In application of flywheels in vehicles, the phenomenon of precession has to be considered.
A rotating flywheel responds to any momentum that tends to change the
direction of its axis of rotation by a resulting precession rotation. A vehicle
with a vertical-axis flywheel would experience a lateral momentum when passing
the top of a hill or the bottom of a valley (roll momentum in response to a
pitch change). Two counter-rotating flywheels may be needed to eliminate this effect.
The
flywheel has been used since ancient times, the most common
traditional example being the potter's wheel. In the Industrial Revolution,
James Watt contributed to the development of the flywheel in the steam engine,
and his contemporary James Pickard used a flywheel combined with a crank to transform
reciprocating into rotary motion.
In a more modern application,
a momentum wheel is a type of flywheel useful in satellite pointing operations,
in which the flywheels are used to point the satellite's instruments in the
correct directions without the use of thruster rockets. |
