NAVY MIL-B-81006 B-1968 BOMBS FREE-FALL DEMONSTRATION OF DISPERSION REQUIREMENTS FOR《散布要求示范自由下落炸弹》.pdf

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1、Licensed by Information Handling ServicesMIL-B-81006B 3.1.2 Initial number of test drops - The initial set of drops for the demonstration test shall consist of an equal number of bombs dropped under each type of maneuver at which the bomb will be used. The types of release conditions considered shal

2、l be subject to approval by the procuring activity. These conditions shall include minimum and maximum airspeeds and altitudes when there are significant variations in a particular maneuver. Decisions in accordance with the provisions of 3.1.4 shall not be made prior to the completion of this initia

3、l set of drops. 3.1.3 Order of test drops after completion of initial set of drops - The initial set of drops specified in 3.1.2 shall be accomplished without regard to the order of the release conditions employed. The release conditions of drops (if any) made subsequent to the initial set of drops

4、shall be in the order specified by a series of random numbers selected from a table of random numbers. Each release condition shall be assigned a number prior to the selection of the sequence of random numbers. The random numbers shall be chosen in groups in such a way that within any group no numbe

5、r is repeated. The size of each group of random numbers shall be equal to the number of release conditions employ.ed. 3.1,4 Decision procedure - The decision procedure shall be based upon the acceptance numbers (%) and rejection numbers (rn) given in Tables I and II (see 3.2) and the test statistic

6、calculated as in 3.1.4.1. The numbers and rn shall be selected from Table I if the bombs used in the demonstration test are classified as having canted fins, or from Table II if the bombs are classified as having uncanted fins. No decision shall be made prior to the completion of the initiai set of

7、drops, as specified in 3.1.2. Subsequent decisions shall be made in accordance with 3.1.4.2, 3.1.4.3 and 3.1.4.4, after each succeeding drop or set of drops is accomplished. 3.1.4.1 Calculation of test statistic - The test statistic for n drops, dn, shall be calculated from the sample data according

8、 to 4.4.4. 3.1.4.2 Aceeptance criterion - The demonstration test shall be con- sidered to lead to an acceptance of the bomb as meeting its specified dispersion requirements when, after the completion of the initial set of drops or after any single drop subsequent to the initial set of drops, the tes

9、t statistic, %, becomes less than or equal to the acceptance number an, and no decision has been previously made to reject, 3.1.4.3 Rejection criterion - The demonstration test shall be considered to lead to a rejection of the bomb as not meetingits dispersion requirements when, after the completion

10、 of the initial set of drops, or after any single drop subsequent to the initial set of drops, the test statistic dn, becomes greater than or equal to the rejection number , rn, andno decisionhas been previously made to accept. Licensed by Information Handling ServicesNIL-B-1OObB 13 9999906 0353Zq 1

11、 MIL-B-81006B 3. .4,4 ContYiue testing criterion - The demonstration test shall be considered to require at least one additional drop when, less than the re- jection number, rn, and no decision has been made previously either toaccept or to reject. 3.2 Acceptance and rejection numbers - The acceptan

12、ce and re- jection numbers to be employed in connection with 3.1.4.2, 3.L4.3 and 3-1.4.4 are given in the following tables: Number of Drops (n) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Table I Acceptance and Rejection Numbers for Bombs with Canted Fins Acceptance Number (an)“ - 0.25 0.51 0.77 1.03 1.29 1

13、:55 1.81 2.06 Rejection Number (rn) 1.56 1.82 2.08 2.34 2.60 2.86 3.12 3.37 3.63 3.89 4.15 4.41 4.67 4.93 5.19 an= -1,821 -I- 0.25911 rn= 1.302 + 0.25911 *A dash (-) in the an column indicates that no accepame decision is possible for the corresponding value of n (i.e. a, 10). n Licensed by Informat

14、ion Handling ServicesMIL-B-8LOObB 13 m 997770b 0358325 3 Ia MIL-B-81006B Table U: Acceptance and Rejection Numbers for Bombs with Uncanted Fins Number of Drops (n) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Acceptance Number (a,)* - 0.12 0.38 0.64 0.90 1.16 1.42 1.68 1.93 2.19 -an=-1.691 + 0.259n rn = 1.43

15、2 + 0.259n Rejection Number (rn) 1.69 1.95 2.21 2.47 2.73 2.99 3.25 3.50 3.76 4.02 4.28 4.54 4.80 5.06 5.32 *A dash (-) in the an co-Jmn indicates that no acceptance d the corresponding value of n (Le. an 5 O). =ision is possible for 4. NOTES 4.1 intended Use - The sampling plans and procedures desc

16、ribed herein are for use in the demonstration of compliance with dispersion require- ments for conventional and nuclear free-fall bombs. Demonstration of acceptability in this analysis is based on bomb impact position and does not include other effects, The specific dispersion requirement will be as

17、signed a classification dictated by the weapon for which the dispersion is specified and will be supplied by the pro- curing activity. Licensed by Information Handling ServicesMIL-B-81006B 4.2 Information for contracting officer - Contracts or orders should specify the following: (a) Title, number a

18、nd date of this specification. ) Items of data required (see 4.3). (c) Dispersion parameter, By in MILS (see 4.4.3). 4.3 Data - For the information of Contractors and Contracting officers, any of the data specified in (a) subparagraphs below, (b) applicable docu- ments listed in Section 2 of this sp

19、ecification, or (e) referenced lower-tier docu- ments need not be prepared for the Government and shall not be furnished to the Government unless specified in the contract or order. The data to be furnished shail be listed on DD Form 1423 (Contractor Data Requirements List), which shall be attached

