File:Military aeroplanes; an explanatory consideration of their characteristics, performances, construction, maintenance, and operation, for the use of aviators (1918) (14780408812).jpg

Identifier: militaryaeroplan00loenrich (find matches)
Title: Military aeroplanes; an explanatory consideration of their characteristics, performances, construction, maintenance, and operation, for the use of aviators
Year: 1918 (1910s)
Authors: Loening, Grover Cleveland, 1888-
Subjects: Airplanes Aeronautics, Military
Publisher: (Boston : W. S. Best Printing Company
Contributing Library: University of California Libraries
Digitizing Sponsor: MSN

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order of least resist-ance and values of K for 25 m. p. h. are given. At higher speeds, stilllower Ks would be expected. The form No. 1, having the least resistance, is, perhaps, the bestform that has ever been tested in a laboratory, and at high speedswould give a resistance about l/25th of the normal pressure on itsdiametral plane. It is the form used in the Parseval non-rigid diri-gibles. It is interesting to note in studying low resistance bodies, howclosely they resemble the shapes of fishes, and of birds, measurementsof a fast swimming fish showing an almost exact resemblance to thisParseval shape. As a general rule, the best streamline body is the one having a fine-ness ratio of 6 and with the master diameter about 40% back of thenose, both nose and tail being fairly well pointed.Struts— The application of fineness ratios, and shapes of least resistance,to improvement in the form of struts, has in many instances tremen-dously improved the performance of aeroplanes. 54 */ NPL
Text Appearing After Image:
THE KKSISTAXCE OF SEXERAI. SFRUTS OF DIFFERENT SHAPE In addition to the form for least resistance, however, the weightof the struts and their strength are factors that must be consideredin choosing the best shapes. We will confine ourselves here, how-ever, to a study of the resistance of various shapes. A group of strut sections are given and K for each one. It isto be noted that the effect of yawing is greatly to increase these resist-ances by presenting the strut sidewise to the air, and it will be neces-sary later to consider the amount of this increase. Inclining the strut to the vertical, as in staggered planes, has theeffect of increasing the length of section in the air stream, and, con-sequently, the resistance does not decrease for streamline shapes, whilefor blunter sha))cs, inclination reduces the resistance considerably. In struts, as in bodies, an increase of velocity is accomplishedby a reduction in the value of K, that is more noticeable the greaterthe fineness ratio, i

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