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HISTORY OF THE OFFICE OF MEDICAL HISTORY
Personnel Protective Armor
Maj. James C. Beyer, MC, William F. Enos, M.D.,
The development and field usage of helmets and body armor in warfare before World War II has been adequately documented by a number of excellent books and reports.1 Most of these references have been utilized in the preparation of this chapter, and in many instances they have provided the sole source of available material.2
During modern times, the helmet has had a rapid rise in general troop acceptability with remarkably little variation in design. The first protection provided for the head in World War I came about in a purely fortuitous manner. General Adrian of the French Army noted that a soldier who had received a head wound due to a rifle bullet explained his escape from death on the fact that he had carried his metal food bowl under his cloth cap. Therefore, following initial experiments in 1914, steel cap liners ("casque Adrian") were issued to French troops in 1915 and led to the characteristic World War I French helmet in 1916. Many of the other countries soon realized the value of a helmet. The British adopted their own design in 1915; the Germans, in 1915; and the Belgians and Italians, in 1916.
Following the decision in 1917 to equip the American Expeditionary Forces with a helmet, 400,000 helmets were initially procured through the British Quartermaster's Department. Subsequently, the same type of helmet was manufactured in the United States under the direction of the Ordnance Department, and approximately 2.7 million helmets, M1917, were produced by Armistice day, 1918. The American helmet was a slightly modified version of the British MkI helmet. The helmet was made of 13 percent pressed manganese steel alloy, 0.035 inch thick, and could be ruptured only by a blow of 1,600 pounds or more. The British helmet had twice the ballistic strength of the French helmet. The helmets of British design produced in the United States had an overall ballistic strength 10 percent greater than that of the original British helmet. The ballistics specifications of the M1917 helmet required it to resist penetration by a 230-grain caliber .45 bullet with a velocity of 600 f.p.s. Numerous experimental models were developed to provide (1) additional protective coverage; (2) improved ballistic properties; (3) adaptability for special functions, such as machinegunner, tank operator, aviator, and so forth; (4) a more adequate suspension lining; and (5) a distinctive patriotic design. Because of the large numbers of helmets of the M1917 design which were produced in the United States, none of the experimental models developed by the U.S. Army Ordnance Department received adoption before the end of World War I.
In the interval between World Wars I and II, the United States continued its research and development program on helmets in an attempt to increase the area coverage, to improve the protection ballistics limit (V50 or that velocity level at which there is 50 percent probability of a complete penetration of the test ballistic material by the projectile), and to facilitate troop acceptance by modification of the suspension system. Changes designed to improve the first two factors required careful consideration in order to be compatible with the weight and comfort limitation imposed by other testing technical services. Concurrent with the changes in weapon design were the demands for modification in the helmet specifications. With the advent of new weapons in the hands of belligerent countries, countermeasures can follow several patterns, such as increasing firepower to overcome the advantages of the new weapon, developing specific antitype weapons, or producing interim personnel protective devices.
Between 1918 and 1934, interest and progress in helmet development were maintained by the Ordnance Department and the Infantry Board. Following a series of experimental models (the model 5A was of pot-shaped design and received extensive testing before it was discontinued in 1932) and tests, it was recommended in 1934 that the M1917 helmet with a modified lining of a hair-filled pad be standardized as Helmet, M1917A1 (fig. 304). The final end item with an adjustable headpad weighed 2 pounds and 6 ounces.
A lull in helmet development occurred in the period from 1934 to 1940 when the first draft call was issued. With the resurge of military life and expenditures, new overtures were made to American industrial firms and to
the Metropolitan Museum of Art in New York in an attempt to improve the protective coverage and ballistic limit of the M1917A1 and to take advantage of recent advances in steel alloy manufacture, liner materials, and mass production methods. In addition, a two-piece helmet was considered desirable to meet the increasing variety and complexity of tactical and climatic conditions.
The following quotation from one of the reports of the Infantry Board reveals the natural evolution of the new helmet from the original M1917 design:
The ideal shaped helmet is one with a dome-shaped top following the full contour of the head and supplying uniform headroom for indentation, extending down the front to cover the forehead without impairing vision and down the sides as far as possible to be compatible with the rifle, etc., and down the back as far as possible without pushing the helmet forward when in a prone position, and with a frontal plate flanged forward as a cap-style visor and the sides and rear flanged outward to deflect rain from the collar opening.
Therefore, the M1917 model was considered suitable for protecting the top of the head and by removing its brim, by adding sidepieces and rearpieces, and by incorporating the suspension system into a separate inner liner, the World War II Army helmet came into being.3 The original test item was known as the TS3, and it received a favorable report from the Infantry Board in February 1941.
The Army M1 helmet (fig. 305) was standardized on 30 April 1941 and was approved on 9 June 1941. It was of two-piece design with an outer Hadfield steel shell and a separate inner liner containing the suspension system. The complete item weighed approximately 3 pounds, with the outer shell accounting for approximately 2.3 pounds and the inner liner, 0.7 pound.
Ballistic protection was afforded only by the Hadfield manganese steel outer shell with the plastic-impregnated fabric liner serving as a light-weight headpiece outside of the frontline area and facilitating the attachment of the suspension system. Various utilitarian functions were also ascribed to the outer steel shell. The ballistics properties of the outer shell had been improved so that it would resist penetration by a 230-grain caliber .45 bullet with a velocity of 800 f.p.s. The Riddell type of suspension (fig. 305C) used in football helmets was modified for the inner liner. The principle of the original Riddell suspension did not contain an adjustable headband, and this feature was developed for the helmet liner. The M1 helmet was a marked improvement over former models (fig. 306) since it furnished increased coverage (fig. 307) over the sides and back of the head and provided a more comfortable fit with the partial elimination of the "rocking" tendency of the older helmets. Following adoption of the M1 helmet, the Ordnance Department retained development and procurement of the outer steel shell and the Quartermaster Department made development and production progress of the inner liner and suspension system.
During the course of the North African campaigns in 1943, the rigid hook fastener of the chinstrap was found to be a source of potential danger by remaining intact under the impact of a blast wave resulting from a nearby detonation and thereby jerking the head sharply and violently with the production of fractures or dislocations of the cervical vertebras. Therefore, it was necessary to redesign the helmet strap with a ball-and-clevis release so that it would remain closed during normal combat activities but would allow for. a quick voluntary release or automatic release at pressures considerably below the accepted level of danger. Following extensive tests by ordnance engineers, a new release device was developed which would release at a pull of 15 pounds or more. This device (fig. 308) was standardized in 1944
The M1 helmet was the standard item of issue to ground troops, Army and Marine, during World War II and the Korean War. Before the standardization of the M1 helmet, 904,020 M1917A1 helmet bodies were manufactured from January to August 1941. During the period from August 1941 to August 1945, 22,363,015 M1 helmets were produced. Troop acceptability was fairly high, but a common complaint, was the lack of stability of the helmet. This problem had its origin, in good part, from the type of ballistic test in practice at the time the helmet was being developed. The caliber .45 pistol ball was the major test weapon, and this type of projectile with its soft lead core and thin gliding-metal jacket will deform easily against the Hadfield steel. When the helmet causes the defeat of this missile at service-weapon velocities, it will be deeply indented, and it was deemed necessary to allow a 1-inch offset
between the helmet and the head. However, battle casualty survey studies during World Wars I and II and the Korean War have shown that the primary wounding agent among the WIA and the KIA casualties was the fragmentation-type weapon. The World War II experiences are universal except for the surveys of some of the Pacific island campaigns where small arms missiles accounted for a greater proportion of casualties. After World War II, fragment simulators in a range of 5 calibers were widely used in ballistics evaluation tests of prospective ballistic materials for helmets and body armor. The advisability or necessity of the present 1-inch helmet offset requires a thorough investigation and evaluation in the development of any new helmet.
A suitable offset will always be necessary to counteract the denting of a metallic helmet or the transient deformation of a nonmetallic helmet, but the prime objective of any protective military headgear is to prevent the entrance of missiles into the cranial cavity. This entrance might be prevented over a
wider range of missile weights and velocities by modification of the present offset concept in helmet design. The missile defeat might result in skull fractures in a number of casualties, but the skull fracture type of injury is amenable to successful treatment by the neurosurgeon.
Despite the widespread use of the M1 helmet by all the U.S. fighting forces during World War II, no definite survey was ever conducted to obtain an accurate evaluation of the value of the helmet. Numerous investigators in various surveys and separate publications in medical journals allude to the undoubted value of the Ml helmet in preventing a. considerable number of deaths and nonfatal wounds in ground troops. However, because of the marked variability of collection methods and evaluation techniques of the investigators, it is most difficult to derive an accurate correlation based on sound statistical methods.
