USSBS Report 25, Tachikawa Airplane Company

8/3/2019 USSBS Report 25, Tachikawa Airplane Company

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THE UNITED STATESSTRATEGIC BOMBING SURVEY if

Tachikawa Aircraft Company(Tachikawa Hikoki K K)

CORPORATION REPORT NO. X(Airframes)

AIRCRAFT DIVISION

February 1947


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THE UNITED STATESSTRATEGIC BOMBING SURVEY

Tachikawa Aircraft Company(Tachikawa Hikoki K K )

CORPORATION REPORT NO. X(Airframes)

AIRCRAFT DIVISIONDates of Survey

20-24 November 1945Date of Publication

February 1947


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tfi I. WPERtNTENDEKT OF'OOC

APR. 8 1947

This report was written primarily for the use of the United StatesStrategic Bombing Survey in the preparation of further reports of a morecomprehensive nature. Any conclusions or opinions expressed in this reportmust be considered as limited to the specific material covered and as subjectto further interpretation in the light of further studies conducted by theSurvey.

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FOREWORDThe United States Strategic Bombing Sur-was established by the Secretary of War on

November 1944, pursuant to a directive fromlate President Roosevelt. Its mission was to

an impartial and expert study of theof our aerial attack on Germany, to be

in connection with air attacks on Japanto establish a basis for evaluating the im-

and potentialities of air power as anof military strategy for planning

future development of the United Statesforces and for determining future eco-policies with respect to the nationalA summary report and some 200 sup-reports containing the findings of thein Germany have been published.

In 15 August 1945. President Truman re-that the Survey conduct a similar study

the effects of all types of air attack in theagainst Japan, submitting reports in dupli-to the Secretary of War and to the Secre-of the Navy. The officers of the Survey

its Japanese phase wereFranklin D'Olier, Chairman.Paul H. Nitze, Henry C. Alexander, ViceChairmen.

Harry L. Bowman,J. Kenneth Galbraith,Rensis Likert,Frank A. McNamee, Jr.,Fred Searls, Jr.,Monroe E. Spaght,Dr. Lewis R. Thompson,Theodore P. Wright, Directors.Walter Wilds, Secretary.

The Survey's complement provided for 300

civilians, 350 officers, and 500 enli-sted men. Themilitary segment of the organization was drawnfrom the Army to the extent of 60 percent, andfrom the Navy to the extent of 40 percent. Boththe Army and the Navy gave the Survey all pos-sible assistance in furnishing men, supplies,transport, and infoi-mation. The Survey oper-ated from headquarters established in Tokyoearly in September 1945, with subheadquartersin Nagoya, Osaka, Hiroshima, and Nagasaki,and with mobile teams operating in other partsof Japan, the islands of the Pacific, and theAsiatic mainland.

It was possible to reconstruct much of war-time Japanese military planning and execution,engagement by engagement, and campaign bycampaign, and to secure reasonably accuratestatistics on Japan's economy and war produc-tion, plant by plant, and industry by industry. Inaddition, studies were conducted on Japan'sover-all strategic plans and the background ofher entry into the war, the internal discussionsand negotiations leading to her acceptance ofunconditional surrender, the course of healthand morale among the civilian population, theeffectiveness of the Japanese civilian defense or-ganization, and the effects of the atomic bombs.Separate reports will be issued covering eachphase of the study.The Survey interrogated more than 700 Japa-

nese military, government, and industrial offi-cials. It also recovered and translated many doc-uments which not only have been useful to theSurvey, but also will furnish data valuable forother studies. Arrangements have been made toturn over the Survey's files to the Central Intelli-gence Group, through which they will be avail-able for further examination and distribution.

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TABLE OF CONTENTSPageThe Corporation and Its Importance in the

Aircraft Industry

The Air Attacks : 7Production Statistics 12

Evaluation of Preattack Intelligence 20

Appendices :

ATachikawa Plant Layout Facing page 22BOkayama Plant Layout 23CKofu Plant Layout Facing page 24DProduction 1929-40 25EBomb Plot of Attack 17 February 1945 1. Facing page 26FBomb Plot of Attack 4 April 1945 2. Facing page 26GBomb Plot of Attack 24 April 1945 3. Facing page 26HDamage Plot of IB Attack 2 August 1945 4. Facing page 26IAir Attack Defense Map 5. Facing page 26JProduction 1941-45 .__ 27


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THE CORPORATION AND ITS IMPORTANCE IN THE AIRCRAFT INDUSTRY

The Tachikawa Aircraft Co., Ltd. (Tachi-Hikoki K K), which in 1944 produced

nine percent of Japanese air-owned and operated three plants located

Tachikawa, Okayama and Kofu (Figure 1).insert on following page.) There was aof about 3,600,000 sq. ft. of fioor spaceroof, most of which was at Tachikawa,

third largest airframe plant in Japan.The company was founded in 1924. The first

production was one reconnaissancein January 1929 in a small building onsouthwest side of Tachikawa airfield. The

te of production on this plane varied from oneten planes per month until mid-1932 when

91 was added to bring total produc-in 1933 to 115. The relatively small size ofplant was shown by a total floor area inof 131,475 sq. ft.

