Two different styles of 3D printable robust control horns for mid-size model aircrafts constructed from foamboard, cardboard and/or balsa, with a wingspan of approximately 1 to 1.5 meters (~39 to 60 inches). The control horns have a large mounting base to provide precise positive control authority with minimum flex and/or flutter of the control surface. They work well with most RC aircraft for 3D aerobatics and/or faster flight.
The parts can be easily 3D printed, without any support, on a modern inexpensive 3D Printer. They can be printed with a variety of materials, including PLA, PETG, ABS and many other types of printable materials.
PLA works well for this application, unless the model aircraft that the horns are installed on will be stored or kept in a high temperature environment such as a parked car in the summer, where the temperature may exceed ~55 C (~ 130 F). At such temperature, PLA will likely deform and warp. Therefore, I strongly recommend using PETG or ABS instead, to print parts.
I have successfully used these horns since early 2018. They solved many issues I encountered with the flimsy hardware normally included in many foamboard kits.