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Zac Weidner
02-04-2009, 08:03 PM
I sent my tail brace wire hardware off to Memphis Propeller on Monday to have them cadmium plated. When I get them back, I'm going to be installing the wires. It seems like a highly frustrating process for someone who has never done the job (like myself). I'm sure all of you who have done it have some great tips and I'd love to hear 'em. I would think that the aircraft needs to be leveled so that the stabilizers can be leveled at the wires are installed. Also, what should the wire tension end up at?
Thanks again,
Zac Weidner

Steve Pierce
02-05-2009, 01:55 PM
Yes on leveling the airplane and the stabilizers. Use a fish scale to get a 12-15 lb. pull should deflect the wire 1/2".

JohnW
02-05-2009, 05:12 PM
(This may seem stoopid, but...) You only do this once, when the airplane is being "final assembled", ONLY. You don't do this before you start to cover everything (such as when following "my advice" about "rigging the airplane BEFORE it is covered") because you CANNOT re-install the bolts for the tailbrace wires under the proper "rig tension" again (sorry, don't mean to "talk down"...just trying to help!). You just can't. That requisite met... Once the airframe is leveled using the plumb bob (and for rigging tail surfaces only -not for checking travels of the surfaces as well- side to side is "important" and fore-to-aft is "okay close". That means you luck out by being able to let some air out of a tire to get the lateral level "perfect"!) proceed as follows:

1) "hang" all four brace wires, pinned in place with the bolts that go there. This means they will be VERY loose when you start. MAKE SURE the little "bushings" are placed in the wires (end brackets) where they are bolted to the horiz stab (top AND bottom) and the "funky washers" are at the top of the vert stab post!!! !!! Properly torque all these tailbrace wire attach bolts BEFORE proceeding. Jam nuts are (there I go again with "the obvious"!) loose. In the "middle", with a decent amount of tension on the wires, make sure the end fittings are attached in place with a "straight pulloff". Loosen and realign, if necessary. Re-torque.

2) Working BY HAND, shorten all four wires with the goal of not being able to work anymore without tools and so that the aft vert stab post is PLUMB, and the horizontal stabs are "LEVELed". Try to keep the same amount of wire "depth" in both ends of each of "nipples" (on the same wire, not necessarily will "all wires" be the same as all the "other wires". This "is what it is" for each wire) throughout the rig process. You don't have to "be a hero" at this point, just get 'em snugged up, and when you are going to start with tools, START with a plumb and level check and tweak wires as required.

3) start "wrenching" the wires a little tighter each side-to-side pair, and a little top vs bottom "sides" until they begin to snug up (when you "prang" a wire at about midpoint, they will soon stop going "bzzzzz"/"thump-thump" and begin to go "twang" a little bit.

(NEVER "force" an adjustment by pulling drastically against the "opposite" wire. You can't do this part "carefully enough", so work in small steps. Be patient and go "around" the tail as many times as you have to...)

4)confirm plumb and levels, and proceed to tighten each wire against its "opposite", with an eye to "plumb and level (I can't say this enough!).

5) continue repeating steps 3) and 4) while rechecking plumb and levels, until desired flying wire deflection is attained. Plumb AND level is paramount.

6) confirm again plumb AND level after each step 5).

When the deflections measure to your satisfaction, you can "finish the job" by making believe you are a piano tuner. Remember, "Opporknockity only tunes ONCE". A "finished job", when "lightly plucked", should elicit the same musical note on the top two wires and a different "same note" on the bottom two wires (top to bottom, they are different length wires...so they will have different "notes" at the same "tension") AND the vert stab is plumb and the horiz stabs are level. This allows you to "play these harpstrings" on every preflight and any disagreement in an originally "tuned" rig will be quickly evident! If you get a "dead prang" at some later date, you have a problem to correct before next flight. The "same note" thing pays for itself in being able to sleep in flight.

