elevator servo binding due to link balls on the inside

[belcom]

I noticed when at full pitch positive or negative when I do...
1. At full positive pitch with full back elevator (cyclic all the way at the bottom)
2. At full negative pitch with full forward elevator (cyclic all the way up)

The elevator servo wheel turns so far that the links attached to the servo wheel on the inside (as per manual) start to bind  against the servo case.  I am using JR 8717s and small JR plastic wheels with holes exactly at 10mm. If I reduce the travel in the Beastx I don't get the blue light and swashpate won't move as far as I want it.

What's up with that?  Anyone else experiencing this?

[Tommy Wagner]

Can you post a picture? 


Tommy

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[Darren Lee]

Pretty sure that's normal.  The solution is not to input full collective and cyclic at the same time.

[RyanW]

I will have to look at my installation again, but I found that you can't use the stock hardware with JR 8717s without the screw heads hitting the case. I tried four different types and brands of JR servo arms, but it didn't make a difference. You have to use a VERY shallow head screw on the carbon wheels for it to clear.

I even tried installing the screw with the nut toward the servo case, then used a Dremel cut off wheel to shave it down and it still hit the case.



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[Branden Wheaton]

I had some JR 8717 on my E7 I used the Futaba servo wheels. I used a washer and the locking screw and was able to push them on with no problem. Since then I had changed them out but they worked fine with no binding.

[Kevin Feil]

I'm with Brandon, We talked about it before and I tried it and Works Great! you have to do a little Modding to the Screws but it can be done.

Kevin

[RyanW]

A washer between the servo arm and the servo output spline?

How do you use a Futaba servo wheel on a JR servo, the tooth count is different?

Thanks,

[Branden Wheaton]

I used a washer in between the servo horn and the servo screw. The washer was just used to force them on. I tightened the screw down pushing the servo horn on after the horn is set in place I removed the washer. I had 25 flights on them with no problem.

[RyanW]

I am glad that you didn't have any issue with it, but if I understand correctly that you are forcing the Futaba wheel on a JR output shaft, then I have to strongly caution against anyone else doing this. Putting a Futaba arm on a JR output shaft will lead to stress cracks and eventual failure.

As for running the JR servo arms- the best to use are the JR arms that have the metal sleeve that reinforces the area around the servo output shaft (splined).

Almost all of the machines I have looked at with JR servos have the carbon plates mounted on the outside of the servo arm, which alleviates the interference with the top of the servo case, but makes the control rods canted out at an angle. If you want the geometry as Matt intended it, you need to have a very shallow head on the screws you use to mount the carbon plate.

[Branden Wheaton]

Very little force is required to do this. The spline on the JR servo is metal so i dont see that being a weak. There is little difference between the two different spline. 

[Kevin Feil]

I heated mine with a hairdryer "not hot just warm" then it relieved it as I drew it in with the Screw and Washer Trick, No stress Cracks when using mild heat. It works just Fine. I have done this before and Never had any issues.. If one doesn't feel comfortable doing this then there are other alternatives of course, I just didn't like the White Small JR wheels with the Carbon Servo Horns.

Kevin

[RyanW]

Kevin- I agree with you on the small JR wheels. They don't have much material around the spline and they have failed on other helicopters in the past. The best to use with the JR servos are the four star out of this package and just trim the arms down. As you can see, they are reinforced with a metal sleeve and almost take a gear puller to get off. - http://www.readyheli.com/JRPSH8711HV-JR-Super-HD-Servo-Arms--Standard-JR-Spline_p_38235.html




My disagreement about using the Futaba arm on JR servos comes from the r/c car guys who would shoe horn what ever servo arm was in their parts box to the servo they had in the car and nine times out of ten the arm would break around the spline. Futaba has 25 tooth spline and JR has 23. Again, I am glad that it is working well for you, but it is an area that I wouldn't chance it.

[Kevin Feil]

well I for one an Not above Trying something different, I like the looks of that servo arm and Will be ordering some. I Will be redoing mine. Thanks for the Heads up on those  Ryan.

Kevin