Accounts concerning a less acclaimed but still vital aspect of aerial warfare – the maintenance and repair of military planes \u2013 are far fewer in number.\u00a0 But, regardless of the conflict, country, or military force, the maintenance, modification, and repair of military aircraft has been an essential aspect of combat flying since the inception of military aviation.\u00a0<\/span><\/p>\n ____________________<\/span><\/p>\n This post covers one such example.\u00a0 It\u2019s an interrogation transcript of a Japanese Petty Officer First Class who served in the 751st Naval Air Unit (3rd Maintenance Unit, to be specific) at Vunakanau, Rabaul, from September of 1943 through February of 1944.\u00a0 He was captured by an American destroyer after the two naval transports on which he was successively a passenger \u2013 the Kokai Maru, and Nagaura Maru \u2013 were sunk in late February of 1944.\u00a0 His interrogation transcript presents an interesting and detailed account of his service as a mechanic on G4M Betty bombers, his activities including adjustment of propellers and engine electrical wiring, with his specific duty being servicing carburetors.\u00a0<\/span><\/p>\n His position as an engine mechanic in the 751st, coupled with having been stationed at Vunakanau (he was present during a 5th Air Force strafing attack against that airdrome in October of 1943), his observations of Japanese military aircraft, and aspects of his military service such as his observations of Allied POWs, open an unusual window upon the history of the Pacific Air War.\u00a0 \u00a0\u00a0\u00a0<\/span><\/p>\n Unfortunately, the man\u2019s name is not given, but the document does provide a few clues about his background.\u00a0 Born on May 5, 1920, in Toyohashi (Aichi Prefecture, on Honshu), he completed six years of primary school and two years of higher primary school (equivalent of American 8th grade)?, and worked as an assistant at a silk cocoon and silk thread processing farm.\u00a0<\/span><\/p>\n Were he alive today, he would be 97 years old.\u00a0<\/span><\/p>\n ____________________<\/span><\/p>\n The Report was discovered at the National Archives at College Park, Maryland, where \u2013 listed as Interrogation Report No. 357 \u2013 it\u2019s one of the 783 ATIS (Allied Translator and Interpreter Services) Interrogation Reports of Japanese Prisoners of War, which date from September of 1942 through September of 1945.<\/span><\/p>\n Importantly\u2026\u00a0 A list of titles of the specific titles of all ATIS Interrogation Reports can be found at the website of Japan\u2019s National Diet Library<\/a>.\u00a0 This is an invaluable resource, for along with the Report Number, it lists the identity of the military unit to which the captured POW belonged, and even in some cases the name of the POW.\u00a0<\/span><\/p>\n ____________________<\/span><\/p>\n Given that the interrogating officer placed special emphasis on radar carried by G4M bombers, this post includes some of the very few images available of the components and features of the Type 3 Ku-6 radar system.\u00a0 (Now, where does<\/em> one find the instruction manual for the Ku-6?!)\u00a0<\/span><\/p>\n I\u2019ve transcribed the Interrogation Report, which is available for you here, in PDF format<\/strong><\/a><\/span>.\u00a0 <\/span><\/p>\n Paralleling the original physical document, the PDF includes four representative sketches drawn by the POW, showing characteristics of the Kyushu Shiden, the modified tail gun position of the G4M bomber, and the configurations of the nose and tail antenna installations of the Ku-6 radar.\u00a0 Note that the POW illustrated the nose radar antenna as projecting “whisker-like” – perpendicular – from the fuselage.\u00a0 However, the images below show the Ku-6 nose antenna as a single mast extending forward from the bomber’s nose, with smaller antenna extending to both sides of the main mast. ____________________<\/span><\/p>\n Here are images of the first two sheets of the Interrogation Report, complete with NARA\u2019s declassification sticker at the top.\u00a0 The first image illustrates the supplementary handwritten notes, and stamps, and signature on the original document.