Isotopes LEXL build in MO

[Isotope]

First spar will be ready for plywood tomorrow. I have worked with alot of epoxy but never t-88. This stuff is great. Long working time and it dosnt run when your turning parts around to apply on multiple surfaces. And cleans up easy enough. Splicing the root filler block was easy and i feel comfortable with it thanks to the input. You guys are more than awesome.

[Kamcoman77]

Looking good!

[Isotope]

How critical is the 29° angle for the strut brace?    Mine came out at about 30~31°. I bought an angle finder for the rest and plan on getting them right on 29°.

[Kamcoman77]

Shouldn't be a problem. You can still mount the fittings at 29°

[Isotope]

Ok befor i go and make two left wings i want to clarify that if i were standing behind the airplane and this was the right front wing spar the plywood would go on the front correct? And on the back of the rear spar? Also the strut braces and solid root piece will have double 1/8" ply over them in the front where it calls out in the plans? See attached. Also is there a grain direction i need to worry about with the ply?

[Brock]

I am learning lots from your posts/pictures/questions.  One of these days it there will be nothing left to do on the airframe and I'll have to start on the wings.  Keep posting.

[Kamcoman77]

Front wing spars get plywood web on front face and rear spars get plywood web on rear face. I'm not sure I understand your question about doublers but my left wing photo shows how I did mine. I ran the grain direction of the outer ply layers spanwise.

[Isotope]

Again prolly thinking to much into it but next question lol. Page 34 on the spar section is shows 9, 3" holes driller in the 3 most outboard section's of the spar. Then on page A it shows 12 holes drilled all the way up next to the strut bace section? What is common conciseness here? It makes since on page 34 him wanting to stay away from drilling holes near a stress point like the spar attachment. I suspect this would be a few ounces saved though if they were drilled out all the way up too it like on the overall view on page A.

[Kamcoman77]

3" holes in front web and 2-1/2" holes in rear. No holes drilled near strut mounting area. Do you not have a Page 33? It shows the holes in the other end of the spar webs. Page 34 shows one end, 33 the other.

[Kamcoman77]

In your post showing Page 35, I just remembered a "gotcha". The strut fitting dimensions for the front spar are correct, but the rear spar is showing the same distance below the spar cap for the hole that the strut bolt goes through. In my opinion this is a mistake. The rear spar cap is 1/4" from the bottom fabric of the wing while the front spar cap is even with the fabric. I think you should add 1/4" to the 5/8" shown for the rear spar bolt hole. This will place the bolt hole for the strut attach 5/8" below the fabric.

[Isotope]

Nice catch but.. I ordered Les's prefabbed mounting bracket kit with holes already drilled.. i dont believe there drilled to this specific dimension. Is this a known error and crucial to fix?
Question i have. The way i installed the 1/2" uprights for web splicing i just put them where ever a 4' piece of ply would land. In that case a couple of them ended up right where a lighting hole would be so i am short 2 lighting holes. Could i drill the 2 holes in the next section over closer to the strut bracket? but dont want compromise this area. What do you think, see attached for where i didnt drill a hole with an "x" and where im proposing to drill a hole with the red circle.
PS: what kind of weight penalty did you add for adding those gussets to the uprights? Did u add them to all uprights? See attached.

[Kamcoman77]

I don't guess the 5/8" below the front & rear spar caps are critical for structure. My only issue was the rear strut was very close to the fabric compared to the front one, so I adjusted the mounting holes to compensate. I have no idea if that is a known error but did not want my rear strut pushed up against the fabric. I put lightening holes where you have the red circles. I put the little 0.8mm ply gussets on all my spars. Added about 8 ounces. The reason for those gussets was some of the vertical upright joints broke when I dropped one of the spars on my concrete floor before I had any ply webbing on it. I figured a gusset on one side and the 3mm ply web on the other made those joints super strong. If I build another XL, I will leave them off. I'm helping a buddy build an XL and we are not using those gussets (photo).