Monday 12 November 2012

The Kawasaki Ki-119

Continuing serendipitously with the Kawasaki theme attention is drawn to a design that was full of Eastern promise but ultimately not to be - the Ki-119. Many envisage and describe this interesting aircraft as a desperate development within the special attacker concept - as a kamikaze aircraft - but in fact the Ki-119 was planned to serve principally as a conventional aircraft, in the sense that it was intended to survive and return from sorties having discharged its ordinance. The 'last ditch' aspect relates to its deployment in the expected final defence of Japan, as Allied invasion forces approached and attempted to land. The design and development of the Ki-119 was directly related to the Ki-67 Hiryu which it was intended to replace - or perhaps more accurately supplant - as one of the imperatives for its creation in the first place was the failure of large scale and rapid production of that superlative design. 

But what of the designation? Bueschel and Francillon both refer to the Ki-119 as a Light Bomber. Shuppan-Kyodo's Encyclopedia of Japanese Aircraft refer to it as the Experimental Ki-119 Fighter Bomber, (試作 キ-119 戦闘爆撃機 - shisaku ki-119 sentoubakugekiki) whilst Kantosha's General View of Japanese Military Aircraft in the Pacific War (1953) uses the term Experimental Attacker  (試作攻撃機 - shisaku kougekiki). Does it matter? Probably not, especially as the design envisaged a multi-role capability as dive bomber, fighter-bomber and fighter. The Ki-119 certainly returned to the somewhat archaic concept of the single engined bomber, primarily to best exploit the supply of Army Type 4 Mitsubishi Ha-104 engines intended for the Ki-67, but might legitimately be described as a true fighter-bomber. Despite its conventional 'single seat fighter' appearance, which is deceiving, it was to be a very large aircraft, more than 3 metres  longer and with a span 2 metres wider than the Ki-100, although sharing some of that type's design characteristics.

Although the Ki-67 bomber was a Mitsubishi design, Kawasaki were heavily involved in its production, building the wings, tails and completing the final assembly. Actual production of the bomber was disappointing, falling far short of what had been planned (81 completed vs 447 planned between December 1944 and August 1945) and that situation was exacerbated by B-29 raids specifically targeting aircraft production plants. The Ki-119 project commenced in March 1945 and in April Kawasaki received a directive to move as much of its aircraft production into underground facilities as possible. The company began plans to set up production in underground tunnels at Mino, Watchi and Misunami but this had not been completed by war's end. Nevertheless the Ki-119 was designed from the outset to be easier to build within these restricted facilities as a series of sub-assemblies and easier to fly by inexperienced pilots who had had less opportunity for training.

There were three proposed configurations for the Ki-119 and all of them retained a basic armament of two 20mm Ho-5 lightweight fixed machine cannon in the cowling position*. Configured as a dive bomber the Ki-119 would carry an 800 kg bomb on the centreline, or a 500 kg bomb on the centreline and two 600 l drop tanks under the wings for an extended mission range. For this role, intended to strike at the capital ships of enemy invasion fleets closing on Japan, it would undoubtedly have had dive flaps installed, probably of a similar slatted design to those fitted to the Ki-48-II. As a fighter bomber it would carry two 250 kg bombs under the wings (and probably other forms of ordinance) to be used against beachheads, landing ships and troop concentrations moving inland. And finally as an escort fighter for those roles it would be armed with additional wing armament of two Ho-5 20mm machine cannon. This multi-role approach to the design would provide simplicity of maintenance and operation by receiving units. Note that in most previous descriptions of this aircraft project the dive bomber and fighter-bomber configurations have been transposed.

