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The Great Blue Heron will be the centrepiece of the Heron Tree that will be built in a few years in Nantes. The pair of waders nest at the top of the tree on platforms 35 m high. The largest of the herons is carried by a special handling arm that ensures the overall movement. It regularly takes off, carrying 18 passengers for a circular flight at a height of 40 metres, lasting about 4 minutes, with a breathtaking view of the city in transformation and the Loire. When it takes off, its wings spread out over a 16-metre wingspan covering the passengers in the gondolas. A pilot installed in a gondola manipulates the bird’s head, giving it life and expression.
The technical constraints on this project are significant, starting with the number and complexity of the Heron’s movements. The neck, the head, the eyes, the spread of the wings, each element of the machine reproduces the attitudes of the Heron in flight to recreate a natural wing beat. At the heart of the artistic
artistic approach, movement is interpreted as a language, a source of emotion. The stage of setting in motion constitutes a key stage of the construction.
In addition, the size of the Heron, the altitude at which it will be placed and the weather conditions to which it will be exposed, in particular strong exposure to the wind, also constitute strong constraints. Materials and designs are designed accordingly. The unit must be able to withstand winds of up to 26m/s (95km/h). However, during the course of the studies, it became apparent that it was impossible to validate the load drop calculations
of the Tree’s structure, and therefore of its solidity and safety, without knowing the reactions of this welded structure to the circular flight of a 30-tonne heron with its arm and counterweight. It was therefore necessary to build this heron and then fly it at ground level.
Since the summer of 2021, the Heron has been tested at sight on the Parc des Chantiers, next to the Nave of the Ile de Nantes. The manufacturers were thus able to set the Heron and its carrier arm in motion. These visual tests made it possible to record the data from this flight, to validate the calculations and to define the operating conditions.