Some aspects of the value of the M1 helmet are discussed by Beebe and DeBakey in their book on battle casualties.4 More recently, Norman Hitchman5 of the Army's Operations Research Office reviewed some of the World War II casualty statistics and reached some important and timely conclusions regarding the value of wearing a helmet in combat. The following observations resulted from this statistical analysis:
1. Of all hits upon the helmet, 54 percent were defeated.
2. For every 100 men wounded while wearing helmets, 9.6 men received wounds in the cranium. Without the helmet, it would be expected that 11.4 men would be wounded in the head.
3. The M1 helmet prevented a number of incapacitating hits equal to 10 percent of the total hits on the body.
4. The estimated savings in total battle casualties means that the helmet in World War II probably prevented wounds in more than 70,000 men. A significant proportion of these men would have been killed had the helmet not been worn.
5. To get the same amount of saving by protecting other regions, body armor weighing more than twice as much as the helmet would have to be provided.
The numerous casualty surveys conducted during the Korean War provide more accurate anatomic localization of wounds in the head region covered by the helmet as related to the total head, face, and neck region, but again it was not always possible accurately to determine whether the man was wearing a helmet at the time of wounding. One survey was conducted by Capt. George B. Coe, Cm1C, in an attempt to determine more accurately the relationship between incidence of head wounds and the wearing of the helmet. One interesting observation was related where men wearing the helmet would assume a prone position to escape missiles from a mortar or an artillery shell and upon striking the ground the helmet would be released from the head and they would sustain a head wound from a second group of shells detonating in the same area.
Accurate information regarding the exact value of the helmet as a protective device is of vital importance in the training and indoctrination of troops. If it can be graphically shown that the helmet is a main line of defense against the greater proportion of projectiles commonly encountered on the battlefield, troop acceptability might be higher. Against the cast iron fragmentation projectiles which were commonly used by the North Korean and Chinese Communist Armies during the Korean War, the M1 helmet probably gave a better performance than with the steel fragments which predominated during the World War II fighting. The relatively soft and brittle character of the cast iron fragments would lend itself to low hardness and toughness and to greater ease of refragmentation and defeat upon impact against the helmet. The U.S. high explosive shell fragment has an average Rockwell "C" hardness of 29-31 and the Soviet cast iron shell fragment has a hardness of 8-14.
Research programs following the Korean War have been directed toward an increase in both the ballistic protection limit and the troop acceptability under varied combat conditions. A multiplicity of factors must be reconciled and coordinated in order efficiently to effect significant changes in either of these properties. World War II investigations proved the efficacy of nonmetallic ballistic materials (nylon and doron) alone or in conjunction with metallic outer shells, but satisfactory field tests were not completed before the termination of hostilities in Korea. With the recent success of these plastics in the body armor developed for ground forces during the Korean fighting, increased emphasis has been given to all forms of research bearing upon helmet development and design.
Notwithstanding the respectable performance of the M1 helmet during World War II and the Korean War, continued improvement should be actively supported. The doldrums of peacetime can prove very lethal to worthwhile
and unspectacular research programs directed toward the development of items of equipment where the present standard items might appear acceptable. Any new helmet, regardless of its V50 superiority, will have to pass the ultimate test of combat troop acceptance, and this is primarily dependent upon the fit and stability of the helmet. The frontline combatant must be indoctrinated and impressed with the protective integrity and necessity of the helmet and equally with the ease and comfort with which it can be worn. Therefore, this is one field of military design where correct tailoring should be obtained commensurate with the imposed limits of the protective ballistic materials. Certain testing procedures on newer experimental helmets would appear to have been excessively delayed, and active aggressive interest in the problem has frequently dropped to a very low level.
Ground Troop Models
In addition to the M1 helmet, a variety of other designs were developed by the Ordnance Department during World War II. These will be discussed in the paragraphs to follow.
Helmet, steel, M1C (Parachutist's).-This helmet (fig. 309) included a modification of the M1 liner (Liner, Helmet, M1, Parachutist's) with a special chinstrap which insured that the helmet would stay on during the opening shock and descent of the parachute. This liner chinstrap was provided with a chin cup, and two snap fasteners secured the steel shell to corresponding fasteners on the inside of the liner and prevented the separation of the two components during parachute jumping. The regular helmet shell chinstrap was worn behind the head. This item was standardized in January 1945, and 392,000 helmets were produced during the period from January to April 1943.
Helmet, T14 series (Signal Corps).-This was an experimental series of helmets designed to provide the combat Signal Corps photographer with maximum protection under extreme operating conditions. The standard M1 helmet restricted necessary movement and adjustments of still and motion picture cameras and prompted the dangerous habit of removing the helmet while being exposed to enemy fire. In May 1944, the Signal Corps proposed that the front segment of the M1 helmet be cut away and an adjustable, hinged visor flap be placed over the cutaway area. The Ordnance Department prepared test models which did not gain wide acceptance during field tests in the European theater. One objection was due to the fact that, when the visor was locked in its upright position, the helmet bore a superficial resemblance to the German helmet. The Metropolitan Museum of Art incorporated this problem in their work on a helmet for the Armed Forces and developed several promising models. Cessation of hostilities in 1945 prevented the completion of an end item.
Helmets, T19 and T20 series (Tank).-In November 1940, Headquarters, Armored Force, Fort Knox, Ky., requested the cooperation of the Ordnance Department in modifying the then existing tank helmets to make them more compatible with the varied functions and hazards of tank crewmen. Concurrently, the Quartermaster Corps was engaged in a design of a new tank crash helmet which would offer protection from blows to the head. In 1944, subsequent correspondence requested that the tank helmet designs embody (1) a liner, incorporating a crash-type suspension, over which could be fitted a modified M1 ballistic shell and (2) the ballistic steel shell with an integral crash-type suspension. The proposed military characteristics required that the helmet would (1) protect the wearer from blows to the head during maneuvers over rough grounds, (2) be relatively light in weight with a comfortable fit, (3) permit full access to and the usage of various sighting devices, (4) permit wearing of radio headsets, (5) allow the forehead of the wearer to rest directly against the tank headrest, and (6) be capable of furnishing either ballistic or crash (bump) protection.
The Ordnance Department developed six experimental series, and the Metropolitan Museum of Art evaluated the models in accordance with the Armed Forces specifications. Series T8 incorporated a ballistic helmet with a crash suspension and T9 provided a ballistic cover for the existing tank crash models (fig. 310). During this same period (1944), extensive work had resulted in a number of prototypes of flyer's helmets, and certain of these were considered as being adaptable to the needs of the combat tank crewmen. The T10 series
(fig. 311A) was very similar to the helmet, T9, but provided an associated crash suspension in the steel shell. Helmet, T12 (fig. 311B) was based directly on the Helmet, M3 (Flyer's) with an internal crash suspension, and T13 (fig. 311C) was prepared without the latter feature and was designed to fit over a cut down M1 liner. The T16 (fig. 311D) series was a modified M3 flyer's helmet with a reduction in certain dimensions to bring it within the limitations of the requisite military characteristics.
Between October and December 1944, helmets of the T10, T12, T13, and T16 series were tested by the Armored Force Board, Fort Knox, Ky. All the samples were found to be excessive in weight and overall dimensions and incompatible with the operation of the various sighting devices. The extensive offset and posterior extension of the helmets were developed to accommodate the radio headset and to provide adequate neck protection, respectively.
In 1944 and 1945, a coordinated effort of the Ordnance Department and the Quartermaster Corps was directed toward the development of an acceptable modification of the M1 helmet shell to be used with the crash suspension-type M1 liner. Helmet, T19E1 (fig. 312) was derived from an M1 helmet shell. Changes in its contour permitted the use of various optical equipment while allowing the helmet to be used in conjunction with the new quartermaster
liner which offered bump protection and clearance for the headsets. An unfavorable report on this helmet was rendered in May 1945 because of the instability of the helmet-liner combination.
After this work on the T19E1 helmet, helmets T20 and T20E1, produced in sample lots, incorporated a head suspension directly within the T19E1 ballistic shell. Finally, the T19E2 and T20E2 series evolved and were based upon a new contour design developed at the Armored Medical Research Laboratory. Definitive reports on these four items were not available before the cessation of hostilities in World War II. However, the consensus was to the effect that further attempts to produce a helmet for use in tanks by modifications of the standard M1 helmet should be abandoned and that the search should be directed toward a completely new and specific tank helmet design. More recent advances in the design of helmets for crewmen of combat vehicles
have made increasing use of nonmetallic ballistic materials and have attempted to provide a headgear with high user acceptability and possessing primary bump protection and secondary ballistic protection. Figure 313 illustrates the present combat vehicle crewman's helmet. The following information on this helmet was released on 25 February 1958 by the Public Information Division, Office of the Chief of Information and Education, Department of the Army:
Tank crewmen will have the first helmet specifically designed for their protection when mass protection tests of a new helmet developed by the U.S. Army Quartermaster Corps are completed. Up to the present time, tank soldiers have worn either the standard M-1 Steel Helmet with liner or football helmets, none of which met their requirements. The new helmet, officially designated Combat Vehicle Crewman's (CVC) Helmet, is constructed of multi-layers of laminated nylon fabric, and has a built-in communications system developed by the U.S. Army Signal Corps. The total assembly weighs about three pounds. Nylon employed in its construction is similar to that of the Army's armor vest. Mounted outside the helmet, the communications equipment includes a microphone on an adjustable boom, a three-way switch for listening or talking by radio or through the tank's intercommunications system, and a cable with a quick-disconnect plug for emergency evacuation from the vehicle. Inside the helmet, snug-fitting earphones reduce outside noise and help guard the ears against injury.
