Original Lift Struts for Sale

[SteveGREEN]

Original '46 BC12-D lift struts for sale. The label on the shipping tube I packed them in years ago says 2 forward and 1 aft. I think the aft one is for the left side, but will check to be sure if someone is interested. Pick-up or delivery if not too far from Denver. I would prefer to ship all three together if shipping. They are as removed, not inspected or resealed. We replaced all four at once, one of which was damaged, hence the missing aft strut. Email me if you are interested. sgreen(one)(two)(two)(six)at comcast(dot)net. Please make a reasonable offer.

[astjp2]

Price?

[3Dreaming]

He says reasonable offer. It would be a gamble if they are serviceable or not. Honestly I would be afraid to pay the shipping if they were given to me. I already have a few sets of junk struts laying around.

[SteveGREEN]

Make me an offer. I don’t really have a price in mind. No idea what shipping would be, but gas is about 1.00/gal here.

Best answer I can give you on serviceability is that they were in good, flyable condition when I put them in the shipping container, in my climate controlled, (Colorado) dry garage. The AD, 2008-04-09, has not been complied with, so from a paperwork perspective, they are not airworthy. Just in a unchanged condition since the last flight.

[PA1195]

If they're still open at the top turn them upside down with the wing side down and tap on the fuselage end. Any corrosion comes out and that's that. I did the corrosion inspection for years with various Piper and Taylorcraft struts. Not worth the time or money to deal with it anymore.

Gary

[astjp2]

See if there is a home builder who needs some aerodynamic tube, they will open the struts up and check for corrosion and if good, the tube can be used on another airplane.

[Hank Jarrett]

I saw a NEAT little machine that was being used to remove rust from a tube. It was a roller that used a belt drive so a motor could rotate the tube along the long axis and had a mechanism to tip it up and down a little. You plugged the tube ends with an abrasive inside and the machine rotated and tipped the tube so the grit would remove the rust. Inside came out really clean when you poured out the rust and abrasive! Kind of like a rock tumbler for REALLY LONG drums. To do a strut you might need to make a couple of plywood rings for the ends of the strut so it could be rotated smoothly but I am betting you could just tape the ends as plugs.

[PA1195]

To what avail structurally would removing internal (or external) rust be? Once corroded metal is lost. Once metal is lost so can be the structural strength. Yes we can arrest further corrosion if preserved with a coating material but someone has to certify the lost metal didn't compromise the strength. Who's going to do that in today's litigious age without approved data?

For example Piper has an AD 2015-08-04 which specifies a minimum thickness for their struts of 0.024". What's Taylorcraft's? Not to argue but it's simply better to have no corrosion or replacement struts if corrosion present.

Edit: I reread Taylorcraft's AD 2002-16-14 and they refer to the following SB 2007-001B. Minimum material thickness are noted on page 5.

Gary

[Hank Jarrett]

The problem is the FAA has mandated X-Ray for determining the rust damage, an NDI technique totally wrong for what they are looking for. That said, we are stuck with it. There are two parts to getting a safe strut. First you have to comply with what the FAA demands, so you X-ray the struts. Second you need to make the strut safe for use if it passes the FAA inspection. I have NO IDEA how you can tell anything but GROSS rust from an X-ray , but it really doesn’t matter. What matters is if the strut will carry the design load and NOT continue to rust or crack. You have to get rid of all the rust and then coat the ID to stop future rust. Follow that with a PROOF TEST. The max load a strut will EVER see (the point where the wing will fail at the strut attach) is WELL below the max strength of the strut (if it isn’t cracked or too badly corroded). The net area of a corroded strut in cross section is enough to take some pretty significant corrosion. If there are no holes in it (or holes that can be made with a pick) and the exterior doesn’t scare the C**P out of you it will probably take the pull test. I wouldn’t use a visibly corroded strut or one with holes in it but I am looking forward to seeing one not break at the failure load for the wing. It is going to be a fun test. Lost metal is NOT the problem. Struts were built with different thickness and dimensions. STRESS concentration is the problem. That is a major problem with X-ray. No one knows all the thicknesses of the materials as built and no one knows how much damage is acceptable. The only way to know is to pull test the strut. As a side a pull test can be done with a simple rig and probably a LOT cheaper than an X-ray, but that method wasn’t invented by the FAA. You HAVE TO DO THE FAA INSPECTION, but no one says you can’t also do the pull test and I will on any unsealed strut I ever look at for use.
My concept is to get an AMOC to REPAIR unsealed struts by welding new streamline tube onto the end fittings (in a fixture) and then proof test them. 4313 says we can splice repair tubing. I just want to use a LONG piece of replacement tube and reuse the end weldments (and hopefully get approval to SEAL the ends at the same time).

