circlips on servo linkages

[Tony Harrison 2]

Just been trying to fix those, er, thingies that fit into a hole on the servo control horn that rotate freely and hold/actuate the rod or snake. Can't remember what they're called: little chromy thing with a short stub, goes through the horn hole, tiny washer goes on followed by an even tinier circlip to retain it. How do people fit these circlips? I've already lost one, when it sprang away to disappear forever in the detritus of my garage floor...

Tips welcomed. Thanks, Tony

[jrman]

Do it inside a large but thin plastic bag, (dry cleaners are the best source). When it goes "ping" and it will, it's saved in the bag.

[Bob Cotsford]

If you really must use linkage stoppers or whatever they're called then I'd recommend the ones that are held on by a 2mm nut. I do use them, but only on throttle connections in ARTFs where the throttle linkage is just a piece of piano wire.

[GONZO]

Circlip retained linkage stoppers, nasty things, only to be used for control surfaces(if you must) on very light weight electric powered models. IMO a crash waiting to happen.

[Tony Harrison 2]

Posted by GONZO on 04/02/2016 17:10:20:

Circlip retained linkage stoppers, nasty things, only to be used for control surfaces(if you must) on very light weight electric powered models. IMO a crash waiting to happen.

Oh dear! I wonder why I was advised to use them? One of many difficulties for beginners like me is that on the one hand, there is lots of willing advice - but on the other, much of it is completely contradictory. Experienced Modeller A swears blind that Gizmo X is the dog's gonads, while Experienced Modeller B says that's a load of rubbish and I shouldn't consider using anything other than Gizmo Y...

I suppose I can epoxy some bits of bent wire onto the ends of my snake inners, instead of using the linkage stoppers. Re snakes, I was advised to use those on my electric glider, but it seems many people believe passionately that these are the devil's work and I should just use straight-line rods made out of amethyst, or unicorn horn, or something.

Suppose I'll have to experiment with everything and find what works and what doesn't. Shame the wheel has to be re-invented constantly.

Thanks, Tony

Edited By Pete B - Moderator on 04/02/2016 20:33:10

[GONZO]

You must have seen the film 'Snakes on a plane' need I say more! They do change length with temperature changes and alter the trim. They can also introduce a degree of slop making the controls feel vague.But, consider the forces and vibrations on an IC powered plane and that plane remaining in control being dependant on a circlip retained linkage stopper. Perhaps others will back me up or shoot me down???

[Andy48]

Posted by Bob Cotsford on 04/02/2016 16:58:21:

If you really must use linkage stoppers or whatever they're called then I'd recommend the ones that are held on by a 2mm nut. I do use them, but only on throttle connections in ARTFs where the throttle linkage is just a piece of piano wire.

I'm happy to use linkage stoppers, they make field adjustments very easy, BUT as Bob says, use the ones held on by a 2mm nut. I always use 2mm locknuts and for a bit of belt and braces, some cyano too.

Welcome to the world of model flying Tony. Eventually you will find which "experienced" modellers offer sensible advice. As a tip, when you are down at the field watch these "experienced" modellers when they maiden a new plane. You'll see some hairy experiences, and some maiden flights which go off perfectly. The latter modellers are the ones to really listen to!

[Don Fry]

Tony, look for the (person) who comes, puts the planes up, chats, goes home, with the same number of undamaged planes. No drama.

[Former Member]

[This posting has been removed]

[cymaz]

LOOK what I've found

[Denis Watkins]

Seagull Models always referred to this device as a "pushrod connector", and the advantage of the design is obvious when setting up control surface positions to servo arm output. BUT, as you all remark, they can produce a castostrophic failure. On my setups, I Use good quality heat shrink, about 10mm long, before and after the connector, and after the throwsvar set, and Allen screw tightened, I slide up the heatshrink snug from both sides of the connector, and shrink the heatshrink as a safety stop. My neck is now on the chopping block yet again LOL

[Bob Burton]

Posted by Bob Cotsford on 04/02/2016 16:58:21:

If you really must use linkage stoppers or whatever they're called then I'd recommend the ones that are held on by a 2mm nut. I do use them, but only on throttle connections in ARTFs where the throttle linkage is just a piece of piano wire.

I have never used linkage stoppers, but I presume that after you have tightened the 2mm nut the stopper can still rotate to allow the linkage to work.

[Bob Cotsford]

Posted by Bob Burton on 05/02/2016 09:01:12:

Posted by Bob Cotsford on 04/02/2016 16:58:21:

If you really must use linkage stoppers or whatever they're called then I'd recommend the ones that are held on by a 2mm nut. I do use them, but only on throttle connections in ARTFs where the throttle linkage is just a piece of piano wire.