Helmets, T21-24 (ground troops).-Throughout the World War II period, investigative work continued in an attempt to improve the standard M1 helmet. In conjunction with the Ordnance Department and the Aero Medical Labora-
tory, at Wright Field, Ohio, the Metropolitan Museum of Art designed the T21, T22, and T23 series.
The T21 (fig. 314) was patterned after the crown of Helmet, M5 (Flyer's), but without the earflaps and with a brim contour based on the M1 shell. Its shape had been established through anthropometric studies of the human head (fig. 315) and provided a curvature in all directions at all points on the body of the helmet. This latter feature was purported to provide a decrease in the size of the helmet with no sacrifice in area coverage while increasing the strength and protection beyond previously possible limits. The shell weighed 2 pounds and 2 ounces and was to be worn with the conventional inner plastic liner.
Helmet T22 was smaller than T21, was a one-piece unit incorporating a head suspension, and was designed to be worn without a liner. Conversely, the T23 was larger in size than the T21 and permitted the use of thicker liners. In the interim between 1945 and the outbreak of the Korean War, modifications of the series just mentioned and additional new series were developed but none obtained approval or standardization.
Shortly after the adoption of the M1 helmet, various investigations revealed that other materials might possess superior ballistic protective limits
and that these materials might obviate certain metallurgical and production difficulties inherent in the Hadfield manganese steel. In 1942, a one-piece helmet was fabricated from the resin-impregnated glass fiber laminate known as doron (p. 682). At this time, doron was under consideration primarily for use in a proposed nonmetallic helmet for civil defense workers, but subsequent tests by interested military agencies showed that existing prototypes did not stand up well when exposed to the rigors of combat life.
Aluminum and nylon in combination had received extensive ballistic testing in the development of body armor for ground troops and flyers, and by 1945 samples of helmets utilizing these materials were being produced. Coupled with the high degree of protection against fragmentation-type weapons was the additional possibility of furnishing equivalent coverage to the Ml helmet with an appreciable reduction in weight. Therefore, the T24 helmet was produced consisting of an outer aluminum shell, modeled after the M1, with an inner laminated-nylon liner. Despite the cessation of World War II hostilities, the helmets were tested and deficiencies noted in the ability of the nylon insert to resist delamination and warpage. The T21E utilized the aluminum and nylon elements but was based upon the contour pattern of the T21. This pattern had evolved from scientific anthropometric studies of the human head and permitted a lower silhouette and closer fit than the M1 design. At the present time (1958), the Helmet, M1, is still the standard item of issue to Army ground troops.
Flyer's Models (World War II)
Despite the fact that the development of protective devices for air forces combat personnel in World War II is somewhat beyond the scope of this volume, it is believed that a brief discussion of the development of some of the helmet models is very appropriate since many of the problems which were encountered were very similar to those seen in the development of certain forms for ground force personnel. The complete story of the development of protective devices for air force personnel has been written by Link and Coleman.6 This work should be consulted by all those who are interested in the medical participation in the development of helmets and body armor in the Army Air Forces in World War II.
By 1943, it had become very apparent that the standard Army helmet required redesigning to make it adaptable to the needs of air forces combat personnel.7 Similar in nature but more extensive in scope, the problem
paralleled the work performed for the Armored Forces. Combat airmen were faced with the situation of wearing oxygen masks and goggles and earphones but still requiring some ballistic protective device for the head. Before an acceptable helmet was available, 35.7 percent of unarmored bomber combat crews sustained lethal wounds in the head region. After introduction of the "Grow helmet" or M4 helmet, this number was substantially reduced. A few of the helmet models which were developed and standardized are discussed in the paragraphs which follow.
Helmet, steel, T2 (Flyer's), standardized as Helmet, M3.-This was a direct modification of the M1 steel helmet shell with an associated adjustable head suspension and cutaway on each side of the helmet body to accommodate earphones. A hinged earplate provided protection over the cutaway earphone area. Because of the immediate need for a flyer's helmet, the T2 received extended service tests and was eventually standardized in December 1943 as Helmet, M3 (fig. 316). This helmet weighed 3 pounds and 3 ounces. Between December 1943 and April 1945, 213,543 helmets of this type were produced. During its development, it was recognized that this type of helmet was unsuitable for a number of confined combat stations where a closely fitting skullcap type of helmet was necessary.
Helmet, steel, T3 (Flyer's), standardized as Helmet, M4.-During the early part of 1943, the Eighth Air Force had combat tested a skullcap type of helmet, and the Ordnance Department proceeded to develop prototypes based
upon this design and field experience. By September 1943, this model was being tested in conjunction with the T2 model. It consisted of overlapping Hadfield steel plates which were enclosed in cloth pockets and mounted in the skullcap cover of fabric and leather. Openings were available on the lateral aspect of the helmet to permit the wearing of headphones. Notwithstanding the decreased protective coverage of this helmet, it could be worn in the restricted space of aircraft turrets where a larger one would not be acceptable. This helmet was standardized as Helmet, M4, in December 1943 (fig. 317A). It weighed 2 pounds and 1 ounce. In February 1944, it was recommended that the length of the M4 be increased to provide an adequate fit over all types of summer and winter leather flying helmets.
Helmet, T3E3 (Flyer's), standardized as Helmet, M4A1.-Shortly after the M4 became standard issue, it was apparent that armored earplates were required, and a number of experimental models were developed and tested. Finally, by April 1943, the T3E3 was adopted to replace the M4 and was standardized as the M4A1 (fig. 317B). It differed from the M4 by having a slight increase in length and by being equipped with attached metal earplates over the temporal regions. This helmet weighed 2 pounds and 12 ounces. A method was also devised to equip the existing M4 helmets with a fitted hood containing metal earplates. In addition, the M4A1 was later modified (M4A2) to improve the attachment of the earplates and to increase its compatibility with other flying gear. After the adoption of the newer model, a considerable number of experimental helmets were developed and tested in a continuing effort to produce a universal air force helmet with extended area coverage, increased protective ballistics limits, wearer acceptability, and compatibility with associated flying goggles and headphones. Because of fabrication difficulties with the overlapping steel plates in M4 helmet series, emphasis was centered upon a one-piece closely fitting helmet bowl with attached earplates. In addition to the Hadfield manganese steel, a number of other metallic materials were considered, and at one time aluminum seemed to provide the promising combination of comparable ballistic protection at a somewhat lower weight. However, during World War II, Hadfield steel continued to be the principal ballistic material for helmets.
Helmet, steel, T8 (Flyer's), standardized as Helmet, M5.-The helmet, T6E4, had a single steel bowl with no associated suspension system, fitted close to the head, and had large hinged earflaps. It was a most promising model, and future modifications originated from the T6 series. The T8 models were based upon the specifications of the T6E4 but incorporated numerous design changes which increased its acceptability over previous models. The helmet consisted of a one-piece steel bowl with a head suspension system and hinged earplates or cheekplates which extended down on to the sides of the face in line with the leather flyer's helmet. The usual webbing suspension system was augmented by a nape strap that held the front of the helmet against the forehead so that there would be no interference with vision. The cheekplates permitted the wearing of earphones and goggles. One additional mod-
ification provided a slight roll to the back of the helmet to reduce the possibility of injury to the neck region during crashlandings. In January 1945, the T8 was standardized as Helmet, M5 (fig. 317C), and was designated for all combat aircraft positions except the upper turret gunner of the A-20 and the ringsight gunner of the B-29. The M4A2 was still used in the two positions just mentioned. The M5 helmet weighed 2 pounds and 12 ounces. Between February and August 1945, 93,495 helmets of this type were produced.
During the period from October 1943 to July 1944, numerous designs for face armor were studied concurrently with the development of flyers' helmets. Most of the models were intended to be worn in conjunction with the helmet and were to provide protection over the lower part of the face, the neck, and the oxygen mask. Both metallic (fig. 318) and nonmetallic materials were tested. The project was suspended in 1944 because of the lack of specific requirement for this type of armor.
"Body armor is not new."8 Some form of personnel protective device has probably been used in every war which has been recorded in the pages of history.
