Warbird Information Exchange :: View topic - Switching to L-5 talk here

Ryan: The problem is the casien glue itself. It's a decent short term use glue...ie a planned life of a couple of years. Unfortunately, time and moisture can have a severe degrading effect on it and it's bond strength. The problem comes where you have joints that have not had the ideal life.....They have bene subjected to lots of hi-lo moisture cycles, lots of the same with temps and have been sujected to lots of trapped moisture. With all of this, the glue can significantly lose it's original bonded strength without having visual degredation.

With that said though, using modern, approved glues, there is the capability to build up new wings, tails, fins ect aithout too much difficulty. I know that Duncan Cameron in the Sentinel Club has been working on converting the microfilm drawings for the L-5 to Cad so that either router tooling can be made or it ported to a CNC router to make the big ribs. Probably the hardest part of building up a set of L-5 wings is the formed plywood sections in the leading and trailing edges and the plywood attach angles within the wing. Every thing else is straight forward standard wood consturction.

I've got one NOS wing for mine that had the cover pulled off when I bought it. It spend almost it's entire life in the top of a hangar, covered with a couple of cotton sheets and it looks like it came out of the wood shop yesterday. Will I install it and fly on it.....I just don't know. Since I have to build up the opposite wing, I'll probably go on and build one for that side too as most parts are mirror images. I need to dig though all my wing hardware and see what I have for compression ribs and tanks straps and from there I will decide which wing version to build up.

BTW... you need to do a long cross country up here and come visit our L-5 playground..hopefully before Taylor moves his to near his school and when Dan Linn is freed to play...

Author:	RyanShort1 [ Fri Feb 12, 2010 8:37 am ]
Post subject:	Switching to L-5 talk here
I'm snipping this from another thread so we can keep it on topic here. Cvairwerks wrote: Ryan: The problem is the casien glue itself. It's a decent short term use glue...ie a planned life of a couple of years. Unfortunately, time and moisture can have a severe degrading effect on it and it's bond strength. The problem comes where you have joints that have not had the ideal life.....They have bene subjected to lots of hi-lo moisture cycles, lots of the same with temps and have been sujected to lots of trapped moisture. With all of this, the glue can significantly lose it's original bonded strength without having visual degredation. With that said though, using modern, approved glues, there is the capability to build up new wings, tails, fins ect aithout too much difficulty. I know that Duncan Cameron in the Sentinel Club has been working on converting the microfilm drawings for the L-5 to Cad so that either router tooling can be made or it ported to a CNC router to make the big ribs. Probably the hardest part of building up a set of L-5 wings is the formed plywood sections in the leading and trailing edges and the plywood attach angles within the wing. Every thing else is straight forward standard wood consturction. I've got one NOS wing for mine that had the cover pulled off when I bought it. It spend almost it's entire life in the top of a hangar, covered with a couple of cotton sheets and it looks like it came out of the wood shop yesterday. Will I install it and fly on it.....I just don't know. Since I have to build up the opposite wing, I'll probably go on and build one for that side too as most parts are mirror images. I need to dig though all my wing hardware and see what I have for compression ribs and tanks straps and from there I will decide which wing version to build up. BTW... you need to do a long cross country up here and come visit our L-5 playground..hopefully before Taylor moves his to near his school and when Dan Linn is freed to play... So, if I'm flying an L-5 that hasn't been recovered in 20 years, is that a possible safety issue? How does one inspect for this? Also, if I was interested in an L-5 that had been stored in a hangar for a while and seemed to be in good condition, could we talk about uh-ohs and how to tell if it's really going to be an OK deal? Maybe this is a phone conversation thing... If so, I'll PM you my number. I'd really like to do a long cross-country in the squadron's L-5 and come up to see you guys, but I need to get my renters insurance re-instated first (soon - haven't had the money for a few months as a CFI) as it's required for squadron aircraft. Ryan

Author:	Cvairwerks [ Fri Feb 12, 2010 9:18 am ]
Post subject:	Re: Switching to L-5 talk here
Ryan: My personal feeling are that wings and tails that have been covered for that long are suspect and need to be opened up. I'm also probably a lot more conservative than other people too.... There are two main spots in the L-5 wing. One is behind the fuel tank. It's problem is the possibility of trapped moisture in that bay and the start of rot. It's one of the few areas per the SRM that no repairs are allowed. The other is around the strut fittings. There again you have the possibility of moisture again and the ensuing problems. The only other bad area that I can think of right offhand is the lower longerons around the tailwheel and two bays forward. They can collect moisture and gunk as they are the lowest spots on the fuselage when parked. Depending on which model you are looking at, that will tell you how easy it is to inspect the area. An ambulance model is way easier as you can practically crawl down inside and look at it all. It's probably easier to show you all the little things on one or two of the ones opened up at the shop. My fuselage is down there all bare and the wings are over in my warehouse nearby. As to coming down, it's probably just as easy and as cheap to jump on Southwest and pop up to Love. I can run over there via road and pick you up without any problem. We just need to plan ahead a little so as to make sure that Lanny is going to be there and that I don't schedule to work that Saturday. We do our overtime schedule for Friday/Saturday night on Tuesday nights, so that give you an idea of my scheduling needs.

