US Air Ordnance Ww2 Markings

Aircraft technical Basics: TM 1-409, Aircraft Armament and Pyrotechnics, 1941: X

Aircraft technical Basics: TM 1-409, Aircraft Armament and Pyrotechnics, 1941: X. - Bombs for Aircraft Section X - BOMBS FOR AIRCRAFT Paragraph General

59

Model

60

Ammunition lot number

61

Ammunition data card

62

Painting and marking

63

Packing and marking for shipment

64

Adapters and boosters

65

Fuzes

66

Care, preservation, and handling

67

Handling at airdromes

68

Assembly and disassembly (fuzing and unfuzing)

69

Functioning

70

Safe altitudes and distances

71

References

72

59. General.-a. Ammunition.-The ammunition described herein is stored and shipped either as separate components or as unassembled complete rounds. In either case the complete round must be assembled prior to use. Use of the term "bomb" will be understood to mean aircraft bomb; that is, bombs for use by aircraft. Standard nomenclature is used throughout this manual


whenever specific items of issue are concerned. b. Classification-Dependent upon the kind of filler, bombs may be classified as explosive, chemical, or inert. Explosive bombs are classified according to purpose; that is, demolition, fragmentation, or practice. Both demolition and fragmentation bombs contain a high explosive filler, whereas practice bombs usually contain a small quantity of low explosive filler (usually black powder), intended solely as a spotting charge. For some purposes the low explosive spotting charge is omitted. Chemical bombs comprise those containing a chemical filler ; that is, a chemical agent which produces either a toxic or an irritating physiological effect, a screening smoke, an incendiary action, or a combination of these. Inert bombs, such as drill bombs, contain no explosive whatsoever. For further description, see the section dealing with the particular type of bomb.

FIGURE 7.-Demolition Bombs. c. Design types-Demolition bombs of current design are commonly referred to as cylindrical demolition bombs of the M-series, to distinguish them from the streamline demolition bombs of the Mk. I and Mk. III series and the cylindrical demolition bombs of the Mk. I series. Figure 7 shows characteristics of these types. In general, fragmentation bombs are relatively small with the body portions designed to provide for the best fragmentation effect. Some are designed with


fins, others with parachutes. Chemical bombs are

FIGURE 8.-Bomb, smoke, phosphorus, WP, 30-pound, Ml, complete round. designed to distribute effectively the chemical filler. A representative type is shown in figure 8. Smaller bombs are designed for either vertical or horizontal suspension, whereas the larger bombs are designed for horizontal suspension only. The fin assemblies for demolition bombs of current designs are of the "box" type. d. Bursting charge explosive train.-The bursting charge explosive train, commonly called the explosive train, consists of a series of assemblies of explosive elements in the complete round so designed and arranged that each element successively transmits the initial fire from the primer to the end that the bomb functions in the desired manner at the target. These elements are usually a primer, time or delay element when required, detonator, booster, and bursting charge, as shown in figure 9. The time or delay element is omitted when instantaneous action is required. In chemical bombs the bursting charge is replaced by a chemical agent and the explosive element corresponding to the booster is called the "burster." This component is still designated "booster" for the 30-pound chemical bomb, Ml.


FIGURE 9. -Explosive train of a demolition bomb. In general, the explosives in the system are arranged in order of sensitivity, from a small quantity of sensitive explosive to a large quantity of less sensitive explosive. 60. Model.-In order that different designs may be readily identified, a model designation, which becomes a part of the standard nomenclature of the item and appears on all drawings pertaining thereto, is assigned at the time the design is classified as an adopted type. The model designation is stamped or stenciled on the item itself in the most prominent manner practicable. In common with other ammunition items, older types of bombs were assigned mark numbers, the word "mark" being abbreviated "Mk." and followed by a roman numeral such as I, II, III, etc. For example, bomb, demolition, 100-pound, Mk. I. The first modification of a model was indicated by the addition of MI after the Mk. designation, the second by MII, etc. Thus, Mk. IMII indicates the second modification of the item originally designated Mk. I. The present system of model designations, adopted July 1, 1925, consists of the letter "M," followed by an Arabic numeral.


