Main spar plan dimension versus what actual dimension is to fit ribs

[Mike49]

I made all rib forms and ribs to the Mylar as spelled out in the manual with the plans. Spar dimension calls out 7 5/8. Actual spar dimension to fit ribs comes out almost .2 over that and the plans tell you to make final dimension to fit ribs. I'm sure the factory ribs and spars match this but how close are the other builders coming to the 7 5/8 dimensions?

[Chris In Milwaukee]

There will be a bit of variance, but not insanely so. I think .2 is within my personal tolerances. The spacing between the fore and aft spars are the critical measurement.

Once you have the nose and center ribs formed use that as the baseline for the overall height of the spar sheet metal to ensure a smooth transition between them. The spar caps should be placed equidistant from the center of whatever the results are.

You should be good

~Chris

[Chewie]

I was over a little bit also. If I were to do it again, I would be extra vigilant about cutting my form blocks to the inside of the profile line. But as it is, I'm not worried.

[Bcone1381]

I agree. The important part is that you have preserved the Riblet Airfoil shape that Bob designed the airplane around. So it a smidge larger...build on and when it's finished tell us how it flies! With that being said, if the black line on the wing profile drawing represents the finished demension of the wing, but we make our form block match the drawing, we then are adding .025 for each rib flange, plus some more for the skin.