The M-26 tank, seen here on an M8 tank transporter, did not enter combat in the European Theater until the final days of WWII. Its armor protection, 90mm gun, and modern torsion bar suspension finally put U.S. tankers on a par with their German opponents. Armor Combat Development 1917-1945 by Dr. Robert S. Cameron This article was compiled on behalf of To overcome the absence of American concepts and technology — including the Directorate of Force Development, tanks, the War Department endeavored the American Liberty aircraft engine — and it provides an historical overview of to produce a copy of the French Renault in a design that would be assembled in the policies governing American tank de- FT 17 light tank, develop a new design France. Intended to spearhead a planned sign in this early period. Together with through Ford Motor Company, and par- 1919 offensive, production suffered from two subsequent articles, it is intended to ticipate in a combined British-French- the slow rate of Liberty engine develop- recognize the basic accomplishments of American effort to build the Mark VIII ment and the priority given to aircraft for combat developments with respect to the heavy tank. None of these endeavors those engines produced. The war’s end Mounted Force from their infancy in proved successful. Rather than simply in November 1918 left the U.S. Army World War I to the sophistication repre- mass-produce a copy of the Renault with a collection of parts that upon as- sented by the Future Combat System. tank, the Ordnance Department modified sembly provided it with 100 Mark VIII the design, although lacking tank pro- tanks.5 When America joined the Entente in duction experience. Delays and confu- April 1917, it possessed no tanks of its The continuation of wartime tank pro- sion resulted, unrelieved by disagree- own. Indeed, the tank originated from duction into 1919 resulted in the Army’s ment whether the speedometer of a tank British and French efforts to end the possession of a tank fleet expensive to capable of less than ten miles per hour Western Front trench deadlock. Follow- maintain and mechanically unreliable. should show kilometers or miles per ing a study of British and French tank Worse, it provided an illusion of tank hour. Only ten American-made Renaults use, however, the U.S. Army established strength that impaired Congressional were built by war’s end.3 the Tank Corps, within the American Ex- willingness to fund the development and peditionary Forces, to organize and train In an early effort to utilize the mass production of new designs. Throughout American tank units.1 Headed by Colo- production capability of the automotive the interwar era, the Army could afford nel Samuel D. Rockenbach, the Tank industry, Ford Motor Company received only one new model a year.6 Corps combined the French emphasis on a contract to mass produce a three-ton small light tanks to accompany advanc- light tank that it would design itself. The exclusive use of tanks in a trench- ing foot soldiers with the British prefer- Over the objection of AEF personnel breaching role resulted in their associa- ence for large, heavily armed tanks to who found the vehicle unsatisfactory for tion with the Infantry. Consequently, the breach enemy positions in advance of an combat, the company produced only 15 National Defense Act of 1920 that de- infantry assault. Consequently, separate by war’s end.4 The Mark VIII repre- fined the Army of the interwar period American light and heavy tank units sented the first international tank design. abolished the Tank Corps and assigned were formed.2 It incorporated British and American tank development responsibility to the 14 ARMOR — September-October 1997 Infantry. The Act precluded experimenta- J. Walter Christie’s tank designs further ties resulted in the development of mo- tion with tank use beyond the narrow reinforced the trend away from tank car- bile combat teams of tanks, self-pro- mission of assisting the advance of the riers. During the interwar years, he built pelled mortars, and riflemen working in- rifleman and seizing ground.7 tanks capable of moving 40 miles per dependently toward common objectives. hour cross country, fording rivers, allow- The mobile, dispersed nature of these ac- Under the guidance of Rockenbach, ing rapid conversion between wheel and tions generated requirements for an ar- now