Buried control linkages

[Stevo]

Hey all..

Shootin' the breeze here. On my Stuka, there's part of me that would like to silver solder a horn to the brace that holds the two elevators in place, and then the control rod runs almost down the middle of the fuselage.

However, when the horizontal stab is glued in and the linkage attached, it looks like the vertical stab and rudder, plus some of the underside of the fuse is all glued in over it all. Anxiety creeps in.. what if needed to get at the linkage...

The alternative is the traditional horn attached to the elevator, with the rod protruding through the fuse. I can make this better by using a Robart horn, sprayed the same colour as the underside of the aircraft, so it's almost hidden.

Thoughts?

[bert baker]

The Precedent Turbulant had a hidden elevator control and was never a problem

[john stones 1 - Moderator]

Do the job right Stevo, you've got the ability so stop whittling.

[Martin McIntosh]

Silver solder it and forget about it as long as you don`t use a plastic link!

[cymaz]

Silver solder the horn. Then either use a Z or a U bend through the horn. It will never fail.

[Danny Fenton]

I am with that lot, silver solder and be done I seal servos into my models, never mind the linkages!!! Even though they are tested thoroughly first though, this may be a little optimistic but so far I have not had one fail (Hagrid would say "should'na said that".

Cheers

Danny

[Trevor]

I agree, go for the hidden approach every time on a scale model. If you aren't confident in your soldering, my favourite method involves epoxy and a bit of brass tube - see pic towards the bottom of this page:

http://www.bartonhewsons.uk/home/modelflying/scale/chipmunkdiary-de.html

Trevor

[Mike T]

You have to be very confident in your SS skills. I wasn't, so when building a Phase 6 recently, I used a joiner saved from a 1/4 scale DB Pup (pre- Stocker) kit. Strong enough - you'd think...

It failed and the subsequent replacement was pretty much as Trevor described, albeit soft soldered:

Edited By Mike T on 29/08/2017 10:35:58

[Stevo]

Oh alright, you guys have convinced me. I'm sound with silver soldering / brazing and so forth so the link will be buried

Now, if only I could bury the rudder linkage

 

Trevor - I love that chippie build!!!!

 

Edited By Stevo on 30/08/2017 10:15:45

[cymaz]

Posted by Stevo on 30/08/2017 10:11:41:

Oh alright, you guys have convinced me. I'm sound with silver soldering / brazing and so forth so the link will be buried

Now, if only I could bury the rudder linkage

Edited By Stevo on 30/08/2017 10:15:45

You will find a way

[Stevo]

How's this??

[Engine Doctor]

Hi Steve I have a similar set up in my Mustang  to overcome the problem I used a ball joint that can be reached through a removable plate .  Z bent is ok for smallish models but will wear with bigger models then vibrate and make irritating noise. The bsll joint I used has a small clamp to enable it to be removed or tightened etc.fortunately the mustang has a inspection plate in that position so no problem with the rivet counters. I'll see if I can find a pic of said ball joint in the build blog or you can look on our club forum look under Pica builds.

Phil

PS you may have a problem getting onto club forum for some reason I cant access it from my tablet ? OK on PC though.

Edited By Engine Doctor on 02/09/2017 18:17:39

[Daithi O Buitigh]

I used to do a solderless variety with control line models - instead of a straight joiner, there was a flat bottomed 'U' in the centre which was connected by a wire loop to a wooden push rod. You just had to make sure that the two ends were parallel

[Stevo]

Blimey Daithi.. That's one hell of a bend for 3.2mm Piano wire..!!

Thanks Phil, I'll take look. Good luck with the Swapmeet tomorrow - I aim to be there

Edited By Stevo on 02/09/2017 18:20:48

[Bob Cotsford]

That's a very neat bit of soldering, but if it was me with my blacksmith ways I'd make it with a big fillet of solder. It wouldn't be as neat but I'd feel more confident burying it where it can't be resoldered if vibration causes it to fracture.

But that's just me.

[kc]

I wonder if wrapping a few turns of thin wire alongside the joint before soldering would increase the area of contact enough to improve security of the joint?

Looking at Mike T's picture of a few days back, my comment would be similar - making the arms that go inside the brass tube about twice as long would be helpful to give more contact for the solder and less chance for movement even if the solder fails.

I would expect the fullsize to have inspection panels so putting one where it is useful on the model would not look too out of place.   Just leaving a hole and eventually covering over with a Solartex  patch or glueing a 1/64 ply cover might be easiest.

I was wondering if that Z bend could actually be engaged or disengaged in situ?   Z bends usually need to swing out at a large angle when fitting.

Edited By kc on 03/09/2017 12:24:27

[Stevo]

Although not too visible in the photo,there is a fillet either side. As you know, with silver solder, once it melts it's like diluted water, and largely travels by capillary action, so difficult to build a subsantial fillet as per 60/40 (soft) solder.

There's not too much play around that Z bend, and yes it almost has to go to 45 degrees to disengage!

[john stones 1 - Moderator]

Looks good to me.

[cymaz]

Cornwall quality control will pass that, excellent

[Stevo]

Does that mean I can repair your Scythe, should it break?

[cymaz]

With soldering like that...anything!

Have you seen my soldering efforts. A smoldering plastic mess surround by solder all over the work bench....and nothing on the metal

[Stevo]

Cleanliness... Emery everything.. wash with IPA..Use lots of borax flux, watch the temperature (use a propane cylinder as it's hotter) Whn its dull red, just touch the SS onto it.

[cymaz]

Thanks for the advice and tips. I will try to improve. Though, my soldering iron seems to get all black and covered in slag/crud very readily. I have to keep cleaning it every time I start with a file to get all the slag off it.

Wash with IPA...beer is the secret!!!

[Stevo]

Sounds like the iron is too hot?

"I have to keep cleaning it every time I start with a file to get all the slag off it.."

No jokes.

[cymaz]

I will get a new soldering iron

Edited By cymaz on 03/09/2017 16:52:43