I had already been building foamboard RC planes for nearly a year when I purchased my first 3D printer. I knew I wanted to combine the two hobbies, but a search of existing plans quickly revealed a Goldilocks problem: the printed parts were either insignificant enough that they did not significantly improve the planes’ build; or so numerous that they basically transformed a foamboard plane into a plastic one. I realized that if I wanted 3D-printed components that made my scratch build planes better without detracting from the integrity (and forgiveness) of the foamboard construction, I should design them myself.
Over the course of multiple prototypes and redesigns, I developed a 3D-printed RC plane chassis. Like an automotive chassis, it provides a secure mount for critical load-bearing features of the plane, including the dowels used to connect the wings to the fuselage, the motor mount, and landing gear. The dowel securement prevents the dowel from tearing through the foam. The motor mount offers a stable motor connection with a precise motor angle that is difficult to reproduce consistently when scratch-building out of wood and foamboard. I also 3D printed lightweight landing gear (66g for a ski set), which attaches directly to the wing dowels, thereby eliminating the need to reinforce the bottom of the plane and allowing simple removal or replacement with alternative gear.
Among the several models I have built incorporating my 3D-printed fuselage support structure is a twin boom pusher. It is a tried and true RC plane design with a few twists: namely, 3D-printed components including the chassis, boom mounts, and landing gear. The plane is built in two pieces with the receiver mounted inside the wing, thus requiring only a single servo wire connection (plus a few rubber bands) to mate the wing and fuselage. I am currently flying on Minnesota ice and snow with 3D-printed skis; once spring comes, I will swap them out for wheels.
For information on this and other builds integrating 3D-printed components, including links to free 3D print files, please visit my website.