I have an Ultra Stick with 7 servos on it. Four of these in the wing are JR Digital DS 811 servos and the others in the fuselage are standard servos. When I do a range check the digital servos chatter but the others do not. Has anyone had a problem with this? What remedies do you suggest? I called Horizon who told me I could buy RF filters (at $13 each) which might remedy the problem. I just don't like the prospect of paying more for digital servos and then when I have a problem with them the remedy is to throw money at the problem in hopes that it might fix it. Any help would be greatly appreciated.

Daryl[8D]

Do they chatter or do they "sing"? If they chatter, the linkages may be fighting each other if 2 of them are connected to the same flight surface.

It could be that your battery voltage is down too. Check your extension cables for tight, clean connections. Better yet, hard wire longer leads to the servos for minimum voltage drop.

I don't think "RF Filters" (whatever they are, maybe chokes???) will fix this problem.

Most digitals will sing, or produce a rather high pitched whine when under a slight load. That's normal. Un-Nerving, but normal...

I had the DS811's in my Funtana, they made a chattering noise but you don't see the arms moving.... apparantly this is normal

I also have the same plane, same 7 servos, and the digitals on the wing. They also chatter with no ill affects. I read a few threads on RCU that say this is normal. I have read that it is just the weight of the aelerons and flaps pushing down on the servo and the servo responding to keep them level. I do not know if this is fact or not, but most responses to this question that I have seen say the same.

Hi,

I knotice someone else is discussing this over at the "ASK DANNY..." forum, you may want to take a peek at that as well.

Best regards,

Wayne Miller

A high-pitched "whine" is normal...

A digital whine is normal. Hitechs really do this. Also many servos will chatter when you are using a 5-cell pack and the voltage is really high. It's nothing to worry about, although your buddies will think there is. 5-cell packs can get up to 7.2v. A voltage regulator like one from Maxx Products (<$20) will cut it down to 6v and eliminate the chatter.

Perhaps when I said chatter I was unclear, this is not the whine from binding that comes normally from digital sensitivity. When I have the antenna down and walk twenty five feet from the plane the four servos on the wing move violently in every direction without instruction from the transmitter. I had a stock JR 600mah nicad battery on it and just traded for a 1400mah nicad (both are 4.8v). The servo extensions are 12!QUOT! JR. If I unplug the wing servos I can walk a hundred feet away with the antenna down and the remaining servos still move only when instructed by the transmitter.
I talked for over 20 minutes on the phone to Horizon yesterday who in the end advised me (since I have other flight packs) to remove the digitals from this plane and install JR 537 standards in the wing of the Ultra Stick and take 811's and put them into another plane.
I intend to try that for this weekend. We'll see.

Thanks for all your input,

Daryl[8D]

Hi Daryl,

At the other forum I mentioned "JR Radios - Ask Danny at JR" under the title "JR-811's digital's wont stop chattering", we were able to confirm that with at least one other person, if you add an noise trap extension cable that the servo chattering stopped.

They also mentioned they are starting another thread to address this issue.

You may find the information interesting.

Best regards,

Wayne Miller

DANGER!!!!!! I lost a plane that did the same thing. I found out after the crash investigation was over that I had a bad switch. Check that out and check the voltages and loads to all your servos too. I use the Hanger 9 Digital Servo & Receiver Current Meter. It works pretty sweet. The last thing is that if you are reusing a reciever from a crashed plane your crystal could be cracked. Check it out.

That's why I love HiTec. I just love that whining sound

Well, it seems I am not alone on the DS811 flutter/chatter or whatever you want to call it. I have had this JR 8103 promo pack with the R700 and 4 DS811, servo switch, battery etc. I love my radio but can't comprehend the attitude that this rapid, wild flutter of our control surfaces is "Normal" or "Ok".

