Whistling Spinner

Description
A device that makes a noise without the use on batteries, that's small light and portable.

This device makes use of resonance in a cavity.

As its an acoustic device we need to provide it with air.

But rather than applying the air by blowing into it we will propel the device at high speed to force the air.

Propulsion at high speed is provided by a wound string.

By pulling the ends of the wound string in opposing directions it causes the string to unwind and propel the spinner.
Once the string has unwound the rotational energy causes the spinner to wind the string in the other direction.
Unless energy is fed back into the system by again pulling the string the process would eventually stop.

Operation

Before use and periodically during use check that the spinner has no issues and that the string is not fraying.

If any issues are found better to reprint a new spinner and to re-thread with a new string.

As a precaution wear eye protection in case there is a failure of t