Japanese Secret Projects - Exper. Aircraft of the IJA and IJN 1939-45

83 Pages·2009·113.79 MB·English

by  E. Dyer

A P A
JAPANESE
SECRET PROJECTS
EXPERIMENTALAIRCRAFTOF
THEUA AND UN 1939-1945
MIDLAND
Animprintof
IanAllanPublishing
JAPANESE
SECRET PROJECTS
EXPERIMENTAL AIRCRAFT OF
THE IJA AND IJN 1939-1945
EdwinMDyer
Contents
JapaneseSecretProjects:ExperimentalAircraft Preface 6 OtherAircraft
oftheIJAandIJN1939-I945 Acknowledgments 7
TheJapaneseRammer. 123
AbbreviationsandGlossary 8
TheKamikazeAirplane 125
Firstpublished2009
MitsubishiT.KATypeO 126
IJA
NakajimaAT27 127
ISBN9781857803174
KawasakiKi-64 9 S-31 Kurowashi 129
KawasakiKi-88 ......................12 T.K.19 131
Allrightsreserved.Nopartofthisbookmaybe
KawasakiKi-91 14
reproducedortransmittedinanyformorbyany
KayabaKatsuodori 17 WeaponSystems
means,electronicormechanical,including
KokusaiTa-Go 20
photocopying,recordingorbyanyinformation JapaneseMissileandGuidedMunitions
MaedaKu-6 22
storageandretrievalsystem,withoutpermission Projects 132
ManshuKi-98 24
fromthePublisherinwriting. SpecialisedBombs 137
MitsubishiKi-73 27
SpecialisedBombs: Fu-Go 139
NakajimaKi-87 28
©EdwinM.DyerIII
NakajimaKi-115Tsurugi. 31
Appendices
NakajimaKi-201 KaryCI 34
MidlandPublishingisanimprintofIanAllan
RikugunKi-93 37 GermanTechnicalExchangewithJapan:
PublishingLtd,Hersham,SurreyKTl24RG.
RikugunKi-202 40 ABriefOverview 142
PrintedbyIanAllanPrintingLtd,
RikugunKogikenseries 43 Bibliography ISO
Hersham,SurreyKTI24RG.
TachikawaKi-74 50 ArtistBiographies lSI
TachikawaKi-94-I 53 TedNomuraHypothetical
VisittheIanAllanPublishingwebsiteat
TachikawaKi-94-II 55 AircraftProfiles ISS
www.ianallanpublishing.com
TachikawaKi-162
andotherIJAjetprojects 59 Index
Witheffectfrom 1stFebruary2010distribution
ofallIanAllanPublishingLtdtitlesintheUnited Personalities 158
IJN
StatesofAmericaandCanadawillbeundertaken Aircraft ............................158
byBookMastersDistributionServicesInc, KawanishiBaika 61 Engines 160
20AmberwoodParkway,Ashland,Ohio44805. KawanishiHIIKSoku 63 WeaponSystems 160
KawanishiK-200 65
KugishOHighSpeedProjects 67
KugishoMXY6 69
KugishoMXY7aka 70
KugishOMXY8/9Akigusa/Shuka 77
KugishOR2YKeiun 78
KCIgishOTenga 81
KyCIshuJ7WShinden 84
MitsubishiG7MTaizan 91
MitsubishiJ4MSenden 93
MitsubishiJ8MSyCIsui 96
Mitsubishi-PayenPaAOO/Suzukaze20 .. 101
MizunoShinryCIII 104
NakajimaFugaku 108
NakajimaJINGekko 112
NakajimaKitsuka 114
Half-title:ProfileartoftheManshuKi-98.PeterAllen
Titlepage:ManshuKi-98inaction.RonnieOlsthoorn
4 5
Preface
Ifyoubrowseanymajorbookseller,youtend localhobbyshopormajorbookretailers did Becauseoftheconstraints onthe number tion ofsome ofthe more interesting aircraft can be viewed as another means by which accuracyin the information provided in this
toseeagoodmanyworksontheexperimen notturnupanythingaboveandbeyondwhat ofpages,therehadtobeaprocessofselect munitions that were deployed or were in Japanese aviation technology was boosted book. Even as the writing of the book was
tal aircraft developed by Germany both Ialreadyknew. Ifound aratherlarge gap in ingaircraftforinclusion.Theplanesselected developmentareincludedalongwithabrief through awartime ally, butmore often than underway,Iwasacquiringadditionalsources
beforeand,particularly,duringWorldWar2. theonlinedatapoolonJapaneseX-planes,at for this volume have been chosen based on discourse on German technical exchange notitwas an expediencyto rapidlyincrease and checking and rechecking data to make
Also, you'd find a fine selection ofbooks on least in English, and so I sought about cor severalfactors.Thefirstwasthenatureofthe withJapanbeforeandduringWorldWar2.A thecapabilityofJapaneseaircraftinthe face sure nothing was amiss. Ofcourse, atsome
the topic ofAmerican experimental planes. rectingthat. plane in terms ofbeing a conventional or a feature in each aircraft chapter is the inclu ofaworseningwarsituationandeverimprov pointIhadto'letitgo'.IfIheldontochapters
Fromtimetotime,youcouldfindmentionof In 1998, I began to assemble a website moreradicaldesign.Thus,while theKugishO sion ofa 'Contemporaries' section. The pur ing Allied fighters and bombers. It is hoped waiting on the next titbit of information to
such'X-planes' ofothernationsamongstthe inspired by Dan Johnson's Luft '46 which D3YMyojomaybearelativelyobscureplane pose ofthis is to illustrate to the reader that theinformationinthis sectionwillbeacata appear, the book would never get finished
textdescribingmorewellknownaircraft.But started in 1997 as a one-stop site about Ger of which only two were built, it was a very designsdidn'toccurinavacuumandsimilar lysttolearnmoreabouttheaircraftpresented andyouwouldn'tbeholdingitinyourhands.