During the Civil War,9 a number of types of protective shields and breastplates were developed by interested parties, and some of these were considered for possible official military usage. However, no standard official form of armor was available, and all forms were purchased by individual soldiers. Two types have been described as being most popular among Union soldiers. These consisted of the "Soldiers' Bullet Proof Vest" manufactured by the G. & D. Cook & Company of New Haven, Conn., and the second most popular
type of breastplate was manufactured by the Atwater Armor Company, also of New Haven. Both types consisted of metallic ballistic material made up of a number of steel plates. The product from the Cook & Company consisted of two pieces of steel inserted into pockets in a regular black military vest. The infantry vest weighed 3˝ pounds, and another model for cavalry and artillery weighed 6 pounds. The purchase price of a vest for an officer was $7 and for that of a private was $5. The Atwater armor consisted of four large plates of steel held in position on the body by broad metal hooks over the shoulders and a belt around the waist. In addition, smaller pieces could be attached to the bottom of this cuirass. This vest was heavier than the Cook models and cost approximately twice as much. The supply of these finished commercial products was augmented by specimens of armor apparently of individual manufacture by some local blacksmith.
During the course of his investigations, Dr. Bashford Dean of the Metropolitan Museum of Art was able to test the Atwater armorplate and found that it would defeat a jacketed bullet fired from a caliber .45 pistol at a distance of 10 feet. In his short but excellent discussion of body armor in the Civil War, Harold L. Peterson felt that the chief factors in the discontinuance of body armor at that time were the inconvenience due to the extra weight and bulk and the marked ridicule of those individuals who were wearing the armor by their comrades who did not avail themselves of the protection.
Dr. Dean in his "Helmets and Body Armor in Modern Warfare" presents a complete account of the history of body armor during World War I. Most of the participating countries developed various forms of protective devices for the torso and the extremities, but the excessive weight or lack of adequate protection restricted their general use in combat. Some form of body armor was seen on all fronts from 1915 through 1918, but only on experimental basis, and body armor was never in general usage. The most successful use of armor was by sentinels, members of patrols, and stationary machinegun crews. Despite the relative low troop acceptability because of excessive weight, it was generally believed that these forms of personnel armor had great potential value.
General Adrian who was instrumental in developing the French helmet was also interested in a number of other devices, including an abdominal shield, a breastplate, and leg armor. Some of the medical officers investigating the casualties of British forces through the year 1916 indicated that more than three-quarters of the wounded men could have been saved if some form of armor had been worn. This assumption was based upon a study of the type of wounds (penetrating rather than perforating) and the preponderance of causative missiles being derived from fragmentation-type weapons (either shrapnel or shell fragment). Similar statistics were derived from studies of French casualties where it was believed that 60 to 80 percent of all wounds were produced by missiles of low to medium velocity.
Maj. Charles H. Peck, MC, Assistant Director, Surgical Service, American Expeditionary Forces stated: "Wounds caused by missiles of medium and low
velocity constitute about 80 percent of all." Therefore, numerous test models were developed by the Ordnance Department and a few of these did reach the stage of field testing, but no final standardization was ever achieved.
The British were interested not only in metallic but also in nonmetallic ballistic material. They developed a silk-lined necklet which was purported to stop a 230-grain pistol ball at 600 f.p.s. However, the primary materials, extremely difficult to obtain, deteriorated very rapidly under combat conditions and were considered costly ($25). In addition, the British also studied a 6-pound body shield that was approximately 1 inch thick and was made of many layers of linen, cotton, and silk hardened by a resinous material. Certain responsible military authorities were also convinced of the possible potential value of body armor, and in 1917 General Pershing said: "Effort should be continued toward development of a satisfactory form of personal body armor."
In the interim between 1918 and the onset of World War II, experimentation in body armor materials and design was maintained at a very low level. However, in conjunction with its general program of developing and testing ballistic materials, the Ordnance Department was aware of the possibilities of certain materials' being utilized for a protective garment for the individual soldier.
In the fall of 1941, the British Army was producing a model of body armor in preparation for a field test, and samples of this model were furnished to the United States. The armor weighed 2 pounds and 12 ounces and consisted of three plates of 1 mm. thick manganese steel. Two plates were to be worn over the front and one over the back of the body. In addition, the Ordnance Department was considering two other forms of British body armor; namely, the Armorette and the Wisbrod Armored Vest. The Armorette was composed of metal plates embedded in a vulcanized rubber-duck foundation which imparted a high degree of flexibility to the model. The Wisbrod vest utilized cloth-covered steel plates which overlapped to provide protection to the front of the thorax and abdomen. Both of these latter two models had been under consideration since the early part of 1941. The models were studied by various testing boards of the interested technical services, but all reports indicated that any advantages of such armor would be very slight as compared to the overall loss of combat efficiency and to the increase in the soldier's carrying load. Therefore, individual body armor for ground troops seemed to be a military luxury which could not be indulged in during an all-out global conflict, and there was no apparent requirement for a standard item of issue. This latter decision was officially reached in November 1942 and led to some decline in the overall interest and developmental program for body armor for ground troops. But shortly after this, an extensive program was initiated for the development of protective armor for the Air Forces. It is of some interest to note that in April 1943 an endorsement was written to the Army Air Forces by the Army Ordnance Department in which it was felt that body armor for general use by ground troops had been rejected because of the apparent loss of mobility of the troops and that an application might well be considered for
combat Air Forces personnel. It was felt that ballistic protection could be provided either by use of personnel body armor or by use of plates or curtains which might be placed in strategic places within the aircraft.
Air Forces (World War II)
The history of the development and usage of body armor by combat crewmen of the Army Air Forces during World War II is adequately discussed in the publication by Link and Coleman. The development of these items was so intimately connected with various casualty surveys-some of which are reported in this volume-and by research work of the Army Ordnance Department that a brief résumé would be appropriate in this chapter. No attempt will be made to give a complete coverage of all items and the rationale behind their development, but the more important models will be described since many of these bear a very close relation to subsequent development for Army ground troops.
The initial impetus to the development of body armor for the American flyer was due to the research and field testing which the British had performed in an attempt to develop some form of personnel armor for their ground troops operating in North Africa. Subsequent to this, in early October 1942, an analysis of wounds incurred by U.S. Eighth Air Force combat personnel revealed that approximately 70 percent were due to relatively low velocity missiles. In one survey involving 303 casualties and conducted before the adoption of body armor, it was found that flak fragments were responsible for 38 percent of the wounds; 20 mm. cannon shell fragments, 39 percent; machine-gun bullets, 15 percent; and secondary missiles, 8 percent. A later survey of 1,293 casualties revealed a similar breakdown of missiles. In addition, it seemed that protection provided to the regions of the chest and abdomen would bring about the highest rate of return in reducing both fatalities (mortality) and total numbers of hits (morbidity).
Therefore, it appeared to Col. (later Brig. Gen.) Malcolm C. Grow, MC, then surgeon of the Eighth Air Force, that some type of body armor might serve to protect aircrew members and save a considerable number of lives among the combat crews. The initial consideration of a ballistic material was based upon previous British experiments which had revealed that a manganese steel plate 1 mm. in thickness would resist penetration of a caliber .303 bullet at a velocity of approximately 1,250 f.p.s. In addition, this material was shatterproof, had high resistance, and was comparatively light in weight. After deciding on this ballistic material, Colonel Grow, in association with the Wilkinson Sword Company, Ltd., of London, formulated plans for a vest made up of overlapping plates of manganese steel. These 2-inch square Hadfield steel plates were secured in pockets and sewed to a backing of flax canvas. Preliminary testing of the armor was so favorable that Lt. Gen. Carl Spaatz, Commanding General, Eighth Air Force, approved the recommendation on 15 October 1942 for the order of 10 suits of armor for experimental testing. Following this,
sufficient armor for crews of 12 B-17's were ordered and received about 1 March 1943. Later, Lt. Gen. Ira C. Eaker who had assumed command of the Eighth Air Force directed that sufficient armor be produced in England to equip all heavy bombers located there and also recommended that armor suits be provided for all heavy bomber units destined for the Eighth Air Force.
The original armor provided complete protection for the anterior and posterior aspects of the thorax. The vest was placed across the shoulder and fastened by closing the dot fasteners over one shoulder. In addition to the vest, a sporran apron section was suspended from the vest by fasteners and provided protection for the abdomen, crotch, and part of the lower extremities. A number of models were made to be worn by various crew members, depending upon their position and function in the aircraft. The pilot and copilot wore a half vest only in the front, and bombardiers, navigators, and gunners wore full vests to secure both front and back protection. A full-width sporran was for men who had to stand during the performance of their combat duty. Other forms were tapered toward the bottom. The full vest weighed 16 pounds; half vest, 7 pounds; full sporran, 6˝ pounds; and tapered sporran, 4˝ pounds. The armor was made to wear over all other clothing and equipment and eventually was constructed so that the complete suit could be quickly jettisoned (fig. 319) by pulling a ripcord.
Numerous casualty surveys10 conducted at various times following the introduction of flyer's armor showed a variable reduction in the total wounds incurred and in the number of fatal wounds over the parts of the body protected by armor. Despite the variability expressed by the various surveys, they all showed one thing in common; namely, that flak suits for combat crewmen were a highly successful and valuable adjunct in decreasing the total number of wounds and the number of lethal wounds in the thoracoabdominal region.
