Fiberglass and epoxy to reinforce flaperon hangers?

15 posts in this topic

Posted

I have to reinforce the flaperon hangars on my bird and have been researching on this forum the ways to go about it. One of the common problems with the aluminum and scotchweld seems to be that the glue isn't always fool proof and some of the photos ive seen you can still see plywood sticking out which means whatever varnish is protecting it can eventually fail and the wood will rot.

That led me to the idea of wrapping the rib tail/ hangar in fiberglass cloth and epoxy. It will reinforce it and weather proof it. If the wood is properly prepped the epoxy should bond the fiberglass to the wood very well and be very weather proof. So has this been tried? It wouldn't surprise me if it has and i just didn't find it in my searching. If it has did it work? If not why not?

Share this post


Link to post
Share on other sites

Posted (edited)

Dean Wilson repaired the aileron hangers on my Dads A model using a fiber overlay method. Its been a few years ago but I believe he used carbon fiber

You have probably ran onto my last repair using Aluminum and scotchweld. A re-coat of spar varnish will be required every couple of years or when a person see it's needed during a preflight. A light sanding and coating takes no time at all and gives me a reason to give them all a good look over. 

:BC: 

Edited by NorthIdahoAvidflyer
spelling

Share this post


Link to post
Share on other sites

Posted

I did try that but still managed to break one so then used aluminum channel that I shaped.  In fairness I only used thin boat glass and 2 layers.  Getting thicker layers to make the sharp corners is a problem.  I'm not saying it is not a viable option just my experience. 

Share this post


Link to post
Share on other sites

Posted

Sounds like it would work to me. Like Paul said, you'll never get it to make the corners. I would just put a piece(s) on both sides. Matt would probably work better than cloth as it is multi directional. After you sanded it smooth, I would make sure to seal the ends with the epoxy. 

Share this post


Link to post
Share on other sites

Posted

Get rot is basically a real thin epoxy that will soak the wood and encapsulate it.  I have seen way too much rot with wood under fiberglass to be crazy about doing it that way.  Seal it up with a thin epoxy or spar varnish but keep it exposed so you can inspect it would be my thoughts on it.  

Just my .02 after having repaired many boat decks and stringers that are wood covered in glass.

:BC:

 

Share this post


Link to post
Share on other sites

Posted

I agree. How many fiberglass boats have u run across that r beautiful but not water worthy cause u stick a knife or a structure tool into it go thro the fiberglass and its all rotten wood inside.  I have a buddy that did that, he not happy about his $150,000 investment.  When he goes out in the water from Valdez and hits a wave the windows fall out cause wood is rotten 

Share this post


Link to post
Share on other sites

Posted (edited)

It can be done though. That is why I said to soak the "end" of the wood.

I have a mid 80's Checkmate that has an encapsulated balsa core. It is perfect. If you seal it up, you're good. The problems with stringers and transoms usually comes from not sealing them off properly when drilling holes to add accessories, motor mounts, etc.

That said, mine are in good shape and are painted and will remain that way.

Edited by Fly-n-Low

Share this post


Link to post
Share on other sites

Posted

Dean Wilson repaired the aileron hangers on my Dads A model using a fiber overlay method. Its been a few years ago but I believe he used carbon fiber

You have probably ran onto my last repair using Aluminum and scotchweld. A re-coat of spar varnish will be required every couple of years or when a person see it's needed during a preflight. A light sanding and coating takes no time at all and gives me a reason to give them all a good look over. 

:BC: 

Yeah I did see your post. You mentioned that you were going to bolt through the aluminum, do you have a picture of that?

Get rot is basically a real thin epoxy that will soak the wood and encapsulate it.  I have seen way too much rot with wood under fiberglass to be crazy about doing it that way.  Seal it up with a thin epoxy or spar varnish but keep it exposed so you can inspect it would be my thoughts on it.  

Just my .02 after having repaired many boat decks and stringers that are wood covered in glass.

:BC:

 

Good to know. Considering I'm not going to cut into the fabric to extend the reinforcement as far forward as possible that would allow a small area that rot could start at and work its way aft. 

