DavidLee
Member
I have a question for all you engineering types out there. It occurred to me that a round sectioned aluminum tube is not the ideal thing to make wing spars out of. The material is not in the correct places so it doesn't handle bending loads particularly well and when you drill holes in it nothing really good happens. On the other hand it seems to work reasonably well although a little heavy for what's it's doing. If it could be "rolled" through a die into an oval shape it would get more material further from the neutral axis and would improve bending characteristics on the long axis. Example: a 1.75" Dia. tube can be rolled out to 2.25" and 1.0" short axis for the same circumference (very close). Rib attachments could be made much closer to the NA and all bolt holes engineered so they pass directly through the NA. Also, any interior web would be more stable if you chose to use one. My real question (if the foregoing are reasonable assumptions) is will the material work harden to a dangerous degree during the rolling process? I once watched Tom Glazer of the "Dawn Patrol" group anneal a tube spar end and then heat treat it by applying soot and burning it off with a torch. If annealing became necessary would that work for a whole wing spar? Thanks in advance for any ideas or thoughts you might have here.....