you did not often see, if at all, books dedi manX-planes. In 1999,mysite, Hikoki: 1946, conventional aircraftin terms ofdesign.The concepts could be found in other Allied to expand one's knowledge of aviation by Thus, invariably, there is the risk ofomitting
catedtoJapaneseexperimentalaircraft.Usu went live to the world. During its first few same applied to the Mitsubishi Ki-83. There nations as well as Axis ones. This section othernations.Alsokeepinmindthatthissec something, interpreting a translation or
ally, one had to visit specialtybook dealers, years, Hikoki: 1946 expanded to encompass fore,thesemoreconventionaldesignsorpro shouldnotinanywaybeconstruedaspoint tion does not list each and every plane that source incorrectly, or just plain making an
hobby shops, or be fortunate enough to be 31 Japanese experimental aircraft and sec totypes received a lower selection priority ing to the Japanese as simply copying the could be considered a contemporary. error.To thatend,corrections,newinforma
abletoreadanotherlanguageinordertofind tions on engine specifications, German air overmore advanced concepts. Another fac workofothernations.Whileitistruethatthe Instead, I have picked the more interesting tion and any and all comments can be
booksonthesubjectofJapaneseX-planes. craft the Japanese were interested in or torconcernedaircraftwhichwerederivatives Japaneseairforcespriortothewarwerevery and haveintentionallylistedonlythe aircraft directed to the authorat the e-mail address
IwasfirstexposedtotheworldofJapanese bought,missilesandmore.Supportforthesite of established production planes in the keen on obtaining as much information on name(s) in orderto not take away from the below.
experimental aircraft in 1988 through the wasgreat.SuchpeopleasartistTedNomura, Japanese arsenal. As SUCh, designs such as aviationtechnologyaspossible(and,insome maintopicathand.Thereaderwill alsofind Ihopeyou, thereader, enjoythebookand
classic bookJapaneseAircraftofthe Pacific PolishauthorTadeuszJanuszewskiandJ-Air theKi-116,whichwasderivedfromtheNaka cases, built and flew versions offoreign air with certain aircraft a section called 'Sur finditaworthwhileadditiontoyourlibraryas
War byRene J. Francillon. I found the book craft.comcontributorsMikeGoodwin,George jimaKi-84Hayate, arealsoexcluded.Athird craft),oncehostilitiesbeganJapanknewshe vivors'.Listedherearethoseaircraftthatsur areadyresource on some ofthe most inter
on the shelf in your typical mall bookstore. ElephtheriouandD.Karacayhelpedthesiteby factor revolved around the pool ofinforma couldnolongerrelyonoutsideassistancefor vived the war and what their fates were, estingJapaneseairplanesofthewar.
Sure, before then, I knew about the classic providing both artwork and data on some of tion available foracertain design.The more their aircraft industry and ensured it could eitherbeingscrappedorescapingthecutting
Regards,
Japanese planes suchas the MitsubishiA6M the planes presented. By 2002, I felt that I'd obscure or unknown the design was, the standonitsown.Thisitdid,producingmany torch. Where known, the Hepburn Romani
ReisenandtheNakajimaKi-43Hayabusa.But exhaustedwhattherewasonthesubjectand higher it was considered over other planes. successfulaircraftthatwereindigenous.The sationsystemisutilised forJapanesewords. EdwinM.DyerIII
Francillon'sbookbroughttomesuchplanes the site enteredastate offinalitywithnofur For example, the scope of the Rikugun influx ofGerman technology during the war Every attempt has been made to ensure [email protected]
as the Nakajima Kitsuka, Mitsubishi J8M therupdateshavingbeendonesince. Kogiken designs were of far more interest
SyusuiandtheTachikawaKi-94. Fastforwardtothefallof2007.JaySlaterof andofalesserknownnaturethantheproto
Myinterestinmilitarytechnologysatonthe IanAllan Publishing e-mailed me to discuss types of the Nakajima G8N Renzan or the
kerbthroughmycollegeyearsbutafterwards the prospect ofwriting a book on Japanese Aichi S1ADenkoofwhich more information
it slowly ramped back up. I found that I experimental aircraft. This was not the first is readily available. Finally, X-planes that
focused myreading onthe militarymachine timesomeonehadapproachedmetodoso. were purely research aircraft such as the
ofGermanyandthesheerbreadthoftechno Butunlike the others, Jayhad awell known Kawasaki Ki-78, those experimental planes Acknowledgements
logical innovationtheirengineersandscien publisherbehind himwho had anumberof constructedpriorto the startofthe war, and
tists churned out. Small arms, armour, X-planebooksinprint,manyofwhichIhadin most ofthe non-combat aircraft (transports,
artillery, missiles, submarines, aircraft, rock myownlibrary.Itseemednaturaltohimthat glidersandthelike)weregenerallyexcluded
etry and much more - no stone was left abookonJapaneseX-planeswouldbeawel fromcontention.Perhapsinafuturepublica
unturnedbyGermany'sscientists.Itwasdur come complement to their existing titles as tion, those designsthatdidnotmakethecut Thisbookwouldnotbewhatitiswithoutthe ion. To Tim Hortman who graciously pro TadeuszJanuszeWSki,JamesLong,RobertC.
ing my studies of German aviation that I well as providing the English aviation histo forthisbookwillgettheirchance. assistance and supportofagood numberof vided his photographs of the KyQshQ J7WI Mikesh,NicholasMillman,RonnieOlsthoorn,
wouldseetheJapanesepopupfromtimeto rianorenthusiastwithareadysourceofded It may appear that few aircraft remained individuals and I would like to recognise Shinden,NakajimaKi-115KoTsurugiandthe MasafumiSawaandAkioTakahashi.Assome
time.Mostoften,itwastheacquisitionofGer icated information on Japanese X-planes. I with suchpruningbutitstill leftasignificant themhere. Nakajima Kitsuka currently in store at the of the works used in researching the book
mantechnologyfordevelopmentinJapan,or certainlyagreed. number ofplanes to choose from, from the Firstandforemost,JaySlaterandhisteam National Air and Space Museum and which were in Japanese, Ryuki Arceno, Nanae
GermanplanedesignsofferedfortheJapan TheworkyouholdisnotsimplymyHikoki: historically important Nakajima Kitsuka and at Ian Allan Publishing. It was Jay who arenolongeravailabletothepublic. Konno, Lara Law and Tekla Munobe pro
ese to purchase. This piqued my interest in 1946websiteinbookform. Yes, someofthe Mitsubishi J8M SyQsui, to more unknown reached out to me and first proposed this During the information gathering phase of vided translations. ForthoseworksinPolish,
learningaboutwhattheJapanesehadbrew aircraft in these pages can be found on the typessuchastheKugishoTengaandKawan bookandthroughhimitbecameareality. thebook,researchsupportandmaterialwas MichalSporzyfiskiwasthekeytranslator.