commanding the Infantry’s tank track movement, and equal speeds for- mored personnel carrier and self-pro- force, tank development focused upon a ward and backward. Although the Army pelled artillery. A new set of tank specifi- medium tank. He sought a design capa- never adopted any of Christie’s designs cations also emerged that stressed mobil- ble of accompanying the rifleman in all for standardization, it flirted with them ity and reliability over firepower and ar- terrain, able to withstand .50 caliber ma- throughout the era and purchased several mor. chine gun fire, carrying close support models. It found them unsuited for the The fresh impetus given to tank devel- firepower, and weighing no more than stresses of military usage and their de- opment by the Mechanized Cavalry co- 15 tons in order to utilize highway incided with a general desire to jettison bridges. Such a balance of armor, mobil- the World War I tank fleet of Mark VIIIs ity, and firepower proved beyond the ca- and Renault tanks. Such tanks did not pability of American tank technology in “One Infantry tank officer permit analysis of the fast moving tactics the 1920s.8 Although three tanks were advised that the “best solu- now advocated by the Infantry and built under Rockenbach’s supervision Mechanized Cavalry. Echoing the senti- between 1921 and 1925, all proved over tion for the present mecha- ments of those personnel associated with 20 tons.9 nized means of the U.S. mechanized development, one Infantry Army is to get the biggest tank officer advised that the “best solu- The difficulties of creating a satisfac- transport we have, load it tion for the present mechanized means tory medium tank encouraged the Infan- all on, and dump it into of the U.S. Army is to get the biggest try to shift its focus in 1926 to light tank transport we have, load it all on, and development. The higher mobility and the middle of the Atlantic dump it into the middle of the Atlantic speed of these vehicles also reflected the Ocean....” Ocean.”16 Army’s preference for a war of maneu- ver over a positional conflict like the The Infantry and Mechanized Cav- Great War.10 In particular, the Infantry alry’s combined interest in light tanks re- sought a tank capable of 12 miles per sulted in the T2-series that became the signer unscrupulous in his business deal- hour, possessing a 37mm main gun, and pattern for the later M3 and M5 Light ings.14 armored against .30 caliber machine gun Tanks. A single chassis served both fire.11 Light tank development also benefited arms. The series introduced the vertical from the creation of the American Ex- volute suspension, necessary to handle The resulting T1 series was designed as perimental Mechanized Force in 1928 the 35-mile-per-hour speed. Although in- a light, fast tank suitable for portage by and the Mechanized Force in 1930. Both tended to utilize a Wright-built Conti- truck. The first model represented a col- forces sought to combine tanks with nental aircraft engine, Guiberson diesel laborative effort between the Ordnance other arms and utilize them in a variety engines equipped some models. In 1936, Department and the Society of Automo- of tactical roles. Neither organization 19 T2s were produced, to be followed by tive Engineers. It embraced the newest could survive, however, in the face of 170 in 1937.17 advances in automotive technology, in- opposition from the combat and service The Cavalry version carried only a ma- cluding the link type springless suspen- arms that feared the loss of personnel chine gun as armament, but the Infantry sion and the use of an all-purpose chas- and funding to them. reacted to the growing efficacy of anti- sis to facilitate standardization. Between In 1931, Chief of Staff General tank guns demonstrated in the Spanish 1927 and 1931, Rock Island Arsenal Douglas MacArthur authorized a new Civil War by seeking heavier armament built a succession of pilot models, each mechanization policy that permitted each and armor.18 The 12-ton M2A4 reflected one introducing new features but ulti- combat arm to control the pace and ex- these concerns, carrying a 37mm gun in mately increasing the tank’s weight to tent of its own mechanization program. a rotating turret and a maximum armor seven tons. The reliability of the series, Although this policy decentralized protection of 25 millimeters.19 Complet- however, demonstrated