The first plane I installed these servos in was the H9 CAP 232 Sport. The 811s were perfect even with 12" extensions on the ailerons. They made a low growning noise as a digital will.
I then installed them in a CG Extreme 330 with the 4.8Vbattery, and could not stop them from moving all of the control surfaces 1/4" to 3/8" rapidly in each direction. This plane requires 18" extensions for the tail servos. I unplugged each servo, one at a time and the only time the chatter would stop was when they were all unplugged except for the 537 throttle servo that had remained unaffected the whole time. Syytematic replacement of the R700, battery and switch assembly were no help. I wouldn't even fly a plane like that so I installed 537s everywhere and had no problem.
I then installed the DS811 set on the new Aeroworks 40 sized EDGE 540. this plane requires 12" aileron extentions in the wing and 6" aileron extensions on the radio as access is very limited when time comes to attach the wing. So with 18" of extension on this setup with an additional connector in line, no problems. I just figured the servo couldn't keep up with the control serfaces of the CG Extreme and tried too hard to maintain center. with the resistance of the pushrods and the relatively better leverage ratio over the scale planes control surface weight, they were fine.

That is fine for everyone except for the 3D flier. 3D planes have a lot more control surface area that has more leverage at the TE on the control system than the scale plane does. I think the DS811 servos work great in the scale plane aplications I have tried them in. they are pretty strong with reasonable speed, hold and center very well. I just wish I could use them in my flip 3D.

Regardless of hearing that this is normal and everything will be ok, I will not use them on my CG Extreme or my Flip 3D due to this chatter. Flying loads change and durring a landing, when airspeed and propwash are low, thats the last place I want my rudder fluttering about. I use HiTec servos that are stronger, faster and less expensive untill JR has something in that class that works better than the DS811s.

I don't like having 4 digital servos I can't use on the plane that I want the digital advantage on. I really think JR should do something other than just blow us off with "That is normal. They all do that. It'll be ok when you fly." Well I say it isn't ok if you want the precision performance that you expect from a digital servo. To me an strong analogue servo is better even if it doesn't center completely. At least you can fly that correction. There is no correction for a fluttering, flapping, chattering control surface.

I am having the same problem as errolw98 described, except they are HiTech 5625 digitals. Only on the ailerons on my H9 Funtana, with 12" extensions. The rudder and elevator are analog HiTech 625s.

When I do a range check, the digitals on the ailerons start fluttering wildly with the antenna down at about 35'. 1/4" to 3/8" each direction. The analog 625s remain rock solid. If I pull up the antenna, the digitals stop fluttering, until I walk out of sight of the plane.

I too don't think this should be "normal", and find it interesting it seems common to digital servos on large control surfaces on our 3D planes, not just JR DS811s.

Voltage measured at each servo is good.

I am going to try:

1. Heavy duty extensions;
2. Twisting the extensions;
3. Torroids on the extensions.
4. 4.8V NiCad vs. the existing 4.8v 2100mAh NiMH

1 is more a current/voltage drop related cure, 2 & 3 combat noise/cross-talk. 4 is an off-chance test that the NiMH is having a current supply problem - not likely with only 2 digital servos that are not in stall.

If the problem is simply the weight of the ailerons at rest, or other non-noise/current issue, I don't expect any of these tests to have an effect. And if so, I'll replace the 5625s w/ 625s.

While we're talking about digies, what are good about them, speed, torque, power?? What?....

gpohly,
I think you will not find the answer in electronics. My situation made no difference if I was 3 feet or 35 feet away. The one thing I tried with moderate success was to get much longer servo arms from DuBro and get the clevis attachment point as far away from the surface as possible while still getting the maximum deflection. It did not cure my problems but helped a lot.

ifly,
We are suposed to want digitals for there precise movement and return to center as well as their power. Why build a high end digital without power? This precision and power are suposed to hold the surface at the dictated angle better.

If you are using analog and digital servos of similiar power I would not think the control surface weight is causing the problem. Some where I read lots of current draw and or voltage across the receiver power bus can cause signal interference. I fly a GP Pitts with eight analog servos using a 5 cell pack. Once in a while I get the jitters on the ailerons after first turning on the receiver battery. No problems after that. I am going to use an isolator on my 1/5 Wildcat because I want to isolate the current draw of the digital servos. 4 cell on the receiver running throttle and retracts then 4 digital servos running rudder elevator and ailerons and 4 smalll analog servos for flaps from the isolator using a 5 cell. Not field tested yet. Isolators are expensive so try to borrow one and test your application.