ingintheiraviationcauldron. sitebuttheinformationherehasbeenfurther ishiK-200. To the artists whose work you will see in provided by several individuals. Their assis Last but certainly not least, my parents,
By this time, the World Wide Web was researchedandrevised.Thismeansthedata Insofarasthebooklayout,aircraftaresep thispublication:PeterAllen,KelceyFaulkner, tance helped to confirm or deny data, pro Edwin and Margaret, for their support and
becomingthe engineofinformationthatitis inthesepagesisfarmoreuptodatethanthe arated by service (IJA and UN) and then Muneo Hosaka, Gino Marcomini, Ted vided asounding board for theories, offered encouragement. Also to Gail Lashley for
today. While I was able to find bits ofinfor site. And for sure, the outstanding artwork alphabetisedbymanufacturer.Thoseaircraft Nomura, Ronnie Olsthoorn and Daniel Uhr. comments on the information or brought always making sure I had my nose to the
mation regarding Japanese X-planes, it was provided makes this a spectacular publica thatwerenotofeitherservice (orwerejoint Through their hard work, the aircraft within newinformationtothetable. Thesefolksare grindstone.
never anything substantive. Stops into the tionandinvestmentforyourlibrary. projects)are listedlast. Missilesandaselec- thesepagescome tolifeinspectacularfash- Shorzoe Abe, David Aiken, Paul Deweer,
6 7
Abbreviations and Glossary Imperial Japanese Army
AOAMC AtlanticOverseasAirMaterialCentreinNewark, Dai-IchiKaigunK6kl1Gijutsu-sh6 1stNavalAirTechnical RikugunKokugijutsuKenkyl1jo AirTechnicalResearch
NewJersey. ArsenalhousedatYokosuka,Japan.Thisgroup Institute.Thisunitconductedresearch,design
FE ForeignEquipment.FEnumberswereusedby wasresponsibleforaircraftdesignfortheUN. anddevelopmentfortheUA.Thefacilitieswere
theUSAAFtomarkcapturedaircraftfortracking Dai-IchiKaigunKokusho IstNavalAirArsenallocatedat locatedatTachikawa.
anddocumentationpurposes. Kasumigaura. Shi Beginningin1931,whentheUNissuedaspecification
Ha AbbreviationfortheJapanesewordforengine, Dai-JuichiKaigunKokusho ThiswastheIIthNavalAir foranaircraft,ashinumberwasassignedtoit,
hatsudoki.Forexample,theNakajimaIHa-35] ArsenallocatedattheHiroNavalArsenalin basedontheyearoftheShowaJapanese
2514-cylinderradialengine.Thiswasusedasa Kure,Hiroshima,whereseaplanes,flyingboats calendar.Forexample,theMitsubishiG7M
designatorforallenginesusedbytheUAwhile andenginesfortheUNwereproduced. Taizanwasdesignedtomeetthe16-ShiAttack
theUNusedtheirownsystem.Eventually,the Hei Literally'gradeC'.Heiismostoftenusedinthe Bomberspecification.16stoodforShowa16or
twosystemswerecombined.Intheexample booktodescribethethirdspecification,suchas 1941.
above,the'3'wastheenginetype(I4-cylinder, 18-shiHei. Shimpl1 Thewordisanalternatereadingofthe
double-rowradial),the'5'thebore/stroke Hik6ki AeroplaneinJapanese. Japanesekanjifor'divinewind'andisusedin
(I30mm/150mm)whilethe'25'wasthemodel Jid6sha Japaneseforcar/automobile. thistexttodescribethoseaircraftforusebyand
number,takenfromtheUNsystem. Kai Fromtimetotime,Japaneseaircraftwould forsuicideunitmissions.ShimpiiTokubetsu
IJA ImperialJapaneseArmy(Dai-NipponTeikoku haveKaiappendedtotheirdesignationwhen KogekitaiistheUNdesignationforsuicide
Rikugun).Inthisbook,UAreferstotheImperial thedesignwasheavilymodifiedbutnottoa units,meaningDivineWindSpecialAttack
JapaneseArmyAirService(TeikokuRikugun pointitrequiredanewdesignation.Kaimeant Force.TheUAwoulduseShimbuTokubetsu
Kokiitai). 'improved'.AnexamplewouldbetheNakajima Kogekitai,shimbumeaning'bandofheroic
IJN ImperialJapaneseNavy(Dai-NipponTeikoku Ki-84-11HayateKai. warriors'or'brandishingasword'.Kamikazeis
Kaigun).Inthisbook,UNreferstotheImperial KaigunKokuHombu ImperialJapaneseNavyAviation notusedbytheJapaneseasadescriptionfor
JapaneseNavyAirService(Dai-NipponTeikoku BureauoftheMinistryoftheNavyofJapan. suicideunitsbutthewordispopularinthe
KaigunKokuHombu). Amonganumberofdutiesofthisbureau,the West.
K.K. StandsforKabushikiKaisha,whichtranslates pertinentoneforthisbookwastheTechnical TachikawaDai-IchiRikugunKokusho FirstArmyAir
asCompany,Limited.Forexample,FujiKokuki Departmentthatoversawthedesignofnew Arsenal.UAairdepotthatrepaired,modified
K.K.wouldbeFujiAircraftCoLtd. aircraftandequipment. anddistributedaircrafttoUAairunits.Italso
Ken Abbreviationforkensan,meaning'research'. Ko Literally'gradeA'.Koismostoftenusedinthe producedtheKi-30,Ki-43andKi-51inaddition
Ki TheUAutilisedKinumbersforaircraft.Kiwas booktodescribethefirstmodelofaplanesuch tobeingonevenueforexperimentalaircraft
theabbreviationforkitaiwhichmeans astheKi-115Koorthefirstspecification,such development.