Just about the time you begin to get with the program with "which way to turn that durn nipple", things will begin to fall into place rather quickly (IF you ever reach that point!). Now, if you find yourself "chasing the last time around" around the airplane, don't hesitate in letting the tension off, evening out your "nipple depth" if required, re-plumbing and leveling, and go at it again. This is where you might "become frustrated". SMALL "adjustments" near the end work best, and "playing piano tuner" is a BUNCH quicker than "fish-scaling" over and over. However, the fish-scale IS the preferred method of setting the tension. Keep re-doing it until the vert is plumb, the horizontals are level AND the tensions are correct (at which point, the "notes" should also be the same. You will probably "hit tune" a couple of times (at least!) only to find you took the vert or horiz out of "plumb", or "level".

THEN, you are "done". If this is your "FIRST TAIL RIG", you are already "going at it" with the "I don't really know what I am doing" attitude. This works FOR you. Your third or fourth airplane (when you start to believe that you know what you are doing) usually are the most frustrating. Take your time, and just as soon as you realize you seem to be beating your head against the wall, back off take a break. You WILL appreciate that your tailbrace wires are really pretty darn snug when you get all done. But you will ALSO know that if the "note on the top" and the "note on the bottom" stay in tune, you are "good to go". If you strip anything, it WON'T "be all right like that", and you'd better seek "professional help" from have somebosy else do it for you , NEXT TIME (with new parts!). Finally...lock down the jam nuts and go PLAY!

Howsat? More than you wanted???

Curly
02-05-2009, 06:11 PM
JW - When you finally hop off the twig (and I hope that will be in the distant future) heaps of experience and knowledge like your last article, will go with you, unless we can convince you to sit down now with a tape recorder or something and put all your tips, tricks and information in a book or on a CD.

I will place my order now - don't care what it costs - it will be worth it.

Do it as a present for your grandkids or donate it to charity or whatever (the "JW Retirement Fund" would be a great charity) just don't take it with you - the rest of us haven't got enough time left to learn it all.

Curly

Bultaco Jim
02-05-2009, 09:12 PM
That really was a "watershed" story by John, wasn't it. If you don't know how to rig the tail after that, you never will. But , Holy Crap - "Opporknockity only tunes once"! He may have been born on Mars, but it's good for us he landed here!

Zac Weidner
02-05-2009, 10:41 PM
(This may seem stoopid, but...) You only do this once, when the airplane is being "final assembled", ONLY. You don't do this before you start to cover everything (such as when following "my advice" about "rigging the airplane BEFORE it is covered") because you CANNOT re-install the bolts for the tailbrace wires under the proper "rig tension" again (sorry, don't mean to "talk down"...just trying to help!). You just can't. That requisite met... Once the airframe is leveled using the plumb bob (and for rigging tail surfaces only -not for checking travels of the surfaces as well- side to side is "important" and fore-to-aft is "okay close". That means you luck out by being able to let some air out of a tire to get the lateral level "perfect"!) proceed as follows:

1) "hang" all four brace wires, pinned in place with the bolts that go there. This means they will be VERY loose when you start. MAKE SURE the little "bushings" are placed in the wires (end brackets) where they are bolted to the horiz stab (top AND bottom) and the "funky washers" are at the top of the vert stab post!!! !!! Properly torque all these tailbrace wire attach bolts BEFORE proceeding. Jam nuts are (there I go again with "the obvious"!) loose. In the "middle", with a decent amount of tension on the wires, make sure the end fittings are attached in place with a "straight pulloff". Loosen and realign, if necessary. Re-torque.

2) Working BY HAND, shorten all four wires with the goal of not being able to work anymore without tools and so that the aft vert stab post is PLUMB, and the horizontal stabs are "LEVELed". Try to keep the same amount of wire "depth" in both ends of each of "nipples" (on the same wire, not necessarily will "all wires" be the same as all the "other wires". This "is what it is" for each wire) throughout the rig process. You don't have to "be a hero" at this point, just get 'em snugged up, and when you are going to start with tools, START with a plumb and level check and tweak wires as required.

3) start "wrenching" the wires a little tighter each side-to-side pair, and a little top vs bottom "sides" until they begin to snug up (when you "prang" a wire at about midpoint, they will soon stop going "bzzzzz"/"thump-thump" and begin to go "twang" a little bit.

(NEVER "force" an adjustment by pulling drastically against the "opposite" wire. You can't do this part "carefully enough", so work in small steps. Be patient and go "around" the tail as many times as you have to...)

4)confirm plumb and levels, and proceed to tighten each wire against its "opposite", with an eye to "plumb and level (I can't say this enough!).

