For making your own flywheel steel should do fine. You're probably not aiming for an 80,000+RPM flywheel that rides on magnetic bearings. So composites shouldn't be needed. The best material, eventually, for flywheels should be carbon nanotubes. They have huge tensional strength, but lousy compression strength. Tensile loads is what a flywheel has, so they'd work great.
It is important to note that not all batteries associated with these computer models are affected. The company is directing all users to its HP Battery Recall website to go through the online validation and replacement process.
HP Stream 11 and HP Stream 13 Notebook PCs - Locating the Product Key for Office 365 Computers that ship with Office 365 Personal also include... ...PCs - Unable to Use or Install Microsoft Office 2007 (Cannot Find Missing Product Key) The Microsoft Office 2007 trial edition is no longer available on HP...