Modifications are indicated by adding the letter "A" and appropriate Arabic numeral. Thus, bomb, practice, 100-pound, M38A2, indicates the second modification of the bomb for which the original model designation was M38. 61. Ammunition lot number.-When ammunition is manufactured, an ammunition lot number, which becomes an essential part of the marking, is assigned in accordance with pertinent specifications. This lot number is stamped or marked on every loaded round and on certain components, on all packing containers, and on the accompanying ammunition data card. It is required for all purposes of record. 62. Ammunition data card.-A 5- by 8-inch card, known as an ammunition data card, is packed in each packing box with the ammunition. When no packing box is required, the data card is placed in an envelope and wired, or otherwise attached to the component. When required, assembling instructions are printed on the reverse side of the card. 63. Painting and marking.-a. Painting-Bombs are painted primarily for the prevention of rust. Paints of different colors are used for bombs of the various types, the color providing an additional means of identification. Following is an explanation of the color scheme : (1) Demolition and fragmentation bombs loaded with high ex-plosive, such as TNT, amatol, etc., are painted yellow. (2) Chemical bombs are painted gray. One green band painted on a chemical bomb indicates nonpersistent gas. Two green bands indicate persistent gas. One yellow band indicates smoke producer. (3) Practice bombs are painted blue. Until such time as the bomb is assembled for use, the word "Empty" is stenciled longitudinally in letters approximately 2 inches high where practicable and in at least .four places equally spaced. At the time a practice or spotting charge is added, the word "Empty" is painted out with blue paint. Exceptions may be found. For example, "Empty" is stenciled only on the shipping carton in which the bomb, practice, 100-pound, M38A2, is packed. In this case it is contemplated that the empty bomb will not be removed from its original shipping carton until such time as it is intended to sand load and add the spotting charge. Hence, no confusion should exist, and it becomes unnecessary to paint out "Empty" when the bomb is assembled for use. When practice bombs, which contain no spotting charge, either explosive or chemical, are to be dropped in training, the fins and rear body portion will be painted black. For such of these bombs as are of the streamline type, the maximum circumference will be the dividing line, while for cylindrical types the junction of the nose and cylindrical body surfaces will be the dividing line. All surfaces to the rear of this line, including the fins, are painted black, while the nose portion of the bombs is painted blue.


(4) Inert drill bombs are painted black. b. Marking.-The following information is stenciled on the bomb body: (1) Type. Examples: "DEMO.," "FRAG.," "CHEM.," or "PRACTICE," whichever applies. (2) Weight and mark of model of bomb. (3) Kind of filler (if filled). Example: "TNT," "AM 50-50," "CN GAS," "WP SMOKE," etc. (4) The word "Empty" is stenciled on unloaded bombs containing no explosive. At the time of loading, "Empty" is painted out with paint of the same color as that on the bomb body. For exception, see painting of practice bombs in a(3) above. (5) Lot number of loaded bomb. (6) Initials of loading plant and date loaded. 64. Packing and marking for shipment.-a. Packing.-(1) All unfuzed bombs have nose and tail fuze openings closed with shipping plugs. These plugs will not be removed except when the bomb is being inspected or the complete round being assembled. (2) In general, bombs weighing 100 pounds or less are packed complete in one package (all required components-but unassembled). Bombs weighing 300 pounds or more are packed and shipped in two packages. One package is the loaded bomb body with shipping bands, the second package containing the fin assembly and other components required for the complete round, similar to that shown in figure 10. (3) Shipments to and in the theater of operations will be by unassembled complete rounds; that is, each bomb will be accompanied by its fins, fuze, etc., as indicated above. b. Marking-Boxes or crates containing bombs, or components, are so marked that the contents may be positively identified. Wherever appropriate, the color scheme used for painting the bombs, described in paragraph 63, is reproduced on the packing boxes or crates