<\/span><\/p>\n ____________________<\/span><\/p>\n Designation and Markings of the 751st Naval Air Group<\/span><\/em><\/span><\/p>\n 4. UNIT OR FORCE 751 Naval Air Unit<\/u>\u00a0\u00a0\u00a0\u00a0 PW believed 751 Naval Air Unit would have been disbanded by now because of severe losses.\u00a0 When unit arrived at RABAUL, Sep 43, it had about 40 airplanes.\u00a0 Owing to ALLIED raids, Unit had only 20\/25 airplanes in Jan 44, and by Feb 44 only 15 were left.\u00a0 On 19 Feb 44, he heard all remaining airplanes were sent on a special suicide mission against ALLIED Naval forces then attacking either TINIAN or TRUK.\u00a0 PW doubted that any survived.<\/span><\/p>\n Change in Tail Markings of 751 Naval Air Unit At KANOYA – Apr 42<\/u>\u00a0 Tail marking was K-300 series in white numbers on dark green background.\u00a0 Thought the K stood for KANOYA.<\/span><\/p>\n At KAVIENG – Aug 42<\/u>\u00a0 Unit name was changed from KANOYA Naval Air Unit to 751 Naval Air Unit and marking was changed simply to the 300 series, the K being dropped.\u00a0 Numbers were painted in white.<\/span><\/p>\n At TINIAN – Jun 43<\/u>\u00a0 The marking was changed to read Z2 followed by 300 series in white.<\/span><\/p>\n At RABAUL – til Nov 43<\/u>\u00a0 The marking was changed back to simply the 300 series painted in <\/span> At RABAUL – from Dec 43 on<\/u>\u00a0 The marking was altered to 51 followed by 300 series.\u00a0 Thought 51 possibly referred to the last two digits of 751.\u00a0 Thought tail marking was changed on Units\u2019 arrival at each new base.<\/span><\/p>\n Unit Losses<\/u> \u00a0(See Sec 7, \u201cModification of BETTY Tail Turret\u201d)<\/span><\/p>\n ____________________<\/p>\n Information about Kawashini N1K2 Shiden Fighter Plane; <\/span><\/em><\/span> 7.\u00a0 SHIPS AND AIRPLANES Super Fighter<\/u>\u00a0\u00a0\u00a0\u00a0 (KYOKUCHI SEN) (#1) (See Appendix \u201cA\u201d).\u00a0 PW had not seen it but another maintenance man who arrived at RABAUL from JAPAN (Feb 44) told him about this airplane and drew him a sketch.\u00a0 PW thought KYOKUCHI SEN was only a factory name and that Navy might already have given airplane another name.<\/span><\/p>\n Following are particulars he heard:<\/span><\/p>\n Type<\/u>\u00a0\u00a0\u00a0\u00a0 Fighter pursuit ship (TSUI GEKI KI) said to be much faster than the ZEKE or the P-38 and thought it was the Navy equivalent of the Army TOJO because he recognized similarities when shown a photo of the TOJO.<\/span><\/p>\n Construction<\/u>\u00a0\u00a0\u00a0\u00a0 Slightly larger in all dimensions than the ZEKE and silhouette from side was \u201cfatter\u201d.\u00a0 Cockpit was set well back (about middle of fuselage).<\/span><\/p>\n Engine<\/u>\u00a0\u00a0\u00a0\u00a0 KASEI, of about 1300 HP.<\/span><\/p>\n Performance<\/u>\u00a0\u00a0\u00a0\u00a0 Could climb very fast and maintain a steady climb at an angle of about 40o<\/sup>.\u00a0 It required as much runway to take off as did the ZEKE.\u00a0 Not capable of more than four or five hours\u2019 continuous flight.<\/span><\/p>\n Armament<\/u>\u00a0\u00a0\u00a0\u00a0 13 mm MGs and 20mm machine cannon.<\/span><\/p>\n Propellers<\/u>\u00a0\u00a0\u00a0\u00a0 Either 3 or 4 blade.<\/span><\/p>\n Manufacturer<\/u>\u00a0\u00a0\u00a0\u00a0 Possibly KAWANISHI.\u00a0 It was originally produced as a float airplane fighter and when tested showed excellent speed, manoeuvrability and climb.\u00a0 Better results were obtained in tests with undercarriage changed to ordinary ground landing gear.\u00a0 It was then decided to make slight modifications and produce it as a regular Navy pursuit ship.<\/span><\/p>\n General<\/u>\u00a0\u00a0\u00a0\u00a0 When first produced in quantity and delivered to Naval Air Units in JAPAN it was used in training.\u00a0 However, because of its frail construction it many times disintegrated in the air, so was temporarily banned from Service about end 43 or beginning of 44, but after it had been reinforced it was used again.<\/span><\/p>\n Y20<\/u>\u00a0\u00a0\u00a0\u00a0 While at RABAUL PW heard of a new Naval Bomber called Y20 or Land Bomber (RIKU BAKU) which was a cross between Type 96 2EB NELL Mk 2 and Type 1 2EB BETTY.\u00a0 It was said to be smaller and much faster than BETTY, carrying a crew of only three or four.\u00a0 It could carry the same bomb load but fly a greater distance than BETTY and was equipped with 13mm MGs.\u00a0 Heard it was made by MITSUBISHI and used by some Naval Air Units.