Bristol was to become inextricably linked with the sleeve-valve engine following it's change over to that format from it's successful poppet-valve engines of the 1920's to 1930's.
The poppet-valve engine range included: Jupiter • Pegasus •
The sleeve-valve range included: • Hercules • Perseus • Mercury • Aquila • Taurus • Centaurus • and the unbuilt Orion.