the viability of mechanized development, it ensured that ing trials in September 1939, the M2A4 the tank’s operation without a carrier.12 mechanization no longer posed a re- missed the August Plattsburg maneuvers, source threat. MacArthur’s policy also and its armor had already been surpassed Since their invention, tanks depended engendered the Mechanized Cavalry to by the German PanzerKampfwagen II. upon railways and trucks for transporta- test the tank’s application to Cavalry tion to and from the battlefield. The The Plattsburg maneuvers demon- functions and implement the conclusions speed of a tank-laden truck column, strated mechanized cavalry’s ability to drawn from the Experimental Mecha- however, barely exceeded three miles use its superior mobility to unbalance nized Force and the Mechanized Force.15 per hour and precluded rapid, mobile op- and envelop a slower force. The maneu- erations. A tank that could safely rely The Cavalry mission included recon- ver’s conclusion coincided with the Ger- upon its own engine, both on and off the naissance, screening, exploitation, pur- man invasion of Poland; both events un- battlefield, increased its versatility and suit, and raiding operations, and it, there- derscored the importance of a powerful permitted a higher tempo of operations. fore, necessitated a more dynamic use of tank force.20 The declaration of a limited Eliminating carriers from tank units the tank than the simple close support national emergency resulted in an order similarly reduced their cost and person- role of the Infantry. Throughout the for 329 M2A4s from American Car and nel requirements.13 1930s, the Mechanized Cavalry’s activi- Foundry Company and marked an ARMOR — September-October 1997 15 awareness of the importance of a tank force to national survival.21 While Po- land’s prewar inventory included 1,000 armored fighting vehicles, the U.S. Army possessed only a variegated col- lection of 450 tanks.22 The fall of France in 1940, however, stunned the War Department and pro- vided the catalyst for changes affecting the design, production, and employment of American tanks. In June, the War De- partment established the National Muni- tions Program to govern the mass pro- duction of war materiel.23 Charged with implementing this program, the National Defense Advisory Commission sought to ensure effective coordination of indus- trial capability and military need. Gen- eral Motors President William S. Knud- sen served on the Commission as the ad- The M3A1 Stuart light tank, with its 37mm gun and light armor, quickly became obso- visor for mechanized equipment. He rec- lete in the European Theater. This 1st AD example has the unique “flag” markings and ommended the abandonment of Ord- yellow turret stripes peculiar to vehicles used in the North Africa invasion of 1942. nance Department plans to utilize heavy engine and locomotive plants to build tanks, advocating instead the building of new arsenals for tank production that ex- 1926. Although the M2 Medium Tank with the British, the 75mm gun could ploited the labor, management, and pro- entered service in the spring of 1940, its not be operated from a hull-down posi- duction expertise of the automobile in- 37mm cannon and eight machine gun ar- tion, and its limited traverse precluded dustry. Consequently, Chrysler Corpora- mament was offset by a maximum armor tracking a moving target. It proved capa- tion built the first such arsenal at De- protection of only 25 millimeters. It also ble of penetrating the frontal armor of troit.24 suffered from being underpowered and most German tanks encountered at a unlikely to fare well against the newer range of 400 yards, but newer models of France’s defeat also pushed the War models of German tanks.28 the PanzerKampfwagen III and IV re- Department in July 1940 to create the peatedly destroyed it at 1100 yards.31 Al- Armored Force with responsibility for The emergence of the Panzer- though the M3 continued in British serv- creating the armored formations now Kampfwagen IV, carrying a 75mm gun, ice in the Far East throughout the war, deemed vital for modern warfare. The led Chief of Infantry Major General its use in North Africa and Europe was new organization absorbed the Mecha- George A. Lynch to declare the M2 me- eclipsed by the M4 Medium Tank, and it nized Cavalry and Infantry tank force, dium