5) continue repeating steps 3) and 4) while rechecking plumb and levels, until desired flying wire deflection is attained. Plumb AND level is paramount.

6) confirm again plumb AND level after each step 5).

When the deflections measure to your satisfaction, you can "finish the job" by making believe you are a piano tuner. Remember, "Opporknockity only tunes ONCE". A "finished job", when "lightly plucked", should elicit the same musical note on the top two wires and a different "same note" on the bottom two wires (top to bottom, they are different length wires...so they will have different "notes" at the same "tension") AND the vert stab is plumb and the horiz stabs are level. This allows you to "play these harpstrings" on every preflight and any disagreement in an originally "tuned" rig will be quickly evident! If you get a "dead prang" at some later date, you have a problem to correct before next flight. The "same note" thing pays for itself in being able to sleep in flight.

Just about the time you begin to get with the program with "which way to turn that durn nipple", things will begin to fall into place rather quickly (IF you ever reach that point!). Now, if you find yourself "chasing the last time around" around the airplane, don't hesitate in letting the tension off, evening out your "nipple depth" if required, re-plumbing and leveling, and go at it again. This is where you might "become frustrated". SMALL "adjustments" near the end work best, and "playing piano tuner" is a BUNCH quicker than "fish-scaling" over and over. However, the fish-scale IS the preferred method of setting the tension. Keep re-doing it until the vert is plumb, the horizontals are level AND the tensions are correct (at which point, the "notes" should also be the same. You will probably "hit tune" a couple of times (at least!) only to find you took the vert or horiz out of "plumb", or "level".

THEN, you are "done". If this is your "FIRST TAIL RIG", you are already "going at it" with the "I don't really know what I am doing" attitude. This works FOR you. Your third or fourth airplane (when you start to believe that you know what you are doing) usually are the most frustrating. Take your time, and just as soon as you realize you seem to be beating your head against the wall, back off take a break. You WILL appreciate that your tailbrace wires are really pretty darn snug when you get all done. But you will ALSO know that if the "note on the top" and the "note on the bottom" stay in tune, you are "good to go". If you strip anything, it WON'T "be all right like that", and you'd better seek "professional help" from have somebosy else do it for you , NEXT TIME (with new parts!). Finally...lock down the jam nuts and go PLAY!

Howsat? More than you wanted???

JW, your posts never cease to amaze me. ;) Thanks for the WEALTH of information! How important is it that the side-to-side tension be equal like you say? If it's really critical, I might be able to use my brother's guitar tuner to get them equal in such respect. I was kinda' figuring that I was going to have to do it just like you said, but I didn't know if there was some "secret" that would help me. Again, thank you tremendously for the "instruction manual".

JohnW
02-06-2009, 09:49 AM
Naw, really. A guitar tuner would surely get 'em equal...but that would be overkill. The real proof is in the "other pudding". When you have the vert stab post plumb, you have the "side-to-side" tensions equal. You CAN have all the wires properly tensioned but still have the surfaces pulled out of "square"...but if your surfaces "repose" were they are supposed to, you either have REALLY LOOSE tailbrace wires, or correctly tensioned ones. There is why I "can't stress the rechecking for plumb/level" enough. Then it becomes an issue of the tension actually being "enough" to support the airloads, yet not "too much" so as to deform structure. Right there is where the fish-scale/deflection "standard" came in. This is simpler than it looks, and its hard enough to locate the 12-15 lb pull for @ .5 1nch deflection. I don't have a CLUE were you would locate the frequency the wire should vibrate at!!! 'Bout all you could do is go "tune" a few -20s or -22s out and about, but I bet you'd get as many different "notes" as there were airplanes in your "samples".

Uhhh, it just occurred to me that you may be questioning the "side-to-side being important and the fore and aft not so much" statement that I made before listing "steps". Errr, that is in reference only to the LEVELING PROCEDURE before you get into the rigging steps, not as applied to the finish rig itself. That is why the 12-15 lbs per 1/2" deflection becomes the "numbers" you are shooting for when the rig is complete [and how do I make this NOT confusing???] and yet "plumb and square" is as (or more) important than "how tight the wires are." The, ummm... its BOTH...take my meaning???

