Lift Strut Inserts RECOVERY

[ksatter26]

I've decided to re-work/re-make some of my strut legs to utilize the delivered upper spar mounts. (You may want to update the pictures in the build manual.) I can cut down the longer ones to make the proper bends for the shorter ones and utilize my scrap material to re-make the longer pair. I will probably just paint them with 2-part epoxy automotive paint rather than powder coat. I will re-work each as I install them for proper fit.

As for the lift struts (tired of waiting for replacement-replacements), I cut out the upper strut inserts (working just the port side for now); drilled out the rivets and used my angle grinder to carefully split the outer tubing to remove the inserts. I polished the inserts and have noted the locations of the existing rivet holes so that I can position the new rivets such that I keep maximum distance from the existing holes in the inserts when re-installed (with rivets and Hysol epoxy).

Today I will re-set the port sweep, dihedral and washout before taking exact measurements for the fwd and aft strut leg lengths. I can then proceed normally with the mounting process. This should get me back on the building path with the port jury strut installation process coming next. It will be nice to be able to finally fold the port wing to get back some of the shop space and too begin work on the starboard wing.

I believe this plan will work. I should have thought of it earlier and I will not need the replacement inserts.

Still outstanding:

(1) Polini prop nut

(2) Starboard flaperon control arm

(3) Wingtip cover plates

(4) Oratex materials

Still hesitant to start chopping up that really nice cowling. It does seem that I will have to seriously modify the lower-fwd "cheeks" to make it fit. Now, being able to get back to the wings, the scheduling of this process can slip out on the timeline.

Weather warmer and good for working but seems that every few days we get late afternoon-evening thunderstorm/hail/tornado warnings (welcome to North Texas). I'm positioned slightly north-east of two Texas reservoir-lakes that seem to channel the weather around my place. Good because I had enough of the weather disaster recovery process with Hurricane Katrina.

[LA F2 Flyer]

Hi Kurt. I personally would be reluctant to use those strut inserts, if the pictures are serving me correctly.

From my understanding, any scoring is a potential starting point for stress fractures, and it would be very hard to spot if this were to occur, since the fractures would be inside the strut tubes themselves.

One would argue that your struts need to be the most robust part of the aircraft, as a failure here would result in the loss of a wing. A failed hinge on a control surface is one thing...a strut failure would be something else entirely in that it would be unrecoverable.

On the other hand (and on a more positive note), I would focus more on the cowl for now. I'm quite experienced with the fear of cutting into a good part and messing something up, but if you have even the slightest experience with fiberglass, a mistake in the form of an "overcut" can very easily be remedied with a patch and some (or a lot of) sanding. Fitting the cowl now is a great way to "pass the time" while you wait for other parts, and won't interfere with any of the other processes. (The only thing to be wary of is to make sure it's mounted back far enough to avoid contact with the propeller.)

Again, just my .02...

Your weather sounds similar to ours in its fluctuations...we finally have a few days of sunshine here, with less wind (hopefully). But still too cold for my taste.

[ksatter26]

Packing the existing rivet holes and any scoring of the insert shaft with the industrial Hysol epoxy should give a good bod to the lift strut legs. With a large, bonded surface area I think the possibility of a stress failure is extremely small. The structural strength of the Hysol epoxy bond (in the spec) is almost as high as the 6,000 pound rating of the rod end bearing. (I believe the new cone-shaped head of the newly designed inserts provide an even longer grip length for the rod end bearing shaft than the older hemispherical head design.)

However, I will probably forgo the strut work this afternoon and thru the weekend to see if the new inserts show up. (9 week wait ... frustrating.)

[LA F2 Flyer]

An excellent counterpoint. Another thing I noticed when fitting the lower strut brackets is that they were very hard to pull out of the strut tubes prior to both riveting and applying the epoxy due to the angles of insertion.

If you were to reuse the lower brackets I would add a full inspection of them to the preflight checklist at the very least.

I WILL say that the epoxy is very robust. I've since used it in a few non-aviation applications.