!!HELP !! JR 8711 servo

[Patrick Holowesko]

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[WangoTango]

Patrick,
Anytime something is not normal, send it back and get it fixed or replaced. I want to see the bad ass video in a flying sort of way. Don't really feel like seeing your plane in the "worst crash" section!
WT

[Mudsurfer1234]

That sounds like what the older JR servos did, like 8411's and the original 8611's, when they would "hunt" for center, and wag back and forth. There's a few guys around here that fly anyway, but with it being an 8711, def. send it in.

[Dan_nO]

The hunt for center as you said...i think it has a little to do with the speed of that servo and, when anything puts any pressure on it it tries to go back to center so fast the control surface has that force or momentum and puts pressure on the oppisite side in its momentum and then the servo fights it the other way, then it goes into that quiver back and forth because it is so fast.

[AHP]

Gee.. Sounds familiar.. Where have I heard of this before? Oh yeah, the 8411 and 8611. Glad to see the new and improved super duper 8711 shares the same 'feature' as its predecessors.. So they recycled the same troublesome geartrain as the 8611 and now it appears they're using the same troublesome pots as well. For the premium they charge, you'd think they'd stop dipping into the same old parts bin and implement a little more innovation.

With that said, it should be fine to fly. As you noticed, once you put a little pressure on the arm the pot see center and stops the wagging. The air and/or vibration will stop it from wagging. I'd send it back when you get a chance; JR's service is excellent and will take care of you, I'm sure.

[AirMcNair]

Your Servo has a problem. I have two of them and they are as strong and as smooth as the day I got them.

Unfortunately there is a return rate on all products in the world, you just happen to receive one of those.

[Patrick Holowesko]

Thanks guys for your input.. i have already flown about 6 times since it has done this and flys great.. i just wanted to make sure i wasn't risking my new plane ... Video soon

[VooDoo Child]

We call it the J.R.detox.I took out 8411-8611in my 35%due to centering shakes,swapped for 5955.In the air the servos responded just fine,it just pissed me of to no end that every time i flipped the switch on,sombody would run over and say,YOUR NOT GUNA FLY THAT ARE YOU ,THATS UNSAFE.That and the time and money involved in these things,you dont want your plane to look like it has terets.Did you try to plug it into a 4.8volt pack.Sometimes 6.0volts dont liki J.R.Cant wait to check the vid!

[Reza]

Guys,

It is absolutely normal! Does 0 dead band ring a bell? On rudder you don't have the weight of the control surface on the servo because it is vertical. Tension of pull-pull cable are not 100% equal therefore, with 0 dead band it tries to find the center. With the slightest amount of pressure from prop wash or by your finger it goes away. Yes servos with 2-4 dead band will not show this because they are not as accurate! If this servo was on Aileron you wouldn't see that. Aileron weight would hold it in center. Normally when gears mesh in after 20-30 minutes of flying you will start noticing this on rudder only! You can go through 100 more servos and they will do that because of 0 dead band.

Don't worry about it at all and fly the heck out of it!

Reza

[Reza]

Another thing to add is if you had 2 servos ganged up you wouldn't see this unless you have perfectly matched them. Reason I am saying this is it is really difficult to 100% match two servo there is always a very slight amount of fight!

[Bunky F. Knuckle]

Loosen the tension on your Pullpull cables, just a SMIDGE!!!! I try to run mine tight, but not High E note tight.

For testing purposes, remove 1 cable from the control horn and then turn everything on, and see what it does.............

I had some 8411's do that, only because they were 5 years old, and never had any service on them, until someone toasted my plane for me! Then I had them checked, and new case tops installed, and JR changed the pots in them.

[Mike c.]

Yeah, my 8411s on the rudder on my carden does that. As soon as u touch it, it stops. A friend of mine has 8411s on his elevators and they wiggle too. I too, have had some people say "Thats not safe to fly like that." I simply smile and say, "No, its safe, she's just wiggling her tail cause she scared of what I'll do to her this flight"

[WOODisGOOD]

What Reza said above is correct. Are you running pull pull or is the servo in the tail of the plane? Adding a second servo and putting a slight bind against the other will correct this. You should use a amp meter to make sure that you do not have too much binding though.

[crazyjoe]

I use the 8611 in my rudder and it did the same thing after about 30 fights. I flew that plane that way for another 2 or 3 hundred flights no issues. I had 8411 on the wing and elevator they did the same thing. I sent them in while still on warranty with a note stating i had 2 or 3 hundred flights. Seven days later there is a box on my doorstep all 5 servos completely rebuilt no charge now now thats service

[Tim F.]

	Quote: Originally Posted by crazyjoe
	I use the 8611 in my rudder and it did the same thing after about 30 fights. I flew that plane that way for another 2 or 3 hundred flights no issues. I had 8411 on the wing and elevator they did the same thing. I sent them in while still on warranty with a note stating i had 2 or 3 hundred flights. Seven days later there is a box on my doorstep all 5 servos completely rebuilt no charge now now thats service

I have a buddy that has a 102" yak with one 8711 and I have seen his do the same thing, It has been flown a lot this way. I think the guys are correct on the 0 deadband and not having the wieght of the control surface on the servo.