1、 MIL-HDBK-669 7999970 0252278 T59 = .MIL-HDBK-669 3 Februant 1997 SUPERSEDIKG 9 August 1968 and NOTICE 1 27 March 1992 MIL-STD-669B DEPARTMENT OF DEFENSE HkNDBOOK LOADING ENVIRONMENT AND RELATED REQUIREMENTS FOR PLATFORM RIGGED AIRDROP MATERIEL AMSC N/A FSC 1670 Provided by IHSNot for ResaleNo repro
2、duction or networking permitted without license from IHS-,-,-MIL-HDBK-bb9 9999970 0252279 995 = MIL-HDBK-669 FOREWARJl 1. This Military Handbook is approved for use by all Departments and Agencies of the Department of Defense. 2. Several general guidance documents are in effect covering technical in
3、formation and operational airdrop requirements for military equipment. Until recently, such information to design engineers for use during the development cycle of an end item has been quite limited. 3 In the past, airdrop requirements for an item usually were given consideration after the design of
4、 the item had been completed and test prototypes fabricated. This was particularly true of standard commercial items that were procured for military use with little or no modification. Then, by utilizing the available provisions and structural members of the item, supplemented by field modifications
5、 which added special hardware components and local reinforcements, the item was adapted to airdrop environment. Occasionally, the basic design of the item was such that suitable field modifications could not be accomplished and the item was determined incapable of being airdropped. 4. With the incre
6、ased emphasis on mobility of military personnel and equipment, the requirement for airdrop capability of materiel must be given greater consideration and positive steps undertaken during the design phases to insure this capability. 5. To meet the need for a reference publication covering detailed te
7、chnical airdrop design criteria, the U.S. Army Natick Research, Development and Engineering Center has prepared this handbook for use by the Department of Defense during the development of military equipment having an airdrop requirement. 6. Beneficial comments (recommendations, additions, deletions
8、) and any pertinent data which may be used in improving this document should be addressed to: Commander, U.S. Army Natick Research, Development and Engineering Center, Natick, MA 01760-5017 by using the Standardization Document Improvement Proposal OD Form 1426) appearing at the end of this document
9、 or by letter. U Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-bbS = 9999970 0252280 607 - MIL-HDBK-669 CONTENTS Paragraph Page 1 . 1.1 2 . 2.1 2.2 2.2.1 2.3 3 . 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 4 . 4.1 5 . 5.1 5.2 5.3 5.4 5.4
10、.1 5.4.2 5.4.3 5.4.4 6 . 6.1 6.1.1 6.1.2 6.1.3 Scope . 1 Scope . 1 Applicable documents . 1 General 1 Government documents . 1 Specifications and standards 1 Order of precedence 1 Definitions . 2 Au.drop 2 Airdropweight 2 Drive-on, drive-off capability . 2 Developing agency . 2 Energy dissipater 2 E
11、xtraction provision 2 Retardation system . 2 Suspension provision . 2 Tie-down provision . 2 General requirements . 2 Tie-down provisions 3 Suspension provisions . 3 Loadspreader . 2 Tow-on, tow-off capability . 2 General 2 Detail requirements . 3 Extraction provisions . 3 Energy dissipater system .
12、 3 Energydissipater 3 Application of energy dissipater . 3 Preparing energy dissipater stacks 3 Distribution of energy dissipater area . 4 Tests 4 Static airdrop tests . 4 Initialtests . 4 Finaltests 4 Instrumentation 4 . 111 Provided by IHSNot for ResaleNo reproduction or networking permitted witho
13、ut license from IHS-,-,-Paragraph 7. 7.1 7.2 7.3 7.4 7.5 7.6 7.7 MIL-HDBK-669 CONTENTS Page Notes Engineering assistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Simulated airdrop impact test . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14、. . . . . . . . . . . . . 5 Approval of airdrop provisions . , . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . 5 Item design and energy dissipater configuration . . . . . . . . . . . . . . . . . . . . , , . . . . . 5 International agreement. . . . . . . . . . . . . . . .
