Another Tail Wire Thread

Archer39J

Archer39J

4 Place Kit Builder
Say I don't want to pay ~$800 for streamline tail "wires". The remaining options are to use at 1/4" dia end-threaded rod per the plans or a 5/32 1x19 cable per what other's have said Bob has approved in other threads.

Couple questions:

If I go with the cable what are the options for connecting these at the tail wire links? I've seen mention of a swaged end which requires additional parts and tooling, I've also seen nicopress mentioned which suggests a shackle and thimble setup which seems... draggy.

If I go with the rod where's a good place to get these? I hear tell it's best to have rolled threads rather than cut so that sounds like they need to be sourced correctly.

Either swaged cable or threaded rod requires purchase of 8 additional AN665 ends too, would have been nice to include that in my Wicks order...
 
For my LSA, I spent a good bit of time researching wires used on certified aircraft and was able to come up with a set(around $225 for all four) that way. Looking through Univair's resources for wire lengths was key.

Unfortunately I think most certified wires are 3/16(10-32 thread) but maybe there are some similar certified four place planes(like Maules or Pacers perhaps) that would use larger wires.
 
Chris In Milwaukee said:
Aircraft Spruce will make wires to whatever length you like, no special tools required:

http://www.aircraftspruce.com/catalo...clickkey=94754
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Oh nice, thanks I hadn't seen that before.

Also I found the Beartracks where Bob specifies how to fab your own which is appealing to me. He calls for cut threads and says something like 1900 hours on such has worked fine. Have those proven to be troublesome? I'm leaning toward fabbing myself per Bob's design.
 
Those wires that I mentioned aren't rigid, though. They're cables with swaged ends on them. It another option beside solid wires. Just in case you didn't notice.
 
Chris In Milwaukee said:
Those wires that I mentioned aren't rigid, though. They're cables with swaged ends on them. It another option beside solid wires. Just in case you didn't notice.
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Yep, braided cables. The option with the most drag is the cheapest, funny how that works. Question is do I get the the swaged fork on one end and use a stud and AN665 on the other, or AN665's for both ends for adjustment? Hmmm.
 
My recollection is that the 1/4" rod is turned down to be below the minimum diameter of the cut thread. That would eliminate a stress riser formed by the discontinuity of the last thread where it would transition back to full diameter. Removing that material from the entire wire in between the threads would be for weight reduction.

So if you are turning the rod down close to a 3/16" diameter, I would be inclined to see if there are off the shelf 3/16" wires availible in the correct lengths and then ask Bob if you could use them.

of course, I would guess Bob already explored this.
 
Rolled threads on 3/16" wires aren't relieved as described. They are 3/16" OD full length.

As Bob's process describes, start with a 1/4" OD rod, thread the ends, and then turn the inner section down to at or slightly below the minimum diameter of the thread.

That leaves the cut threads proud of the surface but leaves the center section thinner than 1/4".
 
Studs with AN665's both ends. One end left hand threads, other end right hand threads. That allows adjustments without twisting the cable.

Bill
 
Making your own tail wires out of 4130 bar stock is something I think only Bob has done. Bob turns the body of the piece down below .200. He does this for another reason that BTAZ didn't mention above. Vibration and potentially damaging harmonic with the full mass of the .250 wire. Turning it down, according to Bob, makes it less likely to develop a harmful vibration.

About ordering cables with swagged ends - if you follow Bob's guidance on what is acceptable you can save some $$ at the expense of some drag. One thing about doing that - the male threaded ends supplied do not have a lot of thread. I want to say 1/2" but that is probably wrong. Point is - your measurement of the length you need has to be pretty spot on. I ordered a set for my Patrol and ended up not using them because they were off too much in length from what I ended up needing. So if you go that route - measure carefully and make sure all the tail surfaces are good before measuring. Mark
 
For clarification/summary as I'm getting confused, production round tail wires use a rolled thread and are not reduced in OD.

