Rotary Couplers

[G-JIMG]

I'm designing and building a 1/10th scale King Air 350CER and want to keep all the linkages hidden.

For the ailerons I'd like to use RDS. There's no problem making the pockets or bending the metal rod but I've hit a wall when it comes to connecting the rod to the (Futaba) servo. There's plenty of cheap solution available in the US (see image of Kimbrough Coupler set) but I can't find anything in the UK.

Does anybody know a UK supplier or have an alternative solution?

Jim G

[Denis Watkins]

Do you mean pushrod keepers Jim, from SLEC UK

Edited By Denis Watkins on 15/06/2018 06:26:48

Edited By Denis Watkins on 15/06/2018 06:27:40

[cymaz]

Here is a thread at for some reading. Top hat couplers is what I think you were asking for. Someone with a lathe might turn a few up for you.

[Dave Hopkin]

Do you mean these RDS Adaptors?

**LINK**

[G-JIMG]

Thanks for the help guys.

Dave, that's exactly what I was looking for, but for Futaba S3150 servos. However, your link led me to rewording the Google search, which in turn led me to a robotics company in Somerset that had exactly what I needed, and at a very reasonable price. Result!

Thanks again,

Jim G

[AVC]

Hi G-JIMG, do you mind sharing the link to the company, please? I'm about to start building an Arado AR-96 and I'd like to use RDS controls.

Thanks!

[G-JIMG]

Hi AVC,

Here's the link **LINK**

[Plummet]

It occurs to me that by the application of Murphy's law, the splines on the bought products will always be different to any servos available.

How about a two tine fork made of piano wire. The tines should be spaced so as to go through the holes in opposite arms of a standard servo arm. The tips of the tines should be bent at a right angle to lock them into the holes when the shaft of the fork is inline with the servo axis. The rotation of the servo will then rotate the shaft of the fork.

Does this make sense?

Plummet

[G-JIMG]

Hi Plummet,

That makes perfect sense, but ............................ I'd considered a number of ways to make a coupler, including soldering a wheel collet onto a washer and then drilling a couple of holes in the washer so I could fasten it to a Servo Ring. However, the model's wing is very narrow and there wasn't enough room for anything involving Servo Rings or Arms to rotate.

The beauty of this product is that it comes with 5 adaptors, each with a different spline count, so it works with a number of Servo types.

Jim G

[kc]

You could always file a flat onto the servo splines so that a collet with set screw will hold. Or use a brass tube with a D shaped insert soldered inside to fit on the flat filed on the servo splines. Some servos used square instead of splines.

[Former Member]

[This posting has been removed]

[G-JIMG]

Hi Percy,

It's because I'm trying to make it as scale as possible, even to the point of adding panel lines, rivet heads, etc.

[Danny Fenton]

Jim, there is another way to do the links and that is to use an adaptor to go from the servo disk to the coupler. I made my own but they are easier to make than something with a spline!!

Cheers

Danny

[Danny Fenton]

Cheers

Danny

[Danny Fenton]

You could make somethig similar by soldering a large collet to a brass washer

[PatMc]

,,,or a strip of brass/mild steel soldered to a collet.

[Danny Fenton]

I saw Ian Redshaw use a variation of RDS using a pushrod to do the coupling from a regular servo arm. This picture is not of Ian's installation, but does show the idea.

Cheers

Danny

[G-JIMG]

Thanks for all the suggestions, especially the homemade solutions. That's normally the way I would go, but in this case the wing is just too thin to accept anything much wider than the servo spline.

I'm using S3150 (10mm) Servos and there's not much room for much else. So unfortunately, on this occasion, I've had to open the wallet and buy a couple of rotary drivers.

Thanks again,

Jim G