phugoid

Meaning

Noun

• An aircraft motion where the vehicle pitches up and climbs, decreasing speed, and then pitches down and descends, increasing speed.

Origin

• Neologism created in 1908 by the British aerodynamics expert Frederick W. Lanchester, from Ancient Greek φυγή ("flight") and εἶδος. In the glossary to his book Aerodonetics, Lanchester explains his coinage thus:
• "PHUGOID THEORY – (Author), from the Greek φυγή and εἶδος, lit. flight-like: The theory dealing with longitudinal stability and the form of the flight path. Hence also Phugoid chart, Phugoid curve, Phugoid oscillation, etc. (Ch. II.) The appropriateness of the derivation is perhaps diminished by the fact that the word φυγή means flight in the sense of escape rather than the act of flying in the present signification."