When operating, the twin rudder Bloch MB 175T model utilizes a dual rudder actuation setup mounted at the wingtips of a white wing assembly. This configuration allows the rudders to pivot both inward and outward simultaneously as the servo cycles, creating a complex control movement.
The maker constructed the airframe using LW-PLA, while the hatch, motor mounts, and landing gear are made from PETG. The mechanical linkage is driven by a central servo horn that pushes two thin metal pushrods toward the wingtips. The structural components are printed in white plastic. Additionally, two large flap or spoiler panels are hinged along the upper forward wing section.
The linkage assembly passed a stiffness test when held in front of the prop at full power and did not flex. This is a positive point, though the maker is still concerned about the linkage's rigidity during actual use. A constraint exists with the hollow elevators, as they cannot be trimmed for additional throw without creating a significant open space.
Overall, the twin rudder actuation system presents an elegant design approach. However, the ability to fully determine if the rudder throw is adequate will only be known after the plane is airborne! This untested flight performance is the central unknown of this work in progress.