Zac Weidner
02-20-2009, 08:08 PM
Okay, I am adjusting the wires today and I have the stabilizers leveled and fin plumbed, but the problem comes with the tension. The bottom is ~17 lb. at 1/2" deflection and the top is ~10 lb. I can see that there should be a different deflection required between top and bottom wires. I have checked each wire 2 or 3 times each in the middle of the wires and the numbers are right.

Lownslow
08-14-2010, 01:19 AM
Just installed mine the way John so superbly described. Sweet!

Lou S.

Rotormech
01-13-2019, 10:42 AM
Zac - did you ever get the top and bottom wires in the 12-15lb range with 1/2 inch deflection?


Sent from my iPad using ShortWingPipers.Org

Steve Pierce
01-14-2019, 07:27 AM
I should have added this Piper service bulletin to this thread. It cover installing the tail on the Super Cub but is the same procedure on a Short Wing.

Stephen
01-14-2019, 10:27 AM
Steve,

Thanks for posting this Service Bulletin.

I think previous advice about plunking the wires to determine the proper tightness was ill advised and can easily lead to over tightening. Measuring deflection of the wire is accurate and easy. Plunk them after measuring, if you want.

J Ryd
02-28-2020, 07:42 PM
I'm currently going through the rigging process from the beginning. After correcting the dihedral and washout I move to the tail. I found the horizontal surfaces are spot on level, the vertical fin slightly canted to the right. While examining the adjustments needed, i find the top side tail brace wire brackets are missing the little funny square washers (40131-00). I was concerned but see in the parts manual that they aren't required untill serial numbers 8000+.
Any thoughts as to why? Brackets, as assembled, all appear in good condition.

Wag-builder
03-03-2020, 11:55 AM
I think they were required when the tail brace wires were changed from the streamline wires to the round wires, but I am pretty sure those washers should be installed. I am sure Steve will make sure I am not telling you something incorrect.

Steve

Steve Pierce
03-04-2020, 08:28 AM
I'm currently going through the rigging process from the beginning. After correcting the dihedral and washout I move to the tail. I found the horizontal surfaces are spot on level, the vertical fin slightly canted to the right. While examining the adjustments needed, i find the top side tail brace wire brackets are missing the little funny square washers (40131-00). I was concerned but see in the parts manual that they aren't required untill serial numbers 8000+.
Any thoughts as to why? Brackets, as assembled, all appear in good condition.
That is when Piper started using the round wires and clevis assemblies on the PA22. Look at the difference between figure 13 and figure 3 on drawing 11825 Fin Tie Rod Attachment. You don't see many 10074 tail braces wires with 10075 fittings anymore. If you are using the 40521 clevis I would use the 40131 washers, have seen everything from J3s on up with cracked or broken clevises.

J Ryd
03-05-2020, 12:34 AM
That is when Piper started using the round wires and clevis assemblies on the PA22. Look at the difference between figure 13 and figure 3 on drawing 11825 Fin Tie Rod Attachment. You don't see many 10074 tail braces wires with 10075 fittings anymore. If you are using the 40521 clevis I would use the 40131 washers, have seen everything from J3s on up with cracked or broken clevises.
Crap! Spend the better part of the afternoon "Tuning up" the tail brace wires the other day. Guess I'll run down to Univair tomorrow to get the washers and redo it.
I do find it curious that the 1/2" deflection is called out for both top and bottomed wires. Being different lengths, this essentially means they are actually at different tensions.

Steve Pierce
03-05-2020, 07:49 AM
Just remove the 1/4" bolt and you should be able to get them in and back together without messing with your rigging. Losening the 3/16" bolts is always a risk of the bushing oming out of the clevis. You can always losen one clevis and count the turns and then put it right back the same. I think the tension balances out.

violinmaker
03-05-2020, 09:03 PM
could somebody here make these priceless instructions a sticky so it can never be lost ?
or- make the man the sticky :-)

cubscout
03-05-2020, 10:26 PM
After you get the angles/tensions worked out satisfactorily, I like to check tuning to about G below middle C when you pluck the wires on preflight. Just remember it's an airplane, not a banjo.

