NOTATUS Hydraulic Motor: 91.6% Fluid Reuse – Prototype and Patent

This technical document describes the NOTATUS hydraulic motor, a high‑efficiency alternative hydraulic motor that reuses 91.6 % of its driving fluid per cycle. Three combined savings methods are presented: conical cavity geometry, permanent fluid retention in peripheral gaps, and a fixed plunger that occupies space. The pump supplies only 8.4 % of the total displaced volume per cycle, resulting in a pump power reduction factor of 9.16. The document includes the prototype status (95 % built), data on the granted national patent (P202690012) and the PCT application (PCT/ES2025/070599) with a favourable search report. An annex answers the most frequent technical objections raised by engineers and mechanical engineering professors, clarifies common misunderstandings (e.g., why the system is not a conventional telescopic cylinder), and explains the energy balance. The document is open access to facilitate collaboration with academic institutions and industrial partners.