Mechanical Rigidity/Video demo Fisher improvement
Video demonstration of improvement to the Fisher Delta
An earlier video showed a potential weakness in the Fisher Delta design: potential bowing of the three panels which are really very tall and are completely unsupported except at the top and the bottom. This video shows how the addition of a triangular outer bracing panel can stop bowing and flexing of all three of the upright panels, the end result being that the rigidity of the entire design is dramatically improved.
Flexing and crinkling of the paper helps highlight the stress points that the panels of a "real" Fisher are under, during load. However these would not occur if cardboard were used instead of paper, producing and demonstrating the desired rigidity at the cost of making it impossible to show the stress points of the panels.
Just as with the base it is critical that the triangular bracing panel be attached firmly in three points per face: ends and middle for a total of nice attachment points.