15、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Supersessiondata . Subject term (key word) listing . . , . . . . . . , , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 iv Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-
16、HDBK-669 D 9999970 0252282 48T MIL-HDBK-669 APPENDIX Paragraph Page 10 . 10.1 10.2 10.3 10.4 10.5 10.6 10.6.1 10.6.1.1 10.6.1.2 10.6.1.3 10.6.1.4 10.6.2 10.6.2.1 10.6.2.2 10.6.2.3 10.6.2.4 10.6.2.5 FIGURES Energy dissipater configuration design equations . 6 Purpose . 6 Equation to determine total e
17、nergy dissipater area 6 Equation to determine impact velocity 6 Equation to determine fiee-drop height 6 Final deceleration value 6 Sample calculations . 7 Case1 7 Calculation of area of energy dissipater required . 7 Calculation of impact velocity . 7 Calculation of drop height 8 Calculation of are
18、a of energy dissipater required . 8 Calculation of height of energy dissipater stacks required 9 Calculation of drop height 9 Analysis . 9 Analysis . 8 CaseII 8 Summary 9 1 . Cushioning Configuration for 3/4 Ton Truck, M37 10 V Provided by IHSNot for ResaleNo reproduction or networking permitted wit
19、hout license from IHS-,-,-MIL-HDBK-669 9999970 0252283 3Lb MIL-HDBK-669 1. SCOPE 1.1 Scope. This handbook defines the loading environments for which items of military materiel experience when airdropped as platform loads, specifies essential design considerations, and establishes a method to obtain
20、a preliminary determination of the capability of items of military materiel to withstand ground impact forces resulting fiom airdrop. This handbook is for guidance only. This handbook cannot be cited as a requirement. If it is, the contractor does not have to comply. 2. APPLICABLE DOCUMENTS 2.1 Gene
21、ral. The following documents are not necessarily ail the documents referenced herein, but are the ones that are needed in order to fully understand the information provided by this handbook. 2.2 Government documents. 2.2.1 SPecifications. standards. and handbooks. The following specifications,standa
22、rds, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the latest issue of the Department of Defense Index of Specifications and Standards (DoDISS) and supplement thereto, cited in the solicitation
23、. SPECIFICATIONS MILITARY MIL-H-9884 - Honeycomb Material, Cushioning Paper STANDARDS MILITARY MIL-STD-8 14 - Requirements for Tiedown, Suspension and Extraction Provisions on Military Materiel for Airdrop (Unless otherwise specified, copies of the above specifications, standards, and handbooks are
24、available fiom the Standardization Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 191 11-5094) 2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of the reference document takes precedence. Nothing in this do
25、cument supersedes applicable laws and regulations unless a specific exemption has been obtained. 1 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- - MIL-HDBK-669 9999970 0252284 252 MIL-HDBK-669 3. DEFINITIONS The following definitions apply to the
26、terms stated: 3.1 in flight. Airdrop. A movement by aircraft, wherein personnel, supplies and equipment are unloaded 3.2 ammunition, field gear or rations. Airdrop Weight. The weight of the item, including external or internal loads such as fuel, 3.3 research and development of the item of military
27、materiel. Developing agency. The agency of the Department of Defense which is responsible for 3.4 stacks without using an external power source. Drive-on. drive-off caDabilitv. Capability to drive a vehicle on or off the energy dissipater 3.5 to dissipate kinetic energy durhg impact. Energy dissipat
28、er. As used in this standard, a crushable material (paper honeycomb) used 3.6 system. Extraction provision. An integral fitting on the item used for attaching the extraction 3.7 in this standard, it may be used between either a wheel, frame, or other member and the energy dissipater to assure crushi
29、ng of the desired dissipater area. Load spreader. A device for increasing the bearing area of a concentrated load. As applied 3.8 Retardation system. A system used to retard and stabilize the descent of an airdropped item. 3.9 Suspension provision. An integral fitting on the item for attaching the r
30、etardation system. 3.10 Tie-down provision. An integral fitting or part of an item for restraining the item to an airdrop platform or to the aircraft floor using tie-down assemblies. 3.1 1 Tow-on. tow-off capability. Capability to tow a vehicle on and off the energy dissipater stacks using an extern
31、al power source. 4. GENERALREQUIREMENTS 4.1 General. Combat and support materiel which is airdropped to combat forces by parachute and/or assault landings should be capable of immediate effective employment. An airdropped item, from the time it is loaded in the aircraft until it is recovered on the
32、ground, will have been subjected 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-669 9999970 0252285 199 W MIL-HDBK-669 to a force loading environment due to the following considerations: (a) Restraint in the aircraft for flight safety. (b