FIGURE 10.-Packing and marking for shipment of bomb, demolition, 100-pound, M30. in the form of bands or stripes. Packing containers for bombs and bomb fin assemblies are further marked with the customary shipping directions and such descriptions as are prescribed by Interstate Commerce Commission regulations. The heavy end is usually indicated for convenience in handling. c. Grating.-The bomb boxes, metal crates, fin assembly crates or boxes, etc., in which bomb components are packed for shipment are listed in TM 9-980. A list of all separate components required for the complete round is stenciled on the shipping container in which these components are packed. It is usual, however, to store these components separately, and when such is the case, "Without" is stenciled above the list of components on the shipping container. When the separate components are packed with their respective bomb or fin assembly for shipment, the word "Without" is painted out and a card listing the separate components as packed is inserted in the accessory tube, tray, or box. Tetryl is the most commonly used booster explosive. Some designs of demolition bombs have one or two auxiliary boosters. In other designs the booster is made an integral part of the fuze. c. Adapter boosters.-When a booster is assembled to an adapter, the combination is known as adapter booster. In general, adapters and boosters are manufacturing components assembled to bombs at the time of loading and are not shipped separately for use in the field. Exceptions,


shipped separately, are boosters for chemical bombs, the latter being known as bursters.

FIGURE 11.-Arming wire assemblies for single fuzes and for nose and tail fuzes. 65. Adapters and boosters.-a. Adapters.-An adapter is a steel bushing fitted to the nose or tail opening of the bomb and threaded to receive the fuze. b. Boosters.-The term "booster" is applied to one of the explosive assemblies in the bursting charge explosive train. Usually it consists of an explosive contained in a metal case, fitted to the adapter.


FIGURE 12.-Fuze, bomb, M103 (nose). 66. Fuzes.-a. General.-Current designs of cylindrical demolition bombs of the M-series are equipped with both nose and tail fuzes. The nose fuze, M103 (fig. 12) is so designed that the primer, delay element, detonator, and booster are integral parts thereof, while in the tail fuzes only the primer, delay, and detonator are integral parts of the fuzes, the boosters being assembled in the bombs at the time of manufacture. These fuzes, therefore, can be more readily assembled to bombs than the fuzes of earlier design which require separate primer detonators. Most of the fuzes of earlier design were mechanical firing mechanisms containing no explosive. An arming wire threaded through an eyelet in the arming pin, the vane strap, or the arming vane, depended upon the type of fuze, prevents initiation of fuze action until such time as the arming wire is withdrawn. Fragmentation bombs and chemical bombs are equipped with nose fuzes only. Caution: The arming wire should not be withdrawn from the fuze except when functioning of the bomb is required or when it is required to unfuze the complete round. In the latter case, instructions on the tags will be carefully followed. When the complete round is installed in the bomb rack, the swivel loop on the arming wire is secured to the arming pawl of the bomb shackle. If retained there when the bomb is released, the arming wire is withdrawn from the fuze, thereby initiating fuze action and releasing the bomb armed. If released with the bomb, the arming wire remains threaded in the arming pin, vane strap, or arming vane, as the case may be, thereby preventing fuze action, and releasing the bomb safe. Arming and safe dropping are more


fully discussed in c and d below. b. Fuze types.-Bomb fuzes are classified according to the method of arming, as follows : (1) Arming vane type. (2) Arming vane type with mechanical delay. (3) Arming pin type. (4) Arming pin type with time delay. (5) Time. Any of these types may be designed for use in the nose or in the tail of the bomb. Nose fuzes, except time, function on impact by direct action; that. is, the firing pin is driven into the primer at the instant the nose of the bomb strikes the target, whereas tail fuzes function by inertia ; that is, the plunger which carries the firing pin continues its forward motion as the bomb is retarded by the resistance of the target. Hence the action of the nose fuze is slightly faster. A time fuze may be designed to function on impact prior to the expiration of the set time. In a strict, sense, time fuzes are always armed despite the mechanical restraint which prevents the initiation of functioning. Removal of this restraint initiates the time train, thereby causing the bomb to function at a predetermined time in accordance with the fuze setting. c. Arming g.-Fuzes in all types of bombs are in the unarmed condition prior to the release of the bomb from the airplane. While unarmed, mechanical restraint prevents the firing pin from moving and firing the primer. In certain types of fuzes mechanical restraint serves to hold the primer or detonator out of line with the firing pin until the fuze has armed.

