Spar repair

[waltermrich]

Re: Spar repair

Thanks for posting that is exactly as I did my repair , except that a router was used instead of a saw to make the cut in the spar, its spelled out in AC 43.13 and it looks just like mine, although I feathered out the plywood doublers where they ended.

Re: Spar repair

very cool!

looks like that original spar was laminated in the x and y plane

neat

Dave

[Dano"T"]

Re: Spar repair

I sliced the rear spar on my cub a couple years ago. The other end though. It was easy.

[IMG][/IMG]
[IMG][/IMG]
[IMG][/IMG]
[IMG][/IMG]
[IMG][/IMG]

Re: Spar repair

I removed the last 24 inches of the rear spar and used it as a template. What you need to do is make what is called a scarf joint , where you have an angle cut into the wood using a router template and a straight bit to cut an angle into the spar on the wing. The template makes a very even and accurate cut which will glue onto a spliced piece made with the same template made on a table.

Thanks Walt,

Dave.

[Hank Jarrett]

Re: Spar repair

If you have problems you can email the pics to someone in the Tribe and we will post them for you till we can get you the gouge on how to do it. Seems like a lot of other people have had minor problems the first time too, but I for one would really like to see how you did it. It is getting to be a lost art.

Hank

[waltermrich]

Re: Spar repair

I have never posted a photo on the Forum and have not yet attempted it but will try

[TimHicks]

Re: Spar repair

Walter,
Do you have any pictures that you can post here?

[waltermrich]

Re: Spar repair

I removed the last 24 inches of the rear spar and used it as a template. What you need to do is make what is called a scarf joint , where you have an angle cut into the wood using a router template and a straight bit to cut an angle into the spar on the wing. The template makes a very even and accurate cut which will glue onto a spliced piece made with the same template made on a table.

Re: Spar repair

Hi Walt,

How did you locate the holes for the fitting?

Seems difficult to do unless you remove the spar. Maybe you did that.

Would like to learn how its done.

Dave

[waltermrich]

Re: Spar repair

For those interested, I completed a spar splice on a rear spar near the butt end , using the procedures described in FAA 43.13 still to be inspected , but I will say to those who are nysayers to a splice I found it easy and a lot simpler than tearing down the wing completely, and the splice is a beautifull piece of wood work and a lot stronger than the original. Whish I knew how to do photos.

[waltermrich]

Re: Spar repair

All your comments are appreciated, Thanks for your input I have a lot to consider, will keep posted, By the way Do you have any more NOS Martin wire Drude

Re: Spar repair

Walter,

I recall that the t-craft stamped ribs are 3 piece and can be dissembled to remove the spar or part thereof. Maybe yours has stamped ribs?

Thinking about it though I would probably opt to replace the spar by removing all front thirds of the ribs, the leading edge, disconnecting the compression struts/ribs from the front spar then put a new spar in place.

Here's why. Its not because you can't splice. Its because to get the root fitting holes in the right spot I would end up taking out the spar and using it as a template on it to get good hole placement. But that becomes paradox to use it as a template to repair itself.

IMHO it would be more convenient to just buy a new spar and put it in because I would not actually have a template to use for the holes.

Does that explanation make sense to you Walt? I know you may not agree I am just asking did I adequately explain it.

Dave

[Joe cooper]

Re: Spar repair

I can say that I have never done a spar splice but I have many years of wood working experience, I can say I think it is do able with proper tooling and clamping, getting the wing cleaned up enough to accomplish a clear area to work around I would think would be the most involved. Removing all the parts of a wing, reassembly and trammeling would to me seem like much more work especially if the wing is otherwise good. Of course I want a new wing but i do not have 2 years to build one, do you know of a good one near Iowa (right).

I remember having the keelson of an e scow sailboat I once owned repaired by a master wood worker. It was as good as new. They take great stress. ( the newer ones are glass) with modern glue, etc. I would think one could repair it having experience. I can just barely run a chain saw so I'm little help. (E scows are more fun than a taylorcraft! Like a Chinese fire drill.) I'm sure, when t crafts were young many were repaired this way as money was scarce and they were a cheap trainer, prone to ground loops, etc. good luck.

[waltermrich]

Re: Spar repair

I can say that I have never done a spar splice but I have many years of wood working experience, I can say I think it is do able with proper tooling and clamping, getting the wing cleaned up enough to accomplish a clear area to work around I would think would be the most involved. Removing all the parts of a wing, reassembly and trammeling would to me seem like much more work especially if the wing is otherwise good. Of course I want a new wing but i do not have 2 years to build one, do you know of a good one near Iowa (right).

[3Dreaming]

Re: Spar repair

I would think it would be lot easier to remove 3 or 4 ribs to reach a broken part of a spar than to dissmantel an entire wing to replace a spar, wood when kept dry and in the right climate will last decades and decades .An expericened wood worker would have no problem creating a scarf joint that would be stronger than the spar itself.

Walter,
I don't think anyone is saying it can't or shouldn't be done. What they are saying is based on their experience working on airplanes that you would be better served replacing the spar instead of trying to splice it. I know that is what I would do. I think trying to make a splice on a spar that is still installed in the wing will be tougher than you think. I can't imagine trying to do precision machining on a spar that is still attached to the rest of the wing.