'airframe'.Thenumberfollowingthe as18-shiKo. TailNumber Forthepurposesofthisbook,thisrefersto
abbreviationwastheprojectnumberforthe KokuHombu ArmyAirHeadquarters.Thisdivisionofthe theUSNavymethodofmarkingcaptured
aircraftunderdevelopmentregardlessofthe ImperialJapaneseArmywasresponsiblefor aircraft.Itisconsideredthatthenumber
manufactureroraircrafttype.Forexample,the researchanddevelopmentofaircraft,aircraft appliedcorrespondedtoshippingallocation
MitsubishiKi-73. enginesandotheraviationequipment.Assuch, numbersfortheaircraftwhentheywere
Ku Abbreviationforkakku,meaning'toglide'. specificationsforaircraftwouldbeissuedfrom preparedfortransporttotheUS.
MAMA MiddletonAirMaterialAreaatOlmsteadFieldin thisdivision.
Middleton,Pennsylvania.Thiswaswhere Kokuki AircraftinJapanese.
capturedJapaneseaircraftwereshippedbythe KI1gish6 AircraftdesignedbytheDai-IchiKaigunKokii
USAAF. Gijutsu-showeregiventheKiigishOdesignation,
NA NotAvailable.Inregardstospecifications,NA acontractionofKokiiGijutsu-shO.Onemaysee
meansthatatthetimeofthebookprinting,the KiigishOaircraftcalledbytheYokosuka
informationonthespecwasunknownandnot designationbutthiswouldbeincorrect. Kawasaki Ki-64 Ki-60/Ki-61 Hein. The Ki-45 was proving to tures which were perceived as rather
available. MitsubishiJI1k6gy6KabushikiKaisha Thefullnamefor
beahorriblytroublesome aircraft. Problems unorthodox in comparison to other more
NAS NavalAirStation. MitsubishiHeavyIndustriesCoLtd.
NASM NationalAirandSpaceMuseum. atsu Literally'gradeB'.atsuismostoftenusedin Designers at times relish the freedom to let with the landing gear, concerns with drag, conventional types. Since Koi's aircraft was
Ne AbbreviationforNenshoRocketto,meaning thebooktodescribethesecondmodelofa theirvisionsdevelopandflowfromthedrafting engine difficulties and more were proving purelyhis own and notcreated to meetany
'burningrocket'inJapanese.Newasusedon planesuchastheKi-93atsuorthesecond boardtothetarmac,readytotaketotheskies. a thorn in Kawasaki's side. It was Doi who sort of specification, Koi would be disap
Japanesejetenginedesignations.Forexample, specification,suchas18-shiatsu. Takeo Doi, working for Kawasaki, was just stepped in to solve the issues plaguing the pointed when the IJAforbade Kawasaki giv
theNe330. ParkRidge ThiswasthelocationofNo.803SpecialDepot
such a designer. Despite the very real work initial Ki-45 design. In addition to working inganyfurthertimetothedesign.
TAlC TechnicalAirIntelligenceCenterlocatedin inParkRidge,Illinois.Capturedaircraftselected
WashingtonDCatNASAnacostia.Thiswas forinclusionintheNASMmuseumwerestored developing,testingandproducingcombatair to fix the floundering Ki-45, by 1940, Doi Doi's disappointment then turned to joy
wheredataonenemyaircraftwascollected hereuntilthecollectionwasculledduringthe craftfortheIJA,Doihadaconceptthathe,on was involved with the preliminary develop when, in October 1940, the IJA authorised
andmaintained.Capturedaircraftwere KoreanWarastheUSAirForceneededthe his own, brought to the fore. Initially, the IJA mentoftheKi-60heavyfighterand the Ki-61 Kawasaki to proceed with developing the
evaluatedatNASPatuxentRiver,Maryland. space. would not hearofthe design but later, when Hein. Ki-64 to meet a requirement for a fighter
USAAF UnitedStatesArmyAirForce. Paul.E.GarberPreservation,Restoration,andStorage
theKi-64tookshape,theirmindwouldchange. Evenwith such responsibilities, Doi had a capable ofamaximumspeed of700km/hat
Facility Aircraftthatsurvivedthecullingat
ParkRidgeweremovedtothisNASMfacility In 1939, Doi was involved with two designofhisownforahigh-speedfighter.His 5,000m (435mphat 16,405ft)and a5minute
locatedinSuitland-SilverHill,Maryland. Kawasakiprograms: the Ki-45Toryuand the conceptincorporatedanumberofnovelfea- climbtothatheight.
8 IMPERIAL JAPANESEARMY 9
To power the Ki-64, Doi would enlist the two coolanttanks holding 83.3 Iitres (22 gal was then crated and shipped to the United
help of fellow engineers employed by the lons) and 117.4 Iitres (31 gallons) respec States for study at Wright Field in Dayton,
Akashiengineplant.Thedecisionwasmade tively. The smallerserviced the front engine, Ohio.
to use the Kawasaki Ha-201 ([Ha-721 II) thelargertherearengine. Giventherelativelylongdevelopmenttime
engine. This was actually a combination of Doitested the Ha-201 and the coolingsys of the Ki-64, US intelligence had already
two Ha-40 engines, the Ha-40 being the temtoaconsiderabledegree.In1942,oneof becomeawareofthedesign.Thus,expecting
licence-built version of the Daimler-Benz theKi-61 Heinfighterswasspeciallymodified theKi-64wouldseeservice,theairplanewas
DB601A. Each Ha-40 was a 12-cylinder, liq totestthe coolingmethodand its trialflights assignedthecodenameRob.