obsolete and recommend develop- was declared obsolete in April 1944.32 but the former exerted a dominant influ- ing a new tank carrying a turret-mounted ence, embodied by the appointment of 75mm and heavier armor. Chaffee con- The M3 Light Tanks also suffered from the Mechanized Cavalry commander, curred with these views and, together a number of problems despite their Major General Adna R. Chaffee, Jr., as with the Ordnance Department, deter- popularity with the British. They pos- Chief of the Armored Force.25 The mined upon the creation of a new design sessed a high silhouette and their angular Mechanized Cavalry emphasis upon mo- based upon the M2 chassis but carrying hull and riveted armor offered poor pro- bility shaped the doctrine and organiza- heavier armament and protection.29 tection. Their short cruising range tion of the armored formations. Despite The larger weapon required a new tur- proved an embarassment in North Africa the European trend toward more heavily ret. While its design began, an interim and resulted in additional fuel tanks be- armed and armored vehicles, light tanks tank was developed that retained a ing built into the hull sides. Other princi- constituted the majority of tanks in the 37mm gun in the turret but also carried a pal series modifications included power new armored divisions expected to per- 75mm gun in its hull. Designated the traverse, periscopes for all crew mem- form an exploitation role.26 M3 Medium Tank, it featured a redes- bers, and the use of the Guiberson diesel Modifications to the M2A4 generated igned hull and superstructure upon an engine to alleviate shortages in the Con- the M3 Light Tank. Lessons learned M2 chassis and utilized the latter’s me- tinental aircraft engine initially intended from France’s defeat included an in- chanical layout. In August, 1,000 of the for the tank.33 crease in frontal armor to 38 millimeters vehicles were ordered and construction Continual modifications to the M3 re- and enhanced protection of the engine began on a new arsenal to build them.30 sulted in the M5 Light Tank. Maximum compartment against strafing. Weight Issued to the British through the Lend armor increased to 51 millimeters, and rose to 13.5 tons, but the German Lease program, the new tank entered two V8 Cadillac automobile engines re- PanzerKampfwagen III possessed 90 combat during the Gazala tank battles of placed the Continental aircraft engine. millimeters of frontal armor. Neverthe- May 1942. These early models suffered Initial Ordnance Department skepticism less, the pilot model completed its trials from engines that overheated after 25 with the idea ended after a prototype in July 1940, and American Car and hours of use and the issuance of the model drove from Detroit arsenal to Ab- Foundry Company received a large pro- wrong fuses for the 75mm gun. These erdeen Proving Ground without mishap. duction order.27 problems had been corrected before the Production began in June 1942 but The fall of France also stimulated me- tank entered combat with American sol- ended in June 1944, following develop- dium tank development, lagging since diers. Although the M3 proved popular ment of the M24 Light Tank. The M5 16 ARMOR — September-October 1997 Field Expedient “Protection” remained operational, however, until late in the war, although outclassed by all German tanks.34 Growing dissatisfaction with the M5’s insufficient turret space, weak armament, and cooling system resulted in develop- ment of a replacement design designated T7. Equipped with a 75mm gun, early trials proved so promising that it was considered a possible replacement for the M4 Medium Tank. The ensuing modifications to the original design, however, resulted in an overloaded and unsatisfactory vehicle. A new light tank design finally emerged in April 1943 that corrected the worst defects of the M5. Designated the M24, it featured a 75mm aircraft cannon, an enhanced torsion bar suspension system that increased stabil- ity and flotation, wet stowage of ammu- nition, power traverse, an electrical firing mechanism, and a Hydramatic transmis- sion similar to that found in taxi cabs. In combat, however, the large floor escape hatch proved vulnerable to mine explo- sions. The M24 marked a significant ad- vance over the M5, but few saw combat Testing ways to improve the Sherman’s protection, units fired captured German