During 1940, production had grown to 1,000a year (Appendix D) . This was after theexpansion program of that year, which1,650,280 sq. ft, to the plant area. Fur-additions brought the total area up to

sq. ft. (Table 1).Table 1Tachikawa Plan! Expansions


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There was close contact with the MiUtaryDivision and later with the Air-

Division of the Munitions Ministry. Thereno record of direct financial aid having been

to the corporation, but Director Fujimotothe Tachikawa plant stated that the govern-

directed banks to make loans for purposesexpansion.

and OperationSaburo Ando was the president of the Tachi-

Aircraft Co., Ltd. ; Masago Asakwa wasmanaging director. The company had three

; Tachikawa, directed by TakashiOkayama, directed by Kazuo Tsut-

and Kofu, directed by Shiro Koshiwara2). In the main, the Tachikawa plantthe engineering and technical staffs

the corporation.

l-ij^ure 2.Organization Chart, Tachikawa Aircraft Co., Ltd.President . Saburo AndoManaging Director Masago Asakawa

Tachikawa PlantDirector Takashi FujimotoAssistant - Moriyuki NakagwaGeneral Aflfairs Sigeo KuriowaFinancial - Toshio KawasakiLabor - Nobuyoshi MasakiMaterial - - Kikuo TsuchiyaSubcontractors - Takeshi HashidaControl .....MinoruChiba

Okayama PlantDirector...- . - - .Kazuo TsutsumiSubdirector RyokichiProduction Hitoshi Nakamura

Kofu PlantDirectorProduction..Assistant.

Shiro YoshiwaraShoji Nomura..Motosuke Yoshiwada

The Sunagawa, or northern, section of Tachi-kawa was the assembly part of the plant. Herewere set up the Oscar and Hickory produc-tion lines, and tooling up for Patsy was inprocess when the war ended (Figure 3). Oscar

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TACMKAWA AIRCRAFT CO

704696472


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final assembly had four lines with 25 machineson each line. Ideal assembly time was 10 daysbut actual time was 10 to 14 days. Hickoryhad two lines with 10 machines on each line.Ideal assembly time was 10 days and actualtime was 10 to 12 days. Two-line production forPatsy was planned with tooling undertaken,but never was put into effect. Okayama andKofu were not developed beyond the "job shop"stage.

Total number of employees expanded rapidlyfrom 9,000 in January 1941 to the peak of 31,-000 in May 1944. At that time 30,500 were atTachikawa and 500 at the newly opened Oka-yama plant. Approximately 5,000 of those atTachikawa were being trained for Okayamaand Kofu production. At the close of produc-tion, August 1945, Tachikawa employed 13,750(Figure 4); Okayama 3,280 (Figure 5), andKofu 2,170 (Figure 6). The big drop at Tachi-kawa was due to the transfer of 10,000 work-men to subcontractors.

The Tachikawa plant went on a two-shiftbasis 1 March 1944. The shifts were ten work-ing hours with one rest hour each. The plantwas inoperative from 0530 to 0730 each day.That procedure affected 76 percent of the directemployees. At Kofu and Okayama, and atTachikawa prior to 1 March 1944, the singleshift 0800 to 1800, with a noon rest hour, wasused.At Tachikawa students and soldiers were

used from April 1944 until August 1945. Theirpeak employment was in January and February1945 when 2,600 students and 150 soldierswere employed.The number of man-hours worked by direct

laborers at Tachikawa reached a maximum of5,100,000 in April 1944 when men were beingtrained for employment at Okayama and Kofu(Figure 7) . Okayama actually was in operationat that time but only 120,000 man hours wereworked that month. As man-hours decreased atTachikawa they increased at Okayama, reach-ing a maximum of 607,000 in June 1945 (Fig-

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8). The number decreased to 2,410,000 atKofii, likewise, reached its maxi-

mum in June with approximately 350,000 man-hours worked (Figure 9)


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Map reference(Figure 10)


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warehouses and their contents were de-in the Okayama urban area attack 29

1945.The Navy 17 February 1945 attack was con-

on Tachikawa's Sunagawa sectiondamaged 166,000 square feet of floor space

E). Oscar production was directlyby this attack. About 40 percent of

wing spar jigs, 90 percent of the weldingand 30 percent of the main wing as-

jigs were destroyed (Photos 1 and 2).Patsy production also received its death

17 February 1945 after a long struggle tointo operation. The wing and fuselage as-

building 106 was 40 percent destroyeddamage to jigs was variously estimated30 to 80 percent.

The Twentieth AF 4 April 1945 attack tookat 0310, using 500-lb. GP bombs which

243,500 square feet of floor area, prin-the sheet metal shop, building 110 (Pho-

3 and 4), and the machine shop and partsbuilding 104, in the north end ofSunagawa section (Appendix F) . The Patsy

assembly building 101 was 20 percentThe Twentieth AF attack 24 April 1945 wasmost destructive of the five attacks in the

of floor area damaged. It likewise finallythe Army that Tachikawa should beThe attack completely destroyed the

assembly building 103, and further dam-the wing assembly jigs. The remainder of

shop building 104 also was destroyed,the contents had been removed and the

was empty. Probably the most seriouswas the destruction of Oscar sub-building 103. Total damage on this

amounted to 570,480 square feet of floor(Appendix G).

