Composite materials on LSA

Talk about airplanes! At last count, there are 39 (and growing) FAA certificated S-LSA (special light sport aircraft). These are factory-built ready to fly airplanes. If you can't afford a factory-built LSA, consider buying an E-LSA kit (experimental LSA - up to 99% complete).

Moderator: drseti

Nomore767
Posts: 853
Joined: Fri Jan 18, 2013 8:30 pm

Composite materials on LSA

Postby Nomore767 » Fri Sep 18, 2015 10:32 am

Yesterday I was looking around a shared hangar and noticed a nice Lancair. I noticed it has a good sized crack in the composite material midway along the left leading edge which had been covered with a good sized piece of duct tape. I don't know if this is the approved 'temporary fix' or what.

I started thinking about my own experiences with LSAs (and GA airplanes) that use composite and wondered how prone are they to these kind of cracks and what's the down-time and cost to repair? How easy is it to get someone qualified to repair something like this?

I have flown a CTLS with a crack at the corner of the baggage door, and a Remos with a cracked wing-tip. From talking to the school the Remos was going to be down quite a while whilst they communicated with Remos in Germany, which was a slow and frustrating process. The CTLS ended up sitting in the hangar a few weeks waiting the repair.
I looked at a Tecnam which had both metal wings and a composite fuselage. It was the heaviest of the LSAs I've flown.

I have an all metal RV-12, which does have fibre-glass wheel pants and top and lower engine cowling. I believe if I had the same crack in the leading edge as the Lancair mentioned above, they could drill out a panel, order a new one from Vans and install. The hardest part might just be getting the paint matched and finished. Still not cheap or a quick fix. but possibly quicker than with composite? I don't know.

I think composite is really good and of course the finish is really nice. Glasiar's new Merlin SLSA is basically a fixed Skycatcher but using all composite instead of metal.
Whilst composite is strong and supposedly lighter weight my all metal RV comes in about a 100lbs plus lighter in empty weight versus say a CTLS and more for a CTLSi, yet the Remos weight is about the same.

So what's the advantage of composite use in LSAs, and other GA airplanes? Over metal and even fabric. Cost, weight, strength?

Seeing this nice plane in the hangar with a wing crack got me thinking.

3Dreaming
Posts: 1984
Joined: Sun Jan 10, 2010 6:13 pm
Location: noble, IL USA

Re: Composite materials on LSA

Postby 3Dreaming » Fri Sep 18, 2015 12:09 pm

There are several advantages to composites. The ability to have nice smooth surfaces, and the ease of molding compound curves. With carbon fiber you have a strength to weight advantage over metal.

I have training in both composite and sheet metal repair. The process is different between the two. With metal you can work through start to finish. With composite you work in steps with curing time in between. I think composite repair is easier in a lot of cases.

SportPilot
Posts: 1060
Joined: Mon Aug 25, 2014 3:39 pm

Re: Composite materials on LSA

Postby SportPilot » Fri Sep 18, 2015 12:18 pm

.......
Last edited by SportPilot on Sun Mar 20, 2016 7:49 pm, edited 1 time in total.

User avatar
MrMorden
Posts: 1733
Joined: Fri Aug 17, 2012 7:28 am
Location: Athens, GA

Re: Composite materials on LSA

Postby MrMorden » Fri Sep 18, 2015 12:21 pm

The CTLSi uses advanced carbon fiber technology that is far superior to the ancient sheet metal and rivet dinosaurs of the past...

Oh wow, I think I was possessed by "someone else" there for a minute, but I'm better now. :lol: 8)
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA

User avatar
MrMorden
Posts: 1733
Joined: Fri Aug 17, 2012 7:28 am
Location: Athens, GA

Re: Composite materials on LSA

Postby MrMorden » Fri Sep 18, 2015 12:28 pm

Were the cracks you noted real cracks in the composite, or just in the gelcoat/paint? My plane has a few gelcoat cracks, particularly around the right side door. None are composite cracks and have no structural implications. They are just ugly. :)

The composite v. metal debate comes down to which set of pros you like better:

composite pros:

* lighter (carbon fiber...fiberglass often heavier)

* more complex shapes easily made

* sometimes less drag depending on construction


metal pros:

* cheaper to repair

* better understood by the mechanic community

* more weather durable


It's just a matter of "pick your poison". No material is perfect. I didn't even include cloth and metal frame construction, which has its own pros & cons. I would prefer conventional metal construction, but obviously I'm not afraid of composite planes since I own one. :)
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA

Nomore767
Posts: 853
Joined: Fri Jan 18, 2013 8:30 pm

Re: Composite materials on LSA

Postby Nomore767 » Fri Sep 18, 2015 12:49 pm

The crack I saw was a definite crack, as in a 'black line' rather than a chip in the finish. Someone had put duct tape along and pressed hard such that you could still see the contours of the crack itself.

If you're the owner of an LSA built mostly (or completely) of composite how would you handle a situation of having a significant crack appear? Apart from being a PITA how would you proceed with it and what would you you estimate (roughly) the down time and cost to be?
Would it have to go back to the dealer?

Are nicks in the surface coating fairly easily repaired and would you still need the same guy to fix that as you would a full on crack?

For cosmetic chips and nicks you wouldn't put duct tape on it right? Is there ever an approved repair albeit temporary which would require duct tape?

User avatar
MrMorden
Posts: 1733
Joined: Fri Aug 17, 2012 7:28 am
Location: Athens, GA

Re: Composite materials on LSA

Postby MrMorden » Fri Sep 18, 2015 1:00 pm

Nomore767 wrote:The crack I saw was a definite crack, as in a 'black line' rather than a chip in the finish. Someone had put duct tape along and pressed hard such that you could still see the contours of the crack itself.

If you're the owner of an LSA built mostly (or completely) of composite how would you handle a situation of having a significant crack appear? Apart from being a PITA how would you proceed with it and what would you you estimate (roughly) the down time and cost to be?
Would it have to go back to the dealer?

Are nicks in the surface coating fairly easily repaired and would you still need the same guy to fix that as you would a full on crack?

For cosmetic chips and nicks you wouldn't put duct tape on it right? Is there ever an approved repair albeit temporary which would require duct tape?


I think I'd find a composite-savvy A&P to inspect it. If they said it needed repair, I'd either let them do it or get it to a specialty composite shop. I know some boat shops have composite expertise in fiberglass and carbon fiber. No matter who repaired it, you'd need an A&P sign off in the logbook. Cost would depend on the nature of the crack; a small non structural crack might be a couple of hundred bucks, a crack along a major structural area could run thousands easily...
Andy Walker
Athens, GA
Sport Pilot ASEL, LSRI
2007 Flight Design CTSW E-LSA


Return to “Light Sport Aircraft”

Who is online

Users browsing this forum: Google Adsense [Bot], rcpilot and 2 guests