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.
March 31, 2015. 1  The recovery partition in an HP desktop or laptop computer is a specific chunk of your hard drive set aside for important system files. 2  Unplug any external devices and cables that are connected to the HP computer, except for the power cord, mouse, keyboard and monitor.