Flywheel

A flywheel comprising:

• a plurality of discs arranged in a stack, including at least first and second end discs at either end of the stack, each of the plurality of discs including a plurality of disc apertures therethrough,
• first and second plate members disposed at opposing ends of the stack, one or both of the first and second plate members including a plurality of plate apertures therethrough for alignment with a corresponding series of disc apertures through the stack, in which one or both of the first plate member and the second plate member include:
• one or more clamping areas in abutment with the respective end disc, and at least one annular concave recessed area which is substantially spaced apart from the respective end disc, and
• connection means for clamping the first and second plate members together about the stack of discs, the connection means extending through each of the plurality of disc apertures without contacting the plurality of discs.

A flywheel comprising

• a plurality of discs arranged in a stack, including at least first and second end discs at either end of the stack, each of the plurality of discs including a plurality of elliptical disc apertures therethrough,
• first and second plate members disposed at opposing ends of the stack, one or both of the first and second plate members including a plurality of plate apertures therethrough for alignment with a corresponding series of elliptical disc apertures through the stack, and
• connection means for clamping the first and second plate members together about the stack of discs, the connection means extending through each of the plurality of elliptical disc apertures without contacting the plurality of discs;
• in which the flywheel achieves a peripheral speed of at least 350 ms-1 during use.