<\/span><\/p>\n PW thought Y20 was the factory number, and had never heard of its official name.<\/span><\/p>\n ____________________ Modification of G4M Tail Turret<\/span><\/em><\/span><\/p>\n Modification of BETTY Tail Turret<\/u>\u00a0\u00a0\u00a0\u00a0 About Jan 43 while 751 Naval Air Unit was at KAVIENG twenty BETTYs went on a bombing mission to GUADALCANAL, and only six returned.\u00a0 Airmen who returned complained that revolving tail turret of BETTY was so sluggish and difficult to operate that they were unable to cope with ALLIED fighters, which concentrated their attack on their tail.<\/span><\/p>\n Unit therefore effected an immediate improvement by cutting away part of the tail turret to allow freer action of tail gun, although such modification made the airplane at least two or three knots slower.\u00a0 They simply cut the section right off and did not add any supporting brackets, or covering shield.\u00a0 The tail was left entirely open, allowing the gunners full traverse of the rear gun. (See Sketch 1 Appendix \u201cB\u201d).<\/span><\/p>\n While at TINIAN, Aug 43, about ten new BETTYs arrived for the Unit and they all had improved tail turrets allowing freer action of the rear gun.\u00a0 The modifications had been effected at the factory in JAPAN, and observed from the top, the tail turret had a \u201cV\u201d shaped section cut away.\u00a0 This type of turret was also entirely open.\u00a0 (See Sketch 2, Appendix \u201cB\u201d).<\/span> ____________________<\/strong><\/p>\n An American POW at Rabaul<\/span><\/em><\/span><\/p>\n (Probably 1 Lt. Bernard E. Sahl of VMF-223, shot down over Vunakanau in F4U-1 57464 on December 25, 1943; Severely burned; mentioned in Report by Lt. John M. Arbuckle; Held captive by 81st Naval Guard Unit; “executed” (euphemism…) while POW, probably mid-1944)<\/span><\/em><\/span><\/p>\n 13. \u00a0MORALE AND PROPAGANDA JAP Prisoners of War<\/u>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 PW had heard that at NOMONHAN, one complete SENDAI Unit, about 2,000 men, was captured by the RUSSIANS.\u00a0 When the truce was made, those men were returned to JAPAN.\u00a0 Unit CO committed suicide and it was arranged for the 2,000 men to be sent back to MANCHURIA, rather than to allow then to remain in JAPAN.<\/span><\/p>\n ALLIED PsW<\/u>\u00a0\u00a0\u00a0\u00a0 On Air Objective Folder No. 92.2 SINGAPORE, PW located an ALLIED PW camp holding thousands of prisoners, as being immediately North of Empire Dock Area. (Target 12).\u00a0 While on a six-hour leave (Apr 42), he had seen three large, two storey barracks, each capable of housing 500 to 600 men under JAP Army standards.\u00a0 White PsW could be seen at the windows and one stood guard at the front of the barracks.\u00a0 There was no fence or wall around camp.<\/span><\/p>\n Aug 42, while KATSURAGI MARU was docked at Target Area 11 for three days, PW saw white prisoners crossing by boat to BLAKANG MATI Island just off the Southern tip of SINGAPORE Island.\u00a0 They did not seem to be working.\u00a0 They wore light khaki clothing. <\/span><\/p>\n In Nov 43, a Fighter was shot down near a native village near VUNAKANAU airfield.\u00a0 Pilot was brought by natives to HQ 751 Naval Air Unit.\u00a0 As there was no interpreter present prisoner was sent to RABAUL.\u00a0 PW heard that prisoner was a Capt.\u00a0 He was about 5\u20197\u201d tall and heavily built.\u00a0 He wore no rank badges but on the sleeve of his flying suit was yellow or gold badge on a black or blue background.\u00a0 The pilot was uninjured except for burns on the face.<\/span><\/p>\n He had seen ALLIED PsW working around RABAUL.\u00a0 It was not customary to guard them since they could be quickly identified if they attempted to escape.<\/span><\/p>\n ____________________<\/span><\/p>\n Here’s an image of G4M1 Betty “367” which the POW – perhaps? – may actually have seen and maintained.\u00a0 The aircraft belongs to the 751st Naval Air Group, and was photographed during the 345th Bomb Group’s strafing attack against Vunakanau on October 24, 1943.\u00a0 The image is one of several pictures of 751st NAG G4M bombers appearing in Lawrence Hickey’s Warpath Across the Pacific<\/em>.\u00a0 Six of these aircraft carry three-digit tail numbers, the leading digit being a “3”. \u00a0\u00a0 \u00a0\u00a0<\/span><\/p>\n The interrogation accorded much attention to the Type 3 Ku-6 radar carried in the G4M bomber.