HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 04, 2012, 06:25 AM
Registered User
Rcflyyer1's Avatar
United States, FL, Sarasota
Joined Dec 2010
331 Posts
Discussion
Elevator Servo Problem?

So I was about ready to go flying with my .60 Cermark F-20 Today but I did a servo test to find out that it couldn't pass the finger test. I have done the finger test where i rest my finger on top of the elevator and move it, and it passed all of those, but today, it couldn't fight my finger. Now the receiver pack just finished charging if that has anything to do with it. I got the airplane used, have flown it about 20-30 times with the servo and it went fine. I am using a 4.8 NiMh pack. I don't know what servo is in the elevvator since it is hidden in the tail but I know it is a futaba. Maybe a 9001 like the rest of the plane. Should I get a Futaba S3010 for the elevator? I'm not sure why this happened all of a sudden and the servo on my other .40 sized sport plane passed the same test on it's elevator. Why would this happen
Rcflyyer1 is offline Find More Posts by Rcflyyer1
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 04, 2012, 07:48 AM
Registered User
tacx's Avatar
United States, MI, Macomb
Joined Apr 2009
2,557 Posts
How hard are you finger testing it?

Could be

Servo going bad. Hopefully not from a heavy finger!

Low battery? This is what I suspect.

Will the servo move the elev. up by itself. And if it does can you push it back down manually. Without forcing it of course.
tacx is offline Find More Posts by tacx
Reply With Quote
Old Nov 04, 2012, 09:28 AM
Registered User
kimchiyuk's Avatar
United States, NY, Eldred
Joined Jun 2012
619 Posts
Does it move normally without pressure applied? How long do you apply pressure? Any abnormal noises? Holding it too long can burn out the circuit board. Personally, my thought is, if it's acting differently than a normal servo should...just error on the safe side and replace it. $20 servo or several hundred dollar plane...HMMM! Don't know about you, but I have always found the elevator to be quite useful in flight! LOL
kimchiyuk is offline Find More Posts by kimchiyuk
Reply With Quote
Old Nov 04, 2012, 09:32 AM
Registered User
kimchiyuk's Avatar
United States, NY, Eldred
Joined Jun 2012
619 Posts
Also as Tacx stated, could be a battery going bad too, but if it voltage tests ok and the other servos/flight surfaces work normally than this would obviously rule out the battery. Also, since you said the servo is in the tail, I'd check to make sure the servo extension hasn't chaffed on the airframe and possibly either worn through some of the wiring or is shorted.
kimchiyuk is offline Find More Posts by kimchiyuk
Reply With Quote
Old Nov 04, 2012, 08:00 PM
Registered User
Rcflyyer1's Avatar
United States, FL, Sarasota
Joined Dec 2010
331 Posts
Quote:
Originally Posted by tacx View Post
How hard are you finger testing it?

Could be

Servo going bad. Hopefully not from a heavy finger!

Low battery? This is what I suspect.

Will the servo move the elev. up by itself. And if it does can you push it back down manually. Without forcing it of course.
I only gently rested my finger on top of the elevator. Never pushed it. I did take the elevator apart and found out the servo is an FP-128 Futaba which only has 33 oz on 4.8V. Could that not be enough torque for a .60 F-20? I am now thinking about putting a Futaba S3010 since it has 77oz of torque on 4.8V. The elevator servo hesitates when I move the stick slowly. So if I move the stick slowly, the elevator servo will jump little by little until it reaches the end and the jumps are really big, maybe 2mm of throw in between each jump. I hooked up a 6V battery to the plane but the servo didn't even move, even though it is rated for 6V so I don't know what that is about..
Rcflyyer1 is offline Find More Posts by Rcflyyer1
Reply With Quote
Old Nov 04, 2012, 09:10 PM
2 Fast 2 Low & 2 Loud
scootrb4's Avatar
United States, CA, Winchester
Joined Nov 2011
3,116 Posts
Quote:
Originally Posted by Rcflyyer1 View Post
I only gently rested my finger on top of the elevator. Never pushed it. I did take the elevator apart and found out the servo is an FP-128 Futaba which only has 33 oz on 4.8V. Could that not be enough torque for a .60 F-20? I am now thinking about putting a Futaba S3010 since it has 77oz of torque on 4.8V. The elevator servo hesitates when I move the stick slowly. So if I move the stick slowly, the elevator servo will jump little by little until it reaches the end and the jumps are really big, maybe 2mm of throw in between each jump. I hooked up a 6V battery to the plane but the servo didn't even move, even though it is rated for 6V so I don't know what that is about..
I'm a noob, but I can tell you your servo is too small and hashed. LOL That 77oz is better (minimum) depending upon your plane size and type of flying you do.
scootrb4 is offline Find More Posts by scootrb4
Reply With Quote
Old Nov 06, 2012, 11:13 AM
Registered User
United States, TX, Weatherford
Joined Dec 2006
1,655 Posts
Kinda sounds like the servo's internal follow up potentiometer is worn out. Lots of jitter, etc. can do that. It is a mechanical device and subject to wear. On due consideration, I would replace the battery, go to six volt and replace the servo. Cheaper than a plane, right?
Chip01 is offline Find More Posts by Chip01
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Help! Bixler Servo rudder elevator problems svenvwier Beginner Training Area (Aircraft-Electric) 6 Sep 26, 2012 08:44 AM
Discussion frustrating elevator servo problem RichFlyer83 Micro Helis 4 Mar 19, 2009 12:09 PM
Question Lama V3 Old 4in1 Elevator Servo Problem ailevin Coaxial Helicopters 4 Jan 29, 2007 10:04 PM
Discussion Problem with elevator servo ormandj Mini Helis 3 Jul 22, 2006 04:02 PM
Berg elevator glitch or servo problem? Larry3215 Radios 8 Oct 02, 2004 01:45 AM