Surveys conducted among heavy bomber combat crew members before and after the adoption of body armor showed the following results. The surveys in the period before the use of body armor were conducted from March through September 1943. The period of survey after the use of body armor was from November 1943 to May 1944. During the March through September 1943 period, 137,130 combat crew members went on bombing missions, and 746 casualties resulted with a total of 896 wounds. This gave a casualty rate of 5.44 men wounded and 6.53 wounds per 1,000 crewmen dispatched on missions. This gave a ratio of wounds received compared to crew members on missions of 0.646 percent. In the November 1943 to May 1944 period, 684,350 crewmen went on missions, 1,567 men were casualties, with a total of 1,766 wounds. This gave a casualty rate of 2.29 casualties and 2.58 wounds per 1,000 crewmen on missions. This gave a ratio of wounds received compared to crew members taking off of 0.248 percent. Therefore, there was a reduction of 58 percent in persons wounded and a reduction of 60 percent in total number of wounds sustained per 1,000 crewmen on missions.
Since there was the important question of whether the foregoing results were due solely to the usage of body armor or due to a number of tactical conditions, such as change either in combat formations or in enemy tactics, a survey was done of the battle damage to aircraft during the same survey period. In the period before the use of body armor, 26.46 percent of aircraft returning to their bases from bombing missions were found to have battle damage. In the period after the use of body armor, 21.47 percent of returning aircraft had battle damage. Therefore, in a comparison of the two periods, one finds a 60 percent decrease in total number of wounds sustained by crewmen following the introduction of body armor and a concomitant 18 percent decrease in aircraft battle damage. Therefore, some of the reduction in the number of casualties and in the total number of hits sustained by the casualties was undoubtedly due to factors other than body armor, but there can be no doubt whatsoever that the main reduction was due solely to the introduction of body armor.
A study pertaining to the anatomic location of wounds sustained during the two survey periods revealed a reduction of 14 percent in wounds of the head
and neck, 58 percent in wounds of the thorax, and 36 percent in wounds of the abdomen. During the survey period among the heavy bomber combat crew members, there was a reduction in fatality of thoracic wounds from 36 to 8 percent and of abdominal wounds from 39 to 7 percent. This meant that after the introduction of body armor there was a reduction of 77.1 percent in the fatality rate of thoracic wounds and a reduction of 82.8 percent in the fatality of abdominal wounds. During the survey period, it was also shown that body armor prevented approximately 74 percent of wounds in the body region covered. After termination of hostilities in Europe, a comprehensive survey of casualty figures showed that the fatality rate for individuals with thoracic wounds fell from 34.9 percent in the unarmored group to 15.3 percent in the individuals wearing body armor. In those individuals sustaining abdominal wounds, the fatality rate was reduced from 32.5 to 15.7 percent. Therefore, because of the untiring pioneer work of General Grow and his fellow medical officers, the value of body armor for combat crewmen in the Army Air Forces was definitely established, but not until the Korean War was a similar situation attained in regard to combat ground troops.
Initially, the flyer's armor, or flak suit, as it was more commonly known, was produced solely by British manufacturers. However, it soon became apparent that they should not be required to be the sole source of supply for the critically needed manganese steel. Nevertheless, a total of 600 suits were made in England. Samples suits were received in the United States in July 1943, and the Army Ordnance Department took over the task of quantity production and improvement in design. From that date until the termination of World War II hostilities, the Ordnance Department and various civilian institutions were responsible for producing approximately 23 types of flyer's armor. The armor workshop of the Metropolitan Museum of Art became the main design research laboratory in the development of flyer's armor. The Air Force Materiel Command at Wright Field, Ohio, had also been interested in development and production of armor, but this function was also turned over to the Ordnance Department.
The initial production of the armor in the United States was based solely on the design which had been developed by General Grow and his British advisers. Hadfield manganese steel plates, of the same composition as that used in the M1 helmet, provided the ballistic protection. These plates were sewed into cloth pockets and fastened to a cotton-duck backing. However, by the end of 1943, a nylon-duck cloth was substituted for the cotton material. The nylon duck weighed 20 ounces to the square yard and increased the ballistic protection limits of the vest.
The Flyer's Vest, M1 (fig. 320), was a close copy of the design which had been submitted from the Eighth Air Force in England. This was made up of two sections which provided protection for the front and back of the body and was fastened at the shoulders by quick-release dot fasteners. It was intended to be worn by gunners, navigators, bombardiers, and radio operators whose combat duties required them to move about so that they
would be exposed to injury from both the front and the back. The complete M1 vest, including both front (fig. 320A) and back sections (fig. 320B), weighed 17 pounds and 6 ounces and provided an area protection of 3.82 square feet. Between August 1943 and August 1945, 338,780 M1 vests were produced.
The Flyer's Vest, M2 (fig. 321), was made up only of an armored front section, very similar to the frontpiece of the M1 vest, and an unarmored backpiece. It was intended to be worn by pilots and copilots and other combat personnel whose duties would allow them to sit in a seat which could have an armored back and provide the protection for the back of the body. The weight of the front section for the M2 vest was 7 pounds and 15 ounces and provided an area of protection of 1.45 square feet. Between August 1943 and July 1945, 95,919 M2 vests were produced. Both the M1 and M2 vests were standardized on 5 October 1943. As mentioned previously, the ballistic protection was provided by 2-inch square overlapping Hadfield manganese steel plates which were enclosed in pockets, and since the original linen canvas stock for the backing was not available in the United States a cotton canvas stock was utilized and later replaced by ballistic nylon stock.
The Flyer's Apron, M3 (fig. 322A) had a construction similar to the frontpiece of the M1 vest and consisted of a roughly triangular piece of armor intended for use in turrets and other positions in the aircraft where space limitation was a factor. It could be fastened to the front of the M1 or M2 vests by means of dot fasteners and had a total weight of 4 pounds and 14 ounces. It gave an area protection of 1.15 square feet. The Flyer's Apron, M4 (fig. 322B), was similar to the M3 but was larger in size and was intended for use by waist gunners and other individuals who could utilize a full length armor. It had a weight of 7 pounds and 2 ounces and an area protection of 1.66 square feet.
In addition to the flyer's apron, it was also believed that some protection should be provided to the groin, the abdomen, and the thighs for personnel who remained seated. The first test item was a groin armor, T12 (fig. 323A), designed in 1943. It consisted of 10 steel plates which were shaped and hinged to give protection to the anatomic areas just listed. The armor weighed approximately 8 pounds and gave an area protection of 235 square inches. A later modification known as T13 was received from the Eighth Air Force in January 1944 and consisted of three sections of overlapping steel plates and weighed approximately 14 pounds and gave an area protection similar to that of the T12. The T13 was modified in March 1944 and standardized as Groin Armor, M5 (fig. 323B and C). It was made in three sections so that the central area could be drawn up between the legs. The side section spread out to provide protection for the upper aspect of the thighs.
The entire piece could be attached to the M2 vest. It weighed 15 pounds and 4 ounces and provided an area protection of 3.72 square feet. All forms of the armor just described were equipped with quick-release dot fasteners and tapes and thongs connected by a ripcord for rapid jettisoning of the armor by the wearer.
The continued research of the Ordnance Department in an attempt to provide an equal or higher level of ballistic protection with an increase in area coverage and a decrease in total weight of the armor soon led to the development of other models utilizing different ballistic materials. The Flyer's Vest, M6 (fig. 324), was standardized on 1 July 1945. This vest had the same function as the M1 vest but was made of aluminum plates with a nylon back padding. The vest weighed 14 pounds and 9 ounces, or 2 pounds and 14 ounces less than the M1 vest, and had an area protection of 4.09 square feet as compared to the 3.82 square feet of the M1 model. The Flyer's Vest, M7, was of the same construction as the M6 and was made to replace the M2 vest. With
the shift of emphasis to back-packed parachutes in the Pacific areas, the armor design had to be modified to fit over the parachutes. This gave rise to two models (M6A1 and M7A1) which fulfilled this function. The models were constructed of aluminum and nylon. In addition to these last two items, a number of other experimental models were developed by the Ordnance Department and the Metropolitan Museum of Art. The T5 series of flyer's armor contained larger overlapping armorplates and were held snugly against the body by an elastic webbing. This provided an increase in area protection with a decrease in weight of the end item.
Concurrent with the interest by both the Army and Navy in laminated layers of woven glass fabric impregnated with plastic (doron), this material was considered in flyer's armor. The T37 series in experimental models showed a replacement of the steel plates in the M1 vest by flat doron plates 2 inches square and 0.130 inch thick. A later modification utilized thicker doron plates that had an outer curvature. However, with the advent of improved aluminum and nylon ballistic material, the doron project for flyer's armor was discontinued.
