz on my first foamie a few years ago and to combat it a member at club recommended a ferrite ring. With the ring, the vibration was reduced but did not stop so I changed to 2.4 ghz and it stopped.
Ferrite ring is also used to combat glitches. I have given him this ferrite ring suggestion and just wanted to put it past you guys...
Any ideas as to why that happens and how it can be rectified?

Vivek has just suggested to rebind the receiver with Tx. So Karma, here it goes, try that and let us know if it stops. Also he asked are you using any camera or voltage display unit on this model? If yes try again after disconnecting it.
Deepak

One thing that is usually recommended in such situations is re-routing the wires so that the high power parts (battery, motor, ESC, and the wires related to them) are kept away from the receiver (and related antenna wires) and servo wires. 

Ferrite rings are pretty much standard equipment in belted electric helis, because they are prone to static issues.  If you are on PPM, the glitches are obvious right away.  If you are on PCM, the glitches are masked by PCM upto a large extent, and so is 2.4Ghz. 

The servo chattering is caused mainly due to power supply or signal noises. Here are the things that I would try:

1, Use the previously mentioned ferrite ring.
2, If chattering still exists, then try a 470uF capacitor across the +ve and -ve power supply terminal. If it improves then use another 470uF capacitor until the chattering disappears.
3, If it doesn't disappear, then use a RC filter circuit on the servo signal line. The R and C value shall be calculated from a starting point and shall be tuned by trial and error. Note that there would be a penalty of slower servo response time by doing this.. but I don't think it would be noticeable.

If nothing helps.. just forget it and go 2.4GHz.

If you are concerned of the initial rapid movement of the servos when turning ON the receiver then you could use a soft turn ON circuit. Lots of resources on the internet.

-Ismail

Its mainly happening due to noise, loose screws, irregular metal contact. does this happen when you are a bit away from the model or all the time?

I am presuming ur plane is electric. ok . if it is, the esc is generally the culprit cause it generates pulses for the motor to work. secondly, u did not mention if ur servos were didital, which r more prone to glitch with a bad esc. solution. try changing the esc first. a esc that causes sever interference will most likely to cause it even on 2.4, and i am on 2.4, and have encountered the problem with digital servos, and it got ok with analogue servos.

Welcome Grp. Capt Tahlan, to this great forum !!!
I cannot really help with the jittering problem, but couldn't resist posting a welcome note here.
We are all lucky to have you here.

A Warm Welcome "DUDE"
Its nice to have you and your comments here Ramesh, this forum has been missing your experience and wealth of knowledge. The plane belongs to Karma and it is 2,4 ghz. He is going to perform all above tricks that the lads have been suggesting and revert to us with his own comments.
Take care and HAPPIES LANDINGS....
Deepak

Gaurav,

How did you know that he was a "Groupie"? Just curious, do you know each other personally?  Welcome Group Capt. Tahlan, Hope you enjoy being here.

"chattering still exists, then try a 470uF capacitor across the +ve and -ve power supply terminal. If it improves then use another 470uF capacitor until the chattering disappears."

Don't remember the exact rating of the capacitors, but I've used this 'technique' in the foll sequence - 1. Across (+) and (-) terminals  2. From (+) terminal to Motor Can body  3. From (-) terminal to Motor Can Body. No problems thereafter.

Cheers!

VC

Quote from: VC on April 08, 2010, 11:54:53 PM
How did you know that he was a "Groupie"? Just curious, do you know each other personally?  Welcome Group Capt. Tahlan, Hope you enjoy being here.

There is a lot of RC discussion on Facebook, including comments by Capt Tahlan where he mentioned that he was a Jaguar pilot for the IAF, and did not go into commercial flying after serving the nation.

I wish if all that RC discussion were happening here

Well, well, well! I wasn't aware of his Jaguar flying experiences at either Ambala/Jamnagar/Gorakhpur. Wherever Grp. Capt. Tahlan was posted, Let's hope he contributes a bit from his wealth of knowledge to make this forum a richer place for the rest of us.

BTW, In welcoming/discussing Grp. Capt. Tahlan, I think I/we am/are hijacking this thread. My apologies.

Cheers!

VC

Hey Anwar,
You have been spying on us havent you....
Ramesh had not heard about this forum, it took a long phone call and some serious bribery and corruption to get him to join us.... LOL.. Only joking..

Jokes aside Caption Ramesh is an EVERREADY Battery waiting to be connected  to all RC lads...

His following on Facebook has jumped up suddenly after all those great videos he has uploaded of Amby Valley.

16 videos uploaded in 1 day... WOW

GROUP CAPTION, HE CERTAINLY WAS AND WILL ALWAYS BE, recently he grouped 30 comments on his one video in 4 hours.....

Can I quote; "Actually 90% tagged were not there, just have fun, and to motivate all in Delhi to get into night, so one day we can launch a dozen night acts  together."

THAT MY FRIEND HIS HIS SECRET WEAPON OF GROUPING THEM ALL ON FBK....

Picture abhi baaki hai dost.....  

Quote from: b4ggu on April 09, 2010, 12:49:51 AM
Hey Anwar,
You have been spying on us havent you....

Anything RC is part of business    So technically it is not "spying", the appropriate term would be "participation"

Karma, i forgot to ask a basic question on the jitter issue, cause if u dont ask the right questions, u can never get to the right solution. First, what make is ur 35 mhz Radio. second, digital or analogue servos, three, on power up how long does the jitter occur, is it for a second only, or does it carry on for 10 to 15 sec and u move ur sticks and it stops, does it stop after a few sec and again starts and stops and is kind of eratic. pl answer all questions clearly.

Thanks guys..Problem solved had three beautiful sorties on a windy saturday..followed Anwars advice and rerouted the wires..Expecially the servo wires away frrom esc wire and it worked..cheers

Hi Guys, Please welcome Karma, recently voted;
"INDIAN REPORTER OF THE YEAR 2010"
A very nice person and a keen aeromodellor always willing to help and eager to learn....

It sure is nice to have you here Karma... Do upload some images of the plane we have have been discussing. Glad this forum helped get rid of the problem... Happy Landings