Special number 3 light tank Ku-Ro: Difference between revisions

{{Infobox weapon

|name=Special number 3 Ku-Ro (So-Ra)

| image= Special No.3 Light Tank Ku-Ro.jpg

| image_size = 250

|caption= Special Number 3 light tank prototype mockup

|origin= [[Empire of Japan]]

|design_date=1943/1944

|number=1 (prototype mockup only)<ref name="Taki"/>

|length={{convert|4.07|m|ftin|abbr=on}}<ref name="Taki"/>

|width={{convert|1.44|m|ftin|abbr=on}}<ref name="Taki"/>

|height={{convert|1.89|m|ftin|abbr=on}}<ref name="Taki"/>

|weight={{convert|2.9|t|abbr=on}} for the tank, with wings added {{convert|4.2|t|abbr=on}}<ref name="Taki">[http://www3.plala.or.jp/takihome/So-Ra.html Taki's Imperial Japanese Army: Special No. 3 Flying Tank "So-Ra" or "Ku-Ro"]</ref>

|suspension=[[Bell crank]]

|speed={{convert|43|km/h|mph|abbr=on}} on road<ref name="Taki"/>

|primary_armament=One Type 100 37 mm tank gun or one 7.7 mm [[Type 97 heavy tank machine gun|Type 97 machine gun]] or one flamethrower<ref name="Taki"/>

|crew=2<ref name="Taki"/>

The '''Special number 3 light tank Ku-Ro''' (特三号戦車 クロ) (also known as the "So-Ra"<ref name="Taki"/>) was an experimental [[Empire of Japan|Japanese]] [[winged tank|winged]] [[light tank]] project, developed during [[World War II]]. It is one of the notable aircraft concepts developed during that war.<ref name=":0">{{Cite book|last=Mrazek|first=James E.|title=Airborne Combat: The Glider War/Fighting Gliders of World War II|publisher=Stackpole Books|year=2011|isbn=978-0-8117-0808-1|location=Mechanicsburg, PA|pages=347}}</ref>

==Context==

The main problem that the army faced was the difficulty of moving armored fighting vehicles long distances over the main islands of Japan to resist seaborne invasion. They came up with the idea that it could be done by equipping the vehicle with wings, empennage, and take-off carriages. Once landed, all the items that needed to make the vehicle airborne would be quickly detached to allow it to go into action as a ground vehicle.

In 1939, the Japanese Army Air Force Examination Department began the concept development of what became the [[Special number 3 light tank Ku-Ro|Special tank No.3 Ku-Ro]]. The glider for this project was given the army designation Ku-6 (Japanese: {{jp|ク六|Ku roku}}), which can also be read or abbreviated as "Ku-Ro", and thus that also became the code name for the tank the glider was intended to carry.<ref name="Dyer">{{cite book |last1=Dyer |first1=Edwin M. |title=Japanese Secret Projects : Experimental Aircraft of the IJA and IJN 1939-1945. |date=2009 |publisher=Midland |isbn=978-1857803174}}</ref><ref name="Pentelic">{{cite web |last1=Pentelic |first1=Marko |title=Maeda Ku-6 |url=https://tanks-encyclopedia.com/maeda-ku-6/ |website=The Online Tank Museum |date= 25 July 2022|publisher=Tanks Encyclopedia |access-date=25 December 2022}}</ref>

==Development==

In the fall of 1943, the [[Imperial Japanese Army]]'s [[Teishin Shudan]] formed the 1st Glider Tank Troop. Before the 1st Glider Troop was established, the only heavy support available to Japan's [[Airborne forces|airborne]] infantry was provided by the [[Kokusai Ku-8]]. This [[military glider]] was able to transport the [[Type 94 75 mm Mountain Gun|Type 94]] and [[Type 94 75 mm Mountain Gun|Type 94]] 75&nbsp;mm [[mountain gun]]s, but these infantry support guns lacked the mobility and anti-tank capabilities required by Japan's paratroopers. The solution to this problem was to develop a glider-portable light tank, but the existing Ku-8 glider was not capable of supporting the weight of a vehicle as large as a tank. So in 1943 and into 1944 the Armoured Army Headquarters (army aviation headquarters) and the Fourth Army Institute of Technology collaborated on a new concept to fill this role, a flying tank. A small tank that could be towed on a [[glider (sailplane)|glider]] by a powered aircraft and then released and glide down to the battlefield along with paratroopers. The tank would detach its wings after landing<ref name="Taki"/> and then be able to provide armour support to the infantry. Rather than using an existing tank or glider design, it was decided that a new tank and new glider should be developed. Work on developing the glider (wing and empennage) was given to [[SunTour|Maeda Iron Works Company]] (Maeda Kōken Kōgyō), while designing and buildingof the prototype tank was given to [[Mitsubishi]].