Thanks for all the comments guys. 

Share this post


Link to post
Share on other sites

Posted

Willja67, Yes, i took the advice of the guy on here and added another bolt forward of the two regular mounting bolts . I have attached a picture marking the location of the added bolt. 

:BC:

 

 

 

Flaperon hinge.PNG

Share this post


Link to post
Share on other sites

Posted

Here is what i did with the bluefox, if thats any help,  i made my brakets, predrilled mount holes, then hysoled and rivited them onto the flaperon hanger totaly incloseing the outer wooden part with hysol, and then painted it all white. 

image.jpg

image.jpg

Share this post


Link to post
Share on other sites

Posted

Willja67, Yes, i took the advice of the guy on here and added another bolt forward of the two regular mounting bolts . I have attached a picture marking the location of the added bolt. 

:BC:

 

 

 

Flaperon hinge.PNG

thanks for , I'm guessing a 1/8" bolt? 

Here is what i did with the bluefox, if thats any help,  i made my brakets, predrilled mount holes, then hysoled and rivited them onto the flaperon hanger totaly incloseing the outer wooden part with hysol, and then painted it all white. 

image.jpg

image.jpg

Looks nice. Kinda wish I could do that but my wings are covered and I'm not cutting into them. 

I did have a thought while looking at these pics; what if you added something like a wing fence on the flaperons, or even end plates on the outboard ends? I know that the fences would add weight and you would have to rebalance the whole control surface so probably not practical but it seems like adding a end plate attached to the outboard hangar could reduce the tip vortex coming off the flaperon and either reduce drag or increase its effectiveness? But having full span flaperons the kitfox might already have enough roll?  Anyway just throwing that idea out there. 

Share this post


Link to post
Share on other sites

Posted

I hear u about not wanting to cut into the fabric on bottom of wing, but honestly ur best to cut into it, it took me 2dYs of contimplating to cut into the wings of my blackfox to update the hanger so b safe to fly.  Sure glad i did that, and u wil b also, and Oratex is a great way to repair ur fabric after u cut into them, it will glue down ontop of ur existing surface with a light scuffing with scotchbrite. I had better aircraft fabric send me some 24"x36" samples and they worked great. Just make them about 8" from tip back up into wing. Worked for me so far may work for u. 

Share this post


Link to post
Share on other sites

Posted

Hey Buckchop,

I understand you used Oratex to patch your non-oratex fabric system. What is your original fabric and paint? When you say "light scuffing" you mean just the top coat paint or did you go back to the sun barrier coat?

Thanks for your input

Share this post


Link to post
Share on other sites

Posted (edited)

Light scuffing of the polytone paint, not thro to any silver but if u do still no big deal, sand enough to get a bite into original surface, and goto it.  Oratex would also work good for emergency fabric repair kit to carry in ur plane, u could stick it down with a hot rock out of a campfire, i think.  But u cant let the glue freeze in winter if u forget to remove it from ur survival pack in the plane, or 100 mile an hr tape works to. Hahahahahaaaa

Edited by Buckchop

Share this post


Link to post
Share on other sites

Posted

I just reinforced my rib tails. You can see that I removed the cap strip immediately above the web of the rib. The lamentations of the wood provided a great depth gauge. Dremel with a rotary file for the edges then a grinding blade did the trick. I then ground down one side of a 3/16” X 7” titanium rod, epoxied it in the gouge extending to the end. I had fabricated aluminum by bending it in a “U” shape. I used a brake to bend it past 90, then put a rod on the bend and completed the “U” in a vise. It was fairly thin, not real sure about the gauge. My buddy had it leftover from his Titan. Making it slightly oversized, after the glue dries I’ll profile it to match. If a truck hits it it’ll probably fail, otherwise it ought to be pretty stout.

Wyatt

Hope the pictures show up, ain’t real good with this.

E05F9C1E-2530-4ABD-AADE-2324CDF3A0D6.thu

567AD638-8722-4535-97E9-018C48F6DDA1.jpeg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now