Zoomzoooie
Well-Known Member
I have been going back and forth on rib and spar design from round tube spars and I beam spars. Each has pros and cons. The rib design I have settle on is 90° bend 3/4" x 3/4" extruded capstrips. The rib design will have supporting intercostals.
The problem with I beam spars is the distance between the front and back spars. The wing cord is to be 46" - 48" using I beam spars, but this narrow cord drastically reduces the spacing between the spars from the required 27.5" to about 24", which would require a drastic redesign of the fuselage, which I do not want to do.
Since some designs of other wings use 2.5" - .065 round tubes with an I beam insert and heavy 1/4" plywood ribs, I want look at using the round tube spars with the aluminum ribs.
The problem is mounting the tubes to the intercostals. The intercostal holes require flanges so not to cut into the spar. The flange bend needs to be 90° and sleeve over the spar tube. The flanges will be drilled and epoxied to the spars similar to wood ribs.
The pic shows the design of the ribs to give you some idea what I want. Replace the I mean spars with tube spars. The front spar will be right at the leading edge and the rear spar is close to where the rear I beam spar would be.
Does anyone know of any existing thin aluminum flanges that would fit over the 2.5" spar tubes? Duct flanges maybe? What grade of aluminum are they?
Has anyone successfully made a 90° round hole flange from thin 2024T3 or 6061T6 sheet aluminum without it cracking?
I have another problem to solve using the tube spars. Where the lift struts mount to the spar would be an I beam insert to strengthen the area where the wing strut mounting bracket is riveted to the tube spar. I need 4 of these inserts. The problem is obtaining them. I will see if I can get them from the two or three kit plane manufactures who are using them. If they will sell me a set, problem solved. If not I need to make some. They are .080" thick by 5 feet long.
I have two thoughts on how to make them. First is to make Z bends on .080" sheet 2024T3 and fit them inside the tubes spars. The other is to use 0.040" and make U bends and rivet them together back to back and fit them inside the tube spars.
Any help on this would be great.
ZZ
The problem with I beam spars is the distance between the front and back spars. The wing cord is to be 46" - 48" using I beam spars, but this narrow cord drastically reduces the spacing between the spars from the required 27.5" to about 24", which would require a drastic redesign of the fuselage, which I do not want to do.
Since some designs of other wings use 2.5" - .065 round tubes with an I beam insert and heavy 1/4" plywood ribs, I want look at using the round tube spars with the aluminum ribs.
The problem is mounting the tubes to the intercostals. The intercostal holes require flanges so not to cut into the spar. The flange bend needs to be 90° and sleeve over the spar tube. The flanges will be drilled and epoxied to the spars similar to wood ribs.
The pic shows the design of the ribs to give you some idea what I want. Replace the I mean spars with tube spars. The front spar will be right at the leading edge and the rear spar is close to where the rear I beam spar would be.
Does anyone know of any existing thin aluminum flanges that would fit over the 2.5" spar tubes? Duct flanges maybe? What grade of aluminum are they?
Has anyone successfully made a 90° round hole flange from thin 2024T3 or 6061T6 sheet aluminum without it cracking?
I have another problem to solve using the tube spars. Where the lift struts mount to the spar would be an I beam insert to strengthen the area where the wing strut mounting bracket is riveted to the tube spar. I need 4 of these inserts. The problem is obtaining them. I will see if I can get them from the two or three kit plane manufactures who are using them. If they will sell me a set, problem solved. If not I need to make some. They are .080" thick by 5 feet long.
I have two thoughts on how to make them. First is to make Z bends on .080" sheet 2024T3 and fit them inside the tubes spars. The other is to use 0.040" and make U bends and rivet them together back to back and fit them inside the tube spars.
Any help on this would be great.
ZZ
