Previously posted a question about lift strut attachment to tubular wing spar with a bolt vertically through the spars. See drawing below.
I tried using Bruhn's analysis book to formulate a a reinforcement to the tension and compression areas of the spar. I'm not an engineer, and need guidance.
I don't know enough or what formula to calculate the loss of strength due to the 3/8" bolt hole in the tension and compression surfaces of the spar.
I can provide the following data for calcualtions if that's helpful, the site does say to provide as much inofrmation as possible.
The eyebolt the strut attaches to is 101 in from the root, and the moment of lift at the strut attachment point from the outboard portion of the wing was calculated to be 10015. WIth an OD of 2.00 and and ID of 1.75, the moment of inertia at the strut attach was .303. This gave a stress developed at this point as 33,052. Increasing the OD to 2.125 as in solution B increases the moment of inertia to 0.533, and reduces stress to 29940. and OD to 2.25 in solution A to increases moment of inertia to 0.742 and reduces stress to 26994. These were calculated with a safety factor of 1.5.
Does solution A create stress risers at the ends of the 2.25in external sleeve? Does the solution B lack sufficient compensation for the loss of material?
@robert DiGiovanni... in this added drawing, the middle presentation shows the original design, the single bolt horizontal through two straps which connect to the lift strut.