XL FRONT SPAR PLYWOOD

[Jim B]

All
I am working on my front spars for an XL and looking for some advice.  The plans call for 1/8" ply on both sides top to bottom to cover the 3/4" solid wood filler and then more 1/8" ply where the wing to fuselage metal bolts to the spar.  If that is correct then the first 2 ribs on the root would have to be cut 1/8" shorter (taken from the front vertical) than the rest of the ribs to ensure alignment at the trailing edge. The additional ply for the wing attachment  and metal attachment bracket will require another 1/4" cut out of the  vertical on the 2 front  ribs.  Now for my question, am I correct in my logic or is there no additional ply on the back of the front spar?
Thanks Jim

[Bob S.]

Sounds about right... the way my wing fir together on my original Legal Eagle, I even put another 1/8" piece on one side front & back so the wing aligned with no stagger... And had to move that vertical quite a bit! And notched out for the attachment plate....

[JTMaze]

Take a looks at Ken's builder log. He put an extra 1/4 vertical at the wing bracket areas.

[Tom XL-7]

yes there are 1/8" pads under all wing fittings ( not full spar, just under ) and they will interfere with the root ribs.
Four of my ribs will have double forward verticle sticks. To be modified later to fit pad and steel fitting.
This should amount to no more than cutting part of the front verticle away, leaving it top and bottom and the second verticle well attached under the gussets( may require light sanding)
The rear pocket will need relief as well. Both sides treated the same way.
Many make all ribs the same then perform a more involved cut and patch operation.
Tom XL-7

[JTMaze]

I’m about a third done with my ribs. I have a little over a 1/32” gap for the rear spar to slide through. This may seem like a dumb question but how in the world do I get epoxy on both the vertical and spar? Do I just put epoxy on the spar and slide the rib over it?

[Tom XL-7]

perhaps a syring would assist in a clean application
hope the link works
they are a buck each but you can be ready - ribs located and clamps at ready  
tom xl-7



https://www.amazon.com/Industrial-Syringe-14GA-Blunt-Needle/dp/B01CKN4HAS/ref=sr_1_19?s=industrial&ie=UTF8&qid=1469731689&sr=1-19&keywords=syringes+epoxy

[Darren C]

I’m about a third done with my ribs. I have a little over a 1/32” gap for the rear spar to slide through. This may seem like a dumb question but how in the world do I get epoxy on both the vertical and spar? Do I just put epoxy on the spar and slide the rib over it?

I had a 1/16" gap between the rear spar and ribs and made 'spacers' from left over timber which were then epoxied in to fill the gap.
The gap was too big to fill with straight epoxy which by itself has nowhere near the strength of the timber/epoxy lamination.

Can see the photos here 

http://www.mykitlog.com/users/display_log.php?user=ontherun&project=2554&category=0&log=226014&row=56

Darren

[Darren C]

All
I am working on my front spars for an XL and looking for some advice.  The plans call for 1/8" ply on both sides top to bottom to cover the 3/4" solid wood filler and then more 1/8" ply where the wing to fuselage metal bolts to the spar.  If that is correct then the first 2 ribs on the root would have to be cut 1/8" shorter (taken from the front vertical) than the rest of the ribs to ensure alignment at the trailing edge. The additional ply for the wing attachment  and metal attachment bracket will require another 1/4" cut out of the  vertical on the 2 front  ribs.  Now for my question, am I correct in my logic or is there no additional ply on the back of the front spar?
Thanks Jim

Hi Jim.

Here are a few photos of what Tom explained.  I build all my ribs the same and then went back and retrofitted 4.

http://www.mykitlog.com/users/display_log.php?user=ontherun&project=2554&category=0&log=224796&row=68

http://www.mykitlog.com/users/display_log.php?user=ontherun&project=2554&category=0&log=226328&row=50

Here's a tip.  Hang off on fitting the 1/8" ply to the both sides of the 3/4" solid wood filler until "after" you have slid all the ribs onto the rear spar or else you will be unable to slide them past that point.

Darren.

[Jim B]

All
Thanks for your advice.  I will add the ply to the back of the spar and put Darren's tip to use on my wings.
Jim

[914pete]

I’m about a third done with my ribs. I have a little over a 1/32” gap for the rear spar to slide through. This may seem like a dumb question but how in the world do I get epoxy on both the vertical and spar? Do I just put epoxy on the spar and slide the rib over it?

I had a 1/16" gap between the rear spar and ribs and made 'spacers' from left over timber which were then epoxied in to fill the gap.
The gap was too big to fill with straight epoxy which by itself has nowhere near the strength of the timber/epoxy lamination.

Can see the photos here  

http://www.mykitlog.com/users/display_log.php?user=ontherun&project=2554&category=0&log=226014&row=56

Darren

Darren, was that rib jig made with a router?

[Darren C]

The rib jig was made with a router. 
An extra set of rib plans were printed for the job and taped in place on the particle board. 
The top curved channel was done first just to be sure I got it right in case it had to be done again.  A piece of 1/4" x 1/4"spruce was bent over timber blocks screwed into the particle board a few inches below the desired cut.  This distance was the gap between the router bit and the edge of the guide fence.  No ruler necessary.  I lined the router bit up to the exact point on the plan, put a piece of 1/4" x 1/4" beside the fence and then screwed a block in beside that.  Did this every few inches.  A long length of 1/4" x 1/4" bent over the blocks and the guide worked beautifully.
The straight cuts were a breeze as I just clamped some scrap timber to the board for router to move along.

Darren

[914pete]

The rib jig was made with a router.  
An extra set of rib plans were printed for the job and taped in place on the particle board.  
The top curved channel was done first just to be sure I got it right in case it had to be done again.  A piece of 1/4" x 1/4"spruce was bent over timber blocks screwed into the particle board a few inches below the desired cut.  This distance was the gap between the router bit and the edge of the guide fence.  No ruler necessary.  I lined the router bit up to the exact point on the plan, put a piece of 1/4" x 1/4" beside the fence and then screwed a block in beside that.  Did this every few inches.  A long length of 1/4" x 1/4" bent over the blocks and the guide worked beautifully.
The straight cuts were a breeze as I just clamped some scrap timber to the board for router to move along.

Darren

Thanks.  I was at Oshkosh last week and did the wood workshop where we build a rib about half the size and stapled the gussets. Effective, but it took a really long time to remove them all.  I'm going to try to make one of these.

[Gemslayer]

Darren had a good illustration, but I have a question.  My XL plans say to mount the bracket to the front spar 5 inches down from the top.  Darren looks like he is mounting the bracket at the top of the spar.  What did you end up doing?

[Darren C]

Hi Gemslayer.

My wings are built according to the LE plans which have the root fittings attached to the top of the spars. 
The LEXL plans are attached to the bottom as you have noted. 
Both ways are correct depending on which wings you are building.

Darren 

[Gemslayer]

Thanks.  That makes me feel more confident that I am doing it right!😎