N6579N
- Thread starter Dover
- Start date
The cracks are in the butt end of the spar. Otherwise the rest of the wood inspection was good. They are due to being in a very arid climate for most of its life. Just a little over 2000 hours total time. Always hangared. Last recover was done in ‘75 in Razorback.
Too bad I can’t inject some gorilla glue into the cracks. Any recommendations for a wood worker? Anybody have a set of drawings for the 14-19 wings? Not sure if I’m willing to spend the money on the wing rebuild.
Serial number 2032. Built in February 1950.
Too bad I can’t inject some gorilla glue into the cracks. Any recommendations for a wood worker? Anybody have a set of drawings for the 14-19 wings? Not sure if I’m willing to spend the money on the wing rebuild.
Serial number 2032. Built in February 1950.
Rob58
Moderator
Dover... I have seen spars with worse cracks still considered airworthy. Virtually every spar has some degree of cracking at the butt end. There are guidelines for determining what is and is not airworthy. The more serious problem that can affect a spar is wood rot, which you do not mention and is unlikely if the aircraft has been well cared for as you say. My belief is that your spars can be repaired and the ends sealed to prevent further problems. Before doing anything further you should take the following actions:
1. Obtain and read Bellanca service bulletin 87A and engineering study 838 which addresses the spar issue similar to what you are reporting. I think this will help you feel better about the condition you have.
2. Send a series of detailed pictures to Randy at AAC, Dave Pasquale, and Dan Torrey. You might send to all of them and then benefit from their collective responses. Note, I try to compensate these guys for their time whenever possible.
Do the research first, then decide on the fate of your aircraft... Rob
1. Obtain and read Bellanca service bulletin 87A and engineering study 838 which addresses the spar issue similar to what you are reporting. I think this will help you feel better about the condition you have.
2. Send a series of detailed pictures to Randy at AAC, Dave Pasquale, and Dan Torrey. You might send to all of them and then benefit from their collective responses. Note, I try to compensate these guys for their time whenever possible.
Do the research first, then decide on the fate of your aircraft... Rob
Just saw the post by Rob as I was typing. Good points. Here are some thoughts of my own.
I am not an expert on this spar butt cracking. However, it has a long history.
Back in the '50's there was a swarm of Bellancas in Southern California, particularly at Torrance Airport. There was also a sizable group of Bellanca gurus which included the ringleader, Slim Kidwell, who was the Bellanca dealer at Torrance. They devised many of the minor mods to overcome this or that deficiency with the factory product.
One of the things they tended to was the spar "checking" problem, which was evident even then. It was addressed by filling the checks with glue and plating over the butt with plywood. My 14-13 had been serviced that way, probably during the rebuild at Northrup School during that era.
I never saw it done, but if I recall the explanation correctly, there was a plate fastened to the spar and glue was pumped in, being careful not to hydraulic the cracks further. Other techniques come to mind. Maybe some way could be devised to vacuum bag the area to fill the cracks. It is my opinion that ALL wood wing Bellancas have at least some spar butt checks.
The cross grain strength of wood is very low, and Giuseppe knew it. That is why the spar straps at the wing butt are slanted to a point midwing. This nearly nulls out the shear force of the spar at the root during flight, so very little shear strength is needed. And shear strength is what is mostly involved with spar butt checks. So, any resorcinol or epoxy ought to work to regain any structural stability lost and prevent further propagation of cracks.
I think the go/no-go for spar butt check repair is that cracks may not extended horizontally in or near the bolt holes. And of course, the wood must not be compromised by decay, etc.
I am not an expert on this spar butt cracking. However, it has a long history.
Back in the '50's there was a swarm of Bellancas in Southern California, particularly at Torrance Airport. There was also a sizable group of Bellanca gurus which included the ringleader, Slim Kidwell, who was the Bellanca dealer at Torrance. They devised many of the minor mods to overcome this or that deficiency with the factory product.
One of the things they tended to was the spar "checking" problem, which was evident even then. It was addressed by filling the checks with glue and plating over the butt with plywood. My 14-13 had been serviced that way, probably during the rebuild at Northrup School during that era.
I never saw it done, but if I recall the explanation correctly, there was a plate fastened to the spar and glue was pumped in, being careful not to hydraulic the cracks further. Other techniques come to mind. Maybe some way could be devised to vacuum bag the area to fill the cracks. It is my opinion that ALL wood wing Bellancas have at least some spar butt checks.
The cross grain strength of wood is very low, and Giuseppe knew it. That is why the spar straps at the wing butt are slanted to a point midwing. This nearly nulls out the shear force of the spar at the root during flight, so very little shear strength is needed. And shear strength is what is mostly involved with spar butt checks. So, any resorcinol or epoxy ought to work to regain any structural stability lost and prevent further propagation of cracks.
I think the go/no-go for spar butt check repair is that cracks may not extended horizontally in or near the bolt holes. And of course, the wood must not be compromised by decay, etc.
The ones on mine has been what looks like an epoxy or fiberglass resin was used to seal them up, the parts plane had what looked like a thick tar or rubber base on it?? Any piece of wood that has been cut and left in the weather will crack at the ends, if you go to saw mills they will paint the end of a log to stop this.
Upon closer inspection we have determined that the repairs listed in the service letter will work on the right wing. However, the rear spar of the left wing the crack goes through to the third hole inboard. Sent pics and info to Randy at AAC and am awaiting guidance.
Who can y’all recommend to do the wood spar repairs?
Thanks
Ben
Who can y’all recommend to do the wood spar repairs?
Thanks
Ben
Dan Cullman
New member
I've seen wings that were repaired at "the factory."
Update
Wings sent to Alexandria. Inspected and all four spars are way out of tolerance due to butt end not being properly sealed and age.
So I’m looking for serviceable wings. Randy has a set but tied up legally.
Or sell the project
Less than 100 SMOH on 2000 TT engine
6 months since AD on prop
2000 hour airframe
Firewall forward is pretty
New leather doe skin interior
Thanks
Wings sent to Alexandria. Inspected and all four spars are way out of tolerance due to butt end not being properly sealed and age.
So I’m looking for serviceable wings. Randy has a set but tied up legally.
Or sell the project
Less than 100 SMOH on 2000 TT engine
6 months since AD on prop
2000 hour airframe
Firewall forward is pretty
New leather doe skin interior
Thanks
Dan Cullman
New member
You've gone this far with the project. Have the wing shop at AEX repair your wings.
Rob58
Moderator
How about posting some pictures of the rest of your plane? Regarding your go-forward plan the decision is: spend a lot of money and have a nice, safe, classic aircraft... or cut your losses and recover maybe 5K. Dan's suggestion is the way to go, the wing shop in Alexandria provides a high quality rebuild, but it's an expensive process. Did they already give you a quote?