bkdavy

My Feedback: (1)

I'm scratch builiding my own design. I'm using pink foam core for the wings, and I'm looking for acceptable wing tubes. Mcmaster has two possibilities:

Alloy 2024 Aluminum Tube .75" Od, .62" Id, .065" Wall Thick, 6' Length for $31
or
Alloy 6063 Aluminum Round Tube .625" Od, .527" Id, 8' Length for $7.

My planned wing tube is 24 inches long (10 inches into each wing half)

Obviously the 2024 (aircraft aluminum) is stronger, but far more expensive. Will the 6063 aluminum be sufficiently strong (I'm targetining 6-7 lbs all up weight, with a 64" span. The tube will traverse approx 4" across the fuselage between the wings.

Will the 6063 be strong enough in this application, or should I bite the bullet for the 2024 Aircraft Aluminum?

Thanks,
Brad

SoCal GliderGuider

What is the wing joiner material?

bkdavy

My Feedback: (1)

The wing is a foam core, sheeted with 1/16 inch balsa. The fuselage is balsa sheeted foam as well. The wing is a mid-wing, so the tube will be the "joiner", unless you're referring to a tube through the fuselage. I haven't decided on that yet, although I'm leanng toward a fiberglass tube. There will be 1/8" plywood sheet on the wing root end, and a 1/8" plywood plate on the fuselage that the wing tube will pass through. The plan is to make the wing removable for transportation. There will be a 1/4" pin at the trailing edge for alignment, and a 1/4" plywood extension into the fuselage with a nylon bolt to join the wings inside the fuselage.

Bottom line is that the wing tube will not be holding the wings to the fuselage, simply transferring lifting forces and preventing the wings from folding in the middle.

Brad

Laird SS

According to my references, 6063 is an alloy for architectural and ornamental applications. Are you sure it will be strong enough. Between the two alloys you have listed, I would choose 2024 since it widely used for aircraft applications. The ultimate strength of 2024-T4 or T351 is 68,000 psi and for 6063-T6 it is 35,000 psi. Which is better for your application? Taking the cheaper item may give you a case of folding wings when that isn't what you had hoped for.

Just my $.02 worth

batchelc

My Feedback: (7)

I would use the 2024. You also have to take into account the harness (temper) of the material. 2024-T3 is widely used for aircraft because it will flex without cracking. For most applications it is not to rigid or soft. It also machines/drills well. You can buy the next size down or up to slip tubes into one another if you want to use a tube for the center section. You can also try a surplus place for metal. The Yard is one that comes to mind. Try www.yardstore.com and give em a call. Chris

SoCal GliderGuider

If you plan to have the wings removable there needs to be a tube fixed in each wing with a joiner going between the wings through the fuse. I suggest either fiberglass or carbon tubes in the wings and either a solid carbon rod joiner or a hardened aluminum tube joiner. Where the joiner rod passes through a fuse you only need to reinforce the wing roots with extra ply. You don't need or really want a tube in the fuse. Depending on the planes size I guess you could leave the joiner in the fuse during transport. Use rubber 0-rings on the insides of the wing roots to keep it some what centered.

If you plan on doing some serious snap rolls you need to secure each wing to the fuse in two places. I suggest Duz type fasteners. Also the anti rotation pin as close to the trailing edge as practical. For connecting servo wires to the fuse you might want to check out 1/10" pin headers. Look for the gold plated square pins and receivers.