VaDiM stands for Variable Direction Mount (which is essentially a PR supername for Thrust Vector Control)

It is a 3D printed mechanical unit that gets mounted on the inside of a model rocket fuselage (of 10cm diameter) and once paired with 2 servos, it can accurately and reliably¹ change the direction of a F-class model rocket motor in order to achieve active stabilisation and control of the rocket.

Structurally, the VaDiM module has 3 main components : the outer manifold, that connects the entire system to the rocket's fuselage, the outer gimbal, that contains 2 servos and the inner gimbal, which holds the rocket motor in a compliant* grip. The 2 gimbal axis pivot on a simple assembly of 4 small screws, 4 bearings and 8 nuts and 4 washers

Fully designed in the open-source 3D software "Blender", implementing a non-destructive workflow, heavily influenced by Chipp Walters' tutorials.

One of the core design goals we've set from the very beginning is ensuring the parts can be successfully 3D-printed without the use of any support materials whatsoever. This ambitious goal crippled the first prototype of VaDiM because there was simply no way to make the servo mounts sturdy enough, as we could essentially only hold the from one side.

The solution to this problem, however, came after a complete re-design of the outer gimbal. Instead of using the naive approach and printing the part vertically, we realized we could use any arbitrary plane as our printing plane. Upon this realisation, the solution presented itself: set a vertical 45° angle plane, perpendicular to the bisector of the 2 planes defined by the servos. This ensured the most printability over the critical region, enabling a complete shroud over the servos, holding them from 4 directions. This is the main breakthrough of the VaDiM system, as the outer gimbal is by far the most complex part out of the 3.