windage
(ˈwɪndɪdʒ)
[f. wind n.1 + -age.]
1. An allowance of space (for expansion of gas in firing) between the inner wall of a fire-arm and the shot or shell with which it is charged: measured by the difference of the diameters of the bore and the shot.
| 1710 J. Harris Lex. Techn. II. 1778 Hutton in Phil. Trans. LXVIII. 84 It would also be an improvement to diminish the windage; for by so doing, one third or more of the quantity of powder might be saved. 1860 Abp. Thomson Laws Th. §117. 238 The windage of a loose ball in the barrel of the piece. |
2. Allowance made (esp. in shooting) for deflection from the direct course by the wind; such deflection itself.
| 1867 Morning Star 30 July 6 At half-past nine the firing commenced..but with a breeze almost too strong for accurate aiming, and considerable ‘windage’ was required. 1891 Conan Doyle White Company iv, ‘Seven yards windage, Hal,’ said one. |
3. = wind n.1 13.
| 1889 Buck's Handbk. Med. Sci. VIII. 11/1 To support the idea of injuries from the ‘windage’ of balls. |
4. The (actual or potential) air resistance of a moving object, esp. a vessel or a rotating machine part; also, the force of the wind on a stationary object.
| 1897 Pemberton Complete Cyclist 78 This will..save a good deal of windage. 1898 Westm. Gaz. 26 May 4/1 [Yachts in which] an innovation is made..giving a maximum of head room with a minimum of windage. 1903 Nature 29 Oct. 635/1 The power wasted by the windage of fly-wheel and dynamo armatures. 1909 A Williams Engin. Wonders of World III. 42/2 The designer has to consider how to curve the [propeller] blades so as to give a maximum thrust for a minimum windage. 1948 Times 24 Nov. 2/2 A new type of anchor designed to prevent warships, particularly aircraft-carriers with their large windage area, from dragging their anchors. 1953 C. S. Forester Hornblower & ‘Atropos’ 60 Their twelve oars hardly sufficed to control their more than forty feet of length, and the windage of the huge cabin aft was enormous. 1958 Engineering 31 Jan. 157/3 The radar aerial..is of parabolic section and slatted to reduce windage. 1961 E. Lightfoot Moment Distribution v. 123 Design against windage is important in skyscraper buildings. 1971 Sci. Amer. Dec. 7/1 If the time cycle between storage and retrieval is long, most of the stored energy [of the flywheel] is lost in windage and friction. 1977 Mod. Boating (Austral.) Jan. 98/1 There is a tremendous amount of windage in that topsides and cabin. |
5. Special Comb.: windage loss, loss of power through the air resistance of rotating parts.
| 1922 Encycl. Brit. XXX. 35/2 In determining the useful H.P. of rotary engines, ‘windage loss’..had first to be determined. 1966 McGraw-Hill Encycl. Sci. & Technol. IV. 449/1 Windage loss is relatively large in air-cooled high-speed machines. |