I would use a stacked flywheel system which has the motor/generator used to spin the flywheels to bring them up to speed and use the spinning flywheels to generate electricity sandwiched between two flywheel storage containers. The system would be sealed to preserve the vacuum. Either a liquid coolant system or forced air cooling system would be used to cool the armature of the motor/generator.
The flywheels would be made from a variety of materials depending on the storage capacity that is desired. If rock quartz doesn't fly apart at 100,000 RPMs, it could be the material of choice since it is more available and relatively inexpensive. Ultra-stressed crystalline molecular solid materials that are formed in a high temperature, ultra-high pressure furnace or mold might be used. Then there are the more exotic high-strength materials that might be used.
The ultimate goal is a kinetic energy storage capacity of at least 100 watt-hours per cubic inch of flywheel material. If it doesn't fly off, a magnetic band could be placed around the circumference of each flywheel that would be facing a magnetic band inside the container to create a linear induction effect. This may increase the storage capacity of the flywheels. It may reduce the need for speeds in excess of 100,000 RPMs for the flywheels to spin which may increase the lifespan of the flywheels.
If I were to install a stacked flywheel system in a family sedan, I would use two primary stacked units for the drive system. Two units with a total storage capacity of 15,000 cubic inches would contain 1.5 megawatts of kinetic energy. If a 20-horse electric motor were used to power each wheel, at a speed of 60 mph, the range would be 1500 miles. A person could travel from New York City to Saint Louis without needing to respin the flywheels up to speed.
There would be smaller stacked units that would power the systems for the car. The brakes, suspension, and steering system would be powered by the units along with all the things a person would expect like a radio/CD player, a TV system for the kids to watch videos in the back, a climate control system, a GPS system, and even a miniature refrigerator and microwave oven for long trips when the driver and passengers don't want to stop for a meal.
If the people did decide to stop for a sit-down meal, the flywheels could be respun up to speed since it takes no more than 15 minutes to respin the flywheels. On vacation, the flywheels could be respun between the time the family wakes up in the motel room and the time they hit the road again. And since it's electric, energy bills will be greatly reduced.
If the total flywheel storage capacity were 2.5 megawatts, at a cost of 3 cents per kilowatt, the price to power the vehicle half way across the country would be $75. A person with an SUV that has a 20-gallon gas tank, at the height the gas prices reached in much of the country would have paid more than that for fuel and the vehicle might have had a range of less than a third of that of the electric.
If the flywheels need to be replaced, for safety reasons, every 2000 times they've been respun, the car might last for decades. It could be a good second, third, and fourth-hand car if it is maintained properly.
If the auto industry had developed stacked flywheel systems years ago, maybe it wouldn't be in the financial mess it is in today. The industry has known about flywheel systems for decades. But it never developed them. Stacked systems would prevent the leakage of the vacuum from the flywheel chambers. With the loss of the vacuum being a drawback, a stacked system could be the answer.
If America wants to build vehicles that don't pollute yet have a good range for driving long distances, stacked flywheels might be the answer.