Thanks. cubscout

Steve Pierce
03-06-2020, 07:49 AM
could somebody here make these priceless instructions a sticky so it can never be lost ?
or- make the man the sticky :-)
Go to the bottom of the page and you can add/edit the cloud tag. Click on it and add words to help you search for it later.

N2709P
09-09-2022, 06:04 PM
An older thread with a new question. Were the old tail wire clevis’s steel and the new stainless? The ones on my TriPacer are steel and the Univair ones are advertised as stainless. When I was installing the new brass nipples and washers, the clevis’s felt very “soft”, almost like they were cracked. I inspected them with a 10X scope and found no damage but they just did not feel right. The Piper SB and AD regarding installing the round wires mentioned the special washers and bushings but no directions as to replace the clevis’s.
N2709P

Steve Pierce
09-09-2022, 06:30 PM
Yes, the old ones were steel, prone to rust and I have found some cracked. New ones are stainless. I have not found a stainless one cracked.

N2709P
09-09-2022, 09:34 PM
Thank you Steve! I bought new stainless ones. Loosing a tailwire has the potential to make a really lousy day. We found the round wires were installed on the aircraft but no special washers or bushings. One wire had vice grip marks necessitating replacement.
N2709P

Subsonic
09-10-2022, 11:19 AM
Hmmmm...mine are original steel (2850 hours), and the clevis's and nuts have a little rust around the edges. They've not been off the plane since I bought it in 2016.

How often should they be inspected? Do they actually need to be removed to be inspected, or can I just wire brush, mask and repaint them in place?

If not, should I remove, clean, inspect, paint, and re-install one wire of the quadrant at a time so to minimize trim changes? How best to proceed?

Steve Pierce
09-10-2022, 02:57 PM
I would clean and touch up in place. The ones I have seen break were really pitted or missing the 40131 washers (https://www.univair.com/piper/piper-j-3/view-all/u40131-000-piper-clevis-washer/).

Service Bulletin 966 (https://www.shortwingpipers.org/forum/showthread.php?12489-Tail-Brace-Wires) is a good reference if you do remove them.

Adam Hile
01-24-2023, 10:16 PM
New question on a '51 Pacer s/n 790. Working on trial fitting everything before it gets covered. I wasn't the one that took it apart. The tail brace wires were installed with AN4 bolts through the horizontal. I see according to dwg 12647X that there is to be a bushing (80012-005) inserted and welded in the horizontal. Got the bushings for the clevis's (82732-072) from work - Preferred Airparts. I see we do have the 80012-005 in stock. Probably ought to get those and have them welded in? Frames are uncovered. Or did some of them use AN4 bolts through the horizontal? Not sure what the difference would be.

Steve Pierce
01-24-2023, 10:27 PM
The clevis has a 1/4" hole. The vertical stab should be drilled for a 1/4" bolt but the horizontal stabs are drilled for 3/16" bolts. The bushings go in the clevis' to allow rotation as the horizontal stabs is rotated slightly up and down with the trim jackscrew. There is a good drawing of the complete assembly.

Kelliots
03-16-2023, 01:17 PM
Steve, so it's OK if the clevis on the upper/lower outboard horizontal stab can move slightly if pushed from the side? It does appear so because of the bushings, for the reason you mentioned above concerning the jackscrew movement. I noticed that my left and right upper clevis' can rotate slightly and didn't know if this was a concern. Thanks much.....

Steve Pierce
03-16-2023, 03:08 PM
It needs to rotate as the stab leading edge goes up and down.

Kelliots
03-16-2023, 03:18 PM
Thanks Steve, makes sense, I noticed where they attach up at the vertical stab they are appear to be rigid and do not rotate - does that sound right?

Steve Pierce
03-16-2023, 03:20 PM
Yes, the horizontal rotated, not the vertical.

Kelliots
03-16-2023, 03:31 PM
Thanks! Looks like I'm good to go but will probably replace the 4 AN315-5 jam nuts and AN960-10 washers as they are old, dirty and may have some corrosion. Appreciate the help!

dgapilot
03-16-2023, 04:48 PM
Don’t forget there are special washers that go at the junction of the vertical stabilizer and the wires.


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Brian
03-16-2023, 11:41 PM
These special bent washers are available from Univair.

https://www.univair.com/piper/piper-j-3/view-all/u40131-000-piper-clevis-washer/