In addition to the improvement in the flyer's vest, similar end items and experimental models were developed in aprons and groin armor. The Flyer's Apron Armor, M8 and M9, were standardized in July 1945 and were to be used with the M6 and the M7 vests. Both of these were constructed of aluminum and nylon; the M8 apron armor weighed 4 pounds and 11 ounces while the M9 weighed 6 pounds and 8 ounces. Additional apron armor to correspond with the M6E1 and M7E1 were also developed. With the replacement of the Hadfield steel plates by aluminum and nylon, a similar change occurred in groin armor. The Groin Armor, M10, standardized in July 1945, was made of aluminum and nylon and was to be used in conjunction with the newer vest. At the termination of hostilities, many very interesting tests were being performed to see if flyer's clothing and equipment could be made of nylon-type cloth and by itself provide some ballistic protection. This would then have reduced the weight of the aluminum-nylon-cloth combination ballistic armor and might have provided a higher protection ballistic limit with a decrease in total weight of the armor end item.
At one time, it was felt that protection should be given to the region of the neck which might be exposed between the helmet and the armored vest. Therefore, a T44 series (fig. 325A) of experimental models was developed and consisted of a Queen Anne's type of neckpiece which was made to rest on the shoulders and attached to the M4 series of helmets. This had the same construction as the M1 vest and consisted of 2-inch square Hadfield steel plates. The development of this item was terminated in June 1945 when a shift was made to aluminum and nylon as the ballistic material. The T59 series (fig. 325B) consisted of curved aluminum plates with a nylon-duck backing which was made to fit the contour of the shoulder and neck. Both frontpieces and backpieces were made to be attached to the armored vest of similar construction. One of the experimental models, T59E2, was standardized as M13 in
September 1945. Tables 249 and 250 show some of the production figures for the various types of flyers' armor and a summary of the weight and area protection. All of the statistics have been derived from various sources and might show some variation from other compilations.
1These figures have been compiled from various sources and do not represent final Ordnance Department compilations.
Following the widespread use and adoption of flyer's armor, a considerable number of other sections of the fighting forces became interested in its possible usage. In October 1943, Motor Torpedo Boat Squadron Number Twenty Five became interested in possible revision or modification of the flyer's armor for their usage. Similarly, the Cavalry Board at Fort Riley, Kans., was also interested in its possible use for mechanized cavalry personnel. In addition, one of the companies producing flyer's armor also submitted samples of a modification of the original design for possible usage in amphibious and other invasion landings. These designs were of various types; some provided only thoracoabdominal protection, and others provided protection for the extremities.
Ground Troops (World War II)
Unlike helmet design, which had a considerable carryover from World War I development and experience, little if any information was available at the advent of World War II on the possible design of a body armor for ground troops. Numerous military authorities had advocated the use of body armor during World War I, but it had only reached a preliminary testing stage before it was generally rejected. During World War I, the United States had developed several types of armor. One, the Brewster Body Shield, was made of chrome nickel steel, weighed 40 pounds, and consisted of a breastplate and a headpiece. This armor would withstand Lewis machinegun bullets at 2,700 f.p.s. but was unduly clumsy and heavy. In addition, the Metropolitan Museum of Art in February 1918 had designed a breastplate based upon certain 15th century armor. Again, this model weighed 27 pounds; all investigators considered it to be very noisy and thought that it markedly restricted all movements of the wearer. Another extremely interesting model was the scaled waistcoats or jazerans which were constructed of overlapping steel scales fixed to a leather lining. The armor was closely fitting and was considered comfortable. The total weight was 11 pounds.
Numerous investigators in the Ordnance Department and in the other technical services had contemplated the development of armor for ground troops in the early stages of World War II. However, very preliminary investigations had shown that most models were too heavy, were incompatible with standard items of equipment, and tended to restrict the mobility of the soldier. Therefore, the development of armor for ground troops was initially rejected as an unsound idea, and the development of a flyer's armor received more or less full attention. However, continued investigation in the development of lighter weight metallic ballistic material and in the relatively new field of nonmetallic ballistic material led to a resurge in interest for armor for ground troops. Therefore, the historical study must be traced through both types of ballistic material, and initially the types of armor utilizing metallic material will be discussed.
It is difficult to ascertain exactly when the redevelopment of armor for ground troops was initiated, but it apparently began sometime near the middle
of 1944. In June 1944, the Army Service Forces requested armor for the protection of soldiers from antipersonnel mines. Another major initiating feature was undoubtedly due to some of the excellent work performed by Lt. Col. I. Ridgeway Trimble, MC, then chief of the surgical service at the 118th General Hospital, Sydney, Australia. Colonel Trimble became very interested in reports concerning the use of armor by Japanese ground troops. After a great deal of difficulty and personal disappointment, he was able to secure a copy of Japanese armor (fig. 326). Based on the Japanese design and his own personal observation as to the areas to be protected and the most commonly encountered wounds and causative agents, he developed a model for ground troop armor.11
In addition to Colonel Trimble's persistence in presenting his material, various other members of the consulting division of the Medical Department of the Army were very instrumental in overcoming some of the prejudice which was present on the part of the services which would use the body armor.
Other types of Japanese body armor (figs. 327, 328, and 329) which were captured in the Pacific consisted of an anterior thoracoabdominal shield with and without lower extremity protection. Various other members of casualty surveys in the Pacific areas, notably in the New Georgia and Bougainville campaigns, were also convinced of the apparent importance which body armor might have in reducing total number of wounds and number of lethal wounds in ground troops.
Based upon the armor submitted by Colonel Trimble and on the various other specimens collected by technical observers of the Ordnance Department in the Southwest Pacific Area, an experimental model was developed and this design was known as vest, T34. The armor consisted of 0.684-inch thick carbon steel plates. Owing to the excessive weight of the end item and also to the development of lighter weight ballistic materials, the T34 series was discontinued. Various other experimental models were being tested at about the same time and one of these consisted of the armor, breast, T36, which was patterned somewhat after a World War I model. The vest, series T39, consisted of a small piece of anterior armor with a stitched nylon-webb backing and utilized various metallic ballistic materials, such as steel or aluminum, in the form of overlapping plates. Numerous other experimental models were
developed, but only those which resulted in a standardized end item will be discussed.
The vest, T62E1, consisted of two pieces, front and back, which were fastened together at the shoulder by quick-release fasteners. The ballistic materials consisted of 0.102-inch thick aluminum plates and a backing of 5-ply nylon cloth. All of the aluminum plates had a slight overlapping to provide thorough protection, and there was a small anterior flap on the frontpiece which was designed to give additional protection to the region of the heart and great vessels. The vest weighed 9 pounds and 10 ounces and had an area protection of 3.45 square feet. The vest, T62E1, was modified in order to provide additional ballistic protection and resulted in the T64 series which was standardized in August 1945 as the Armor, Vest, M12 (fig. 330).
This M12 vest was made of thicker aluminum plates than the T62E1 series and had additional layers of nylon cloth. It weighed 12 pounds and 3 ounces and provided an area protection of 3.45 square feet. The design had been modified to provide greater protection for the anterior portion of the thorax both by increasing the width of the main frontpiece and also by increasing the size of the anterior flap over the heart and great vessels. In addition, some increase in protection was provided for the axillary regions. However, the areas of the junction of the neck and thorax and of the axillary regions were still relatively uncovered and, as it was seen during the use of
the M12 vest during the Korean War, provided a ready access for the entrance of missiles into the thorax. An Apron, Model T65, was also produced to be attached to the M12 vest in order to provide ballistic protection for the lower part of the abdomen and the groin region. The apron could be attached to the bottom of the vest by quick-release fasteners. It was made of 21-ply nylon cloth, weighed 1 pound and 9 ounces, and had an area protection of 0.66 square feet.
A considerable number of the vests and aprons were produced and were scheduled for field testing and observation by a joint medical-ordnance-infantry team12 just at the cessation of the war in the Pacific. In July 1945, 1,000 T62E1 vests with the T65 apron and 1,200 T64 vests were shipped to the Pacific theater for field testing, but this was never accomplished. Therefore, the vest received considerable experimental testing, but it was not until the Korean War that it was utilized in the field. With the rebirth of body armor during the Korean War, the M12 vest was used initially by American troops in conjunction with the newer all-nylon-type vest. Following the completion of the initial surveys and standardization of the final end item, all U.S. frontline troops were equipped with the newer all-nylon or doron vests, and the M12 vests were used by Republic of Korea troops.
The following tabulation shows some of the production figures for ground-type armor in World War II:
1For June 1945.
The production of the M12 vest was slated to continue to a certain degree after August 1945, and before the termination of hostilities it was estimated that 100,000 vests of this model would have been produced by September 1945. Table 251 is a summary of the type of armor and its corresponding weight and area protection.
Following the termination of hostilities in the Mediterranean and European Theaters of Operations, it soon became very evident that some type of protective devices would be required by personnel engaged in minefield clearance. As early as June 1944, the Office of the Chief Engineer was engaged in the development of a protective device for the combat boot. The overall project was later coordinated with the Ordnance Department and led to the development of the T16 series of crotch armor.