uid-cooled powerplant and the Ha-20I was beganinOctober1942andranthroughtothe
formed throughhavingoneengineinfrontof endof1943.Becauseofthisthoroughtesting,
thecockpitandthesecondbehindit.Therear theconstructionoftheKi-64wasdelayedand KawasakiKi-64- data
engine drove the first of the contra-rotating sodid notreach completionuntil December
propellers and it had a variable pitch. The 1943.Nevertheless,Doiwassatisfiedthatthe Contemporaries
RepublicXP·69(US),HeinkelP.I076(Germany),CaproniCA.I83bis
front engine drove the second propeller, cooling system would grant an additional
(llaly)
which was ofa fixed pitch. Both propellers 41km/h(25mph)totheKi-64andbattledam
were three-bladed. All told, the Ha-201 was agewould notsignificantlyreduce the effec
Type Fighter
expectedtoproduce2,350hp. tiveness of it and as such the exhaustive
Crew One
The use of the Ha-201 was not the most testingwasworththeeffort.
novelfeatureoftheKi-64.Itwasthemeansof WiththeKi-64complete,flighttestingcom Powerplant
cooling the engine that was notable. The menced in December 1943. Fourtest flights OneKawasakiHa-201([Ha-72jll),24-cylinder,inverted-V,liquid
Ha-201 was to be cooled by a steam con were successfully made without mishap. cooledenginedeveloping2,350hpattake-off,2,200hpat12,795ft,driving
densing system. A tank of 15.4 gallons of However,onthe fifth, the rearenginecaught two,metal,3-bladedcontra-rotatingpropellers
waterwasfittedintoeachwingandtheouter fire.Thetestpilotwasabletolandtheaircraft
wingsandflapsservedasthecoolingsurface, and the fire was quenched. Mechanics Dimensions
Span 13.48m 44.2ft
totalling23.99m'(258.3ft').Theportwingser stripped the engine out of the Ki-64 and
Length 1I.00m 36.1ft
viced the front engine while the starboard returnedittotheAkashiplantforafullrepair.
Height 4.24m 13.9ft
wing providedcoolantto the rearengine.As TheKi-64itselfwasreturnedtothecityofGifu
Wingarea 28m' 301.3ft'
the water coolant turned to steam, it was which, at the time of World War 2, was a Wingloading 3.47Ib/m' 37.3Ib/fl'
pumpedoutinto thewingswhere thesteam majorindustrialcentre. Powerloading 2.17kg/hp 4.81blhp
would condense back into water which in Plans were made to improve the Ki-64 by
turn was pumped backinto the engine. The replacing the 2,350hp Ha-201 with an Weights
mainbenefitofthissystemwaslowerdragon enhanced model that could generate up to Empty 4,050kg 8,9291b
the airframe as the need for air inlets was 2,800hp. The propellers would be replaced Loaded 5,100kg 11,2441b
removed or minimised. Each laminar flow withtwo,constant-speedcontra-rotatingpro
Performance
wing housed the fuel tanks and one 20mm pellersthatwereelectricallyoperated.Itwas
Maxspeed 690.3kmlh 429mph
Ho-5 cannon while two more were fitted in envisionedthatwiththesemodifications,the
at5,OOOm at16,405ft
the fuselage deck. One drawback to the Ki-64Kaiwouldbeable toattaina topspeed
Range 1,0OOkm 621miles
wingsbeing packedwiththe coolingsystem of800km/h(497mph). Climb 5min30secto5,000m(I6,405ft)
apparatus was that it left little room for the UnfortunatelyfortheKi-64,repairworklan Ceiling 12,000m 39,370ft
fueltanksandconsequentlytheKi-64'soper guished,especiallyinthefaceofmorepress Fuelcapacily 618litres 136gallons
ational range suffered. The majority of the ingneedsfortheJapanesearmsindustryand
fuel was carried in the fuselage, the tanks theproductionofmoreconventionalaircraft. Armament
being placed in and around the space left As a result, both the Ki-64 and the Ki-64 Kai Two20mmHo-5cannonsinthefuselagedeck,one20mmHo-5cannon
availablebytheHa-20I engine.Themainfuel were cancelled.AfterJapan's surrender, the ineachwing
tankwassituatedinfrontofthecockpit,hold Ha-201 was stillatAkashi, its repairs incom
Deployment
ing306.71itres (81 gallons). Underitwas the plete. When US forces arrived in Gifu, the
None.OnlyoneKi-64wascompletedandflownbeforetheendofthe
oilreservoir,holding79.51itres(21 gallons)of Ki-64was found and technical teams gutted
war.
oil for the engines. Behind the cockpitwere theairplaneofitscoolingsystem.Thesystem
10 JAPANESE SECRET PROJECTS: EXPERIMENTAL AIRCRAFT OFTHE IJA AND IJN 1939-1945 IMPERIAL JAPANESEARMY 11
Kawasaki Ki-88
..
..
1943theKi-88wouldbenearingcompletion.
'"
The IJA, however, had other plans for the 'o"
Ki-88. After inspecting the mock-up and in o:I:
W
reviewingtheprojectedperformancedataof Z
:::::;l
the plane, itwas seen thatit offered no real
advantage overotherdesigns theninopera
tional use, notably the Kawasaki Ki-61 Hien.
Thus, Kawasakiwasorderedtoterminateall
workontheKi-88.
KawasakiKi-88- data
Contemporaries
BellP-39Airacobra(US),BellXFL-IAirabonila(US),BellP-63King
Cobra(NATOcodenameFredinRussianservice)(US),GudkovGu-I
(Russia)
Type Interceptor
Crew One
Powerplant
OneKawasakiHa-140,liquid-cooled,turbo-orsuperchargedengine
developingI,500hpdrivingathree-bladedpropeller
Dimensions
Span 12.37m 40.6ft
Length 10.18m 33.4ft
Heighl 4.14m 136ft
Wingarea 27.49m' 269ft'
InAugustof1942,theIJAsawaneedforaair nose. To get around this, Takeo placed the how best to accommodate a large calibre Weights
Empty 2,949kg 6,5031b
craft that, inits primaryrole, would serve as 1,500hp Ha-140 liquid-cooled, turbo- (or cannoninasingleengineaircraft.
