How to 3D Print an Aeroplane - Day 10 - Sectioning the tail booms.
This part of the design is a bit tedious I'm afraid. We need to section the boom into parts that can be printed. The screen cast is around twelve minutes but that doesn't include the time just spent thinking about how each cut could be printed and assembled, what is structural and what isn't.
I have ended up with two main parts, the forward boom that connects to the wing and an aft part, that includes a section of the fin. I think I have given myself enough of an area to glue to the wing to keep it strong. By having the fin integrated into the boom it should be easier to line everything up correctly. We are then left with the two top and bottom fairings at the front. I had to move the fin outboard slightly to avoid an unprintable overhang, this required me to move the horizontal stab outboard as well, extruding the length at the centre the same amount. We will still need to do another mirror to get these updated parts for the right hand side at some point.
I still have concerns about the booms. They are long and thin which can be problematic for 3d printing. As the nozzle of the printer moves about near the top of the model it can knock the component clean of the build plate or alternatively the drag from the filament being laid down can wobble it, leaving you with an unsightly an un-straight tail boom. Using a brim adhesion to the print bed helps give the part a solid footing but it still may not be enough. It's possible that we will end up chopping it down further into shorter parts. I'll then use a wooden bbq skewer through the centre to make up the structural integrity.
At the stage the boom isn't yet finished, we need to figure out how to actuate the elevator. Where are we going to put the servo? In the wing? In the tail? I'm going to come back to this later on.