Jury Strut Riggin

[Pearson]

What are the do's and don'ts of installing the jury struts.

I was putting mine back on yesterday and noticed they aren't exactly perpendicular to the bottom of the wing. Is that a big deal?

Are the wing struts supposed to be exactly straight, or should they have a slight bow upward at the jury strut. I was thinking that as the wing loads up, the jury strut would hold the wing struts down in the middle unless you started with a slight bow upward.

[Robert Lees]

Re: Jury Strut Riggin

Richard:

I've done six or seven lift strut replacements here in the UK because of the AD. In all cases, we've got the jury struts at perfectly 91 degrees to the underside of the wing (allowing for the 1 degree dihedral ).

It would be a big deal to me that you couldn't get them right, but probably not an airworthiness issue. And yes, the jury struts are supposed to be straight down, vertical, and parallel to eachother, when you stand 30 feet in front of the aircraft and "eye" the alignment of each of the jury struts. And the lift struts should be straight when you crank your head under the wing to look down their length to the fuselage fitting. No bow at all.

It's a good idea to completely remove the jury strut fittings (the hollow fittings) from under the wing (this allows you to have a good look at them to make sure they're not broken, corroded, cracked etc.)

Set the locknuts on these fittings so that you have the most thread showing on them.

Then by eye (remember 30 feet in front of the aircraft?) hang the jury struts vertically from the underside of the wing, and see where they meet the lift struts. Some fore-and-aft adjustment will be required to get the jury struts to meet up with the lift struts in the correct place.

Instead of using the AN3 bolts to do this rigging, I use 3/8" diameter screwdrivers for the initial setting-up (this makes it easier to twist the hollow jury strut brackets).

If you've got new lift struts, some jiggery-pokery may be required on the lift strut clamps (the ones that wrap around the lift struts) to get it all to align.

The big trick is that once you have the vertical alignment of the jury struts correct, then all you need to do is screw in (or out) the top hollow fittings to get the lift struts in a straight line (that's where using a 3/16 screwdriver helps). Use some tape around the lift struts to act as a buffer between the clamps and the lift struts (I use electricians tape of the appropriate colour)

Once it's all in line & vertical, replace the 3/16 screwdriver with the proper AN3 bolts & nuts and away you go. Don't forget to lock up the locknuts on the hollow fittings underneath the wing.

It's worth replacing all the hardware while you're there.

Hope this makes sense and helps, and sorry if I'm teaching Granny.

Rob

[Forrest Barber]

Re: Jury Strut Riggin

plastic tape is a no no , will create moisture & rust. Use the correct tape, at the factory we used a 3/4 white Industrial tape , usually one and one half wrap. More if necessary. Struts straight , jury struts 90 degree to wing undersurface. Vertical is okay too!

[flyguy]

Re: Jury Strut Riggin

What is "industrial tape?" Is it the fabric based stuff that is commonly refered to as friction tape and is used all over the the BC12's originally to tie down lines and such? I have only ever seen it in black.
DC

[Forrest Barber]

Re: Jury Strut Riggin

Black friction tape was used by Taylorcraft for the purposes you mention. The source for the White "friction" tape we have here is Jim & Dondi Miller, Aircraft Technical Support 1-877 877-3334
It is the chafe tape from a company in Lowell , Mass.

[Forrest Barber]

Re: Jury Strut Riggin

Black friction tape was used by Taylorcraft for the purposes you mention. The source for the White "friction" tape we have here is Jim & Dondi Miller, Aircraft Technical Support 1-877 877-3334
It is the chafe tape from a company in Lowell , Mass. used over ribs, rivets, AND under the strut fittings good stuff!

[Robert Lees]

Re: Jury Strut Riggin

...used over ribs, rivets, AND under the strut fittings good stuff!...

The anti-chafe tape to which I think Forrest refers is sold by Poly-Fiber (through Jim & Dondi & other dealers). It is cotton-based.

IMHO, it is not suitable for the purpose that Forrest mentions, in that it will retain moisture unless sealed with polybrush.