[PA1195]

Thanks Hank for the comments. Life's too short for me to ride rusty especially with STC SA1-210's potential for a 1500 GW. But others may be more cavalier or wear parachutes. In addition to the Pipers that have had failed struts due to corrosion, the failures I've seen with struts are in compression particularly the rear strut with high snow or rear wind loads. Example below from this winter. The snow load was 17# per square foot @ 170 sq ft = ~2890# total. The plane's GW is 1650# x -2.0 G's rated = 3300#.

Gary

[Hank Jarrett]

A crippling failure in compression is a completely different failure mode. You are right though, it needs to be looked at in any AMOC and will be. As I see it the problem with compression failures is usually from load distribution being all wrong for the design compared to NORMAL flight loads. Snow load on a wing causes all sorts of strange load paths that will fail a perfect strut too. Repairing struts isn't something I would take lightly. The testing would have to show that all the loads a NEW strut could handle could also be handled by the repaired one. Snow load is one that most struts are NOT designed to take and are one of the main reasons for the jury struts. They make the strut two short struts in compression instead of one long one. That drives the compression cripple strength up significantly. Before I ever flew with a repaired strut (or let anyone else use the process) there would be significant testing (more than the FAA or the factory ever did). Nothing cavalier about it. Life is too short. I just think the FAA got ridiculous about our struts because they believed a con man who owned the TC at the time who had no idea what he was talking about. He was looking to make a quick buck. The FAA was embarrassed that they got conned and wanted an easy way out. He gave it to them.

[astjp2]

So are you admitting engineers get conned by the average joe to get their own way? Lol

[PA1195]

Prior to failure on this particular Citabria the wing tips bent down primarily at the rear followed by the ailerons drooping. The fabric showed buckling underneath. The inclined angle of the plane ~10-12* typically would put more load on the rear strut. I drive by every day to see my Taylorcraft and walk the dog and observed the progression. The owner never brushed the snow off during winter unless forced and I notified the airport routinely but to no avail. Finally a tail wind of about 15 made it fail while I was walking nearby. Someone did come by and remove the snow later. He hadn't flown the plane in years and it was out of license and deemed unairworthy due to the fabric condition.

At factory loads on unmodified planes the original struts are probably ok. At 1280, 1351, or especially 1500# on floats with all the bouncing around I'd want no potential issues with structural integrity.. My Airframes struts cost me $2K and ended the periodic compliance issue. I dealt with Piper's strut and fork AD's for years on several planes and learned to fix it once and for all with sealed struts and HD forks.

Gary

[Hank Jarrett]

So are you admitting engineers get conned by the average joe to get their own way? Lol

Admit it? No, I scream it from the roof tops, and I AM an engineer!
Hank

I think all engineers should be required to work as mechanics in their area. Book smart tool stupid engineers are a world wide problem!

[PA1195]

It would help to have a database to draw upon for these AD's.....strut fittings and struts....just to see how many actually are compromised when inspected. It's not a large task to R&R a single strut at a time and rough check for internal corrosion outside of the normal intervals. Tap and empty followed by an internal preservative if apparently airworthy.

Same for the potential landing gear corrosion issue. R&R after examining. We shouldn't have to be provoked by AD's to thoroughly inspect our aircraft. Not every year but after 45-75 years there's reason to suspect that rust never sleeps especially in climates with combined heat and humidity.

An AMOC with a reasonable method would benefit. Wiley's plane was the extreme. The TCDS holder yelled fire and the FAA threw water on everybody.

Gary