circlips on servo linkages

[IanR]

Shaunie, how do you "solder" the Solder Extenders onto the wire? Do you use a flame or can it be done with a soldering iron? My soldering iron is a 40 watt job.

[Shaunie]

Ian,

A 40W iron should be ok, usual rules apply, total cleanliness (of the parts, you don't need to glove or mask up), pre- tin the parts and don't do it after you've screwed the rod into the snake. If crimping it needs to be deep enough to distort the inner otherwise it can pull off.

Shaunie.

[Shaunie]

I prefer to put the socket end in the vice, take care not to damage the thread, and almost fill it with solder. You can then put the rod in whilst it is still hot. If the whole joint is still molten then you have sufficient heat.

Shaunie.

[IanR]

Thanks Shaunie. It sounds as though it is the same method as soldering bullet connectors onto the esc and motor leads.

Ian

[nigel newby]

Just found this thread. I have the same problem. They are the second one that Martyn show in his piccys. I think I have some metal adjustable clips so will see if I can solder those on to the steel piano wire I am using. Should be fun, but not any worse than fitting silly little circlips.

Nigel N

[Martin McIntosh]

Not even bothering to read all of this thread but all I can say is to bin any of these rubbishy `pop through a hole` or `screw on and fit a grub screw to a push rod` types because on anything other than an indoor foamie you are just asking for them to fail. I banned these in my club. If you had an accident which was attributed to one of these then your insurance company would pick it up and take a very dim view.

If you do not know how to make up a proper linkage just ask an experienced club member or on this forum.

Many beginners who start with ARTF`s will assume that these are the norm but they certainly are not.

[Martin Harris - Moderator]

Posted by Tony Harrison 2 on 05/02/2016 15:47:01:

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

 

If the E clips are of decent quality, I rather like that version and would use them in preference to the lock-nutted ones. The clips should go on with a pair of pliers around the clip and the rod if the groove is correctly machined.

However, except for a throttle linkage I wouldn't use them for any control function - the danger of slipping on the control rod is too great.

I know that some will claim that suitably tightened and threadlocked, theirs will never slip but I've found enough which have failed to grip properly when checking out clubmates' models to convince me not to use them.

Edited By Martin Harris on 04/12/2018 20:14:54

[PatMc]

I've use them for years on several models, always with either piano wire inner, or metal bowden cable inner, or bike spoke end of pushrods. Never used threadlock & never had any problem.
If anyone told me he'd banned them at my club I'd tell, as a very experienced modeler him to foxtrot with Oscar.

.

[nigel newby]

Martin M I am ok on making linkages> I normally use either push pull or a Bowden type. As this plane is not new I though that I would use a push rod for a linkage, and thought that this type of fitting was ok. I seemed so much easier than soldering etc. Also not being able to really secure a cable to the fuselage. The Bowden type were not really an option. The ones I was trying to fit seemed a great idea, especially for adjustments. Now I know better!

Martin H the real problem with the fittings is that the circlip is so small. It is about the size of a match head, so you cannot really hold it in ones paw. Long nose pliers tend to bring it to the pin at too steep an angle. The wife's tweezers are not to bad to get it into position, but then you have to fit it. Ping is a very common sound, along with a few expletives.

Nigel N

[Martin Harris - Moderator]

Have you tried smallish conventional pliers with the circlip located in one of the transverse serrations at the front of the jaws?

[Denis Watkins]

Posted by nigel newby on 04/12/2018 20:40:56:

Martin H the real problem with the fittings is that the circlip is so small. It is about the size of a match head, so you cannot really hold it in ones paw. Long nose pliers tend to bring it to the pin at too steep an angle. The wife's tweezers are not to bad to get it into position, but then you have to fit it. Ping is a very common sound, along with a few expletives.

Nigel N

I glue these onto thin brass tube Nigel, with a PRITT STICK

Allow to dry

Pritt Stick is weak in this application

Push over the pin, and when you feel and hear the circlip click

Just pull away the brass tube, and the glue joint breaks

[nigel newby]

Martin H and Denis, Thanks for the advice, but looking through my spares found a couple of bits I think they were called nipple extensions! that have now done the job. Trust me they will not becoming off in a hurry. So just to make sure when all test flights have been carried out I will more than likely stick a bit of epoxy on them so I have belt braces plus on them.

Nigel N

 PS only the wing spars and fitting the ASP 70 4 stroke when she arrives and all will be ready. Oh and making a new windscreen.

Edited By nigel newby on 05/12/2018 02:05:09

[Nigel R]

Those circlip type quick adjusters are the very work of the devil. Those nipple links are a close second on the road to hell.

Passable for zero-load use, i.e. throttle.

For controls; Z bend or decent clevis = proper job.

YMMV, obviously.

[Bob Cotsford]

Posted by Nigel R on 05/12/2018 10:29:15:

Those circlip type quick adjusters are the very work of the devil. Those nipple links are a close second on the road to hell.

Passable for zero-load use, i.e. throttle.

