Yup. 20+ years for the Morgans and no issues at all.Our aluminum tube frame was quick to build and stupidly strong. And I agree the double sided gusset is going to outlast notched tube for preventing out of axis wiggles and rubbing. We left an air gap. I would think the only time I want notched tubes butting against each other is if we're about to heat and fuse those suckers. Rivets will not prevent vibration from slowly deforming that joint over the years until it's loosey goose.
Now will any riveted tube and gusset variation last 60 years of hard flying like a 4130 bush plane? I'm not sure. But we could slap one together in a weekend with no special skills or techniques.
Yup, it works.For an aircraft designed for quick assembly, why bend tubing or angle? Just create the frame from straight sections and gusset them together at whatever angles are necessary to build the structure.
Couple of Morgans have been crashed, the upper and lower square tube longerons are 1" x 1/8" thick, and have proven to be very robust in the incidents.The welded 4130 frames have a great reputation for protecting occupants in a crash. I do wonder how an AL gusset frame would compare in crashworthiness if built to the same weight as the analogous 4130 frame, and with crashworthiness as a specific design objective (e.g. beefier tubes, gussets, triangulation where needed to keep the front from collapsing into the cabin, etc). Maybe a few more pounds of AL in the right spots could make the structures close to the same in this regard, and retain the ease-of-construction advantages of AL tubes and gusseted joints. There have been Sonexes that did a very good job of protecting the occupants.
Nope, square is fine, have done it.Square tubes will have the same problem as angles. It will twist when you try to bend it, particularly in compound curves, like the lower longeron in most tube and fabric designs.
Litespeed beat me too it, but i have mentioned the Morgans, oh a 100 times i guess before, and all your questions are answered.
Having actually built one, it's a the bees knees for simplicity and ease of construction.
Look and learn is all i can say, many of you are making life hard for yourselves otherwise.