Final answer:
A flywheel in a piston engine smooths out engine vibrations by acting as a reservoir for kinetic energy, absorbing energy during high power output, and releasing it during lower demand. Jet turbines, however, spin rapidly to generate thrust and do not use flywheels.
Step-by-step explanation:
The question pertains to the function of a flywheel in conventional piston engines. A flywheel is a heavy rotating mechanical device that is used to store rotational energy. Its inclusion in piston engines is crucial because it smooths out engine vibrations that are a result of the thrust from individual piston firings. The flywheel achieves this by acting as a reservoir for kinetic energy: it absorbs energy during periods of high power output and releases it during periods when the energy demand is lower, thereby maintaining a more consistent engine speed and reducing the vibrations.
In the context of jet turbines, the principle is somewhat different because these engines do not typically have flywheels. Instead, jet turbines are designed to spin rapidly to generate thrust; the rapid rotation of the turbine blades is fundamental to the engine's ability to propel aircraft. The design and materials used in jet turbines aim to withstand the extreme conditions and forces encountered during flight.