Taylorcraft BC12-D ZS-BLD.
When I stripped the fabric off the wing to inspect the wood spars, I was VERY surprized to find a crack in the read spar between the wingroot attatch and the jury strut mound.
Not only was it a crack at 90 deg to the grain but also it seemed to be an old crack .
Strangely the aircraft flew like this it seems for many, many years
( I have had the same thing in the same place on the rear spar of an Aeronca 11 AC I rebuilt in NSPT, weird!)The only option really was to do a splice repair to the spar and some Spruce was imported for the job. What made this job difficult was that I had to do the splice with the spar still inside the wing.
Many folks think that the joint like that will not be as strong as a one piece spar, but if done acording to the AC-43 standards it will surpass the original spar. That is why I put the plywood on either side of the joint (because the book said so!
) even though the factory spars had simple splices less the end plates.This splice was rather tricky in the sense that the spars have no adjustment at-all on the struts or the root mounds. If I was out by just a few mm in length of the new spar it would affect the sweep and maybe the incidence , this was in the back of my mind the whole time.
Lucky for me I managed to get the length to the nearest 0.5mm........I recon that will be OK
Interestingly the front spar looked very nice still and had a 1942 stamp on the wood!
I will be installing the new supplied leading edge plates. I also stripped the wing to a bare kit and had every metal bracket, compresion strut and drag wire bead blasted ,primed and painted with 2k.
Fabric on this is PolliFiber as on the tail already completred.
We had to wait for Butt-rib be manufactured locally and this kept the project back a few months, they are now complete and hopefully the wings can now be finally assembled ready for fabric.
Theuns