\u00a0 The following three images, from the USAAF photo collection at Fold3.com, show a G4M2a bomber equipped with this device, as well as other notable aspects of the G4M2.\u00a0 This aircraft \u2013 763-12 \u2013 is the subject of a three-view illustration in William Green\u2019s 1969 book Famous Bombers of the Second World War<\/em>.\u00a0<\/span><\/p>\n ____________________<\/span><\/p>\n Photographed at Clark Field in 1945, aircraft number \u201c12\u201d of the 763rd Kokutai is shown under examination by members of the Air Technical Intelligence Division of the Army Air Force, with Sergeant H.W. Willis (from Beckley, West Virginia) prominently appearing in two of the images.\u00a0 <\/span><\/p>\n The photo caption for this image (A-68394 AC \/ A30416) states that the aircraft had been strafed by P-51s but was not badly damaged.\u00a0 Sergeant Willis is standing next to the port gun window.\u00a0 The portly yet nicely streamlined shape of the fuselage is quite apparent, as are the dorsal and tail mounted Type 99 cannon mounted in those positions.\u00a0 Also visible are the radar antennas mounted in the tip of the nose, and, alongside the rear fuselage.\u00a0 The latter is entirely consistent in configuration with the description given by the POW.<\/span><\/p>\n This image (68389 AC \/ A30413) shows Sergeant Willis examining the port Type 99 cannon. \u00a0(Is he handling an ammunition magazine?)\u00a0 Notable details include what appears to be a flash suppressor at the cannon\u2019s muzzle; the cylindrical notch at the rear of the waist position for stowage of the cannon (via the flash suppressor); the circular fuselage entry hatch upon and around which the Hinomaru has been painted; the mounting struts for the radar antenna.\u00a0 Also, notice the rectangular data plate painted below the port stabilizer.<\/span><\/p>\n The last of the three pictures (68390 AC \/ A 30414) of Sergeant Willis and Betty 763-12 shows fascinating aspects of the plane and its equipment.\u00a0 Enlargement of the data plate shows the serial number to be \u201c2134\u201d.\u00a0 Though very faint in the photo, someone has hastily scrawled the warning \u201cBOOBY TRAPPED! \u00a0DO NOT (rest of the text is illegible, but the meaning is clear)\u2026\u201d below the horizontal stabilizer.\u00a0 The cut-away modification to the tail gun position described and sketched by the POW is very obvious.\u00a0 Finally, the life raft.\u00a0 The photo caption states that Sergeant Willis is, \u201c\u2026examin[ing] the novel life raft with which the plane is equipped.\u00a0 He is using the bellows which inflate the boat.\u00a0 The raft is made of light rubberized material [and] is propelled with wooden paddles.\u201d<\/span><\/p>\n __________________<\/span><\/p>\n The Rising Decals company (Czech Republic), manufacturer of aftermarket decals and detail sets for Japanese aircraft of the Second World War, has produced an update kit for creating 763-12 based on Hasegawa\u2019s 1\/72 G4M2<\/a>.\u00a0 This image shows the components of the update set, further illustrating the configuration and mounting of the Type 3 Ku-6 antennas.<\/span><\/p>\n This image, from the website of the National Air and Space Museum<\/a>, shows a Type 3 Ku-6 (Model 4) radar set and associated connecting cables.<\/span><\/p>\n Here are three views of the cathode ray tube utilized in the Ku-6 Radar<\/a>, also from the National Air and Space Museum website.\u00a0<\/span><\/p>\n ATIS Interrogation Report 357, from Records of the War Department General and Special Staffs, Assistant Chief of Staff (G-2) Intelligence Library Project File, ATIS Interrogation Reports.