I have an Armstrong mast which tapers outwards towards the top so a simple profile doesn’t fit as nice it could.
For a bit of a challenge i used photogrammetry (lots of photos stitched together to make a 3d model) and then fixed splines to this in Fusion360 to create a solid parametric model. This model can then can be used for the guide the pod. A bit of an overkill but was a fun process to learn and could be used by others for getting approximations of board or propellor shapes. All you need is your phone, good light and a few minutes to capture the shape.
Work flow
- Polycam on iOS, take lots of photos. A dusting of talcum powder or cocaine helps with the detail.
- Export as GLTF (free)
- Convert to STL using an online tool.
- Open with fusion360
- Create several planes in which to the draw profiles.
- Draw profiles as closes as possible to the STL. Using sectional analysis helps with this.
- Draw connecting rails passing though profiles. Project/ intersect helps with getting points on the profiles.
- Loft though the profiles using the rails as guides.
- Check and adjust.