33、) Deployment of the extraction system. (c) Deployment of the retardation system. (d) Deceleration at ground impact. The item should be designed to withstand the forces due to the four conditions stated herein. 5. DETAIL REQUIREMENTS 5.1 Tie-down provisions. Tie-down provisions used to restrain the m
34、ateriel and prevent displacement in flight should conform to MIL-STD-8 14. 5.2 Extraction provisions. Extraction provisions used for attachment of the extraction system should conform to MIL-STD-814. 5 -3 Suspension Drovisions. Suspension provisions used for attachment of the retardation system shou
35、ld COOITII to MIL-STD-8 14. 5.4 Enerm dissipater system. Each item to be airdropped should be designed to accommodate the current energy dissipater system in order to provide maximum protection against damage on ground impact. The item should withstand a deceleration force ration of G+1 or 19.5 plus
36、 or minus 10 percent, times its airdrop weight when decelerated from a velocity of 28.5 feet per second to zero feet per second on ground impact, and should comply with the performance requirements of the applicable end item specification when airdropped with the current energy dissipater system. (
37、See also 7.5). 5.4.1 Energy dissipater. The energy dissipater should conform to MIL-H-9884, double-faced, 3- inch thick panel. This material crushes at an essentially constant dynamic crushing stress of 6300, plus or minus 900, pounds per square foot to 70 percent strain. Crushing stress rises rapid
38、ly beyond the 70 percent strain. 5.4.2 Application of enerm dissipater. A minimum number of stacks of the energy dissipater, based upon the total area of the dissipater material required, the bottom configuration of the item, and the local and overall structural strength of the item should be applie
39、d. The deceleration force of G+l or 19.5 times the item airdrop weight will be met by using 3.1 square feet of energy dissipator crushing area for each 1,000 pounds of item airdrop weight and a total thickness of 12 inches of energy dissipater composed of four layers of 3-inch thick panels. Arrangem
40、ent of stacks should facilitate the item to be placed on the stacks with a minimum of mechanical handling equipment. Wherever possible, it is required that the dissipater configuration for wheeled or tracked items permit drive-on, drive-off, tow-on, or tow-off capability. 5.4.3 Preparing energv diss
41、ipater stacks. Glue the layers of energy dissipater to each other and to the skid or platform. Where the underside of the item in contact with the energy dissipater stack 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-HDBK-669 9999970 0252286
42、025 MIL-HDBK-669 does not present a flat contact surface, a wood load spreader should be used. The load spreader should be glued to the top of the energy dissipater stack and should be of sufficient thickness and size to insure crushing the entire area. 5.4.4 Distribution of energy dissipater area.
43、Consideration should be given to the distribution of the dissipater area on the under surface of the item as well as the total area of the energy dissipater material used. The bearing area of the dissipater material necessary to produce 18.5 G net deceleration with built-up items such as vehicles, i
44、s less than the under surface of the item. The item in these instances, should withstand the dynamic compressive stresses at impact and the stresses due to the relative motion of the parts of the item. 6. TESTS 6.1 Static airdrop tests. Simulated airdrop impact tests are detailed to establish the ca
45、pability of the item to meet the deceleration force and performance requirements of 5.4. 6.1.1 Initial tests. Initial tests are to be made with deceleration force levels less than G+1 level specified in 5.4. The total thickness of the energy dissipater stack should be 12 inches to permit a crushing
46、stroke of approximately 9 inches. Use the equations in the appendix in determining the impact velocities and the total deceleration force levels selected. The developer should select the lower deceleration force levels for the initiai tests to preclude extensive damage resulting to the test item. 6.
47、1.2 Final tests. The requirement of 28.5 feet per second ground impact velocity specified in 5.4 will be attained when the item is free-dropped fiom a height of 12.7 feet. Measure this height fiom the lowest point on the bottom of the skid or platform upon which this item is positioned and the impac
48、t surface. Rig the item for test using a skid or standard platform with predetermined number and sizes of energy dissipater stacks, and load spreaders, ifrequired. Figure 1 illustrates a typical vehicle rigged for test. The test is to be conducted using a concrete impact surface. The dissipater conf
49、iguration should be designed to minimize rebound by placing the energy dissipater material under rigid fiame members of the item. The platform or skid must strike the impact surface at an angle of not greater than 2.5 degrees in any direction for airdrop results to be valid. The platform or skid should be approximately paraliel to the impact surface prior to drop. The item, 1 +!.2&2 (10) (-7) (1) V = 21.45 ft./sec. The im