FiGURE 13.- Fuze, bomb, M106 (tail).


FIGURE , 14.-Fuze, bomb, M105 (nose), assembled. When a bomb equipped with an arming pin type of fuze is released armed, the mechanical restraint controlled by the arming pin is removed incident to the release of the bomb. The arming pin type of fuze may be designed to arm immediately after the arming pin is ejected or with delay arming as in the case of the M104 (fig. 18), and M109 (fig. 16) nose fuzes. In these fuzes a time delay feature is initiated when the arming pm is ejected. The arming vane type of fuze does not arm immediately after release of the bomb, but only after the arming vane has made a definite number of revolutions and the bomb has fallen a corresponding distance from the aircraft.


FIGURE 15.-Components required for complete round No. 524, bomb, fragmentation, 20-pound, M41.

FIGURE 16.-Fuze. bomb, M109 (nose). d. Safe dropping.-The need may arise for releasing a bomb over friendly territory in which case it is desirable that the bomb land without functioning. In order that bombs may be dropped safe, the arming wire is released with the bomb, thereby preventing fuze action, and the bomb lands without functioning.


FIGURE 17.-Bomb, fragmentation, 23-pound. M40, complete round.

FIGURE 18.-Fuze, bomb, M104 (nose). 67. Care, preservation, and handling.-a. In general, bombs and bomb components will be handled and stored as provided in TM 9-1900 (now published as TR 1370-A). Components, which are not in themselves waterproof, are packed in moisture resistant or waterproof packing. The seals of such packings should not be broken until the items are required for use. b. When bombs are to be assembled and handled as complete rounds incident to installation on airplanes, due care will be exercised to prevent any shocks or blows which might cause accidental functioning, or any damage which would prevent proper functioning when released from the airplane. Primer detonators and detonators will be handled with the greatest care at all times. They are especially sensitive to heat and shock. They should not be dropped, however short the distance, nor permitted to strike or be struck by other objects. c. Prior to assembling and handling service bombs, personnel should be trained in such drills and practices with drill bombs and inert components as will insure safe and proper assembly. d. Bombs and components will be maintained in serviceable condition.


68. Handling at airdromes.-a. At airdromes the following method of handling, assembling, and fuzing bombs has proved satisfactory. It involves the use of the following vehicles and equipment : (1) Truck, bomb service, Ml, together with equipment and accessories carried thereon. (2) Trailer, bomb, M5, together with equipment and accessories carried thereon. b. At the distributing point, all of the necessary bomb components for the required complete rounds are loaded on the trailer, which is then moved to the bomb fuzing point, the location of which is determined by consideration of convenience and safety. At. this point the complete rounds are assembled. The assembled complete rounds are then delivered to Air Corps personnel at the bomb service point (the aircraft) for installation in the airplane. The following conditions will ordinarily determine the specific method of assembling, fuzing, and delivery of complete round bombs to the airplane : (1) Ease of handling due to weight and design of bomb. (2) Clearance between the bomb bay of the airplane and the ground. Where clearances permit, installations of the assembled bombs in the airplane may be facilitated if the trailer load of bombs is maneuvered under the bomb bay, otherwise the assembled bombs may be delivered under the bomb bay individually by means of the bomb tray and lift truck, or by hand, dependent upon the weight of the bomb. 69. Assembly and disassembly (fuzing and unfuzing).-a. Assembly and disassembly of the ammunition described herein include only those operations which are ordinarily required in the assembly of complete rounds in the field. These include such operations as fuzing and unfuzing of explosive bombs; sand loading, inserting practice charges, and fuzing of practice bombs; assembling fins, gaging, etc. These authorized operations are completely described in the paragraph dealing with the particular fuze or bomb. Since the method of assembling a particular model of fuze to each of several different models of bombs is the same, it is described under the fuze concerned in a later section. Operations such as sand loading, assembling fins, etc., which must be performed before fuzes are assembled, are included in the assembly operations described in the paragraph devoted to the particular fuze. Under no circumstances will components such as fuzes or primer detonators be disassembled. b. Prior to assembly of a complete round, all mating parts such as fuzes and fuze cavities in bomb bodies will be examined. Threads must be clean and all surfaces free of foreign matter so that fuzes will screw properly into the bomb. For those fuzes requiring the separate attachment of a primer detonator, special care is required to insure that there is no foreign matter in either the


