Flywheel rotor with conical hub and methods of manufacture therefor

A flywheel energy storage system, comprising:

• a motor-generator;
• and
• a rotor, said rotor comprising:
• an outer, primarily cylindrical portion including first fibers having a predetermined first tensile strength for storing the majority of total system energy;
• and
• a hub portion including:
• a conical member formed from second fibers of a second predetermined second tensile strength;
• and
• an inner cylindrical member operatively connected to a rotatable shaft, said inner cylinder member comprising:
• a hexagonal cylinder;
• a spring surrounding said hexagonal cylinder;
• and
• a plastic annular member, wherein said hexagonal cylinder and said plastic annular member are operatively connected by said spring,
• wherein said conical member operatively connects a first end of said outer cylindrical portion with said inner cylindrical member,
• wherein said first tensile strength is greater than said second tensile strength, and
• wherein a portion of said motor-generator is disposed within a cavity defined by said conical member.