antitank in World War II.35 weapons against hulks. Above, a soldier examines the damage done by a 60mm shaped charge that blew away bags of cement before perforating the transmission casting. Spare The M4 Medium Tank entered produc- track sections were also employed, as seen on the Sherman below, at the 1st AD’s crossing tion in October 1941, and during the of the Arno River in Italy during 1944. course of the war over 70,000 of all con- figurations were built. This output was achieved by distributing production be- tween 11 major firms and over 100 sub- contractors. Use of the same chassis as the M3 further simplified construction. A variety of models were built around dif- ferent power plants developed by the automotive industry in an effort to opti- mize performance and reduce the high demand for aircraft engines. Other modi- fications included armament of a 76mm gun or 105mm howitzer, the introduction of horizontal volute spring suspension, and the incorporation of wet ammunition stowage. The last feature necessitated over 2,500 changes to the vehicle’s lay- out.36 Later versions also carried a tele- phone for communication between the crew and supporting infantry.37 In general, however, the M4 proved mechanically reliable, and highly mo- bile. The tank’s principal weaknesses lay Questions concerning the adequacy of tanks for exploitation rather than de- in an inadequate main armament and ar- the M4’s armament began to emerge in stroying enemy armor. mor protection. Tank crews feared that 1943 and triggered a dispute between the He also opposed the Ordnance Depart- those M4s equipped with gasoline en- Armored Force, the Army Ground ment’s preference for developing an en- gines were firetraps following reports of Forces (AGF) responsible for combat tirely new heavy tank, because of the de- tanks bursting into flames upon being developments, and the Ordnance Depart- crease in M4 production that would oc- hit. Tests conducted at Fort Knox, how- ment. The Armored Force wanted to cur while industry retooled for a new ever, determined that the cause of the mount a 90mm gun on the M4, but AGF tank.39 fires was not the gasoline, but the pene- opposed this idea. Its commander, Lieu- tration of the tank by ammunition de- tenant General Lesley J. McNair, consid- Adverse publicity concerning the signed to explode inside the tank and ig- ered this action unnecessary since weakness of the M4 in encounters with nite its combustible components.38 American doctrine stressed the use of German Tigers and Panthers throughout ARMOR — September-October 1997 17 Above, although the U.S. did not field a heavy tank in time for WWII, it developed the 60-ton M6 early in the war. The few that were made never went into combat, the Army relying instead on mass production of the M4 Sherman. At left, the M24 light tank did join the fight during the final months of the European Theater. Its torsion bar suspension was a big improvement over the vertical vo- lute spring system of the Stuart series, and its 75mm gun was a formidable main armament for a tank of its size. gun, but overall numbers stimulus for AGF, the Ordnance Depart- of the M4A3E2 produced ment, and the Armored Force to agree amounted to only 254.40 upon the production of 250 T26s.41 The Ordnance Depart- The 3d and 9th Armored Divisions re- ment continued to advo- ceived the first deliveries of T26s in cate a heavy tank, and January 1945. Mixed teams of civilian had already acquired de- and military experts provided new sign experience. It had equipment training, and their efforts developed the M6 Heavy stimulated theater demands for addi- Tank following France’s tional tanks. By May 1945, the T26 be- defeat. None of the 50 came standardized as the M26 and 200 vehicles produced entered had been issued to combat units in combat, but the tank’s Europe. By war’s end, only 20 had en- dual main armament of a tered combat, including the capture of 3-inch gun and a 37mm the Remagen Bridge. None saw action in gun mounted coaxially, the Pacific Theater of Operations, al- its 25-mile-per-hour though they were requested for use on speed, its track skirts, and Okinawa.42 ballistically shaped hull had been innovative for By the war’s end, American tank de- the early war period. Be- velopment had drifted toward more ver- ginning in 1943, the Ord- satile tank designs capable of performing nance Department