Military aeroplanes, simplified, enlarged; an explanatory consideration of their characteristics, performances, construction, maintenance, and operation, specifically arranged for the use of aviators and students . saction is most decidedly affected by altitude, and a study of this willlead us to see why every aeroplane has a ceiling, i. e., a definite limitto the height it can attain in flight. There is another very important conception with regard to airresistance determinations. Disregarding the effects of inertia andacceleration of an obiect, the air pressures are the same in action 44 whe
Military aeroplanes, simplified, enlarged; an explanatory consideration of their characteristics, performances, construction, maintenance, and operation, specifically arranged for the use of aviators and students . saction is most decidedly affected by altitude, and a study of this willlead us to see why every aeroplane has a ceiling, i. e., a definite limitto the height it can attain in flight. There is another very important conception with regard to airresistance determinations. Disregarding the effects of inertia andacceleration of an obiect, the air pressures are the same in action 44 whether the object is moved against the wind, or the wind againstthe object. Motion through the air gives rise to two distinct kinds of resis-tance : 1. Pressure, generated by the impact of the air on an object, and 2. Friction, generated by the flow of the air filaments past thesurface of the object. Characteristics of Air Flow. Having defined air, the manner in which it flows may be con-sidered. Air either flows smoothly past an object in stream lines —continuous filaments — or it breaks up into swirls and eddies, due totoo abrupt a change in flow. The accompanying photographs of airflow illustrate THE FLOW OF AIR. UPPER LEFT, .\ FLAT SURFACE — UPPER RIGHT, A SPHERE— LOWER LEFT AND RIGHT, STRUTS OF DIFFERENT FINENESS It is apparent that a spindle or fusiform shape, gently dividingthe air at the front, and gradually permitting the filaments to closetogether at the rear, will give a smooth flow, which amounts to thesame thing as a very low resistance. It is also evident that a flat sur-face creates very great disturbance, and consequently high resistance. The curve of the stream lines, necessary to prevent disruptingthem, may be computed for any speed, by applying fluid it must be kept in mind that a form of this kind gives its low re-sistance, only at one particular speed, since the path of flow is affectedby the speed. It is unnecessary here
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectairplanes, bookyear19