Author:	RyanShort1 [ Fri Feb 12, 2010 9:39 am ]
Post subject:	Re: Switching to L-5 talk here
At the rate the squadron charges for the L-5 it might be worth the effort to get one other guy to hop in the back seat and split the costs on a quick trip up there. That way you'd also get to see one of the birds I'm talking about. I'll look into it. Also, ya'll are invited for our "L-bird" gathering on April 17th. We're think we'll have 3-6 L-5 vets present if all can attend! Ryan

Author:	bdk [ Fri Feb 12, 2010 4:26 pm ]
Post subject:	Re: Switching to L-5 talk here
My experience is that it is the fabric that holds an L-5's wings and tail together. If you don't belive me, pull the fabric off and most of the skin (like the leading edges) may come with it. Also, cotton fabric is very hard to remove from the plywood after all those years. That being said, I've never heard of an L-5 wing failing in flight. I think that many, if not most L-5s are flying with mostly original wood and glue joints.

Author:	N3Njeff [ Fri Feb 12, 2010 4:41 pm ]
Post subject:	Re: Switching to L-5 talk here
bdk wrote: My experience is that it is the fabric that holds an L-5's wings and tail together. If you don't belive me, pull the fabric off and most of the skin (like the leading edges) may come with it. Also, cotton fabric is very hard to remove from the plywood after all those years. That being said, I've never heard of an L-5 wing failing in flight. I think that many, if not most L-5s are flying with mostly original wood and glue joints. Apparently that is the feeling among the L5 community. I know the cad plans have been in the works for a few years now and the plan was to produce wing kits. This would be a great thing for the L5. I know that many of the PT guys are doing extensive rebuilds and are in the works using approved epoxies of today. I have been very impressed with what I have seen from the PT guys. Eventually at some point, the L5 community will need to follow suit. I am interested in hearing from taylor on how extensive they got into the wood work and if they found any issues.

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Author:	RyanShort1 [ Fri Feb 12, 2010 4:47 pm ]
Post subject:	Re: Switching to L-5 talk here
bdk wrote: That being said, I've never heard of an L-5 wing failing in flight. I think that many, if not most L-5s are flying with mostly original wood and glue joints. Me either, but I wouldn't want to be the first! Ryan

Author:	Taylor Stevenson [ Tue Mar 02, 2010 3:02 pm ]
Post subject:	Re: Switching to L-5 talk here
Ryan, I'd hesitate to fly an L-5 that hasen't been opened up in 20 years. If it's a later model it probably has the resorcinol (sp?) glue wings (a blackish looking glue) that are usually good after 60 years. We did very little repair to my wings as they were resorcinol and sturdy as heck, but for a covered bird with questionable history, I'd do some mighty detailed inspection. Like Cvair, I'm pretty conservative about safety issues though. By the way, you really do need to come up sometime. I'll have the L-5 in Nashville until the summer, so hopefully I can fly down to Stinson and visit ya'll then. Taylor

Author:	wacoykc [ Tue Mar 02, 2010 11:02 pm ]
Post subject:	Re: Switching to L-5 talk here
But then we come back to the age old question of who is signing off the airplanes with the modern epoxy glue? Only a few field approvals have been given as far as I know.

Author:	Avn-Tech [ Wed Mar 03, 2010 2:21 am ]
Post subject:	Re: Switching to L-5 talk here
Group, The glue issue has come up and been addressed by SOPA (Jim Gray) a couple of years ago. As I remember, the FAA has not authorized the use of different glues. No one at the FAA wants to stick their neck out and authorize use of modern products. So we are stuck using 50+ year old technology. ALso if I remember correct, someone is working on new wings (poss, already flying in Australia). I have talked to Jim about building Aluminum wings (Like Citebrea does) to retrofit the L-5 fleet. Jim told me that the L-5 was originally designed with metal wings. but the wings were redesigned, due to the wartime shortage of metal. Unfortunatly I have been busy, and have not been able to work on restoring my L-5 (I have 3). Laterrrrrrrr Avn-Tech

Author:	N3Njeff [ Wed Mar 03, 2010 5:57 am ]
Post subject:	Re: Switching to L-5 talk here
Well someone is doing it as there are PT's out there now that have 337's approved for THE WEST system.

Author:	wacoykc [ Fri Mar 05, 2010 1:35 pm ]
Post subject:	Re: Switching to L-5 talk here
And I think these are all one time deals. There have been a few other antiques done with the West system as well.

Author:	N3Njeff [ Fri Mar 05, 2010 3:47 pm ]
Post subject:	Re: Switching to L-5 talk here
wacoykc wrote: And I think these are all one time deals. There have been a few other antiques done with the West system as well. Thing of it is. My friend asked around the PT guys and one has did his wings with 337's and he made copies of his paperwork for him....................if done once, can be done again. Just the simple fact that there are people (FAA) that are out there that are willing to work with us.

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