jr 8711's shaking

[harv]

Hey guys, i went out to the field yesterday planning on flying my extra. When i turned on my plane the ailerons started shaking up and down rapidly. once i started to move them or when i pushed it with my finger it stopped. But when i move my ailerons again they do it when i get to center. Anyone know why this happens(its a 42% extra and there is 2 servos per aileron. 8711s). Im also running smartfly euquilizer II's in each wing. on a JR 9303 system. Are my servos fighting each other?

[rcairflr]

Welcome to the club... My JR 8711 does the same thing on the rudder with a push pull setup.

[dbcaster]

It's the Smart-Flys. Try running the servos directly to the receiver or into a JR Matchbox and you will see how much smoother they are. The 8711's don't like the Smart-Fly Eq's.

[Edgeman 540]

A friend of mine purchased 2 8711's and installed them on his 40% Carden Extra's elevators and one did the same thing which your describing.He sent the one back to Horizon and they said there was apoxy in the servo.Anyway they fixed it for free,sent it back to him and it was fine there after.
I think their apoxy story was B.S and didn't want to admit that they past off a bad servo.After all how could anything get into a sealed case???
I personally have several 8711's and never had any issues.

[harv]

cool guys, This problem occured jsut recently though. I have put 30 flights on these servos and jsut 2 days ago i did some 3d stuff(hard snaps, rollnig harries fast point rolls etc) and it never did it on the ground at that time. I pretty sure it cant be the EQ but what do i know. ill check it out. Ill run the ailerons off one servo on the gound and see if it does it still.


thanks

[3D-Seth]

They tend to do that sometimes, but the air pressure from the air over the wings makes it stop, just like if you were to put your finger on it.

Seth

[dbcaster]

Harv,
The reason I say it is the Eq's is because I had the same exact problem. It worsened over time as well. Mine was not like the typical rudder shake that I have seen when there is no load on the surface. The aileron has weight on it so it is different. Just for fun, try running one servo through the EQ and see how notchy it is. Then plug the same servo directly into the receiver and see if it smooths out.

[bodywerks]

Sounds like your gears are wearing, causing the backlash to be more pronounced, and the servos are trying to stay centered. Welcome to the life of a JR servo owner. Don't worry about it until the servos start oscillating slowly or the shaking doesn't go away in flight, as this is a pot issue, which also seems to be common on the 8711. My buddy has gone through 5-6 of them (bad enough that they were replaced under warranty) in 125 flights, and all remaining units had their gears replaced after only 90 flights. He was using an EQ10 for matching, but the plane was set up by a Smart-fly AND JR sponsored pilot. He never mentioned anything about 8711's not liking Smart-fly eq's.
It seams to be a hit/miss type of thing, too, as many people are not having problems, and my servos are still tight after 30 flights.

[harv]

Ill fly it again and if I feel it in the air ill check the EQ II and if its not them ill probably send the four of them back.

[harv]

I took a look at the servos today. They are still shaking, but one side worse than the other. M left side shakes, but not as severely. The right side however is bad. I tried it again and it was shaking. about 1/8th in each direction. I unhooked one servo and it was even worse. IT was atleast 1/4 inch of movement in each direction. Ill try and get some video footage tonight. If i want to send the servos back, can I send them DIRECTLY to JR?

[rede2fly]

shure thats where you send them is to horizon hobby. and by the way you paid for that shaking. i am using 2 of the 8711 and 1 shakes and the other dosent. on the one that was shaking i noticed that the pull pull lines on my rudder was a little loose and i tighten them up and it went away. but i can tell you one thing,, i have been very brand loyal to jr for almost 20 years and i wont use any other radio but theirs,,, but i dont think i will ever buy another one of their servos. i have a hard enough time not shaking myself but i do have to say i have only had a problem with the high torke digital servos

[xtra330]

my ailerons shake on my Katana - normal JR 'jitters' - more than likely the pots are going and yes they do wear like the 8611's....i fixed mine just like we did back in the day......turn the pushrods just a little bit on each servo (to keep tension on the flight control) jitters stopped.......for now ;-) These are going through the Powerbox System.

[rcheliman]

Mine just seem to jump then go back to center, more prominent on the left elevator I thought I was to close to the plane with the transmitter because when I back off about 5ft it stops, Any thoughts guy's I'm running the Spectrum 9100 RX with two 6.6 volt A123's unregulated with JR 8711's on all surfaces. It's in a 35% Aeroworks Yak 54 with a JR 9303 2.4 radio, that I just finished and haven't flown yet. Noticed all the jumping when I was setting up the control surfaces for flight.

Mark

[off2fly]

JR has the best customer service in the business,I have heard the 8711's get nervous w/higher voltages are you over6 volts?

[bodywerks]

	Quote: Originally Posted by rcheliman
	Mine just seem to jump then go back to center, more prominent on the left elevator I thought I was to close to the plane with the transmitter because when I back off about 5ft it stops, Any thoughts guy's I'm running the Spectrum 9100 RX with two 6.6 volt A123's unregulated with JR 8711's on all surfaces. It's in a 35% Aeroworks Yak 54 with a JR 9303 2.4 radio, that I just finished and haven't flown yet. Noticed all the jumping when I was setting up the control surfaces for flight. Mark

I have the exact same setup but in a 42% plane. That twitching happens for me whenever I am in the garage with it or even in the driveway close to it. Never had the problem at the field. I am sure what we experienced is signal swamping.