Turnbuckle installation 101!

[Bubbleboy]

Im at the stage of making and installing the cables for the undercarriage legs. They have turnbuckles so the cable tension can be adjusted. I havent used turnbuckles before and have been reading up on what I need to be doing. All I can find is that there should be no more than 3 threads exposed at each end once adjusted.

 

To those who have done this before, how do I set these up at the start? Do I unscrew each end all the way out and some how work out how I get to the "no more than 3 thread exposed at each end"?...or maybe you screw the ends in so far before starting?

 

Can someone chime in here and educate me on this please?

 

Scotty

 

 

[M61A1]

I would reckon it'll be a bit of trial and error initially, but not too much. I can't really visualise what it is you are making, but I would reckon that you might setup so that there is maybe 4 threads extending past the body, then swage your terminals as tightly as you can (meaning as much cable tension as you can maintain while swaging), then by the time you tension it you should be able to suck up at least 1 thread, giving you 3 exposed, with no more than 4 threads clear inside. The trial and error bit will be just working out how much thread you will use to get the correct tension, with some adjustment left for later on when your cable stretches a little or things sag.

 

The AC 43.13-1b section 9. paras 7-165 to 7-167. may give you a better visual clue.

 

 

[cscotthendry]

When I made a cable for the Nynja, I did it as follows:

 

I drilled two holes in a board the same distance apart as the measurement between the fixing points. I put a bolt through each hole and put an eye on each bolt. Then, I set the turnbuckle to the middle of its adjustment range. Then I cut and threaded up the cables through the eyes and swages. I pulled everything as tight as I could and then triple swaged the swages.

 

HTH

 

 

[kaz3g]

Hi Scotty

 

Wondering what cables, swages and turnbuckles you are using?

 

You have probably already heard that there have been some problems with stainless cables and fittings in GA? The fittings have been found with stress fractures and there is now an AD mandating 15 year replacements.

 

Only some makes are covered at present, and only ss, but my LAME is pretty sure all cables, ss or not, in all GA types will be mandated shortly.

 

I had my Annual Inspection done at Transaero at Maryborough (Vic) on Friday. I got the cables and pulleys checked over very carefully...all good. They aren't ss and have been in for a number of years although the total hours flown are relatively low.

 

The Auster is running well, comps are good, everything sweet and I felt better knowing she was all ok on the way home as we got bashed about a bit in the late afternoon thermals beneath a fairly impressive cloud street.

 

Kaz

 

 

[Camel]

Never done this job before but have done a lot of rigging and would think that it would be pulled initially with another cable or tierfor to set up and get aligned then you would have a better idea of lengths of cable and position of turn buckles when you install them. Just a suggestion, good luck.

 

 

[Bubbleboy]

Hi ScottyWondering what cables, swages and turnbuckles you are using?

 

You have probably already heard that there have been some problems with stainless cables and fittings in GA? The fittings have been found with stress fractures and there is now an AD mandating 15 year replacements.

 

Only some makes are covered at present, and only ss, but my LAME is pretty sure all cables, ss or not, in all GA types will be mandated shortly.

 

I had my Annual Inspection done at Transaero at Maryborough (Vic) on Friday. I got the cables and pulleys checked over very carefully...all good. They aren't ss and have been in for a number of years although the total hours flown are relatively low.

 

The Auster is running well, comps are good, everything sweet and I felt better knowing she was all ok on the way home as we got bashed about a bit in the late afternoon thermals beneath a fairly impressive cloud street.

 

Kaz

Thank you to everyone!

Kaz...I am using 1/8 gal cable and copper Nicopress swages. I hadnt heard of what you have mentioned so thank you for that. These cables support the Jenny style wooden undercarriage gear.

 

Scotty

 

 

[M61A1]

Here is a link to the CASA airworthiness bulletin, it is in regard to stainless steel terminals, and will not affect the use of nicopress type swages.

 

http://www.casa.gov.au/wcmswr/_assets/main/airworth/awb/27/001.pdf

 

 

[Bubbleboy]

Very interesting..thank you! I dont have any of that style so hopefully ok!

 

Scotty

 

 

[Marty_d]

Hi ScottyWondering what cables, swages and turnbuckles you are using?

 

You have probably already heard that there have been some problems with stainless cables and fittings in GA? The fittings have been found with stress fractures and there is now an AD mandating 15 year replacements.

 

Only some makes are covered at present, and only ss, but my LAME is pretty sure all cables, ss or not, in all GA types will be mandated shortly.

 

I had my Annual Inspection done at Transaero at Maryborough (Vic) on Friday. I got the cables and pulleys checked over very carefully...all good. They aren't ss and have been in for a number of years although the total hours flown are relatively low.

 

The Auster is running well, comps are good, everything sweet and I felt better knowing she was all ok on the way home as we got bashed about a bit in the late afternoon thermals beneath a fairly impressive cloud street.

 

Kaz

A newbie question to those in the know....

 

Are aviation control cables "standard" steel cable? Are they specified to be a certain number of strands in a certain number of bunches? Should they be mild steel, stainless, galv, etc? If they are a specialist aviation item, are they available "by the metre" in Australia?

 

Thanks, Marty

 

 

[Dafydd Llewellyn]

Normally aircraft control cables are 7 x 19 stainless to Mil-C-18375. Minimum size 1/8 inch for primary controls. Look up FAA AC 43.13-1 Chapter 7. Available from Skyshop (Aircraft Spruce)