Well it is back to building at last! Today I fabricated the seat backs. Like the floor these are made from 0.050 6061-T6 aluminium with the edges folded up for stiffness using the bending brake. I'd been puzzling for some time how to fix these such that they were easily removable. My initial idea had been to use hinges with removable pins like Vans at the bottom but this still left the issue of how to fix them at the top. Luckily, my next door neighboor Daryl was passing while I was pondering and immediately suggested hanging them from the cross members - brilliant! So I fabricated a U-channel to fit over the top cross member from two pieces of extruded 3/4" right angle. The first section was riveted to the back of the seat using countersunk rivets and then the second piece match drilled to it to give a good fit over the cross member. This was then riveted to the first section. Then two pieces of 0.063" aluminium sheet were cut out to fit over the lower cross member and riveted to the sides of the seat back. Together the two hangers locate the seat backs securely whilst allowing them to be easily removed. The seat backs were designed to take exactly the same size foam as my Vans RV9A which will allow me to use the same fabric patterns as I used for upholstering the Vans. The seat bottoms will then be 3" thick foam which should be nice and comfy and provide protection against any hard landings.
Well it is back to building at last! Today I fabricated the seat backs. Like the floor these are made from 0.050 6061-T6 aluminium with the edges folded up for stiffness using the bending brake. I'd been puzzling for some time how to fix these such that they were easily removable. My initial idea had been to use hinges with removable pins like Vans at the bottom but this still left the issue of how to fix them at the top. Luckily, my next door neighboor Daryl was passing while I was pondering and immediately suggested hanging them from the cross members - brilliant! So I fabricated a U-channel to fit over the top cross member from two pieces of extruded 3/4" right angle. The first section was riveted to the back of the seat using countersunk rivets and then the second piece match drilled to it to give a good fit over the cross member. This was then riveted to the first section. Then two pieces of 0.063" aluminium sheet were cut out to fit over the lower cross member and riveted to the sides of the seat back. Together the two hangers locate the seat backs securely whilst allowing them to be easily removed. The seat backs were designed to take exactly the same size foam as my Vans RV9A which will allow me to use the same fabric patterns as I used for upholstering the Vans. The seat bottoms will then be 3" thick foam which should be nice and comfy and provide protection against any hard landings.