Loaded 3,899kg 8,5981b
aninterceptorflying sorties to defend instal super-) charged engine in the fuselage, InJuneof1943,Takeo finalised hisdesign
lations, airfields and other assets that were behind the cockpit. The three-bladed pro for the Ki-88. Apart from the use ofa 37mm
Performance(specificationsareestimationsbyKawasaki)
considered important and therefore subject peller was driven using an extension shaft cannonandthe engineplacement, the Ki-88
Maxspeedal19,685ft 600kmjh 373mph
to enemyattack. Design specificationswere that ran from the engine to a gearbox con borenofurtherresemblancetotheP-39.The Range I,198km 745miles
drafted by the IJAfor the aircraftand itwas nected to the propeller. In essence, Takeo Ki-88 had adeep fuselage to accommodate Climb 6min30sec105,000m(I6,404ft)
Kawasaki who put forth what they felt was builttheaircraftaroundtheHo-203. the Ha-140 engine that was situated below Ceiling 11,000m 36,089ft
theanswer:theKi-88. The mainadvantageofplacing the engine and to the rearofthe cockpit. Theairscoop
Priortodraftingtheirdesignspecifications, inthefuselagewasthatitallowedthecannon fortheHa-140'sradiatorwasmountedonthe Armament
the IJAhadsifted throughanumberofideas tofirethroughthepropellerhub,producinga bottom of the fuselage, just forward of the One37mmHo-203cannonandtwo20mmHo·5cannons
beforesettling onaplane thathad to have a more stable firing platform that resulted in wingroots.Theradiatoritselfwaspositioned
Deployment
heavyarmamenttoensureitcouldinflictsig improved accuracy. Another advantage was backfromthescooponthebottominteriorof
None.TheKi-88didnotprogresspaslamock-upandpartially
nificantdamagetoenemyaircraft,especially thatitallowedaskilfuldesignertomake the the fuselage, almostdirectlyunderneath the
completedprototype.
bombers, and alsogoodhandling character nose more streamlined, enhancing speed pilot's seat. Jutting out on the left side of
istics to make it not only a stable gun plat performance. the fuselage, justabove the trailing edge of
form,butalsotoavoidasteeplearningcurve A good number of references infer that thewing,was the scooptoprovideairto the
fornewpilots. Takeo'sdesignwasinspiredbythe BellP-39 turbo- or super-charger of the Ha-140. The
To this end, Tsuchii Takeo, adesigner for Airacobra. While there is no evidence that landinggearwas conventionalandthemain
Kawasaki, began work on what would specifically states that Takeo simply copied gear retracted into the wings, while the tail
become the Ki-88. Takeo selected a 37mm theAmerican fighter, theP-39wasinlimited wheelwasfixed.Afueltankwasprovidedin
cannonastheprimaryweapon,supportedby operational use by the time design work eachwing,mountedbehindthewheelwells.
two 20mm cannons. It is probable that the began on the Ki-88 in 1942, notably seeing On either side and to the bottom of the
37mm Ho-203 cannon and two Ho-5 20mm actionintheBattleofGuadaIcanal.Thus, the Ho-203cannonwere theHo-5cannons.
cannons would serve as the armament fit Japanesewereawareofthedesign.Whether With the final design complete, work
with all three weapons fitted in the nose. anexamplewasevercapturedforanalysisis beganonafullscalemock-upoftheKi-88and
GiventhesizeoftheHo-203(whichwasalit unknownbutcertainlyintelligencewasavail this was completed sometime in 1943. In
tleover1.53m(5ft)inlength,weighing88.9kg able on the plane. Or, it maybe that Takeo addition, work had already begun on con
(196Ib)),thispresentedaprobleminsqueez arrived at the same conclusion as did H.M. structionofthefuselageandwingsforapro
ing them, along with the engine, into the Poyer, designerofthe P-39,whenlookingat totype and it was expected that by October
12 JAPANESE SECRET PROJECTS: EXPERIMENTALAIRCRAFT OFTHE UAAND UN 1939-1945 IMPERIALJAPANESEARMY 13
Kawasaki Ki-91
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KawasakiKi-91 - data
Contemporaries
Focke-WulfTO'Transozean'ProjektB(Germany),Focke-WulfFw191C •
(Germany),FockeWulfFw300(Germany)
Type High-Atlilude,Long-RangeBomber
Crew Eight
Powerplant
FourMilsubishiHa·214Ru,18·cylinder,superchargedradialengines
developingamaximumof2,500hp;eachenginetodriveafour-bladed
propeller
Dimensions
Span 47.9m 157.4ft
Length 32.97m 108.2ft
Height 9.99m 32.8ft
Thisstorycentres onthe failure ofabomber DC-4E four-engine passenger aircraft was Nakajima submitted the Ki-68 version using Wingarea 223.99m' 2,41l.l1ft'
that inspired the development of another funded by five airlines and Douglas with either the Mitsubishi Ha-IOI or Nakajima
new type. The Nakajima Ki-68 and the United Airlines building and testing the one Ha-I03 engines in place of the Nakajima Weights
Empty 33,999kg 74,9551b
Kawanishi Ki-85, both four-engine, long prototype. While the DC-4Ewas impressive, NK7AMamoru II unitsontheG5NI. Kawan
Loaded 57,999kg 127,8651b
rangebomberdesigns,hingedonthesuccess in terms ofits operating costs it did notadd ishi alsosubmitted their Ki-85 which was to
oftheUN'sNakajimaG5NShinzan(Mountain up. The aircraft was complex and this usetheMitsubishiHa-IIIMengines.
