Flywheels were used in the early days of Moon Town to store energy collected by solar panels during the day for use at night. They were a cheap option because the vast majority of their mass could be manufactured locally even when fabrication facilities were still fairly primitive. They took advantage of an approach developed by Professor John Vance of Texas A&M. The flywheels were made of flexible material, which permitted construction with far looser engineering tolerances by using a hub design that can gimbal to correct for imbalances and vibration. A good paper of his on the subject is available on a server of UNT – go to page 200 to read A Concept for Suppression of Nonsynchronous Whirl in Flexible Flywheels
This early sketch omits a feature of flexible flywheels as designed by Vance, that having the hub be some distance above the outer ring of the flywheel allows control of whirling. A version of this design was patented by Bill Gray (now withdrawn) with plans to commercialize it through Velkess Inc. That design used a single central shaft which connected the bulk of the flywheel with the motor/generator above it. A small demo of their design is shown in a promotional video they made, shown below.
This design doesn’t require the fiber elements to be bonded together, they only have to be bundled. Once manufacture of long glass fibers from regolith has been accomplished, initial modelling indicates cable made from those would be a good material for such flywheels. This is another instance where the work of James Blacic in LBSA-1 is heavily leaned on. He felt it was a conservative estimate that lunar glass made of a mix of silicate minerals would have an ultimate tensile strength of 3.0 GPa, with a specific gravity of 2.8 .
Current 3d models:
There is a channel on our Discord server for discussion of the design of this equipment. Come join if there is anything you’d like to comment on or ask – https://discord.gg/eeQnFcHgry
Also see the Projects page for general guidance on designing for Moonwards – materials, infrastructure, transport, practices, and main reference works.