Blueprint: Flywheel Store for Smoothing and Bridging Duty (from DOI 10.5281/zenodo.24108995)

Design blueprint for the flywheel energy store designed in the source paper (DOI 10.5281/zenodo.24108995): a hoop-wound carbon-fibre rim of 71.7 kg and 0.64 m diameter spinning at 17,905 revolutions per minute in a vacuum housing on active magnetic bearings, storing 2.977 kWh and delivering 2.009 kWh through its working speed range. DESIGN BLUEPRINT - SIMULATED, NOT MEASURED - NOT BUILT. The blueprint prints at full size the limit that decides the application: the machine self-discharges at 1.41 percent of its stored energy per hour (a continuous 42 W standing draw), reaches half its stored energy in 35.4 hours and is empty in about 71 hours, so it is the wrong store for overnight-to-seasonal duty. It is specified for high-cycle smoothing and minutes-long bridging at 10 or more full-equivalent cycles per day, where the source paper prices delivered energy at $0.108 per kilowatt-hour and below, undercutting batteries whose cycle life is exhausted at that duty. Full build specification: rotor geometry, mass and material layup, hub and shaft, magnetic and touchdown bearings, containment and housing with the untested 108 kg containment allowance stated openly, motor-generator and power electronics as specified in the source paper, vacuum and standby arrangement with the full standing-loss budget, assembly sequence, operating envelope, tolerances and unspecified quantities as given in the source (no balance grade or tolerances are specified there and none are invented here), failure modes including rotor burst containment, bearing failure and standby-loss growth, and the maintenance regime. Total system mass 264 kg; capital cost $7,000. Every quantity is from the source paper or derived from its parameters by the accompanying compute.py (derived items marked). Civilian stationary energy storage only. AI use disclosed: this blueprint was drafted and its calculations scripted with the assistance of Dave, an artificial intelligence assistant; the named author is responsible for the design choices and for publishing the self-discharge limit at full size. No hardware was built or tested.