So a typical 3/16" wire will have about 3" or so of thread on either end and the un-threaded portion will remain 3/16"

A cut thread will leave a stress riser at the end of the thread where it transitions back to the full rod diameter. Bob eliminates this transition by reducing the OD of the unthreaded portion of the rod down to the minor diameter of the thread(.206" for 1/4-28, .187" for 1/4-20, reference here(https://www.engineersedge.com/screw_threads_chart.htm))

I wasn't aware of the vibration concern Mark brought up but makes sense though perhaps hard to quantify. Dropping the diameter would "tune" the wire for a higher resonant frequency at a given tension. But I would bet you could walk up to ten different aircraft and strum the tail wires and get ten different notes.. :)

I do know that round wires have dramatically more drag than streamlined but it is recommended the lower wires be round as they are more resistant to nicks. I believe there is an AD about this for some of the Pipers.

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I plan on using aluminum streamline tubing over the 1/4" rod. Not sure what size has enough inside diameter to accommodate the rods but wouldn't weight much. It's used in the RC world. Very cheap too!
 
Mark Goldberg said:
Making your own tail wires out of 4130 bar stock is something I think only Bob has done. Bob turns the body of the piece down below .200. He does this for another reason that BTAZ didn't mention above. Vibration and potentially damaging harmonic with the full mass of the .250 wire. Turning it down, according to Bob, makes it less likely to develop a harmful vibration.

About ordering cables with swagged ends - if you follow Bob's guidance on what is acceptable you can save some $$ at the expense of some drag. One thing about doing that - the male threaded ends supplied do not have a lot of thread. I want to say 1/2" but that is probably wrong. Point is - your measurement of the length you need has to be pretty spot on. I ordered a set for my Patrol and ended up not using them because they were off too much in length from what I ended up needing. So if you go that route - measure carefully and make sure all the tail surfaces are good before measuring. Mark
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Thanks for the warning, I was wondering about getting the lengths just right. Sounds like 2 AN665 per wire would be prudent if I go that route. Waiting to hear back from my local metal shop about some 4130 bar, I still think I like that solution best.
 
Since I was bored.....

Bruntons gives a "Min. strength Spec." for 3/16 wires as 2100lbs for round, 2400 lbs for streamlined. (http://www.steenaero.com/products/flying_wires.cfm)

The common "Breaking Strength" spec for 7x19 5/32 stainless cable is 2400 lbs.(http://www.fairburyfastener.com/cable_specs.htm)

So if one could "tease out" an appropriate length set of 3/16" wires from production aircraft using data available at Univair, it would probably be worth talking it over with Bob.

UPDATE; per Mark G. the cable needs to be 1 x 19. 1x19 5/32" stainless has a higher "breaking point" (2800 to 3300 lbs, https://www.chain-cable.com/wirerope.htm ) so would seem to eliminate off the shelf 3/16" tail wires as a possible option.
 
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If you use wire/cable - you have to use a non stretchable cable like 1 x 19. Not normal control cable which is made to have some stretch. I used 1 x 19 cables on my FlyBaby as these wires hold the wings on. Mark
 
BTAZ said:
Since I was bored.....

Bruntons gives a "Min. strength Spec." for 3/16 wires as 2100lbs for round, 2400 lbs for streamlined. (http://www.steenaero.com/products/flying_wires.cfm)

The common "Breaking Strength" spec for 7x19 5/32 stainless cable is 2400 lbs.(http://www.fairburyfastener.com/cable_specs.htm)

So if one could "tease out" an appropriate length set of 3/16" wires from production aircraft using data available at Univair, it would probably be worth talking it over with Bob.

UPDATE; per Mark G. the cable needs to be 1 x 19. 1x19 5/32" stainless has a higher "breaking point" (2800 to 3300 lbs, https://www.chain-cable.com/wirerope.htm ) so would seem to eliminate off the shelf 3/16" tail wires as a possible option.
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FWIW, Normalized 4130 yield strength of 63,100 psi at .200" diameter results in 1980 lbs yield strength.
 
Here is what I did: I had studs swaged on both ends of 1x19 cable and simply adjust by putting in one turn at a time. The cable will never be able to come out.

