Spar Plywood

[Jlwright]

I have looked but so far haven't found information about the type of 1/8 inch plywood to use for the spars on my XL.  Some of the information I've read say that 45 degree Plywood is for spar webs but most of the plywood at Aircraft Spruce is 90 deg. The 45 degree is a lot higher too. Since this an ultralight is the 90 degree plywood OK to use? Also, there are several types of birch plywood with different ply materials like basswood or Poplar. A link to what most are using at Aircraft Spruce, Wicks, or a file on the forum would be great. Thanks

[rockiedog2]

i used this for the webs and the metric for all else. i've never used 45 degree in any of my planes

http://aircraftproducts.wicksaircraft.com/item/aircraft-plywood/birch-and-poplar-plywood-aircraft-grade-mil-p-6070/1-8x2x4b90?&plpver=10&origin=keyword&by=prod&filter=0

[rockiedog2]

oh yeah i bt it in 4x4 sheet so could orient the grain the way i wanted it with no probs. i want the grain going spanwise. others want it the other way. 4x4 allows either way. seems like on the LEU one 4x4 sheet did all the webs. dunno about the XL

[Jlwright]

Thanks Joe.  I was planning on buying a 4 X 8 so that I could have the web as long as possible without a joint but that may not be a big deal. 
I would really like to hear what others have done as well. I am pretty informed on how to build with aluminum but this is a whole different ball game.

[leshoman]

I used the 4'x8' 1/8" maghony sheets from ACS with 8' lengths as spar plates

[Jlwright]

Les, what was the reason to use mahagony?  Thanks

[Sam Buchanan]

I used 1/8" 2'x4' Birch from Aircraft Spruce for inexpensive ground UPS shipping.

[leshoman]

I picked up all my material at once from ACS and that was the least expensive and lighter than birch.  Saving weight

[Sam Buchanan]

I used 1/8" 2'x4' Birch from Aircraft Spruce for inexpensive ground UPS shipping.

I forgot to mention that Aircraft Spruce will roll 4'x4' 0.8mm gusset ply so it will fit into a 12"x12"x60" box if you request it. The rib capstrips can go in the same box.

The 1/8" birch I used was 90*.

[Jlwright]

I understand about the weight savings. Every ounce counts.
Sam, did you use scarf joints at the ends of the 4 ft. Material. Were you able to buy 4130 in lengths that would ship UPS or did that have to come on a truck? When I looked it showed 130 inches was the longest you could ship. I remember you said you used 12 ft. Long material. Maybe I just answered my own question. 
I know all these questions have been asked a hundred time before me but I do appreciate the help. I remember all the questions I asked on the RV forum when I first started building my RV 9 and after several years of building others were asking the same questions. I tried my best to help even though it seemed like I'd answered the same question over and over again.

[Sam Buchanan]

I understand about the weight savings. Every ounce counts.
Sam, did you use scarf joints at the ends of the 4 ft. Material. Were you able to buy 4130 in lengths that would ship UPS or did that have to come on a truck? When I looked it showed 130 inches was the longest you could ship. I remember you said you used 12 ft. Long material. Maybe I just answered my own question.
I know all these questions have been asked a hundred time before me but I do appreciate the help. I remember all the questions I asked on the RV forum when I first started building my RV 9 and after several years of building others were asking the same questions. I tried my best to help even though it seemed like I'd answered the same question over and over again.

No scarf joints, the webs are butt joined at the 1/4" stations for ribs.

I was able to find three long tubes locally. The lower longerons are spliced between stations 1 and 2, but could be spliced elsewhere if needed due to supply or shipping needs. You can see where the lowers needed to be spliced in this photo:

[Dan_]

Sam, did you use scarf joints at the ends of the 4 ft. Material.

If you were of a mind to scarf here is a how to for thin stuff...