Speed
Recess).TheG5Nwouldprovetobeafailure resulted in maintenance issues, which As it was, the G5NI proved to be adismal
Maxspeed 580km/h 360mph
andinturnledtotheterminationoftheKi-68 increasedthecostofusingtheplane.Support failure. The NK7A engines were problematic at9,808m at32,t80ft
andKi-85programs;thereforetheUAwasleft for the DC-4E was withdrawn and Douglas and underpowered and the aircraft was too Range 9,000to10,000km 5,592to6,213miles
withoutalong-range bomberproject. Itwas wasaskedtosimplifythedesign.Asaconse heavy and complex. These difficulties con Climb 20min30secto8,000m(26,246ft)
Kawasakiwhosteppedintofill thegapwith quence, the DC-4 saw operational use with tributedtotheoverallpoorperformanceofthe Ceiling 13,500m 44,291ft
theirowndesign. the USArmyasthe DouglasC-54Skymaster. G5NI.Despitetheproblems,threemoreG5NI
In 1938, the UN was enamoured with the In early 1939, the sale of the DC-4E was aircraftwerebuiltfollowedbyafurthertwoair Armament •
Twelve20mmcannons,twocannonseachinoneoffourturretslocated
ideaofabomberthatwascapableofoperat completed and arrived in Japan to be craft that replaced the NK7A engines for four
inthenose,undersideoftheforwardfuselageandtopandboltomof
ingupto6,486km(4,030miles)fromitsbase. reassembled. By this time, the UN had Mitsubishi Kasei 12 engines. The two addi
theaftfuselagerespectively.Afifthturretmountedtheremainingfour
In part, this was due to the initial desire to informed Nakajima to be ready to studythe tionalaircraftweredesignatedG5N2,buteven
cannons.Standardbombload4,000kg(8,816Ib)(perhapsupto8,000kg
striketargetsdeepinRussiafromManchurian DC-4E to produce a suitable bomber devel theKasei 12enginescouldnotresuscitate the
(17,636Ib)forshorterrangedmissions)
bases. Later, when Japan went to war with opmentfromit.Afterhavingbeenflownsev designandtheproblemsremained. Duetoits
the United States, a need to attack the US eral times, the DC-4E was then reported as complications, theG5NI wasneverusedasa Deployment
mainland was identified and it was recog having'gonedowninTokyoBay',butinreal bomber.TwoG5NI (usingKasei 12s)andtwo None.Prototype60percentcompletebytheendofthewar.
nisedthatatwo-enginedesignwouldnotsuf ityhadbeenhandedovertoNakajimawhose G5N2aircraftwereconvertedtotransportsand
fice- fourengineswouldberequired.Onthe engineers tookitapart.Withinayear, Naka servedinthisroleuntiltheendofthewar.The
understanding that the Japanese aircraft jimahadbuilttheprototypeG5NI whichfirst AlliesgavetheG5NthecodenameLiz. bomberdesignsonthe table.Kawasaki,see bomberandengineerJunKitanowouldwork ingB-29Superfortresswhichwastobemass
industryhadverylittleexperienceinbuilding flewon10April1941.TheG5NI usedonlythe By May 1943, the cancellation ofthe G5N ingtheopportunity, immediatelygottowork withDoitohelpturntheaircraftintoreality.In producedinlate1943.FourMitsubishiHa-214
suchaircraft, the UNusedtheMitsuiTrading landing gear layout, wing design and radial hadalsobroughtthedemiseofboththeKi-68 ondesigninganewbomber.Themanbehind June 1943,Doiand Kitanobegan theirinitial 18-cylinder radial engines were chosen to
Company as a cover to acquire a Douglas engine fittings from the DC-4E coupled to a and the Ki-85 (of which Kawanishi had a the Ki-91 was Takeo Doi, an engineer research and by October, work on the first powerthe Ki-91. As the plane was expected
DC-4Efour-engine airliner,ostensiblyforuse new fuselage, tail design and a bomb bay. mock-up constructed by November 1942), employedbyKawasaki.Itwashisgoaltosee design concept for the Ki-91 was underway. to operate at high-altitude, provisions were
byJapanAir Lines. The development ofthe The UA planned to produce the G5NI and leaving the UA with no active four-engine the developmentofasuccessfulfour-engine The Ki-91 was slightlylargerthan the Boe- made to utilise superchargers with the
14 JAPANESE SECRET PROJECTS: EXPERIMENTALAIRCRAFT OF THE IJAAND IJN 1939-1945 IMPERIALJAPANESEARMY 15
engines and the projected maximum speed surisationsoas toavoidholdingupdevelop try. This would change by the close of 1944
Kayaba Katsuodori
was 580krn/h (360mph). To provide for the mentandallowitsflightcharacteristicstobe when B-29sbegan to operate from the Mari
anticipated IO,OOlkm (6,214 mile) range, measured. Oncethepressurised crewcabin anaIslandsandby1945bombingraidswere
eachwing carriedeightfuel tankswithafur for the Ki-91 was ready, subsequent aircraft far more frequent. In February 1945, a raid
ther two mounted in the fuselage above the weretohaveitinstalled. heavily damaged the factory in which the
bomb bay. For weapons, the Ki-91 was to InApril 1944,afull-scalewoodenmock-up Ki-91 prototype was being constructed. The
carryaheavyarmamentoftwelve20mmcan wascompletedandKawasakiinvitedIJAoffi damagewasextensive,ruining the toolsand
nons.Fivepower-operatedturretsweretobe cials to come and review the Ki-9l. Up until jigs. With the loss ofequipment needed for
used; oneinthe nose, one onthe underside thistime,theprojectwasaprivateventureby future production coupled with dwindling
oftheforwardfuselage,oneaboveandbelow Kawasaki to which considerable company supplies ofaluminium, the IJA decided that
theaftportionofthefuselage,andthelastin resources has been allocated. Ifthe IJA did fighters to combat the marauding B-29s had
the tail. The bottom turrets were remotely not find the bomber to theirliking, itwould becomeahigherprioritythanbombers. Any
controlled while the remainder were havebeenawasteoftime,effortandmoney. hope ofutilising such bombers was at best
manned. The tail turret was to mount four Fortunately,theIJAsawpotentialintheKi-91 slim. With the Ki-91 at 60 per cent comple
cannons while the rest had two cannons and work continued. In May, the IJA tion, Kawasaki stopped further work on the
each. As far as bombs, a total payload of inspected the Ki-91 mock-up and immedi bomber and the project was officially can
4,000kg (8,818Ib) was envisioned and the ately ordered production of the first proto celledinFebruary1945.