20、to and made a part of the contract or order, 4.3.1 Demonstration test data - The demonstration test data generated in the application of this specification shall be reported to that official of the pro- curing activity designated in the development or procurement specifications or contract. Specific

21、 data reporting procedures shall be proposed by the contractor and shall be subject to approval by the procuring activity. 4.4 Definitions - 4.4.1 Dispersion - As used herein, the term dispersion indicates the difference between he computed center of impact and the actual impact of each round which

22、cm be achieved with free-fall bombs exklusive of the effects due to bombing system and, in the case of a bomb dekigned with canted fins, the effect of spin. Also, the bomb dispersion referred to does not include the effects of variation in weather, bomb weight, and launching disturbances. 4.4.2 Unit

23、s of measurement - The dispersion shall be measured in mils in the plane normal to the bomb trajectory at impact. A mil is defined as the ratio of a unit distance in the plane normal to the bomb trajectory at impact to a thousand units of trajectory arc length. (Mils = 1000 x distance in normal plan

24、e f trajectory arc length). 4.4.3 Dispersion parameter - The dispersion specifications for free-fall bombs are given in terms of the dispersion parameter B. The parameter B, inMILS, is theradius of acircle,locatedintheplanenormal tothebombs theoretical trajectory with its center at the theoretical m

25、ean impact point and encompassing 99% of the total population for a given bomb type, For a given bomb, the value of B to be employed in the demonstration test wilL be specified in the development or procurement specifications or contract (see 4.2.c). 5 Licensed by Information Handling ServicesI 4.4.

26、4 Test Statistic - The test statistic is defined by I where n is the number of drops, B is as defined in 4.4.3 and I - *ri2 = (Xi-Xn)2 + for bombs designed with uncanted fins. The Values xi and Yi are defined inmils in the plane normal to the theoretical trajectory of the ith drop at impact and are

27、related to the observed errors in the ground plane in the following way: Where A Ri and ADi are the range and deflection errors in mils, respectively, observed in the ground plane and Wi is the angle of impact of the theoretical trajectory. The values Gn and yn are the sample means of Xi and Yi in m

28、ils, respectively, for all drops. The range and deflection errors are the differences between the computed point of impact and the observed range and deflection (see Figure i). The computed impact point for any drop in a sample is the impact point of the trajectory computed for the observed conditio

29、ns of that drop. The computed trajectory is based on the best estimate of the drag coefficient available for the weapon under consideration, *It is noted that the ri values must be recomputed after each new drop using the 2 been formulated so that the probability of accepting a bomb whose true dispe

30、rsion parameter is B or less is not less than 90% and the probability of accepting a bomb whose true dispersion parameter is twenty percent or more larger than B is not more than 10%. 4.5 Example of calculations - Suppose that the compliance of the MARK XX bomb to its dispersion specification is to

31、be demonstrated. Imagine that for this type bomb, the dispersion specification of the contract indicates the dis- persion parameter B = 10 mils. The MAFtK XX is designed with uncanted fins and is intended for use under three different nominal release conditions: Licensed by Information Handling Serv

32、icesMIL-B-8100bB 13 W 777770b 0358328 7 MIL-B-81006B Licensed by Information Handling ServicesLicensed by Information Handling ServicesMIL-B-8LOObB 13 77977Qb 0358330 7 a _ _ MIL-B-81006B Computed: Range (feet) Deflection (feet) Trajectory Length (feet) Impact Angle (degrees) A Ri (feet) X. (feet) (

33、mils) (feet) i (mils) (mils) 1 - 3 X 1 15644 13 27100 71.6 51 48 1.77 -77 -2.84 -0.24 These data result in a test statistic value of 2 36549 140 53450 64.9 -280 -254 -4.75 -156 -2.92 3 18099 37 25990 56.3 71 59 2.27 137 5.27 -2 2 2 2 1 3 d 3 =- 100 (xi -%) + yi = (2.01) + (-2.84) + (-4.51) + (-2.92)

34、2 i=l which indicates that at least one additional drop should be made (since O d3 2.2). The fourth drop, from the list of random numbers, is under release condition A. Assuming that the errors in the fourth drop are x4 = 0.69 mils and y4 = 1.01 mils, then the sample mean of he range errors for the

35、four drops is Xn =-0.01. The test statistic becomes: 4 d- 4 - 1 i=l c (xi -xn) -2 f Yi 2 = (1.78) + (-2.84) + (-4.74) + (-2.92)2 + (2.28)2 + (5.27) + (0.70) + = 0.767 Again, an additional drop is required (since O d4 2.47). The fifth drop is made under release condition C. Assuming that the followin

36、g data are obtained for the fifth and successive drops: Licensed by Information Handling ServicesMIL-B-83OObB 13 m 9999906 0358333 9 m MIL-B-8 100 6B Random Release d n n Number Condition - - 5 6 7 8 9 10 11 C .79 B .84 C .90 A .92 B. .94 A .96 C 1.00 The decision to accept the Mark xx bomb as meeti

37、ng its dispersion specification is made after the eleventh drop (dll all, i.e., 1.00 1.16). 4.6 Mathematical development of sampling plans - Details concerning the mathematical development of the Sampling plans contained in this specification are in the NWL document, “Theory and Application of Quali

38、fication Test Plans for Munition Dispersion.“ This document also contains information on Average Sample Numbers and Operating Characteristic Curves for the sampling plans used in this specification. Custodians : Navy - AS Air Force - 15 Preparing Activity: Navy - As (Project No. 1105-0008) Review Activities: Air Force - 15 Licensed by Information Handling Services