My threads are cut not rolled, so there is that, but everything has 3/4" or more of thread engagement so I'm not concerned.

The Brunton wires are the best option, but I think what I did is perfectly safe, and if you have a lathe and order the pre-made cables from ACS, it could be done pretty cheap.
 

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Archer39J said:
Say I don't want to pay ~$800 for streamline tail "wires".
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Its still painful, but my tail wires from Steen Are Lab (purchased with a group buy) invoice dated June 2017 was $547 + $72 shipping = $619.

Going back to the Univair option I keep asking some reasonable questions...
1) Does BTAZ have his Univair Invoice to cross reference the parts?
2) Could Univair tell us which wires from there stock will fit our aircraft?
3) If none are an exact fit, would Univair manufacture them for us if a group buy was organized by us for a small production run?
 
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Matt - for flying you need jam nuts on the end fittings. They tighten the threads to each other and keep vibration or chattering in the threads down. Mark
 
Mark has put time and effort into developing a source for tail wires. He should be rewarded for that so I am not going to "spoon feed" alternative solutions

I did the homework starting here( http://www.univair.com/technical-resources/) to find out what "standard" tail wire lengths are available and found a set that worked for my LSA

Details are in my build log and typical "off the shelf" round wires without terminals are around $35/pc.( http://www.univair.com/search.php?se...31-002&Search= ) while typical streamlined wires are around $85/pc ( http://www.univair.com/aeronca/contr...ailbrace-wire/ ) at Univair
 
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Mark Goldberg said:
Matt - for flying you need jam nuts on the end fittings. They tighten the threads to each other and keep vibration or chattering in the threads down. Mark
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There are jam nuts, that's a mockup picture. But thanks for the heads up.
 
Bcone1381 said:
Its still painful, but my tail wires from Steen Are Lab (purchased with a group buy) invoice dated June 2017 was $547 + $72 shipping = $619.

Going back to the Univair option I keep asking some reasonable questions...
1) Does BTAZ have his Univair Invoice to cross reference the parts?
2) Could Univair tell us which wires from there stock will fit our aircraft?
3) If none are an exact fit, would Univair manufacture them for us if a group buy was organized by us for a small production run?
Click to expand...



1. Details of what I used for my LSA are in my build log but typical "off the shelf" 3/16" round wires without terminals are around $35/pc.( http://www.univair.com/search.php?se...31-002&Search= ) while typical streamlined wires without terminals are around $85/pc ( http://www.univair.com/aeronca/contr...ailbrace-wire/ ) at Univair

2. Of course not. It is our job as a builder to work out the correct part number. If someone doesn't want to do that, buy them from Mark.

3. I doubt it. "Standard wires" will have a price and availability advantage because of volume. I'm sure Univair(and all the other sources) are re-sellers only.
 
Mark does not supply tail wires. Mark promotes the group buy thru Steen Aero Lab in order to help us, the builders of his kit save cost. He does not get involved beyond that. In other words, the wires are ordered by the builder from Steen, Shipped directly to the builder by Steen, and payment was made by the builder to Steen. I already have my wires. I think your method is superior. Post #19 was request to help the community and I believe takes no business away from Mark.

I won't apologize for what I wrote above. Helping others and removing barriers to building is a good thing. If Rebranding it as spoon feeding becomes widespread this forum has no purpose to exist.
 
Looking at the Univair website I can't find any supporting documentation for those wires that specify their length. So it'll take some more digging to find that out. If I were building an LSA it sure would be nice to know what part numbers others have used. If I find a suitable part for the 4-place I'll post it here.

ETA: Steen prices are $847 for the whole package, $547 for just the wires. So $41/piece for terminal assemblies? That's the group buy discount, individually it's $200 more.
 
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Given I didn't purchase the "group buy" tail wires, obviously I have misunderstood how the purchase is handled. My assumption was it was similar to the windshield where a custom part number has been created by the manufacturer(in the windshield case, LP Aero) and is only available through Mark and that Mark is rewarded(as he should be) for his efforts.

