Repairing Crushed Composites?

[CSpaced]

Unfortunately I had a mishap yesterday and my composite Edge has been damaged. I had a dead stick and panicked resulting in the airplane coming in too fast and toppling over at the end of the runway. It flipped tail over nose and broked the rudder, and the fuselage received some damage along the left side of the turtle deck. From just behind the front of the turtle deck to about 6 to 8 inches back and from the top of the turtle deck down the left side towards the belly pan it got crushed. The outside and inside skins are fine (doesn't even look damaged) but the foam on the inside is destroyed.

Soooo, I've never repaired a composite before so any info you guys can give me on it would be greatly appreciated. Can it be repaired or should I try to locate a new fuse?

Thanks!
Chris.

[eagle1]

got pics?

[CSpaced]

Not yet, but I can go take some. You can't really see any damage but I'll see what I can do.

[eagle1]

what did on mine is to cut out what is crushed and add some laminated 3/ 32 balsa(laminated with 1/3oz cloth then glassed that in on inside letting the resin seep in the cracks sand thin paint.

[CSpaced]

Thanks for the tips eagle.

In lieu of some photos (which didn't show up anything) here is a brief video.

[Colonel Klank]

My Comp Super Extra got stepped on behind the canopy. We just used carbon fiber cloth and premium epoxy resin. We did a criss-cross pattern and it is ten times stronger than new and only added a few ounces of weight.
Since the airframe is seven years old, we did not do any cosmetic work on the outside except for a few well-placed decals.

Sorry no pics of the inside.

Good Luck!

The Colonel

[CSpaced]

	Quote: Originally Posted by Colonel Klank
	My Comp Super Extra got stepped on behind the canopy. We just used carbon fiber cloth and premium epoxy resin. We did a criss-cross pattern and it is ten time stronger than new and only added a few ounces of weight. Since the airframe is seven years old, we did not do any cosmetic work on the outside except for a few well-placed decals. Sorry no pics of the inside. Good Luck! The Colonel

Was it (or would it be) just enough to reinforce it on the inside, or did you lay down cloth on the outside too?

[rdgood]

Chris - Was there any damage futher back???

I am thinking if that's it - You might be able to do inner layup.

I have done similar layups with west systems and carbon fabric before and had very good results. The biggest problem is getting in there and getting the mold release off of the inside and roughing and preparing the inner surface to adhere to the resin and cloth.
Since it delamed it may mean taking off some paint and having it repainted maybe?? Kinda hard to tell since I am not seeing it in real life..

Bare in mind - I am no composite expert ..
I am sure there will be varying opinions on this particular repair.
It does look repairable though - IMO...

Hope this helps -

Ronster

[Colonel Klank]

	Quote: Originally Posted by CSpaced
	Was it (or would it be) just enough to reinforce it on the inside, or did you lay down cloth on the outside too?

We just put cloth on the inside. Rough up the surface real good before laying it up. This gives the resin something to grip on to. Of course, we straigtened up the cracks before getting to the cloth and resin.

It is waaaaay stronger than the original structure.

[Vic3D]

Dang Chris I don't have any suggestions because I dunno anything about composite materials, but that sure sounds uglier than it looks.

[CSpaced]

Thanks for the help guys, Vic - yeah it sounds pretty nasty!

[CSpaced]

	Quote: Originally Posted by rdgood
	Chris - Was there any damage futher back???

There was no damage further back than what I showed in the vid. Other than that one spot the fuse is in perfect shape.

[eagle1]

I used heavy cloth not weave on the inside of my 2.6m that I pancaked to repair the bottm just in front of the landing gear mount, same glass you would buy at autozone,(bondo brand) should be enough to repair your damage.just laminate the inside.if the glass is seperated from the foam remove it with a exacto knife just try to keep the foam in tack, I also ca'd the spots that I could to help hold in place until the resin dried,also bondo brand. works great.

[Tired Old Man]

The trick to a good composite repair is pressure. You need to be able to apply pressure to the carbon to get it as thin as it can be, which is pretty thin for one layer.

The outside can be repaired using a layer of 12 ounce uni directional carbon with pieces of wax paper over it, with a good tape used for pressure over the carbon. When you start the carbon repair get the carbon as wet with epoxy on both sides as you can and squeege out excess epoxy. For patch work I like to lay down a piece of wax paper on the bench, apply epoxy to the wax paper, lay the cloth in the epoxy with a piece of wax paper over the cloth, push the epoxy through the carbon, then flip the carbon and wet it again. Carbon must be wet all the way through for the best strength. Once the carbon is completely wetted what you squeege out is not needed.

The inside gets a little tougher. Best would be to obtain some styrofoam blocks you can cut and sand to the inside shape of the fuse. Do the same as the outside with the carbon and wax paper or saran wrap and use the styrofoam shape as a pressure source. Takes time but works well. Make your patch about an inch larger overall than the damaged area.

Make sure you rough sand the damaged area and clean it all with alcohol before doing the patch!!

If you used enough pressure the new layers of carbon will blend into the original with very little edging. A little spot putty at the edges will blend the edges.

Wear three or four layers of surgical gloves so you can remove a layer every time they get fouled with epoxy. That keeps the rest of your plane free of epoxy smudges. Sweaty but sure saves a lot of clean up later. I like to use System 3 epoxy materials but everyone has their own preference. Have everything ready to go before you mix any resin. Once it's mixed the clock is ticking and there's no looking back. That includes having paper towels and alcohol for quick clean up wiping at your fingertips.

[BillJ]

I just finished work on two Comp ARfs with crush problems... Lots of good info has already been stated.. If their aren't any breaks...glass on the inside with some 2 oz ribbon and some WEST SYSTEMS epoxy... I used wax paper over my repair to smooth things down... Now on the outside if you've got those long fishers that kind of look like a mole ran up and down your fuse...I roughed mine up with sand paper...You may find the top layer of glass/paint peeling off...But then filled back in with WEST SYSTEMS and micro balloons...Put a wax paper cover taped on...Sanded when dried... Any other holes in the repair got the BONDO ( Evercoat Poly Flex ) and prep for paint....