The simplicity of the tubular boom fuselage used in some older ultralights like the Hummer, Drifter, etc. is very appealing. That said, availability of the right diameter/thickness/alloy tube can vary a lot by location and over time. It's also probably not as simple as it looks as you need a thin tube with reinforcements at critical points if you are not going to accept the weight penalty of a thick tube from nose to tail.
What about making a tubular boom fuselage from rectangular metal sheets wrapped around circular or polygonal bulkheads, creating a series of nested tubes using the appropriate thickness for the stresses in each section? I could even see adding 90-degree flanges to the end of the sheets so that, as long as the bulkheads are located at sheet junctions with bent tabs toward the ends, you'd have access to both sides of the rivet holes for easy fabrication (rivet squeezer or pulled rivets) and inspection as you go.
Good idea or a waste of time?
Cheers,
Matthew
What about making a tubular boom fuselage from rectangular metal sheets wrapped around circular or polygonal bulkheads, creating a series of nested tubes using the appropriate thickness for the stresses in each section? I could even see adding 90-degree flanges to the end of the sheets so that, as long as the bulkheads are located at sheet junctions with bent tabs toward the ends, you'd have access to both sides of the rivet holes for easy fabrication (rivet squeezer or pulled rivets) and inspection as you go.
Good idea or a waste of time?
Cheers,
Matthew