Perhaps I misinterpreted your questions as "accusatory" ("Here are the specifics of my wire purchase, now put up or shut up.") and leading ("Why would Univair have any idea what the correct wires are for a Bearhawk?").

As far as "spoon feeding", myself and others have provided some relative strength numbers(most with references) for the "options" (Custom wires, 1x19 5/32" cable, 3/16 stock wires, 4130 rod reduced to .200" between threads), I have posted in more than one thread(including this one) what worked for my LSA and I have provided a link where common production lengths can be found and priced.

A Patrol or four place builder now needs to "Pick up the torch" and see if there are production wires that would fit and get Bob's blessing for their use(note the LSA plans specify 10-32 for the wire fittings so there isn't a question whether typical 3/16" wires are an acceptable diameter).
 
I recall thinking Steen's price on the terminal hardware was high, though made of stainless. I think I got cad plated thru Spruce.
 
Assuming "S.S." means something like 18-8 (annealed) it seems doubtful Univair wires are suitable replacements for wires specified by Bob's design. The significantly lower yield strength in addition to the reduced diameter takes it pretty far below the envelope for my taste, the yield of SS is 49% that of 4130 alone, and I doubt there's much over design given what I've seen elsewhere.

Looks like I'm back to ACS pre-made cables.
 
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The profiled SS wires have been cold worked and are therefore stronger than the round bar. 4130 round bars and SS round bars are not equivalent and the breaking strength is only one of the factors for this design. As always it's your experiment.
 
And that's why I refuse to put forth more than suggestions as it is up to the builder and their research to make their own judgement.

That said, AFAIK, there are only two companies in the world making these wires, Bruntons and one in NZ( or possibly Australia, was discussed in a different thread). It is very likely that the wires being resold by Univair, Spruce, and the rest are coming from Bruntons and the price delta reflects volume.

As far as "strength isn't everything", that is absolutely true. A bit of research will turn up a couple Fly Babies that lost their wings in flight, likely because builders replaced the wing landing/flight cables defined by the print with flying wires for cosmetics. For various reasons, the wires cracked and failed catastrophically where cable is much more tolerant of vibration.

So if I was building a Four place or Patrol, I would see if there were "standard production" appropriate length wires available. If there aren't then I would choose one of the already defined/approved methods(Bruntons, cable, made from 4130 rod)

But if there were "Standard production" appropriate length wires available, I would give Bob a call and post the conclusion here.
 
A call to Univair and APR 2007 issue of Beartracks revealed some facts and allows truthful comparison between Bob's tail wires and what Univair can offer the Patrol and Four Place builders.

Bob's design calls for round 4130 steel tail wires that are 42.5" and 48" long, .200" in diameter with .250 cut threaded ends.

Univair's tail wires are all round, none are streamlined, made from 302W stainless steel. The longest that the offer is 42.5." All are .168" diameter with .125" rolled threaded ends. Univair has their wires made up. They cut the wire to length, then send out the wire to have the threads rolled by a subcontractor, 1000 wires at a time.
 
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On my Patrol, I am using 5/32 ss wire with swaged ends. A fork on one end and stud with threaded fork on the other. I called Bob to get the wire diameter.
 
Bcone1381 said:
A call to Univair and APR 2007 issue of Beartracks revealed some facts and allows truthful comparison between Bob's tail wires and what Univair can offer the Patrol and Four Place builders.

Bob's design calls for round 4130 steel tail wires that are 42.5" and 48" long, .200" in diameter with .250 cut threaded ends.


Univair's tail wires are all round, none are streamlined, made from 302W stainless steel. The longest that the offer is 42.5." All are .168" diameter with .125" rolled threaded ends. Univair has their wires made up. They cut the wire to length, then send out the wire to have the threads rolled by a subcontractor, 1000 wires at a time.
Click to expand...


Perhaps Univair has expanded their offerings since 2007 as not all of Uniair's wires are round(or perhaps they manufacture the round wires and resell the streamlined).

