The groundwork of practical naval gunnery; a study of the principles and practice of exterior ballistics, as applied to naval gunnery, and of the computation and use of ballistic and range tables . ght corresponding to V, <^, may .withoutappreciable error be taken as the time of flight for the actual firing data. 245. Now let us return to our standard problem and find the data for Column16 in the range table; deviation for lateral wind component of 12 knots; for our 12 gun at 10,000 yards. We have the above formula, and also TFi2z= -7q\—^—^ yardsper second. X =30000 log 7 = 2900 log
The groundwork of practical naval gunnery; a study of the principles and practice of exterior ballistics, as applied to naval gunnery, and of the computation and use of ballistic and range tables . ght corresponding to V, <^, may .withoutappreciable error be taken as the time of flight for the actual firing data. 245. Now let us return to our standard problem and find the data for Column16 in the range table; deviation for lateral wind component of 12 knots; for our 12 gun at 10,000 yards. We have the above formula, and also TFi2z= -7q\—^—^ yardsper second. X =30000 log 7 = 2900 log colog </. = 4° 13 14 sec log T= log 12 log 6080 log 60x00x3 = 10800 log colog 10 Z)i2Tr = yards log Section 2.—The Effect of Motion of the Gun Upon the Motion of the Projectile. 246. As in the case of the wind, we resolve the horizontal velocity of the gundue to_the ships motion into two components, Gx in the plane of fire, and Gz at rightangles to that plane; and determine their efiects separately, the first aflecting therange only and the second the lateral deflection Figure 22. 247. Let Gx be the resolved part of the speed in the line of fire in foot-seconds, change inpositive when with and negative when contrary to the flight of the projectile. Then to motionevidently the true initial velocity of the projectile is the resultant of Gx and V, and,as shown in Figure 22, V receives the increment AV = Gx cos , while (f> is decreased by A<^ = --—^^. But by equations (208) and (206), these two changes in V and, respectively, will cause a change in range given by 2n (Gx cos ^ Gx sin ~ XAAo 2n-l\ V 7tan2y COS (f> [.-) _ 2 tan J n 2Ai-l V 11 162 EX XTEEIOE BALLISTICS lateraldeviationdue to mo-tion of gun. Now as tan 2<^ = -^-^?- the above expression becomes which, when ^ is small enough to make tan^ ^ negligible in comparison to unity,reduces t
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectballistics, bookyear1