Ki-91 wastohaveatricyclelandinggearwith type. Kawasaki planned to construct the Had the Ki-91 achieved service, plans to
thenosegearusingasingletyreandthemain Ki-91 at a new plant in Miyakonojo in attacktheUSmainlandwereinplacetooper
landing gear using dual tyres. A semi MiyazakiPrefecture.However,theIJAdidnot ate the bomberfrom the Kurile Islandsusing
recessedtailwheelwasalsoinstalled. want to wait for the construction of a new temporarybases,while anotherplantostrike
Anotherfeature ofthe Ki-91 was tobe the plant and directed Kawasaki to use their HawaiiwasformulatedusingbasesintheMar
use of a pressure cabin for the eight man established factory in Gifu Prefecture. By shall Islands. The second plan was rendered
crew. But the development ofsuch a large June 1944, the constructionoftheprototype obsoletewhentheJapaneselosttheMarshall
pressurisedcabinfortheKi-91 wasexpected Ki-9l hadbegunattheGifufactory, together IslandstotheAlliesinFebruary1944.Asanote,
to take some time toimplement, evenusing withthenecessarytools andjigs toproduce contemporary images sometimes show the
knowledgefromanotherofDoi'sdesigns,the furtheraircraft. Ki-91 as having abombbaybatteryofdown
Kawasaki Ki-I08,atwin-engine high-altitude However, June would see the first B-29 ward firing cannons for aground-attack role.
fighter fitted with a pressure cabin for the raidsoverJapan,butastheattackswerefew While the Japanese were interested in such
pilot.Therefore,itwasdecidedthattheinitial andfarbetween,workontheKi-91 continued concepts, thereisnoevidencethatKawasaki
Ki-91 prototypewould be builtwithoutpres- despitetheworseningsituationforthecoun- envisionedsuchataskfortheKi-91.
Kayaba envisioned that his design fora fast, designing such an engine. The main draw TheKatsuodoridepictedhereisshowninthe
point defence interceptor would sweep backwitharamjetengineisthatatsubsonic coloursandmarkingsofthe71stSentai.Itis
through the Allied bombers like the kat speeds its performance is poor. Below interceptingTOkyO-boundNorthropB-35bombers
suodoribirdhuntsforfish.Impressedwiththe 612krn/h (380mph), a ramjet suffers signifi ofthe44thBombSquadron,40thBombGroup
operatingfromTinian.
prowessofthekatsuodori,Kayabanamedhis cantlossinspeedandbecomeshighlyineffi
design afterthe bird. But as we will see, his cient in terms of fuel consumption. The been purchased from Germany. His interest
visionwastomeetwithaharshreality. ramjet typically requires another power in aviation saw him produce four aircraft
The genesis of the Kayaba Katsuodori sourcetobringtheaircraftuptothespeedat designs: the Hino No. I, No.2 and the No.3
began as far back as 1937 with the Kayaba whichtheramjetcanoperateefficiently.Typ and No.4 Kamikaze-go airplanes. However,
RamjetStudyGroup,acollectionofengineers ically, this speed is at least 966km/h eachofthesedesignswasafailure. Pressure
andscientistswhosoughttoinvestigateram (600mph). Once the ramjet reaches that from his militarysuperiors sawHinogive up
jet propulsion in Japan. The concept of the speed the engine is self-sufficientand, with onaviationby1912.
ramjet was actually patented in 1908 by out fuel injection moderation, would propel However,in1937,Hinowasinspiredtocre
French engineer Rene Lorin, but it was the the plane to speeds far in excess of the ate a tailless glider. The project was taken
Russian I. A. Merkulov who first built and design's ability to handle the high tempera overbytheKayabaSeisakusho(KayabaMan
testedone,theGIRD-04in 1933.Aramjetisa turesandMachnumber.
ufacturingWorks)andthenbyDr. Hidemasa
verybasic engine with few moving parts. In The Kayaba Ramjet Study Group saw the Kimura who worked for the Aeronautical
simple terms, it uses the high pressure air benefitsofhighspeedwitharelativelyeasyto Research InstituteoftheTokyoImperialUni
generated by the aircraft's forward motion manufacture engine. The group produced versityunderDr. Taichiro Ogawa. The result
andforcesitthroughtheinlet.Theairisthen two testmodelsbeforethe final product, the was the HK-l. The HK-I (standing for Hino
mixedwithcombustedfuel-thisheatstheair Kayaba Model I ramjet, was realised. The Kumazo)wasbuiltbytheItoHikokiK.K.and
andisforcedoutoftherearoftheengine,pro Model I was projected to be able to offer was completed in February 1938. It was
viding forward propulsion. Unlike pulsejets speeds of 900km/h (559mph). With the purely a research glider to test the tailless
(which were to be used on the Kawanishi enginecomplete,allthatwasneededwasthe concept. Testing commenced in December
Baika, seePage61), the fuel flowiscontinu aircrafttofititinto.
1938 with ground towing at Kashima in
ous. Without getting into the specifics of a The airframe design began with Kumazo Ibaraki Prefecture and the first air released
ramjet,adjustmentsinthedesignoftheinlet Hino.Hinowas anofficerin the IJAand had flights began in September 1939 at Tsu
(tomaximisetheintakeofair),combustor(to beenthefirstJapanesetounofficiallymakea danuma in Chiba Prefecture. Because it
ensureeffectiveoperationduringflightmove flight on 14 December 1910 when he acci showedpositiveresults,theIJAtookaninter
ments)andtheoutletnozzle(toeffectaccel dentallytooktotheairinaHansGrademono estin the concept. The HK-I waspurchased
eration increases) all come into play on plane while hewas taxiing. This aircrafthad bytheRikugunKokugijutsuKenkyiijoinApril
16 JAPANESE SECRET PROJECTS: EXPERIMENTALAIRCRAFTOFTHE IJAAND IJN 1939-1945 IMPERIALJAPANESEARMY
17