Their Citabria upper wire ( http://www.univair.com/aeronca/contr...ailbrace-wire/ ) is streamlined and 48.56" long with 10-32 threads(3/16")so it might(and it is completely up to the builder to discuss this with Bob) work for the 48" wire.

This non-streamlined Cub wire( ( http://www.univair.com/search.php?se...31-002&Search= ) is 41.5" long(again 10-32 threads, 3/16" diameter) so might work for the 42.5" wire(again, discuss it with Bob).

Note the "Nominal dimension" of Brunton's wires refers to the diameter close to the threads and not the cross section of the center. Refer to second and third items in the "Tie Rod Notes" section here ( http://www.steenaero.com/Products/flying_wires.cfm? )

I don't know how the wires fit on the four place or Patrol, but for my LSA I had to trim my "off the shelf wires" to length and Dave(refer to the "DavzLSA build thread" in the LSA Plans Build forum) also recently had to trim his "LSA Specific" Brunton wires to length.

Also, not all "Certified" wires are/were rolled threads. Some interesting reading here( http://sbeaver.com/Bucker/index.php/...rt-mainmenu-82 ) highlights that the "long term producer, now defunct" McWhyte wires were cut threads as well as discussing other things of interest with regards to material selection.

With regards to issues coming from "plans deviations" causing wire/wing failures, see here( http://www.bowersflybaby.com/safety/hinton.htm )

And I certainly agree posters should be very careful to "identify" speculations/opinions or provide references for items presented as facts.
 
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Consult with an engineer you trust before proceeding with weaker materials of a smaller diameter.

I'm looking at other options.
 
Exactly!

Do your research, weigh the facts supported by references(not people's opinions) and make an informed decision you are happy with.
 
Regarding the 4130N option,Marcusofcotton in an earlier thread provided a number but I wanted to add a reference for the next time "Tail Wires" comes up.

Yield strength(where the material permanently deforms) is given in lb/in^2 in this table ( https://www.engineersedge.com/materi...roperties1.htm )

A .200" diameter round 4130N has a cross sectional area of Pi*R^2 or 3.14 *.100 in.*.100 in. which equals .0314 in^2.

So the yield strength of a .2" diameter 4130N rod is ((63250 lb/in^2) * (.0314in^2)) which equals 1,986 lbs. This seems to be below any of the options discussed so far'. Quite frankly, I was surprised by that.

Out of curiosity, I ran the same yield strength calculation for 3/16" round 316 stainless(http://www.hmwire.com/New%20PDFs/Sta...sion_Chart.pdf ) and got around 1625 lbs which is well below Bruntons "Min. strength Spec." (for 3/16 wires, 2100lbs for round, 2400 lbs for streamlined. (http://www.steenaero.com/products/flying_wires.cfm)

It would be interesting to know if Bruntons "Min. Strength Spec." represents a breaking point spec(as defined by tensile strength, calculated as 2450 lbs for 3/16" round 316 stainless ) or a yield spec. If it's a yield spec,. than work hardening adds roughly 30% to the yield strength of annealed 316 stainless which I think is "Pretty cool!"..
 
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If you use the ultimate tensile strength for 316 annealed you get ~2,200 lbs for 3/16" rod, which is consistent with the 2,100 lbs Steen lists for 3/16" round wire. This suggests they're using the ultimate breaking strength. But again that's just one part of the equation.

If you're looking for equivalency with Bob's April 2007 Beartracks design you're going to want to use the yield strength as your guide, since we're not just interested in the ultimate strength but how much load the rod can bear before deforming plastically.

Then there's the modulus of elasticity, in effect the "springieness" of the material, which will have an effect on the vibration and fatigue characteristics. The stainless steels we've discussed are close, but not identical to, 4130.

Then there's the fatigue limits for each material...

All these things need to be looked as as to how they will affect the strength and life of the part in its intended environment. Anyone can punch out numbers, but that's where Bob's experience as a designer of homebuilt aircraft should lead the discussion.

But what I personally will not do is say "Well they have similar breaking strength" and call it good.

