The main actor for the solar sail is this so-called endless fock roller.
The system from sailing consists of two components. On the one hand, the fock roller, through which a rope or small dew is pulled and the axis begins to rotate.
At the other end of the axis of the sail, a so-called vortex is attached. The sail can then be wound around its own axis
Now the sail is wrapped around itself over the diagonal. Since it turns out that there is often an understanding problem here, I created a small animation:
The thick diagonal is the wrapping axis with the fock roller on one end and the vortex at the other end. The fock roller is pressed when rolling in.
The two finer ropes are for unrolling and clamping the other two corners of the sail.
Square sail logically means four fastening points. Since we have a very thick insulation and with a 20 sqm sail really big forces occur due to the wind and the train, I decided for a fastening on the house side to stainless steel pipes, which are screwed to a rafter at the upper end and concreted in at the lower end:
The two opposite brackets consist of 65 cm bottom sleeve in which two 2.60 meter stainless steel pipes are inserted. In winter or for mowing the lawn, it is possible to remove the poles and provide them with plugs:
Due to the state of the sun, the brackets are not built quite symmetrically. That is what is intentional.
To the material list