h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

The abbreviation in footnote number 1 should be changed to UHI. By substituting the letter I for the number 1, the phonetic sound can become Huey.

In the body of the text, it is not realistic to imply that most American helicopters share the Huey's characteristic, dramatic sound. Some UH-1 helicopters have recently been fitted with four-bladed rotors instead of the original two-bladed designs. These turn more slowly and thus moderate the distinctive sound associated with Huey's in the Vietnam era. (Augusta-)Bell 212 and 214 helicopters are essentially up-rated Hueys and continue to perform many civilian, rescue, transport and training roles around the world.