Also Matweb is a good source for different material properties: http://www.matweb.com/index.aspx
 
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The Matweb site is excellent and going into my bookmarks.

And definitely, strength isn't everything. One link I provided earlier(http://sbeaver.com/Bucker/index.php/bracing-wire-alert-mainmenu-82) seemed to indicate Bruntons used 431 stainless (which per the Matweb link has a higher tensile strength than 316) but apparently also had cracking problems and subsequently changed to 316.

But there is some "precedent for suitability" in that pretty much every typical light GA air frame that requires tail wires uses "stainless"(much too generic a term). It is unfortunate that suppliers provide undefined "strength specifications" and that the specific material isn't always stated in catalogs which adds to the challenge of identifying suitable "shelf items" to adapt,
 
Well that's true about the precedent. Just if your design calls for 4130 and you swap in SS you're coming close to halving the force it takes to permanently deform that part. But maybe it is just the breaking force that matters I don't know, I just engineer galleys, not small airplanes :)
 
I think a factor that can't be over stressed in this conversation, is that we're discussing properties of 4130 NORMALIZED to 316 ANNEALED. To be clear, 'Normalized' is heat treated to a specific strength and hardness. 'Annealed' is heat treated to achieve a soft condition. Because the 4130N is machined and used, without additional mechanical or heat treatment, discussion of it's properties is fine. The 316 Brunton's wires undergo significant mechanical working, which changes the mechanical properties. What we what we don't know, is details of the properties of the Brunton's wires, as worked and ready for installation. We know the alloy and and we know their strength claims. Tensile or yield? Elongation properties? We don't know.
Don't get me wrong. I haven't given the subject enough thought to consider either one to be superior. I'm just reluctant to consider a comparison without full understanding of the Brunton's properties, which they just might not reveal.
I gotta admit, though, after following this thread, I've been looking at my tail wires REAL HARD these last couple of days...

Bill
 
While not equivalent they both end up relieving stress in the metal. Regardless, from the breaking strength provided by Steen it seems we can infer they are using annealed 316 from what we calculated. The profiled wires having a higher breaking strength demonstrates the effect of work hardening when forming that shape. Rolling the threads will harden the 316 locally.

ETA: Never mind, since they don't call it a breaking strength...
 
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I did a quick, but conservative, calculation and figure a pound of total downforce generates about 1/2 pound of tension in each top wire. If the wire is good for 2k pounds that translates to a total downforce of 4k pounds. I am guessing the failure mode has a lot more to do with the bending forces on the threads from vibration and handling. I just feel better with flexible wires vs solid.
 
Archer39J said:
Well that's true about the precedent. Just if your design calls for 4130 and you swap in SS you're coming close to halving the force it takes to permanently deform that part. But maybe it is just the breaking force that matters I don't know, I just engineer galleys, not small airplanes :)
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Depends on what you are using for the calculation.

Yield strength for 4130N at .2" diameter is 1,986 lbs

Yield strength for 3/16" round 316 stainless in its annealed state is 1,625 lbs so "worst case" you are roughly 15% below the "lowest yield strength approved" 4130N solution.

But oddly, the "Min. strength spec." for the Bruntons 3/16" wires is in the 2100 to 2400 lb range. If this is a breaking strength spec(note this number is close to the calculated Tensile strength of 3/16 diameter round annealed 316 stainless) then their yield spec is very likely lower than the 4130N option. If Bruntons "Min. Strength" spec is actually a yield strength that is increased because of the "cold working", then even the 3/16" Brunton wires are "stronger" than the 4130N option.

I did find this table( http://hghouston.com/resources/mater...ing-properties ) that indicates both the yield and tensile strength of 316 stainless can double from the "annealed" to the "Full hard"(referenced to their Rockwell hardness number) condition. Interestingly, it follows that if one can determine whether the Brunton spec is a tensile strength or yield spec., one could then back out the required/desired Rockwell number and the amount of "work hardening" imparted during manufacture.

