Scarf joints on wood spars

A

aalexander

New member
I started peeling fabric off of my wings (1972 7ECA) and i was a bit surprised to discover that the rear spar had 2 scarf joints in it. It appears that it came that way from the factory. There is no record of a repair to the spar (there was some damage to the wing but the log entry only mentions replacing 2 ribs and recovering. The joints seem to be well done, and it looks like the the original finish. It the joints were done after the plane left the factory, the spar would have had to have been completely removed and completely refininshed, and as far as I can tell, except for the repaired portion, the wing has the original covering. This has me scratching my head, why would bellanca build a wing with not one, but 2 scarf joints?

Also, the joints are just the scarf joints, nothing else. As far as I can tell from reading 43-13 (and I may not be reading correctly) a splice on a rectangular spar requires a doubler on each side of the joint.

Are these legal splices, or am I reading too much into 43-13.

Any advice is appreciated,

thanks Andrew
 
These were probably factory splices. They differ from the 43.13 because the factory was able to approve this type of manufacturing during certification. I belive there is a disclaimer in the service manual about this style of construction.
Paul
 
Yes, Factory rules on spar construction differ from 43.13.
In fact you make a spar our of 6-7 little pieces of wood if it works out right.

Just remember that 43.13 is meant to error on the conservative side.
 
jerrymjr said:
Yes, Factory rules on spar construction differ from 43.13.
In fact you make a spar our of 6-7 little pieces of wood if it works out right.

Just remember that 43.13 is meant to error on the conservative side.
Click to expand...

I'm seeing that. Now that I have all the fabric off the wings, all the spars have at least 1 scarf joint, one has 3 joints.

THanks for the feedback.
 
Let me tell you, it could be a hell of a lot worse. email me if you want to know how some know it all SOB can make it inpossible to get anyone to inspect your plane, even if there is nothing wrong with it.

info [AT] stiglerparts [DOT] com


Matt
 
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