The model T16E4 was based on a previous flyer's model and originally consisted of a central crotch section with two overlapping metal plates which were hinged on the sides. Later, the central hourglass-shaped section was developed with two lateral phalanges made up of nylon material. The central area continued to be made of small overlapping metal plates and was fastened by means of straps to the cartridge belt. A later model, the T16E6, provided a reduced area coverage through elimination of the central protection in the
rear and a reduction in the size of the lateral leg phalanges. However, some increased protection was provided in the region of the groin and genitalia. This model was also constructed of a combination of 2-inch square manganese steel plates and nylon-duck material. It was believed that the crotch armor could be used in conjunction with other items of personnel armor and some locally improvised lower extremity protection for those individuals engaged in mine clearance. The model T16E4 (fig. 331) weighed 3 pounds and 6 ounces and provided an area protection of 1.15 square feet.
There is a dearth of medical statistics in regard to the positive importance of crotch armor for such personnel. However, numerous casualties were seen during the Korean War who suffered extensive saddle-type injuries due to detonation of landmines. It is very conceivable that protection in the region of the groin, the upper part of the thighs, and the buttocks would have been of some value for these individuals. Therefore, in conjunction with the development of the thoracoabdominal vest during the Korean War, an all-nylon crotch armor was produced, but it was not intended for general usage. It was advocated only for personnel engaged in specialized tasks, such as mine clearance.
In May 1945, samples of eye armor were being manufactured by the French Army, and designs to fit the U.S. M1 helmet were collected for testing by the Army Ordnance Department. These models were not considered adequate, and a new series of eye armor, T45 (fig. 332), was developed. This consisted of a plate of manganese steel, the same as that in the M1 helmet, and was provided with small vision slits. The entire structure was mounted in a rubber dust-goggle frame. Close coordination between the Ordnance Department,
Engineer Corps, Army Ground Forces, and the Office of the Surgeon General showed that the T45E6 (fig. 332B) was the most acceptable design, and it was standardized on 10 January 1946. Notwithstanding the cessation of hostilities by this time, it was believed that a standard item was required for the clearance of minefields in occupied countries.
It is of some interest to note that other types of protection for ground troops very similar to that which was tested in World War I also saw some consideration during World War II. An example of this was a project on mobile shields (fig. 333) which was initiated in September 1943. It was considered that the device could be manipulated by a single man and that it would provide protection against rifle and machinegun bullets at a very close range. This would permit the soldier to close in on highly fortified positions and provide protection for soldiers stationed in advanced observation posts. It was believed that the ballistic protection would have to be provided by armor-plates of considerable weight and thickness and that the entire device would have to be transported by means of wheels. In order to provide the degree of ballistic protection considered necessary, the planners thought the weight would have to range in the neighborhood of 150 to 200 pounds. After a very brief consideration, the entire project was discontinued.
The use of nonmetallic ballistic material for body armor was a result of close liaison between various developmental agencies in both the Army and Navy and only reached the possibility of a possible end item in the Navy. However, because of the association of the Army Quartermaster Corps and Ordnance Department in its development, some brief mention of it would be appropriate at this time. The search for a nonmetallic ballistic material stemmed partially from a desire to reduce the overall weight of metallic body armor and also because of the critical shortage of the metallic material during World War II. Therefore, an active search was carried out by research and development people in all branches of the military services. Two of the most active sites of research were the Research and Development Branch of the Military Planning Division, Office of the Quartermaster General, and the Naval Research Laboratory. The Quartermaster Corps was interested in
obtaining a nonmetallic material both for body armor for ground troops and for usage in civilian defense helmets. The Naval Research Laboratory was interested in the possibility of body armor for use by Marine ground forces and certain shipboard personnel. The Army Ordnance Department was also actively engaged in this search and was responsible for all ballistic evaluation tests. Woven glass-fiber fabric impregnated with plastic (doron) had been considered in August 1944 for use in flyers' armor, but the program was discontinued following the favorable test results with aluminum-nylon combinations. The doron was to be utilized in the form of 2-inch square plates, 0.130 inch thick.
A number of industrial concerns instigated active research programs, and in May 1943 the Dow Chemical Company laminated a fibrous glass fabric which immediately proved very promising. The initial product consisted of layers of glass filaments of Fiberglas bonded together with an ethyl cellulose resin under high pressure. Some of the individuals working with Col. (later Brig. Gen.) Georges F. Doriot, then director of the Military Planning Division, Office of the Quartermaster General, decided that the project should be known as the "Doron Project" in his honor. Therefore, the glass fiber laminate manufactured by the Dow Chemical Company became known as and continued to be called doron.
The initial material was known as doron, Type 1, and future modifications consisted primarily of variations in the bonding resin in order to give a more adequate ballistic performance over a wider temperature range. Most of the
body armor developed during World War II utilizing doron was prepared from a form known as doron, Type 2. In addition to the military developmental agencies, numerous private industries were also involved in the research, development, and production of doron material. These included the Westinghouse Electric Corporation, the Continental-Diamond Fibre Company, the United States Rubber Company, the Hercules Powder Company, the American Cyanamid Company, the General Electric Company, The Firestone Tire and Rubber Company, The Formica Company, the Monsanto Chemical Company, and numerous others.13
Because of biservice interest in the possible usage of doron, a Joint Army-Navy Plastic Armor Technical Committee was established. This committee included members from the Office of the Army Quartermaster General, the Naval Research Laboratory, the Navy Bureau of Ships, the Office of the Army Chief of Ordnance, the Navy Bureau of Medicine and Surgery, and the Navy Bureau of Aeronautics.14 The purpose of the committee was to coordinate all research and development efforts and also to facilitate the production of doron. Ballistic research had provided sufficient information so that it was possible to calculate that a 1/16-inch plate of 8-ply doron, Type 2, would have a protection ballistic limit sufficient to stop a caliber .45, 230-grain bullet fired from the standard service automatic pistol at a velocity of 800 f.p.s. Therefore, in order to provide some degree of safety over this calculated minimal V50, it was felt that the material for body armor should be made up of 1/8-inch 15-ply doron, Type 2.15 The Army Ordnance Department felt that a better correlation could be attained between the use of nylon-aluminum combinations and protection ballistic limit, body coverage, and total weight of the finished item. Therefore, doron was tested in a considerable number of experimental models, but the consensus was that Hadfield steel or aluminum-nylon combinations were superior. Therefore, no end items were developed in the Army program utilizing doron as the ballistic material. However, the Navy felt that doron was a most promising material and continued toward the development of some form of armor for Marine ground troops and shipboard personnel.
The 1/8-inch thick doron plates were utilized by the Navy in two forms; namely, (1) by placing eight panels into pockets on the outside of the Navy kapok lifejacket and (2) by sewing plates on the inside of the pockets of the standard-issue Marine Corps utility jacket. The armor used in both jackets weighed 4 pounds and covered a body area of approximately 3 square feet.
In an attempt to provide a more drastic demonstration of the ballistic properties of doron and also to determine whether the doron armor could be closely applied to the body or would require some offset, a most courageous demonstration was conducted by two Navy officers. Lt. Comdr. Edward L. Corey, USNR, wore the new armored lifejacket vest and permitted an associate, Lt. Comdr. Andrew Paul Webster, USNR, to fire at him with a caliber .45
pistol. There was complete defeat of the bullet, and this demonstration was repeated 21 times with no serious injury.
As a result of the total testing procedure, the Marine Corps requested that a full battalion of landing troops be equipped with armored jackets. Approximately 1,000 jackets were prepared and were intended to be used with a Marine division during the Okinawa operation. A survey team from the Naval Research Laboratory and from the Office of the Quartermaster General of the Army were to conduct surveys on both armored and unarmored men in an attempt to ascertain the jacket's actual value and also guide future design in developmental programs. Unfortunately, the Marine division which was to conduct these tests was not employed in the Okinawa operations. A few of the armored jackets were probably used in the last phases of the fighting on Okinawa, but no large-scale survey was conducted.
The development of doron was sufficiently advanced so that armored doron jackets could have been available for the troops at the time of the invasion in Normandy and undoubtedly would have been very instrumental in saving a considerable number of lives. However, there is always a great deal of reluctance and inertia which has to be overcome before the using agencies will accept body armor. This is not meant as a reflection upon the Ground Forces but rather exemplifies their innate and natural desires for a battle to reach a swift and successful conclusion. This can only be accomplished by having the largest number possible of active fighting men who can swiftly and completely perform all combat duties. Therefore, any form of personnel armor has to be completely compatible with all equipment required for the performance of these duties, impose a minimal additional weight load, be comfortable in all climatic conditions, impose little if any restriction on mobility, and finally have a high degree of troop acceptability. If it can be graphically demonstrated that body armor can be constructed so that it will meet all imposed military characteristics, there is a more general acceptance of the item by the Ground Forces.
