8717 HV Servos

[TheBigE]

Hello,

Just want to check, but there are no fit up issues with JR8717 Servos.  I have seen them on some setups, and wanted to make sure that the included servo arms and mountings will work for the JR Servos.   

TIA

[Chris Sexton]

I have the 8917HV cyclics on mine, the mounts are perfect, but the included CF servo arms won't bolt up to any of the provided servo wheels. I had to use DuPro arms.  I know you can get JR wheels that they will work on, but my LHS had a set of JR DuPro arms with the recommended 20mm ball offset.

Here is a picture of my servo setup.

[Tommy Wagner]

Oops

[Tommy Wagner]

No issues with the ds8717 just use the small circle horns. You will have to enlarge the holes in the carbon fiber arm just a small amount

Tommy

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[TheBigE]

I am having difficulty fitting up the servo arms with the supplied servo wheels.   I am using the round JR wheels and two holes line up, so I drill the other two.   No problem.   But once I mount to the servo, the bolts rub agains the servo case.   I also had to grind down the white arm for the Elevator servo as it looks like it could be rubbing on the frame.  I am using JR 8717HV servos

Thinking, I mac go another route. 

@cdsexton  what servo arms are you using?  Du Pro or Dubro?  Do you have a link.   I may also look at some other servos arms. 

Thanks

[TheBigE]

It almost appears that the large JR servo arms, have a hole at 20 mm.   I would have to enlarge the hole on the servo arm, but I am not sure there is enough material there to enlarge the hole much bigger.

[Bill Martin]

Esprit model has a aluminum JR servo arm and so does Ready Heli a makado arm at 20mm but it will need to be taped to a 3mm

[Pete Busch]

I used the large JR servo wheels. Put the carbon fiber arm that came in the kit on it for a template then just dremmel out the excess white. When your at the point your centering your servo's/arms just move the carbon fiber arm to 90, mark it, then drill out the four holes and bolt them together. 

[GAR]

I used the large JR servo wheels. Put the carbon fiber arm that came in the kit on it for a template then just dremmel out the excess white. When your at the point your centering your servo's/arms just move the carbon fiber arm to 90, mark it, then drill out the four holes and bolt them together.

That is what I did also.

[TheBigE]

Thanks, I ended up using the small JR servos wheels as two holes line up and the other two need to be drilled.  When installled there is the smallest of gap between the nut and the servo itself that I am convinced it is not rubbing.   

I was thinking about going with the large round servo arms as you can get an exact 90 degree fitup with zero trim in VBar.   Other than getting to the elevator servo, it would be a really easy switch.   

[RyanW]

I need to post some photos... maybe this evening... of my install. In my experience, the stock JR servo wheels are not adequate for direct to swash with 8717 type servos. The weak link is the actual 'plastic' around the splined servo output shaft. It can develop cracks and fail at the most inopportune time. This is why the came out with the new composite arms with a metal strengthening ring- http://www.ronlund.com/rcheli-prod/JRPA207.html



I used the cross arm and trimmed off the excess. I used a nearly flat head machine screw to attach to the carbon arm. The pictures I post will clear this up.

As a side note, I tried literally every arm made for JR servos with the stock Synergy hardware and none of them work without the bolt head hitting the case. I flipped the bolt over and trimmed the bolt where it was flush with the hex nut and that was still too much sticking out of the back of the servo arm. I found some flat head machine screws that clear the case. That is the key, no matter which servo arm you use.

Will post follow up photos later.
Thanks,
-Ryan

[TheBigE]

Ryan,

I look forward to the pictures.   I have the set of servo arms you have in your picture as well.  I have always worried about the servo centers on JR servos and think with the direct coupling to the Swash on a Synergy that the load on the center plastic is even higher.   I am waiting for a set of AL arms to arrive and I am going to try and tap those for the 3mm ball of the synergy.   

Erik

[Kevin Feil]

Great Tip Ryan, I didn't realize they had those, Makes sense! I have had one fail before and fortunately didn't harm the heli. Good Tip, Look forward to the Pics.

Kevin

[RyanW]

I apologize, I didn't get pictures. I do have a good excuse though!!! I went out to the hangar, tossed a little foamy warbird in the air for a few minutes, then took the E7 out. I flew it until the timer went off and pretty much forgot about everything else I was supposed to do this evening

[Kevin Feil]

you lucky dawg!!! I just walked in after a 14 hr day doing run ups on a Gulfstream G2 I just rebuilt, all I could think about was how pretty it was out side and my heli's where 73 miles away..lol  We will let you off the hook just this time Ryan..lol

Kevin