Jr Sport ST125mg Problems ?

[en1]

I was wondering if any of you have experienced problems with the ST125 Mg Jr Sport servos in 1/4 Scale planes?

Ailerons not centering correctly along with elevator halves
and one elevator half geeking a little.
Another plane at our field had similar problems with the same servos. ???

[Vic3D]

Well, they're not digital so they won't exactly be 100% precise, but they should center decently... If not maybe you got a bad batch... What voltage are you running?

[en1]

I have 4 more Jr 8411's ordered allready.....

I have the voltage set at 5.9v through Fromeco regulators w/5600 mah pack.
this plane is at 27th flight. I noticed a problem this weekend for the first time but will not fly till problem is solved.

[skull1971]

I heard of this problem today at the field, on the 125'S. The 126's that problem was to have been fixed. I hope so because I have one on the rudder of my new Christen Eagle.

[en1]

These servos have worked great till now the are in my 27% Hanger 9 Extra 260, W/DA 50. I am at flight 27.
They are on the elevators and ailerons, they are getting replaced by 4 more 8411's
like I have on the rudder. I will send them back as they are only a few months old and use them on my next smaller plane project. I am going digital completely on this plane as It is a real blast to fly, outstanding power w/ Menz 23-8 prop, and I would hate to lose it.

[WangoTango]

en1,
Let's get everyone up to speed on 125MG's....... A first batch of these gizmos came out a little more than a year ago and they were the sport flyer's new best friend....... A 30 dollar high torque, metal geared servo! They were torque-y and a bit slow but you could outfit a good sized plane for cheap and still be reliable. Along comes the centering problems and guys with dual elevator programing capability with computer transmitters were able to compute out the problem most of the time. Then came aeronautical surprise #106 in a continuing series: Pull full up elevator for instance...... Let go of the stick. (As in "twang" back to center) The elevator would then snap back to center. Oh, but NO! You get an optional little feature that gets yer attention like nine inch nails being drawn ever-so slowly down a bone dry chalk board. (hairs on the back of your neck are standing on end and your teeth fillings are starting to give you deep down pangs, huh?) Once the elevator reached the center position, you got a little extra surprise for your entertainment dollar....... It proceeds to go to full DOWN position and THEN snaps back to center! (Go ahead..... ask me how I know and just exactly when the worst possible moment would this little phenomenon occur????) You have to have a 30 pound 1/3 scale Little Toot that flies just a tad heavy on the sticks go through this little exercise to fully appreciate the situation!! Yeah buddy!! I meant to do that outside loop at forty feet! Why you askin'???
Well, Horizon found that the factory installed a resistor on the pot that was a wrong value and this was the excitement that you too could enjoy on other flight surfaces if you were lucky enough to install one of these jewels on it! They (Horizon)were the usual great service organization they are and did a total swap on my six units I had on the TOOT. I think the eventual fix was to come out with the new and improved 126MG just recently. I have a couple and they are great and trouble free. The second generation 125MG's are still working well but I'm not operating them on 6 volts. (Another little problem that could crop up...... They were a bit voltage sensitive.) All's well that ends well in JR Land.....
WT

[Eury]

I've got a 126mg on rudder on a plane, and it's a great servo, however, I can tell you that the centering issue is not fixed. If you are looking for your surface to center up perfectly every time, look elsewhere. It'll get it in the neighborhood, but it's always off by a different amount every time. I don't care on the plane it's on, but a large plane where precision is important it would be unacceptable.

[exeter_acres]

this is the case with most analogs.... some are MUCH better than other....

this is where digi servos shine

[en1]

I feel much better now knowing that others have had issues with these servos, and I will pay the price for the digitals from now on.
The description WangoTango tells, I was lucky NOT to experience nearly as much I got away with a couple of unexplained half rolls, and when taxi-ing in I saw elevator half do the little jig you described and it was not consitent at all then it went away and the plane went back in the hanger...I was lucky !

[CSpaced]

I had bought the st125mg flight pack when it first came out and sure enough I had the same problem with surfaces travelling past their center points before returning to center. I sent them all back to JR and they fixed 'em all up for me and had them back to me in under two weeks. Now they reside in my UCD were they regularly get thrashed without any signs of falling back to their old habits.

[JimC-MD]

I am glad to know about this little issue and that there is a resolution. (no pun intended) I do have to say this though..........

Setting up a larger bird is not an inexpensive activity. There is always a temptation to look for a bargain or alternative. There are several guys in my club that are getting into bigger planes now that they know they can be operated off of our relatively small field. Many are putting sport servos in them and I have been trying to discourage this practice. I do not think it is reasonable to expect a $30 servo to perform like an $80-100 servo. Heck, I do not use $30 servos in my .60 class birds any more. I like the performance and precision of high quality servos. Everyone that has is flying sport servos and has had a pull on the sticks of one of my planes comment on the feel and precision of the plane. It costs money.

I have many planes where the electronics are as much or more than the plane and engine. I like the results and have VERY few problems. It is worth the price IMO.

[en1]

I have to agree with you JimC-MD I have just experienced my first plane with digitals in it in a UCANDO 3D .46 size with a OS .50 Hyper heli engine and the servos in that plane are the 8231 JR's they really do work better. I have seen the light and from now on will buy nothing but the better electronics.

I also want to thank everyone who gave their input to my post I learned a lot from all of you.