Mitsubishi based the tank on their [[Type 98 Ke-Ni light tank]]. The weight was reduced to 2.9 tons from 7.2 tons and the crew was brought down from 3 to 2. A single mockup of a prototype tank was built and named the "Special number 3 light tank Ku-Ro".<ref name="Taki"/> The commander sat in the turret and acted as both gunner and loader. The driver's position was located in the chassis. The turret was rear-mounted and housed the tank's only weapon, a [[Type 100 37 mm tank gun]], the same used by the Ke-Ni. There was no coaxial or hull mounted machine gun. There were plans to mount either a flamethrower or 7.7&nbsp;mm [[Type 97 heavy tank machine gun|Type 97 machine gun]] in place of the tank's 37&nbsp;mm gun.<ref name="Taki"/>

===Glider===

{|{{Infobox Aircraft Begin

|name=Ku-6

|image=

|caption=

}}{{Infobox Aircraft Type

|type=[[Winged tank]]

|national origin=[[Empire of Japan]]

|manufacturer=[[Maeda Aircraft Corporation]]

|designer=

|first flight=

|introduced=

|status=Experimental

|primary user=

|number built=1

|developed from=[[Type 98 Ke-Ni]] (ostensibly)

}}

|}

The glider developed for the Ku-Ro was the '''Maeda Ku-6''' a 700&nbsp;kg [[twin boom]] craft, which was specially designed to fit the tank. It was designed by The Aeronautical Institute of the Imperial University in [[Tokyo]]. It was designed with all the requirements that the Army's Troop Transport Command needed.<ref name=":0" />

When mounted in the Ku-6 glider, the Ku-Ro had a wingspan of 22 m, a length of 12.8 m and a total weight of 4.2 tons.<ref name="Taki"/> The glider was designed to be towed behind a [[Mitsubishi Ki-21]] [[medium bomber]]. The [[Continuous track|tracks]] of the tank were unable to match Ki-21's take-off and landing speeds and since taking-off and landing would cause a great amount of damage from friction to the tracks, a pair of detachable [[ski]]s were made part of the glider. The glider, after being launched and landing could quickly be disassembled and removed from the Ku-Ro tank.

====Specifications====

{{Aircraft specs

|ref=Fighting gliders of World War II<ref name=Mrazek>{{cite book |last1=Mrazek |first1=James E. |title=Fighting gliders of World War II |date=1977 |publisher=Hale |location=London |isbn=978-0312289270 |pages=[https://archive.org/details/fightinggliderso00mraz/page/84 84-86] |url-access=registration |url=https://archive.org/details/fightinggliderso00mraz/page/84 }}</ref>

|prime units?=met

<!--

General characteristics

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|crew=2

|capacity=1 light tank ({{cvt|6174|lb|order=flip}}

|length m=

|span m=21.9

|height m=

|wing area sqm=60.3

|aspect ratio=<!-- sailplanes -->

|airfoil=

|empty weight kg=697.6

|gross weight kg=3498

|max takeoff weight kg=

|more general=

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Performance

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|perfhide=y

|cruise speed note=

|stall speed kmh=

|never exceed speed kmh=

|glide ratio=

|sink rate ms=

|lift to drag=

|wing loading kg/m2=

|more performance=

}}

==Project fate==

By 1945 the project was cancelled, even though Maeda had completed the prototype glider in January of that year.<ref>{{cite book|last=Mrazek|first=James|title=Airborne Combat|year=1975|publisher=Stackpole Books|isbn=0811744663|pages=486|url=https://books.google.com/books?id=kkcwSnVaMw8C}}</ref> Only a mockup of the prototype tank had been completed by Mitsubishi.<ref name="Taki"/> The cancellation was caused by a combination of technical problems, related to the poor maneuverability of the glider and stress on the tank, and the changing nature of the war for Japan. The [[Pacific War]] was going poorly for Japan by 1944. The Japanese had lost [[air supremacy]] to the [[United States Air Force]] and the chances of any large Japanese aircraft towing a glider being intercepted and shot down were very high and would mean not only the loss of the aircraft but the tank, as well. As with many innovative weapons projects launched by Japan in the final years of the war, production could not advance beyond the prototype stage duetomaterial shortages, and the loss of Japan's industrial infrastructure to the [[Strategic bombing during World War II|Allied bombing of Japan]].{{sfn|Tomczyk|2005|pp=3, 5, 29}}{{sfn|Zaloga|2007|pp=3, 22}}

**[[Antonov A-40]], a Russian flying tank

**[[Baynes Bat]], an experimental British design

*[[Japanese tanks of World War II]]

{{reflist}}

* 木俣滋郎『幻の秘密兵器 恐るべき先駆的技術の集大成』廣済堂出版 1977年<br/>（後に光人社NF文庫から再版 1998年 {{ISBN|4-7698-2204-9}}）

* {{cite book | last = Tomczyk | first = Andrzej | year = 2005 | title = Japanese Armor Vol. 4 | publisher = AJ Press | isbn = 978-8372371676 }}

* {{cite book | last = Zaloga | first = Steven J. | author-link = Steven Zaloga | year = 2007 | title = Japanese Tanks 1939–45 | publisher = Osprey Publishing | isbn = 978-1-8460-3091-8 }}

*[http://www3.plala.or.jp/takihome/So-Ra.html Taki's Imperial Japanese Army Page - Akira Takizawa]

{{Japanese Army Glider Designation System}}

[[Category:Experimental and prototype tanks]]

[[Category:History of the tank]]