I have never used linkage stoppers, but I presume that after you have tightened the 2mm nut the stopper can still rotate to allow the linkage to work.

The ones I've used have a thread free zone on the shank which is the part inside the servo arm. They can still lock up if overtightened so I use thread locking compound or CA to lock the nuts at a point where the fitting can rotate but not flop about.

[Engine Doctor]

Best advice is throw them in the bin . Buy a set of "Z"bend pliers to make your own snake ends from threaded wire or use the sping clevis' supplied by slec or with snakes . As in another post I have used them on throttle linkages in the past but don't trust them on any control surfaces .

[kc]

Tony, you said " I suppose I can epoxy some bits of bent wire onto the ends of my snake inners, " - epoxy probably won't hold well. Get the proper little screw thread adaptors . One end screws into the snake inner and enough projects for the screw on clevis with some room for adjustment. Adaptors need to be same make as snakes as size varies slightly and they dont hold tightly if mixed.

[Martyn K]

Is this what we are talking about? I have lost the plot somewhere..

Edited By Martyn K on 05/02/2016 12:14:09

[Martyn K]

I use these now - without any problems

Nice big head to screw down and locked with a bit of blue locktight

[J D 8]

Posted by Engine Doctor on 05/02/2016 10:43:48:

Best advice is throw them in the bin . Buy a set of "Z"bend pliers to make your own snake ends from threaded wire or use the spring clevis' supplied by slec or with snakes .

+1 on the above.

[Steven S]

I use Martyn's type also.

[Tony Harrison 2]

Posted by Martyn K on 05/02/2016 12:11:59:

Is this what we are talking about? I have lost the plot somewhere..

Edited By Martyn K on 05/02/2016 12:14:09

Yes Martyn - the ones I have are like your second (lower) illustration.

rgds Tony

[Tony Harrison 2]

Posted by kc on 05/02/2016 11:18:16:

Tony, you said " I suppose I can epoxy some bits of bent wire onto the ends of my snake inners, " - epoxy probably won't hold well. Get the proper little screw thread adaptors . One end screws into the snake inner and enough projects for the screw on clevis with some room for adjustment. Adaptors need to be same make as snakes as size varies slightly and they dont hold tightly if mixed.

Thanks kc - dunno what brand the snakes are but I got them from Stan Yeo (Phoenix Models) in Newton Abbot. Probably a fairly common item. I was looking at epoxying wire to the inners, with heatsshrink on top, but it would make rather a stiff bulky lump...

rgds Tony

[Bob Cotsford]

I use either an inch or just over (30mm?) of 2mm studding screwed half into the snake inner with a 2mm clevis and a locknut, or a 2mm pushrod with the threaded end screwed in the snake inner and a Z bend at the servo horn.

[Tony Harrison 2]

Posted by Bob Cotsford on 05/02/2016 18:37:58:

I use either an inch or just over (30mm?) of 2mm studding screwed half into the snake inner with a 2mm clevis and a locknut, or a 2mm pushrod with the threaded end screwed in the snake inner and a Z bend at the servo horn.

Bob, not sure what you mean by "studding" in this context - to me the word refers to a type of partition wall construction... I wonder what those snake inners are made of? I'd assumed they were wire. I have some clevis thingies, and some pre-bent wire bits, will play around - or go and buy the right bits.

rgds Tony

[Shaunie]

Posted by Tony Harrison 2 on 05/02/2016 19:12:14:

Posted by Bob Cotsford on 05/02/2016 18:37:58:

I use either an inch or just over (30mm?) of 2mm studding screwed half into the snake inner with a 2mm clevis and a locknut, or a 2mm pushrod with the threaded end screwed in the snake inner and a Z bend at the servo horn.

Bob, not sure what you mean by "studding" in this context - to me the word refers to a type of partition wall construction... I wonder what those snake inners are made of? I'd assumed they were wire. I have some clevis thingies, and some pre-bent wire bits, will play around - or go and buy the right bits.

A builder not an engineer then! To an engineer studding is a piece of rod with a thread down its length. In this context it's normally a piece of wire with a thread about 30 mm long on one end. This can be screwed into the end of a plastic pushrods for a secure fixing. They often look like a bicycle spoke without the bent mushroom end.

personally I now only use pushrods with a steel wire inner, I got fed up with re-trimming for every flight. My planes now only need trimming once a season after that they fly straight and true, until the next poor landing that is!

I either put z-bends on the wire end or solder/crimp a threaded end on it. **LINK** like these. Don't forget you can only solder steel rods not stainless and crimping does not mean "squashed with pliers".

I prefer closed loop "pull-pull" linkages if poss.

Shaunie.

[Andy48]

Tony, see here:

**LINK**

Oops, not quick enough Shaunie

Edited By Andy48 on 05/02/2016 21:33:42