Lift Strut Fairing

[Dave S]

All,

On our 2008 S7, the factory plastic lift strut fairings were installed on the lift struts. One of the four which was installed did not end up quite as straight as I would have wanted (as observed AFTER the hysol set up). It's not much, nobody else notices; but, you can guess the person who built it does:o. Given that these are bonded with hysol, what kind of challenges do you think I would encounter in removing one of the lift strut fairings to replace it with a new one? Also, the strut is not powdercoated; but, epoxy primed and finished with Aerothane.

Thanks,

Dave S

[Esser]

I don't think you will be able to without scratching the spar and introducing stress risers. To remove hysol it needs to be heated up to about 450 and then pried off in chunks with a screwdriver or similar. If she flies fine, leave it

[Northof49]

Dave
I did something similar ,but it was one of my plastic leading edges .
I removed it and the old hysol it wasn't that difficult , I used a Good
Firm plastic scrapper to separate the two ,without damaging the leading edge,then I sanded off the old hysol
It was time consuming removing the hysol but it was well worth it in
the end .Mike

[HighWing]

Dave,
No experience with the Hysol used now in the construction, but lots of experience looking at the flaws no one else notices - even when they are pointed out to them. Just finished a new coat of paint on the Nose Cowl. Glad I did. as now when I walk up to the airplane there is no longer that magnetic force grabbing my attention.

[Floog]

I think if you 'unzip' the trailing edge of the strut fairing, it should peel right off of the hysol because the bond is very weak on the PVC.. Getting the hysol off of the strut itself would be the challenge. At any rate, it would be a lot of work to remove and replace. One would have to re-join the strut fairing intersection as well.

[Tomfox]

Sooo - I am getting ready to install these fairings on my SS7 that has just been completed. Seeing this issue coming, I plan to only spot bond the fairings - probably four places - so that if I have to remove them I won't have such a big issue. Any thoughts?

Thanks
Tom Livermore
N316DA - SS7 Supersport Rotax 912ULS

[jrevens]

Sooo - I am getting ready to install these fairings on my SS7 that has just been completed. Seeing this issue coming, I plan to only spot bond the fairings - probably four places - so that if I have to remove them I won't have such a big issue. Any thoughts?

Thanks
Tom Livermore
N316DA - SS7 Supersport Rotax 912ULS

I don't know if Tom ever got an answer to his question, but I would like to ask it again for myself. Using the factory plastic fairings, are most builders now only bonding in a few spots along the strut, and are they applying Hysol to both top & bottom contact surfaces? Do you bond the trailing edges also, or just rely on the "zipper"?

[Floog]

I 'stitched' Hysol into the PVC strut 'pocket'. No adhesive on the trailing edge 'zipper'..The Hysol bonds very well to the strut. It really doesn't matter about the weak bond to the PVC fairing. The fairing is locked in place within the 'pocket' when the Hysol sets up and the trailing edge is 'zipped' up. In other words, the fairing can't turn on the strut because of the way it is extruded. After almost 1,000 hrs. of abuse, nothing has come loose or fallen off :) Hope this helps, John.

[jiott]

I bonded both top & bottom surfaces with a very light bead full length; I am sure this was overkill. I did not bond the trailing edge zipper; it seems to be quite strong, especially with the top & bottom surfaces bonded.

[Floog]

Hey, Jim what are you doing up so late? Had a good flight with Scott today. We met in the Dalles. Hope all is well!

BTW, I forgot to mention, I also used Hysol on both top and bottom surfaces of the PVC pocket.

[jiott]

Yes Floog all is well. Finished my annual a week ago and had one good 3 hour test flight. I thought about going out yesterday, but too many black snow clouds drifting around.

I always hope to see you chime in on these build questions. You did such a beautiful job on your SS7 I think your opinions carry a lot of weight.

[Floog]

Thanks for the kudos, Jim. Just flew across the Cascades for the NW Trade show in Puyallup tomorrow and Sunday. Should be a fun experience!

[N213RV]

This is a very timely discussion for me. Last night I hysol'ed my first fairing on. I scuffed the strut with 100 grit sand paper and cleaned the inside of the fairing and strut with acetone. I installed the fairing dry, then used a 1.5" piece of wood to hold the fairing back end open at the base of the strut. I used Floog's approach and stitch glued the fairing top and bottom about every 12-18". I just slid the piece of wood up to the next area and used a small metal dental spatula to push in the hysol. I then zippered the back end closed and aligned the fairing. Seemed to work well for the first fairing. I hope to do the remaining 3 today.

More to come.....

[efwd]

What exactly does "stitch" mean when applying Hysol? Intermittent application vs a continuous run?
Eddie

[N213RV]

What exactly does "stitch" mean when applying Hysol? Intermittent application vs a continuous run?
Eddie

Yes, I glued about a 3" section every 12" or so.

[Dorsal]

FWIW, I "temporarily" installed the factory faring with no adhesive of any kind. That was 500 flight hours ago and they still work great. I got part way though making carbon fiber ones then got busy with other "life" things (still hope to finish them some day).

[jrevens]

Hey Finn,
It's great to hear that you're still 'kickin'! Those fairings are heavy... carbon fiber or something like what Highwing did would be really great. I think I'll stick with the factory plastic ones or I'll never finish this thing!

[kmach]

How much do the plastic ones weigh?

[jiott]

I believe they weigh about 12 lbs.

[Dorsal]

Hey Finn,
It's great to hear that you're still 'kickin'! Those fairings are heavy... carbon fiber or something like what Highwing did would be really great. I think I'll stick with the factory plastic ones or I'll never finish this thing!

Thanks John, pretty busy but still get to play with my plane.
IF i finish the carbon fairing they would come in around 4 lbs for the set. The plastic ones work fine and they are tough too.