Forrest, are you sure you are correct in your thinking?

The everyday vinyl electrical tape that I mentioned above, that I have used on jury strut clamps for over 15 years without an ounce of water retention, corrosion or other degredation being evident, works fine. Vinyl tape will not retain moisture (witness many aircraft with vinyl decals).

Rob

[Pearson]

Re: Jury Strut Riggin

Thank you Rob and Forrest. I am just now getting around to putting the jury struts back on after replacing my wing struts with new ones from Airframes Inc. While I had it all apart I repainted the jury struts and all the clamps and fittings. I took the nuts off the attach fittings during painting, so the old adjustment is gone.

Rob your info about the setup will help. I need to go back and redo some stuff. The first thing is to find the tape you referred to Forrest. The old clamps had electrical tape, so I naturally used more of the same. Oh well, I guess I should have checked with the masters first.

Thanks again!

[Robert Lees]

Re: Jury Strut Riggin

The old clamps had electrical tape

...and were the old struts or old clamps corroded around that tape?

[Forrest Barber]

Re: Jury Strut Riggin

Robert , over here we still have to conform to the Type Certificate and black electrican tape is not it. Maybe check with the TC holder I only go by the Final inspection sheet used by the factory here in Alliance.

[Pearson]

Re: Jury Strut Riggin

Amazingly, the struts were not corroded or rusted under the clamps.

Thanks again.

[Pearson]

Re: Jury Strut Riggin

Forrest,

I am attempting to find this "White Friction Tape" you told me to use under the jury strut clamps. I have looked at all the local hardware stores and autoparts. Is there someother type of business that might stock it locally?

Is this the stuff that is made of thick cloth, like what you use to cover up rib stitching?

Thank you!

[Robert Lees]

Re: Jury Strut Riggin

Sorry to poke a stick in a nest of adders, but how is one expected to

conform to the Type Certificate

when the (design) data upon which the Type Certificate is based is unavailable to those attempting to adhere to said Type Certificate?

In other words, from where can your everyday Taylorcraft driver get the drawings? And how does this unfortunate situation differ from the driver of any other (even modern) aircraft?



Let me answer the last bit myself, with an example:
I am the owner of an Airbus A380. My maintenance organisation, approved under ICAO regulations, has full copies of the maintenance manuals, repair manuals, design & other drawings, certification documents & data, down to the last nitty-gritty detail, pertinent to ensure the ongoing airworthiness of my Airbus.

So where on this little Taylorcraft earth upon which I live, am I to know or find out that some particular tape that is probably no longer manufactured is used under the jury strut clamps? From the drawings?

Get real, guys. Or at least get the Feds to get real. I use various FAA AC's for my maintenance (and I'm in the UK where FAR's and AC's have little jurisdiction!). If it's not in there (or in the aforementioned unobtanium), I use common sense.

One might argue that if one's IA signs the aeroplane as being airworthy, then it is legally airworthy in the eyes of the FAA, and that's all the owner needs.

But another might question to the FAA: how many IA's actually really know all the design issues that ensure a Taylorcraft conforms to the type certificate? And have "approved" data to back that claim up?

I think I can name one...but he's too busy to be the IA of all Taylorcraft, I'm sure.

Just one last edit after Birdlegs' post: before it might be suggested that in the UK, Taylorcraft are operated under a different airworthiness regime to that in the rest of the known world: UK Taylorcraft still have certification from the UK CAA (part of JAA, part of ICAO), so don't go there.



Sorry for the rant.

[birdlegs]

Re: Jury Strut Riggin

This is seemingly open for interpretation, I was instructed (by a notable
I.A.) who is a curator of a museum full of flying antiques. To mount these
very struts on white nylon electrical wrap after masking and coating with
good quality spar varnish or epoxy varnish. Honest,
Birdlegs

[jdoran]

Re: Jury Strut Riggin

Rob,

Stop ranting and tell us how you got that 3/8" screwdriver to fit in the 3/16" hole?