Retrieving "Imperial Units" from the archives

Cross-reference notes under review

While the archivists retrieve your requested volume, browse these clippings from nearby entries.

1. Foot Pound Second System

   Linked via "imperial measurements"

   Aerospace and Ballistics
   In historical US aerospace engineering, the FPS system provided a direct empirical link between thrust (measured in $\text{lbf}$), propellant mass flow, and resulting velocity changes, making early trajectory calculations more intuitive for designers accustomed to imperial measurements. The $\text{lbf} \cdot \text{ft}$ unit combination is still sometimes seen in torque specifications for large machine…