chapter 7 the spirule

The Spirule: A Revolutionary Tool

The Spirule, a tool designed to aid in creating root locus plots, emerged from the need for a precise and durable solution for engineers. It became a significant teaching aid and symbol of innovation in control systems.

• The first production batch of 513 Spirules was      manufactured in 1951. ​
• Evans formed the Spirule Company in 1952 to      distribute the tool widely. ​
• Over 100,000 Spirules were shipped globally by      1980, indicating high demand.

Growing Interest in the Spirule

Following the introduction of the Spirule at the AIEE meeting, interest in the tool grew significantly, leading to numerous inquiries and orders from academic institutions and engineers. This demand highlighted the tool's utility in teaching and practical applications.

• Approximately seventy attendees expressed interest      in obtaining a Spirule after the presentation.
• Orders came from prestigious institutions like      MIT, Stanford, and Caltech. ​
• The Spirule became a staple in servomechanism      courses across various universities. ​