| 释义 |
phugoid, a. and n.|ˈfjuːgɔɪd|
[f. Gr. ϕυγή flight (n.2: erron. taken for flight n.1) + -oid.]
A. adj. Of or pertaining to the longitudinal stability of an aircraft flying a nominally horizontal course in a vertical plane; applied spec. to a slow fore-and-aft oscillation in which the flight path assumes the form of a series of shallow waves and the aircraft undergoes synchronous increases and decreases of speed.
1908F. W. Lanchester Aerodonetics ii. 37 The Phugoid theory deals with the longitudinal stability, and the form and equations of the flight path of an aerodone. Ibid. 40 This is the general equation to the curves of flight or the phugoid equation. Ibid. iii. 59 The plotting of the phugoid curves forming a complete series, from the straight line representing the path of uniform gliding, to the tumbler type of curve with constants varying to any desired degree, may be termed a phugoid chart. 1920Flight XII. 817/1 They would talk of bumps and pitching when, of course, they merely meant anabatics or katabatics, or peradventure nothing more serious than a phugoid oscillation. 1965G. Sutton Mastery of Air v. 125 The enhanced speed brings about an increase in lift, which ultimately stops the descent and causes the machine to climb again. At the top of the climb the machine has insufficient lift to maintain itself and if left alone will fall again and so on. This is the phugoid oscillation, consisting of a wave-like path or a series of loops. 1974H. Ashley Engin. Anal. Flight Vehicles iii. 62 The latter situation arises..during the higher portion of the entry trajectory of a lifting glider. The long-period or phugoid longitudinal mode may then have a period as great as half the total interval required for entry.
B. n. A phugoid oscillation.
1908F. W. Lanchester Aerodonetics ii. 42 With these two equations we are in a position to investigate the general characteristics and particular forms of the curves of flight or Phugoids, as they may be appropriately termed. 1945Jrnl. R. Aeronaut. Soc. XLIX. 346/1 He became so interested in a phugoid that he allowed it to develop beyond control, and he found himself spinning inverted at 33,000 feet. 1948L. M. Milne-Thomson Theoret. Aerodynamics xvi. 309 A phugoid is the path of a particle which moves under gravity in a vertical plane and which is acted upon by a force L normal to the path and proportional to V2, the square of the speed. 1975L. J. Clancy Aerodynamics xvi. 485 The consequence of the disturbance is an oscillation in which the aircraft successively gains and loses height, while losing and gaining forward speed. This oscillation is known as a phugoid. |