had multiple tactical roles and that incorpo- also sought to improve rated a better balance of armor, fire- the M4 Medium Tank, power, and mobility. Light tanks contin- focusing upon transmis- ued to function in a reconnaissance role, 1944 only deepened the three-way rift. sions, suspensions, larger guns, use of an reflecting the American preference for The M4A3E2 represented an improvised autoloader, and increased armor and fire- fully tracked vehicles over the cheaper solution. A 42-ton heavily armored M4, power without sacrificing mobility. Inde- armored cars favored by foreign powers. the tank was initially designed for close pendently, the Ordnance Department The M4 Medium Tank and M26 Heavy infantry support during the Normandy continued to develop a heavily armored Tank, however, represented the emer- campaign, but the U.S. Third Army found tank carrying the 90mm gun, resulting in gence of the main battle tank concept them useful in leading armored columns, the T26-series of heavy tanks. The dem- that would shape Cold War tank designs. where their heavier armor increased their onstrated inadequacy of the M4 Medium Production and design had matured since survivability if attacked. Some of these Tank in combat against heavier German the confusion of World War I, and bene- tanks carried the more powerful 76mm vehicles in 1944 finally provided the fited from the effective utilization of the 18 ARMOR — September-October 1997 automotive industry in all phases of tank 13General Service Schools, The Employment of 29Peter Chamberlain and Peter Ellis, “M4 Me- development. The controversy over the Tanks in Combat (Ft. Leavenworth, Kan.: Gen- dium (Sherman),” in Duncan Crow (ed.), Ameri- M4’s replacement, however, resulted in eral Service Schools Press, 1925), p. 8. can AFVs of World War II (Garden City, New American combat troops entering com- 14George F. Hofmann, “A Yankee Inventor and York: Doubleday and Company Inc., 1972), pp. bat with inferior equipment and under- the Military Establishment: The Christie Tank 53-54. scored the importance of coordinating Controversy,” Military Affairs, XXXIX, 1 (Febru- 30Chamberlain and Ellis, “M3 Medium the needs of combat forces with doctrine ary 1975), pp. 9-10. (Lee/Grant),” pp. 41-46. and technological ability. 15The Adjutant General Major General James 31Memorandum from Major General Ernest N. F. McKinley, “War Department policies for Harmon to the Commanding General, Allied mechanization,” April 5, 1935, p. 1, MHI Ar- Force, “Modern Equipment for the 1st Armored chives, Willis D. Crittenberger Papers. Division,” May 21, 1943, MHI Archives, Ernest Notes 16Notes of discussion following lecture of Ma- N. Harmon Papers; George B. Jarrett, “Middle East 1942,” unpublished manuscript, pp. 55-56, jor Oswald H. Saunders at the Army War Col- 62, 90, MHI Archives, George B. Jarrett Papers. 1Robert L. Collins, “Report on the Develop- lege, “Status of Mechanization—1933,” Septem- ment of the Tank Corps,” in The United States ber 18, 1933, p. 24, MHI Archives, Army War 32Chamberlain and Ellis, “M3 Medium Army in the World War 1917-1918, Reports of College Curricular Archives. (Lee/Grant),” p. 51. Commander-in-Chief, A.E.F, Staff Sections and 17Ellis and Chamberlain, “Light Tanks M1- 33Ellis and Chamberlain, “Light Tanks M1- Services (Washington, D.C.: U.S. Department of M5,” p. 3. M5,” pp. 8-12. the Army, Historical Division, 1948), p. 220; 18George A. Lynch, “Final report of Major 34Forty, United States Tanks of World War II, Dale E. Wilson, “‘Treat ’Em Rough!’ The United General George A. Lynch: A summary of infan- pp. 57-60. States Army Tank Corps in the First World War,” Ph.D. dissertation, Temple University, 1990, Uni- try developments during his term of office,” April 35Robert J. Icks, “M24 Chaffee Light Tank,” in 30, 1941, p. 7; report of Colonel Stephen O. versity Microfilms International Order Number Duncan Crow (ed.), American AFVs of World Fuqua, U.S. Military Attaché, Spain, Report No. DA9107939, pp. 9, 12. War II (Garden City, N.Y.: Doubleday and Com- 6862, July 25, 1938, “Analysis of Tank Casual- pany Inc., 1972), pp. 105, 108, 110-112. 2S.D. Badsey, “The American Experience of ties—Spain,” MHI Archives, Willis D. Critten- Armour,” in J.P. Harris and F.H. Toase (eds.), berger Papers. 