Naturally, the Medical Corps is immensely interested in any item which brings about a reduction in morbidity and mortality of battlefield casualties. During World War II, medical treatment of the battle casualty had reached a high degree of excellence, and if hostilities had continued it would have soon become apparent that some additional means would have to be provided for the reduction of total number of wounds and number of lethal wounds. In other words, something would have been required forward of the battalion aid station level in an attempt to prevent men from being wounded and to reduce the number of men who were being killed instantly. Unfortunately, this lesson of body armor was not learned until late in World War II, and it was not until the Korean War that the numerous sceptics were convinced and body armor was accepted wholeheartedly.
Let us hope that peacetime stagnation will not completely shackle the developmental program so that in the advent of any future hostility body armor will be available at its immediate onset.
REPORT OF DEVELOPMENT OF A DESIGN FOR BODY ARMOR FOR THE FOOT SOLDIER
On or about 1 September 1942 I read in the Sydney newspapers about an armored Japanese vest captured in New Guinea by Australian soldiers during the Papuan campaign, and consulted Dr. Dew, Professor of Surgery at Sydney University, as to where I might procure such a vest. He wrote to Colonel W. J. Hailes, Medical Directorate, L.H.Q. Victoria Barracks, Melbourne, whose letter of 12 September 1942 told me that work along these lines was being studied in the Middle East by a member of the Medical Research Council of Great Britain. Lt. Colonel R. V. Graham's letter of 16 November 1942 written from the 103rd Australian General Hospital stated that he had asked his son who was in New Guinea at the time to try to procure such a vest for me.
Colonel C. A. Jillet, D.D.O.S. First Australian Army, wrote 30 November 1942 that the First Army had not received such equipment.
Letters written to the Police Departments of the cities of New York, Chicago, Pittsburgh, and Los Angeles resulted in replies during January and February 1943 telling of the protective armor used by them.
19 November 1942 I wrote Brig. General Hanford MacNider asking him to try to procure a vest for me in New Guinea, and asking him for his ideas on protection for foot soldiers.
Colonel C. N. Kellaway, of the Australian Army, and Director of the Walter and Eliza Hall Institute of Research in Pathology and Medicine, personally brought me from Melbourne information relative to work done by the Body Protection Committee of the Medical Research Counsel of Great Britain.
25 November 1942 I called on Colonel C. C. Alexander, Chief of Staff to Maj. General Richard Marshall, Commanding General, SOS, to ask him how to procure a Japanese vest telling him that I had for a long period thought some practical armor protection could be worked out for ground troops. Colonel Alexander was most interested and advised me to see Colonel Carroll, the Chief Surgeon, and Colonel Thorpe of G2. Colonel Carroll was enthusiastic and spoke of his having thought of including the spade of the entrenching tool as body protection. Major Suave in Colonel Thorpe's office promised to obtain the Japanese vest for me.
9 January 1943 a letter came to me from G.H.Q., SWPA., Rear Echelon entitled "Captured Japanese Bullet Proof Vests," which attached a letter from the office of the Director of Staff Duties, L.H.Q., Australian Army, acknowledging my request on 24 November 1942 for the loan of a Japanese Bullet Proof Vest, adding that the only one in the possession of the Australian Army was being tested at the Broken Hill Pty. Steel Works, Newcastle, N.S.P., and suggesting that I inspect the vest at these premises.
17 February 1943 I received a captured Japanese vest (fig. 334) from Commander J. C. Morrow of the Australian destroyer "Arunta" through one of his officers, Midshipman Norman H. Smith. I showed it to Colonel Carroll and Colonel Alexander and on 26 Feb. 1943 had the Signal Corps make drawings and pictures of it.
16 April 1943 the U.S. Quartermaster Department of G4, SOS, asked me to try out some plastic material as possible use in body armor so Major Coleman of that department and I made some firing tests on the shooting range at Long Bay, N.S.W., the plastic material being easily pierced and fragmented by the caliber .45 automatic pistol and Thompson submachinegun bullet.
22 March 1943 Mr. R. M. Service of the Australian Army Inventions Directorate forwarded to me the analysis of the armor plate of the captured Japanese vest and that of some Australian steel submitted by an Australian civilian, a Mr. R. Welch, who was trying to interest the Australian and American armies in a steel jacket made of individual pieces of steel approximately 4 inches square, linked together with a hinge on all four edges. Mr. Welch's armor was put on by inserting one's head through a hole in the center of the gar-
ment, like putting on a poncho. Beginning at this time, at the request of Mr. Welch and Mr. Service, Lt. Colonel D. Garrison of the U.S. Ordnance and myself tested Mr. Welch's vest on the firing range as well as a model based on the Japanese vest in my possession and made for me by chief operating room nurse, 1st Lt. A. M. Seney. The plates for my vest were six large ones (fig. 335), overlapping and placed inside the vest, in accordance with the Japanese plan (fig. 336). However, my plates were made from plaster casts moulded on a man of 150 lbs, 5 ft. 7 in. in height and covered more of the regions of the collar bones, the upper part of the breast bone, the flanks and the lower abdomen than did the Japanese.
Mr. Welch kindly offered to hammer out for me some steel plates in exact accordance with my plaster casts, and we used these new plates of mine to test on the firing range as well as testing his linked steel armor.
His armor proved entirely unsuitable, because a missile striking a hinged joint would penetrate the armor in the majority of instances.
25 March 1943 I sent to Brig. General C. C. Alexander, Hq. USASOS, APO 501 the first summary of my study on protective body armor, telling of my possession of the Japanese vest and recommending a vest "constructed along the lines of the captured Japanese one" for our own army. This report was forwarded by General Alexander to the Chief Surgeon and the Chief Ordnance Officer, SOS Headquarters, APO 501.
13 June 1943 Brig. General J. L. Holman wrote to me requesting that my set of Japanese armor be sent to the Chief Ordnance Officer in Washington, D.C. through Base Section 3, APO 923. This armor was sent by me 17 June 1943, and acknowledged by General Holman 20 June 1943.
16 September 1943 I wrote General Holman objecting to a public demonstration of body armor before the press by Mr. R. Welch at Base Section 7. The armor was apparently that of his design since the Sydney newspaper account, dated 15 September 1943, spoke of light steel plates linked together; but the enclosing tunic in the photograph published by the newspaper was similar to my modification of the Japanese one. Mr. Welch's original armor had no tunic. The performance of the vest against various types of firearms was reported in this paper. The demonstration was made without consulting our army or intelligence at any time.
23 December 1943 Colonel W. C. Cauthen, Chief Ordnance Officer, USASOS, APO 501, wrote asking that the vest which I designed be submitted to the Chief of Ordnance. This vest was taken to the Ordnance at APO 501 by me 2 January 1944 and kept by Ordnance 501 for me until my return from duty in New Guinea, 15 April 1944.
15 February 1944 Maj. General N. F. Twining, Commanding General of the 15th Air Force, wrote, asking me to bring my vest to the attention of the Head Flight Surgeon of the 5th Air Force. I was in New Guinea at the time but submitted the vest to the office of the Flight Surgeon at APO 501, 15 April 1944.
20 April 1944 a complete set of blue prints of my vest was made at the office of the Surgeon, 5th Air Force.
23 April 1944, at the direction of the Chief Surgeon, USASOS, APO 501, I submitted a final report of the body armor to the Research and Development Board, Hq., GHQ, APO 500 with an endorsement by the Chief Surgeon, Brig. General G. B. Denit. The receipt of this information was acknowledged by Dr. G. R. Harrison, Chairman of this Board. The final model of the vest submitted by me differed from the Japanese in the following particulars:
"a. The vest and its metal plates are designed in a larger size than the Japanese. The plates were hammered out of steel from plaster casts moulded on a soldier 5'7" in height weighing 150 pounds. These plates should fit all soldiers except those of an extremely small or large stature. (A marking of "medium" in Japanese characters on one of their vests indicates that they are manufacturing them in more than one size.)
b. The space at the base of the neck just above the breast bone and the region of the large blood vessels just beneath the collar bones are covered in the new design.
c. Better metal protection is given the flanks and the lower part of the abdomen.
d. A metal plate is added on the inside of the back of the vest to cover the base of the spine and the kidney areas.
e. The button arrangement of fastening the vest down the front has been eliminated because it takes too long to discard the vest by this method. The front of the vest should be in one piece. The vest should be fastened by one or two clasps along the left side of the chest and flank, and by a clasp on each broad shoulder strap of the vest. These last two
clasps should be arranged sufficiently low on the shoulder so as not to be pressed on by the rifle when carried on the shoulder or by the butt of the rifle when firing. By this arrangement the vest can quickly be discarded in any direction even with overlying cartridge belts, etc.
f. A small curved strip of metal should be incorporated into each shoulder strap to help prevent the wounds incurred by missiles entering the chest through the space above the collar bones, when a man is charging with the upper part of the body bent forward.
g. In soldiers or sailors in stationary positions, where extra weight is not so important, such as crews of antiaircraft guns, additional metal plates could be added to protect the back and shoulders from gun fire."
I. RIDGEWAY TRIMBLE,