\u00a0 (NARA Records Group 165, Box 325, Entry 79, Shelf Location 390\/33\/27\/5-6\/7)\u00a0 <\/span><\/p>\n Green, William, Famous Bombers of the Second World War<\/em>, Doubleday & Company, Inc., Garden City, N.Y., 1960 (Mitsubishi G4M Type I, pp. 52-58)<\/span><\/p>\n Green, William, Famous Fighters of the Second World War<\/em>, Hanover House, New York, N.Y., 1958 (Kawashini Shiden pp. 111-116)<\/span><\/p>\n Hickey, Lawrence H., Warpath Across the Pacific – The Illustrated History of the 345th Bombardment Group During World War II<\/em>, International Research and Publishing Corporation, Boulder, Co., 1984 (751st Naval Air Group G4M bombers, pp. 78-79)<\/span><\/p>\n Thorpe, Donald W., Japanese Naval Air Force Camouflage and Markings – World War<\/em> II<\/em>, Aero Publishers, Inc., Fallbrook, Ca., 1977<\/span><\/p>\n National Diet Library of Japan (English-language version), at http:\/\/iss.ndl.go.jp\/?locale=en&ar=4e1f<\/a><\/span><\/p>\n Index to all ATIS Interrogation Reports, with English-Langauge descriptions<\/a>, at National Diet Library of Japan (click hypertext)<\/span><\/p>\n","protected":false},"excerpt":{"rendered":" The central focus of literature about military aviation has traditionally revolved around the men – the aviators – who fly and fight within combat aircraft.\u00a0 Accounts concerning a less acclaimed but still vital aspect of aerial warfare – the maintenance and repair of military planes \u2013 are far fewer in number.\u00a0 But, regardless of the … Continue reading Japanese Technology at War: The Interrogation Transcript of a Japanese Naval Aviation Mechanic in 1944<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,60,157,2],"tags":[335,318,328,341,316,315,317,336,329,320,319,326,327,323,321,343,342,344,339,340],"class_list":["post-2285","post","type-post","status-publish","format-standard","hentry","category-aviation","category-military-history","category-second-world-war","category-technology","tag-1-lt-bernard-e-sahl","tag-751st-naval-air-group","tag-763rd-naval-air-group","tag-341","tag-allied-translator-and-interpreter-section","tag-atis","tag-atis-interrogation-reports","tag-f4u-1-57464","tag-httparawasi-wildeagles-blogspot-com","tag-mitsubishi-g4m-betty","tag-mitsubishi-g4m-rikko","tag-records-group-165","tag-records-of-the-war-department-general-and-special-staffs-assistant-chief-of-staff-g-2-intelligence-library-project-file","tag-rising-decals","tag-type-3-ku-6-radar","tag-3-ku-6","tag-342","tag-g4m","tag-340"],"_links":{"self":[{"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/posts\/2285","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/comments?post=2285"}],"version-history":[{"count":36,"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/posts\/2285\/revisions"}],"predecessor-version":[{"id":2958,"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/posts\/2285\/revisions\/2958"}],"wp:attachment":[{"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/media?parent=2285"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/categories?post=2285"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/thepastpresented.com\/index.php\/wp-json\/wp\/v2\/tags?post=2285"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n<\/span><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/ATIS-Interrogation-Report-357-1944-07-19-1-628x1024.jpg\")
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<\/a>Excerpts from the text of the document follow below…<\/span><\/p>\n
\n<\/u><\/span><\/p>\n
\n<\/u><\/span><\/p>\n
\n white, Z2 being dropped.<\/span><\/p>\n
\n Possible Reference to Mitsubishi Ki.67 Type 4 Hiryu Bomber<\/span><\/em><\/span><\/p>\n
\n<\/u><\/span><\/p>\n
\n<\/strong><\/p>\n
\n<\/strong><\/p>\n
\n<\/u><\/span><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/Astounding-Science-Fiction-1951-03678_edited-2-1024x823.jpg\")
<\/a>____________________<\/strong><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/G4M-A68394AC-A30416-1024x797.jpg\")
<\/a>____________________<\/span><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/G4M-68389AC-A30413-Sgt-HW-Willis-1024x795.jpg\")
<\/a>____________________<\/span><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/G4M-68390AC-A30414-Sgt-HW-Willis-Booby-Trapped-1024x799.jpg\")
<\/a><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/Rising-Decals-G4M-Type-3-Radar-Detail-Set.jpg\")
<\/a>____________________<\/span><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/KU6-Radar-a19710992000all.jpg\")
<\/a>____________________<\/span><\/p>\n![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/KU6-Radar-NASM-693D8FBD64EC2_06-1024x710.jpg\")
<\/a> ![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/KU-6-Radar-NASM-693D8FBD64EC2_04-1024x404.jpg\")
<\/a> ![\"\"](\"http:\/\/thepastpresented.com\/wp-content\/uploads\/2017\/06\/KU6-Radar-NASM-693D8FBD64EC2_03-1009x1024.jpg\")
<\/a>References<\/span><\/p>\n
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