Carl

In my case, installing four analogue JR 537s cured the problem completely. Even with the poor mechanical advantage of a close clevis to surface set up. I thought this was due to the 537s not trying so hard to find the exact center point of the surface throw. In testing to figure this problem out I used two 4.8 V 1850 NiMh receiver packs. One at full charge and one that had four 14 min. flights on it, my second JR R700 reciever and a second powefr switch. No difference was noted at the time untill I installed the 537s. All with the sam HD JR extentions.

The DS811s were fine in a scale aerobatic EDGE 540 and a CAP232 with less surface deflection and area and more resistance to pushrod movement. They seemed to find and hold their center without passing it back and forth just fine in that aplication.

What is the difference between the digital and analog BB or standard servos...What's so good about the Digitals....?????

I have some information about this on my web site:
http://www.geistware.com/rcmodeling/articles/servos.htm

The author is a Moderator on this system

Simply put, digitals blow analogs out of the water in terms of resolution.

Same problem here with the ds811's. One thing I noticed is that the tighter things got, and the more throw there was, the more they shook. I also noticed it was more on the return to center than anywhere else. If I moved the trims way to the right or left.. it gave a lot less probs. So.. I guess "They" (jr?) are saying this is normal.. great. there goes my idea of getting them fixed on the warranty. It seams like this is as bad as flutter and would tend to "tear apart" your plane. Is that not right?

I think I may have fixed the prob with the ds811. I have been testing tonight trying to figure this one out. It appears that it does it only at the center position. I could flick the rudder and it would start vibrating. I started adding subtrim and it stopped at around 10.. I added 10 more and it does not do this anymore. I have the UCD .60.. so.. it has a very large control surface on rudder that was causing the problems. After adding the subtrim.. just twisted my clevis a few times to make that the center and it works fine. I am not saying I lie this..but.. it appears to work. This worked with trim too, but, did not want to waiste trim steps until I was in the air and needed them.

I flew my fluttering DS811s on the ailerons of my Flip 3D for three flights. Even with sub trim in the channels to center the arm for a 90 degree start, the fluttering on the ground was embarrassingly severe with or without the engine running. Even though there was no flying problem this time, I am not going to risk my plane further with these. My gut feeling tells me it is just a matter of time. I still don't like this as once the plane lands, even as speed is still up, the fluttering starts immediately as the plane rolls out over the runnway surface.

Come on JR, I do not like your answer and will find another alternative to these servos. This is rediculous. Something is wrong with these things. Make a product update or recall. If I were on a plane that displayed these symptoms, I would get off and take another plane or alternative transportation method.

Sending them in for warranty repair at this point would be frustrating and fruitless until you step up and admit that a problem exists and you have the cure for it. I don't see that comming very soon. I'm quite certian that the engineers all thought the MD80 Jackscrew was just fine before it failed and killed a plane full of people through a "maintainance" problem. Is a spectator or pilot going to have to be struck and injured or killed by a plane with these servos gone wild before you fix or replace them with something that works? Will it take a judge's ruling that a problem exists and the liability is yours before you do something for the consumers of this poor product?

Look for mine on ebay or in my trash can if you want them.

My sentiments exactly. Everyone is saying you need to make the hole larger for the servos and back out the servo mount screws.. This of course did not work in my case. It is basically masking the initial problem anyways. I don't care how tight what is.. there is no reason for these things to have a seizure when you just flick them a little. I have seen posts all over this forum and on the internet. It upsets me that I have to send them in and be down while I wait. I also think that it will not get fixed when I send it in.. but.. we will see. Maybe they will be good enough to send an equivalent different servo.. I have never seen customer support THAT good, but, you never know.

Has anyone sent one of these in to JR to see how well the warranty works? Did it fix the problem? I have not seen it posted anywhere.. of course.. I have not seen anyone say they sent them in. I like the jr stuff I have for the price, but, if this cannot be fixed.. it will not be worth the anything at all.

WHAT?????

Thats just retarded.