What is also interesting is that there are currently three "approved" solutions that vary considerably in their "strength" properties, their aerodynamics, and their vibration behavior.

1x19 5/32" round cable is pretty far in behavior/properties from machined round 4130N which is itself different than the "Cold worked" streamlined 316 stainless of the custom Brunton wires.

Then add in that wire tension isn't carefully set(which means the resonant frequency is different from one plane to another), that the end fittings can be "rigid"(Bob terminals), offer flex in one direction(eye terminals to a tab) or a wide range of movement(some cable terminals and "production wire end terminals" akin to Cub parts) and either we are really lucky or the design is pretty tolerant.

This has been a very interesting discussion and, like BDflies said, I am looking at my tail wires with a new level of awe and healthy respect.
 
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Ah, I missed that they spec "cold drawn" bar too, which could mean anything. And I had it in my head they said "breaking" not "Min. Strength". So yeah, there's not really a way to tell. Though as work hardening increases your fatigue strength suffers, something to keep in mind.
 
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Also of consideration is the punishment for failure. I've read accounts that ranged from "didn't notice till I was on the ground" to "fell out of the sky"...
 
Interestingly enough the quote from this reference( http://hghouston.com/resources/material-property-data/stainless-steel-data/cold-working-properties ) states that "Cold working increases the fatigue strength of the austenitic stainless steels. However, the fatigue strength of these cold worked alloys is reduced by notches, as compared to notched fatigue strength in the annealed condition"

So while actual fatigue performance goes up, susceptibility to a complete failure from a nick also goes up.

Which explains the AD ( http://myplace.frontier.com/~air.bourn/Pacer/ADs/AD60-01-07.htm ) on Pipers requiring repetitive inspections of streamlined lower tail wires with the inspections eliminated for round lower tail wires
 
Yep, I just read a thread on the ShortwingPipers forum relating several "no factor" experiences and one "dang near bought it" account.

If nothing else, this thread changes my pre-flight for tail wires which will now include a "wipe them down with a rag and feel for nicks" instead of just a visual and pluck check.
 
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And now I've also learned that some cold worked stainless alloys can become magnetic (https://www.azom.com/article.aspx?ArticleID=1140 ) which might explain why my compass isn't happy. I mounted it with stainless screws(confident that the base material is naturally non-magnetic) but, if they happen to have rolled instead of cut threads......
 
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I would pay the $800. Those streamline wires are a thing of beauty. I bought round (bottom) and streamline (top). I will feel secure knowing they are back there protecting my tail. When you consider all the money you have to spend to complete a flying airplane, then consider the consequences of a component failure, I'd look elsewhere to save money.
My .02
Gerry
Patrol #30 Wings
 
Aren't there so many tempting rabbit holes that we pass on our building journey... So many times I have had the option of "spend the money and get it done" vs "spend lots of time researching and spend less money but then still end up spending the same money later." There is value in the education and in the fun of chasing the rabbits, but the tuition for these lessons is reflected in the build time.
 
Question on the lower tail wire attachment - the factory drilled holes in the fuselage lug/bracket are 3/16 and AN664 clevis ends are 1/4. I'm hesitant to upsize the hole and reduce the edge clearance. The alternative seems to be an AN3 clevis bolt and bushings. How are others doing this?
 
I wish I had more experience with other light aircraft, but I don't. There is some kit stuff that should have been sorted a long time ago. Bushings are way to prevalent in the BH. 1/8" cable hardware ends up using 1/4" fasteners, but to save weight the kits use 3/16" fasteners, and bushings. It should have been way to easy to upside to 1/4" fasteners, but they never did.

Bushings suck, and you will lose them. There is am aviation clevis fork that fits 1/8" cable, but has 3/16" holes. Spruce sells it as engine control forks, but they are over 3000 lbs strength (1/8 cable is 1900). I used a lot of them in lieu of turnbuckles.
 
You should never need to remove those connections for anything routine. When I removed them for repairs on one occasion, I never lost the bushings.
I do agree they seem unnecessary, but it's a non-issue long term once the build is finished.
 
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