36Chamberlain and Ellis, “M4 Medium (Sher- Armoured Warfare (New York: St. Martin’s 19Constance McLaughlin Green, Harry C. man),” pp. 53-55, 57-59. Press, 1990), p. 126. Thomson, and Peter C. Roots, United States 37George Forty, M4 Sherman (New York: Ster- 3Wilson, pp. 113-115; Robert I. Icks, “Four Army in World War II: The Technical Services: ling Publishing Company, 1987), p. 58. Decades of Mechanization: Our Record of Com- The Ordnance Department: Planning Munitions 38Report submitted by Major General Alvan C. bat-Vehicle Development,” Army Ordnance, for War (Washington, D.C.: Office of the Chief Gillem, Jr. to the Chief of Staff, “Report of Ob- XVII, 102 (May-June 1937), pp. 333-334. of Military History, Department of the Army, servations at European Theater of Operations and 4Collins, pp. 222-223; Icks, “Four Decades of 1955), pp. 197-198. North African Theater of Operations,” August 1, Mechanization,” p. 335. 20Adna R. Chaffee, “The Seventh Cavalry Bri- 1943, p. 8, GCM Foundation, National Archives Project, Xerox No. 2300; Jarrett, “Middle East 5Collins, pp. 221-222, 224; Icks, “Four Decades gade in the First Army Maneuvers,” Cavalry 1942,” p. 195. of Mechanization,” pp. 333-334. Journal, XLVIII, 6 (November-December 1939), pp. 450-461. 39Charles M. Baily, Faint Praise: American 6Badsey, p. 127. 21Harry C. Thomson and Lida Mayo, United Tanks and Tank Destroyers during World War II 7U.S. War Department, The National Defense (Hamden, Conn.: Archon Books, 1983), pp. 25, States Army in World War II: The Technical Act Approved June 3, 1916 as Amended by Act 27, 81, 86. Services: The Ordnance Department: Procure- Approved August 29, 1916; Act Approved July 9, ment and Supply (Washington, D.C.: Department 40Baily, pp. 116, 120. 1918; Act Approved February 28, 1919; Act Ap- proved July 11, 1919; Act Approved September of the Army, 1960), p. 225. 41Robert J. Icks, “The M6 Heavy and M26 29, 1919; Act Approved June 4, 1920 (Washing- 22Steven Zaloga and Victor Madej, The Polish Pershing,” in Duncan Crow (ed.), American AFVs ton, D.C.: Government Printing Office, 1920), Campaign 1939 (New York: Hippocrene Books, of World War II (Garden City, New York: Dou- Section 17, p. 15; Timothy K. Nenninger, “The Inc., 1985), p. 88. bleday and Company Inc., 1972), pp. 77-78, 80- Development of American Armor, 1917-1940,” 23Thomson and Mayo, Procurement and Sup- 82, 85, 89-90. Master’s thesis, University of Wisconsin, 1968, p. ply, pp. 12-13. 42Icks, “The M6 Heavy and M26 Pershing,” pp. 62. 24Peter Chamberlain and Chris Ellis, “M3 Me- 92-93. 8Samuel D. Rockenbach, “The Tank Corps,” dium (Lee/Grant),” in Duncan Crow (ed.), Ameri- Lecture given to War Department General Staff can AFVs of World War II (Garden City, New members at Tank School, September 19, 1919, p. York: Doubleday and Company Inc., 1972), pp. 7, U.S. Army Military History Institute (refer- 38-39. enced subsequently as MHI) Library; Samuel D. 25Memorandum from The Adjutant General, Robert S. Cameron, the Ar- Rockenbach, “American Tanks Since the World AG 320.2 (7-5-40) M (Ret) M-C, “Organization War,” 1923, pp. 3-4, MHI Library; Samuel D. mor Branch historian, earned of Armored Force,” July 10, 1940, George C. Rockenbach, “Weight and Dimension of Tanks,” BA degrees in history and eco- Marshall Foundation, National Archives Project, February 1923, MHI Library. Microfilm Reel 36, Item 1479. nomics at the State University 9Icks, “Four Decades of Mechanization,” pp. 26“War Department Armored Force Field Man- of New York at Binghamton 336-337. ual; Tactics and Technique; Chapter 7: The Regi- and a doctorate in history at 10R.H. Allen, “A Resume of Tank Development ment (Tank) Light and Medium,” July 7, 1941, Temple University. Formerly a in the United States,” Lecture at Army War Col- MHI Archives, Willis D. Crittenberger Papers. history instructor at Temple and lege, October 27, 1929, pp. 2-3, MHI Archives. 27George Forty, United States Tanks of World several other colleges in the 11Chris Ellis and Peter Chamberlain, “Light War II (New York: Sterling Publishing Company, Philadelphia area, he also Tanks M1-M5,” in Duncan Crow (ed.), American 1983), p. 42. AFVs of World War II (Garden City, N.Y.: Dou- 28Army Ground Forces Board No. 2, Develop- teaches history at the Armor bleday and Company Inc., 1972), p. 3. ment of Armored Vehicles (Ft. Knox, Ky.: The Center. 12Allen, pp. 4-5; Icks, pp. 337-338. Armored School, undated), I, Tanks, pp. 94-95. ARMOR — September-October 1997 19