For controls; Z bend or decent clevis = proper job.

YMMV, obviously.

No, my views too. If the pushrod is long enough to go through one of these then it's long enough to put a Z bend in it. Not far behind come the 3 hole connectors for hooking up two wire elevator pushrods to a single servo. Chuck 'em, bind and solder the joint or just add a second servo.

[Wihtgar]

I'm just looking at re-building a WOT 4 Foam-e I acquired a while back. It has no rudder/elevator servos and I intend fitting some hitec ones. Now, unless I'm very much mistaken, it appears to use the push-rod connectors shown by Martin above.

I don't know whether they are the nut or circlip devises but there must be a lot of these flying around without any apparent problems or am I mistaken?

Nig

[Bob Cotsford]

On an electric powered foamy they seem to survive within limits, but I've seen them advocated and used on 60 + size IC models where they can be subjected to a fair amount of vibration and much higher loads.

Apart from the issue of security they are another source of flex in the control run as they put a twisting force on the arm, which may not be a problem on foamy sized surface loads but can be an issue on other types of model.

Once upon a time it was acceptable to drive ailerons via a central servo and long snakes arcing through the wing to the control surface. Why? Because we had nothing better at the time. We just accepted sloppy controls. We have much better ways of terminating a control run than these linkage stoppers, as I said previously why not a Z bend? Yes, they are a quick fix but I really believe they are only fit for use on the smaller, lightweight models. I wouldn't go as far as pushing for a club-wide ban, it's down to individuals to use some common sense.

To quote Nigel, YMMV. Nothing to stop you feeding snakes through your wings and driving your ailerons from a single FD16 servo either.

[Bob Cotsford]

ps - if you do use them, a drop of thread locker or CA helps to keep them secure.

[Nigel R]

If you cannot form Z bends, you can always do an L bend, and use a swinging keeper. About 1000% superior to screw lock thingies.

As Bob says, screw locks are fine for a lightweight foamie.

Although I'd be thinking of Z bends while I was using them.

[Martin Harris - Moderator]

Posted by Bob Cotsford on 05/12/2018 12:54:46:

Apart from the issue of security they are another source of flex in the control run as they put a twisting force on the arm, which may not be a problem on foamy sized surface loads but can be an issue on other types of model.

A very good point, Bob. Not only the flex but you can add some rock at the pivot too!  That rock may also allow fretting at the fixing screw to wear the rod and loosen the screw's grip over time.

Any additional movement can also increase the possibility of flutter once control surfaces are of a significant size/mass at increasing airspeeds - another reason for avoiding their use in larger models.

Edited By Martin Harris on 05/12/2018 13:42:35

[Martin McIntosh]

A couple of years or so ago a club mate asked me if I could fix the retracts on an ARTF Mustang he had purchased from a model shop proprietor who had assembled it. This was OS 91 FS powered so not too small.

The central servo just had those pop in the hole things fitted which just flopped around thus losing a lot of the available travel. Easily solved with ball links.

To think that people use these on control surfaces causes the mind to boggle, but then if they are what is supplied then unsuspecting newbies will not know any better, hence as club safety officer at the time I had no choice but to ban them since the committee members could have been held responsible should an accident have occurred.

[Martin Harris - Moderator]

I'm generally in agreement Martin but in law, isn't it the pilot who is responsible for the safety of his model? While we advise against them, the use of these devices, especially in the case where they are pre-installed or supplied for the purpose by manufacturers, is tolerated on smaller models with dire warnings to check their security regularly!

In terms of any possible ramifications, our club took the step of renaming the club's "Certificate of Airworthiness" which suggested something with an official status to "Permit to Fly" with the following qualifying statement:

This document is to be used to make a secondary check that the aircraft has no obvious defects and must be completed before any new or substantially repaired model is flown at the club site. Note that it is not possible to assess all aspects of a model’s airworthiness by visual inspection. It remains the pilot’s responsibility to ensure that the model is airworthy and, in his judgement, capable of completing the proposed flight safely.

In terms of insurance, the BMFA cover extends to cover members against claims resulting from errors on their part - I would argue that failure of a linkage that was subsequently found to be inadequate or poorly maintained is in this category and the cover would be valid.

Edited By Martin Harris on 05/12/2018 14:50:08

[Martin McIntosh]

I agree about the bit concerning the law but the pilot, especially if he is a new flyer, may not be aware that the rubbish he has bought may not be up to standard.

[Martin Harris - Moderator]

Posted by PatMc on 04/12/2018 20:27:23:

I've use them for years on several models, always with either piano wire inner, or metal bowden cable inner, or bike spoke end of pushrods. Never used threadlock & never had any problem.

...unlike the pilot of this model at my club who asked me to try to diagnose some rather unusual handling having just about managed to land successfully:

Edited By Martin Harris on 21/12/2018 00:39:59

[Stuart Z]

Stopped using swing keepers when I bought a “Z” bender! Only leaves adjustment at the control surface end, but reduces the amount of control loss.

S