fuze or primer detonator cavities. Anything which resists the free entrance of the primer detonator into its socket when the fuze is screwed into the bomb might result in a premature explosion, since the primer detonator is very sensitive to friction and shock. c. Fuzes should be examined for any deterioration, such as heavy rust or corrosion which might impair proper functioning. Only serviceable fuzes will be used. d. Suspension lugs should be examined for any damage which might weaken the lug or its attachment to the bomb body. Lugs for horizontal suspension should be gaged by means of a standard bomb shackle or suitable gage to assure proper center distance and alinement. e. The fin assembly should be examined for security of attachment to bomb body and for straightness and alinement of fins. f. The assembly and disassembly (fuzing and unfuzing) operations described herein will be done at a safe distance from magazine or other points where explosives are stored. g. Bombs, as assembled complete rounds, will not ordinarily be on hand except in sufficient quantities to meet immediate requirements. Any assembled complete rounds in excess of such requirements will be unfuzed and components restored to their original packings. Prior to repacking, components will be inspected and those which were originally sealed will be resealed. Only experienced personnel will be charged with these duties. b. Each type of demolition bomb is separately discussed in TM 9-980. 70. Functioning.-The functioning of bombs is primarily dependent upon the action of the fuze or fuzes fitted thereto. The functioning of each fuze is described in the paragraph devoted to that fuze. The functioning of each type of bomb is described in the paragraph dealing with that type. 71. Safe altitudes and distances.-Altitudes and distances at which airplanes and ground troops are considered safe from fragments are published in AR 750-10. 72. References.-The officer will find the publications listed below of great help in the supervision of armament work. a. Army Regulations. Transportation by Water of Explosives, In flammables, and Chemical Warfare Materials AR 30-1270 Ordnance Field Service in Time of Peace AR 45-30


Storage and Issue AR 700-10 Range Regulations for Firing Ammunition in Time of Peace AR 750-10 Qualifications in Arms and Ammunition Training Allowances AR 775-10 b. Technical Manuals. Ammunition, General TM 9-1900 Precision Bombing Practice TM 1-250 Bombs for Aircraft TM 9-980 c. Standard Nomenclature Lists. Bombs, Aircraft, All Types, and Fuzing and Miscellaneous Components SNL S-1 Ammunition Instruction Material for Grenades, Pyrotechnics, and Aircraft Bombs SNL S5 Firing Tables and Trajectory Charts (includes list of bombing tables) SNL S-69 d. Ordnance Field Service Bulletins. Ammunition, General OFSB 3-1 Ammunition Reimbursement Prices OFSB 3-7 Aircraft Bombs and Bomb Components OFSB 3-8 Unsafe Ammunition OFSB 3-11 Ammunition Nomenclature and Shipping Names OFSB 3-12 e. Miscellaneous. Ordnance Field Service Circulars. Ordnance Field Manual FM 9-5 Ordnance Safety Manual, 00 Form No. 7224. Complete Round Chart. 00 Form 5981 (latest revision).

US Air Ordnance Ww2 Markings

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