Results of the 10 July 1945 attack were neg-On 2 August 1945 there evidently wasspillover from the Twentieth AF area attack

only IB's hit Tachikawa and about 50,-square feet of floor area was burned. Allfires were controlled (appendix H).

In addition to the attacks reported by Tachi-kawa the Twentieth AF reported that on 13April 1945 a single B-29 dropped 10,500 poundsof HE bombs on the plant but Tachikawa hadno record of that incident.The damage figures quoted in this report are

those reported by Tachikawa ofllcials. UnitedStates Strategic Bombing Survey report, "Eval-uation of Photographic Interpretation, Japa-nese Homeland, Part 3, Indu.strial Analysis"(Photo Intelligence Unit, USSBS) contains ad-ditional findings from plant investiga.on.Tachikawa oflicials reported there was nomachine tool damage in any of the attacks.There were 237 casualties in all, 152 of them

fatalities.Tachikawa plant had a well-devised air at-

tack defense system. The plant was divided intofive areas with general defense headquarters inthe main ofl^ce building 201. Each division hadfour subdivisions; watchers, fire fighters, res-cue squads, and emergency repairs. Chief ofthe air attack defense was Fujimoto, the plantdirector. The various plant departments werefu'lher organized to supply food, transporta-tion and other defense necessities to the defensedivisions of areas (Appendix I). Similar butless elaborate systems were set up at Okayamaand Kofu.Urban Area AttacksThe urban area attacks did not interfere

drastically with Tachikawa production, exceptat Okayama where warehouses storing Tachi-kawa materials were destroyed. Most of theworkers lived close enough to the Tachikawaplant to escape the great Tokyo attacks.

Production at Tachikawa began to declinelate in 1944 as machines and workmen wereremoved to Okayama and Kofu, and whiledestruction of subcontractors' factories affectedproduction to some degree it is diflicult to deter-mine how much the decline was accentuated bythis interference.


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Photo 1.Bomb d.imayc to Buildint; 102, Oscar winj; assembh structure, n lebruary, 1945,Navy carrier-based attack.

Photo 2.interior ot Oscar wing assenibl) structure, Building 102.10


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Photo 3.Interior of sheet-metal shop. Building 110.

Photo 4.Sheet-metal press in Building 1 10. Note blast walls.704696473

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Production StatisticsBefore 1941 Tachikawa had produced a total

of 3,115 aircraft (Appendix D) of which 2,047were trainers and 665 were reconnaissanceplanes. From 1 January 1941 to the end of thewar, 6,645 planes were produced (Appendix J)Of these, 2,629 were Oscar fighters, 62 bomb-ers, and 439 reconnaisance planes with the bal-ance trainers and transports. Annual corpora-tion orders and production were as followsYear


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300


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Tachikawa attempted to put Patsy into pro-duction for 15 months without success. In early1944 there was trouble with Patsy jig designsbut in May 1944 one plan was accepted. It washoped that the skilled labor for Patsy assemblywould be furnished from the Oscar and Hickorylines ; however, this transfer was not made be-

cause of the emphasis which the Army put oOscar production.The February and April 1945 attacks dan

aged or destroyed 80 percent of the Patswing and fuselage jigs and in June the enginmodel was changed from HA 43 Model 01 tHA 42 Model 11 (Figure 14).


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TACHIKAWA

AIRCRAFT

AIRCRAFT

REPORTX


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Production at Okayama and Kofu was hardly beyond the planning stage (Table 4)Table 4Okayama and Kofu Production, November 1944-August 1945


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Until mid-1942 MIS correctly estimatedi)roduction. Thereafter, until SeptemberTachikawa produced an average of 25of this type each quarter than MIS esti-After the third quarter of 1943 MISthat Ida was replaced at Tachikawa

Ki-72, a plane which was never producedthe company.Hickory production was estimated at 55month by December 1944. Actual produc-that month was 35 and the average for

year had been 42. Production of the trainersand Ki-17 and the transport Thelma

correctly attributed to Tachikawa, but

MIS was mistaken in believing that productioncontinued through 1944 and into 1945. Thetrainers went out of production in early 1943and the last Thelma had been completed inMarch 1942.No reports of Okayama or Kofu production

were made by MIS. It is probable the reasonthat Tachikawa was not seriously attacked un-til April 1945 after the Nakajima and Mitsu-bishi aircraft plants had been badly damagedand forced into dispersal, was the correct intel-ligence that, in spite of its size, Tachikawa rep-resented less than 10 percent of Japanese air-craft production.

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TACHIKAWA PLANT1924-1945

LEGENDi 1935a BeforeI 1940

1942IMIJ 1943m. 1944^ 1945

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USSBS Report 25, Tachikawa Airplane Company

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Transcript of USSBS Report 25, Tachikawa Airplane Company