sealed struts and rod ends

[BrianK]

I bought a new Pacer after the insurance company totaled my Clipper. The log book on the Pacer says that the right struts were replaced with new struts and that the left ones were not available and were magnetic particle inspected. There are several things in this entry that have me baffled.

First, how in the world do you find internal corrosion on the strut by magnafluxing? My guess is that what the mechanic meant is that he had two of the rod ends magnafluxed and replaced the other two. Is there any kind of magnetic particle inspection that can be done on the strut for the A.D.? I know of punch testing, eddy current testing, and ultrasonic testing, but that is all I am aware of.

Second, all of the struts have the large size forks. I know that all of the newer sealed struts use the large size forks and some or maybe all of the old unsealed struts used the smaller forks. Since I have the large forks does that mean that I also have the sealed struts or were there unsealed struts made that used the large forks also?

Is there any way to determine if I have sealed or unsealed struts without taking them off? The logs don't have part numbers or a brand for the ones that were supposedly replaced and they look the same on both sides. I have not been able to dind any part numbers on the struts either, but may not be looking in the right place.

[Wayne]

Both new struts and rebuilt struts are avalable sealed. all of the old struts have small forks. Atlee Dodge and one other company that I know of welded up all the holes closed, cut the bottom end open, inspected for corrosion, and welded in a new fitting to accept the larger fork, oiled and sealed the strut. Both companys have stcs for their mods. Univare lowered their price from around $900 to less then half that to compete with the modified ones. This put them out of the lift strut buiseness. I think there is another company making new ones, someone here will know who they are.
If there are no holes drilled in your struts to mount doar stops, and fearings, and they have the large forks then they are either new Univare or stc modified struts. Look closely for the paperwork to make the other 2 legal.
I believe that before the last ad on the struts requiring sealed struts and large threaded end fittings came out there was an ad that required changing the fittings to a rolled thread design. Make shure your struts are of the sealed, large fitting design.
Ultrasonic inspection is the recomended test for the struts. The fittings are tested for cracks with magnetic particle inspection. Punch testing isn't legal and ruins a $xxxx point on a Mall fabric tester.
If your struts have door stops mounted to them with screws screwed into the struts or the top strut fearings are mounted with screws that are screwed into the struts then there are holes drilled into the struts. They are definatly not sealed. These are the wholes that are welded closed to maks sealed struts.

[7083]

Brian, Wayne
I believe the other company doing the strut alteration was Jensen. They used 7/8 inch diameter forks versus the 5/8 inch from univair (The original Piper were 7/16 or 1/2). A friend of mine had some jensen struts on his exp wagabond.

Jim Miller

[clprcpt]

"Punch testing isn't legal...."?? How so? That's the method put forward in the AD.

[Wayne]

I wasn't aware of Jensen making or modifying lift struts. They are the manufacturer of the fork end fittings used in my F Atlee Dodge modafyed lift struts. Jensen provided the 006 forked end fitting per STC SA1587NM. F Atlee Dodge holds STC S4635NM to cut open, inspect, and install the 5/8-18 threaded insert, linseed oil the inside of the strut and seal it with an O-ring and nut.
Brian, I went back and read the latest AD for the lift struts. It states that when the Jensen forks are installed magnafluxing the forked end fittings is no longer required. Check your forks, I fear that they may not be the sealed struts with large forks. My instolation has the forks screwed into the struts. An O-ring is between the end of the strut and the jam nut on the fork. Remove the lower cuff and examine the end of the strut/fork joint. you will either see or not see a black O-ring there. Also, any holes drilled in the strut no matter how small arn't supposed to be there.
Here is where I go in a grey area. The former owner of my plane, and a close friend, told me when I baught the plane that this was the second time he had to buy new forked end fittings. The first time was when an earlier AD came out requiring magnafluxing and replacng if cracked, the cut thread end fittings. Or just replacing the fittings with the new stronger rolled thread virsion. He didn't need to re-thread the struts to accept the new ones so there was no change in size. This sounds like what you discribe.
Even if your struts arn't the newest design, its not that bad. I talked to F atlee Dodge a number of years ago. They said that out of hundreds of struts modifyed only 2 or 3 had any appreciable corrosion in them. This is very good. The end fittings at 7/16" or 1/2" dia. are strong enough to hold up a semi truck. I would bet on it that the reason a fiew fittings have shown cracks in the threaded area is shear stupiddity.
Adjusting the wings is done with the struts. It is aquard to remove the strut from both mounts to turn the fork to lengthen or shorten the strut. The easy way to ruin the fork is to leave it attached at the botton and turn the strut. If you do this you will need to pull down on the strut for it to clear the wing. The threaded portion of the fork is now bent and primed for failure.
I would not replace lift struts if a ultrasonic inspectoin was done,and rolled thread forks checked cairfully for streightness were installed. These forks should be readily available since most were replaced with sealed ones.

[Steve Pierce]

The magnetic particle inspection was for the fork. It is legal to punch test the struts and the Jensen struts require punch testing every five years if I remember correctly. Look at the top of the strut near the wing fitting. Univair struts have a "U" stamped on them with an "L" inside of the "U". I can take some pictures of the Jensen struts if it will help.

[Wayne]

I beg your pardon, I re-read the AD and found I was in errer. The Service buliten that the AD was based on does use the Maul fabric tester to check for corrosion. The ultrasonic method approved in the AD is a better method that doesn't destroy the tip on the tester though.

[Steve Pierce]

Wayne, You are correct. Testing struts does uncalibrate the Maule tester. I have an old Seyboth tester I used to use on struts. Thank goodness all the airplanes I maintain have sealed struts and I don't have to punch anymore.

[12944]

I bought a complete set of struts, sealed with the big forks from Big Lake Alaska. They ended up being about $400/ea. I like them better than the Atlee Dodge. I am very pleased with them and I have used them on about three other customer aircraft.

[Stephen 998]

I agree that Airframes Inc (Big Lake Alaska) has a very good product. The welding is good and they use stainless harware. The other choice is Univare, which has brought their priece down since Airframes came on the scene. I have one Univare strut and three Airframes struts.