Progress on the Ki-119 project was rapid and by June a full-scale mock up had been built and production drawings almost completed. Then two devastating B-29 raids on the Kawasaki plant at Kagamigahara on 22 and 26 June effectively halted further progress. In the first raid the Ki-67 parts assembly, sub-assemply and final assembly shops were badly damaged, together with the administration building. In the second raid the whole site was effectively knocked out with a number of essential facilities such as heat treatment, hydraulic press and acetylene gas systems destroyed or damaged beyond repair. The design team immediately began work to replace the damaged drawings in anticipation of being able to produce a prototype aircraft by November 1945. This restoration plan was first compromised by an attack on Gifu in July which destroyed most of the remaining Kawasaki workshops and then finally derailed by the atomic bomb attacks on Hiroshima and Nagasaki.

The Ki-119 was to be of metal construction with a main spar of Extra Super Duralmin (ESD), and the rest of the structure of Super Duralmin (SD) and Duralmin. Production aircraft were to have a three-bladed Hamilton-type propeller of 3.6m diameter but due to the bomb damage to facilities the prototype was to be fitted with a four-bladed Junkers-type propeller. A wide-track undercarriage incorporated shock absorbers from the Ki-102 to provide durability in rough field landings by inexperienced pilots. Several innovative features were planned, including high-pressure oil hydraulic operating systems for the undercarriage, oil cooler shutter, wing and cowling flaps and gun charging. An electrically operated auto-pilot was planned but pending its production the aircraft would have automatic rudder control only. The reason for the off-set position of the oil cooler, a feature of the turbo-supercharged Ki-100-II, is unknown. There is no indication of plans to instal a turbo-supercharger in the Ki-119 and it seems unlikely to be related the centreline bomb carrying arrangements. 

The Ki-119 design was integral to the 'striking defence' concept of the Army within a scenario which could not have envisaged the deployment of atomic bombs by the enemy. It remains a significant aircraft design representing the planned, if not actual, final aerial defence of Japan against invasion. In this respect, and as far as modelling goes, it has tended to be overlooked for more obscure experimental project types.

It is a special privilege to be able to illustrate this blog post with images of a superb 1/48th scale model of the Ki-119 crafted by Mr Sumito Koyama from the Racoon resin kit. Of special interest is Mr Koyama's convincing realisation of the probable late-war colour scheme and markings, better reflecting the simplicity and functionality of the aircraft - as well as its likely appearance had it actually gone into service - by comparison to some of the more fanciful depictions seen. Tail markings would perhaps have represented adaptations of those used by former Ki-67 regiments or by other light bomber/assault aircraft units, as well as fighter units, so there is considerable potential for 'what if' builders to use their imagination.

The Racoon kit may be hard to find and the only other kit I am aware of is the 1/72nd resin kit by Unicraft Models and shown built up here of which more details will be provided later. I can find no reference to any vacform kits of the Ki-119 in any scale which is rather surprising.

* The Imperial Army designated all automatic weapons above 11mm in calibre as kikan hou (機関砲)- machine cannon - regardless of the type of ammunition fired. The Ho-5 (Type 2 lightweight machine cannon) was in effect a scaled up version of the Ho-103 13mm machine cannon firing a 120 x 94 cartridge at a rate of 850 rpm with muzzle velocity of 820 ms. The ammunition available for this weapon included practice ball, three types of armour piercing tracer (APT), explosive incendiary, explosive and two types of special incendiary. The fighter version of the Ki-119 was to be armed with four of these weapons, two synchronised firing through the propeller arc from the cowling position and one in the inner section of each wing, firing from outside the propeller arc.

Source credits: Richard M Bueschel; René J Francillon; Ryusuke Ishiguro & Tadeusz Januszewski; Sumito Koyama (Racoon Model images); Robert C Mikesh;  


Dan Salamone said...

Thanks as always Nick, a beautiful model of an elegant design.

Mark Smith said...

I really like this - kudos to its builder for a superb job, and thanks for telling me about a kit I never knew existed, Nick. Most of Raccoon's subjects have been superseded by better kits from the mainstream makers, but it doesn't look likely with this one. I too think the finish and general appearance quite convincing!

Mark Smith

Ken Glass said...

Hello Nick,

Thanks for making this posting. Mr. Koyama's work with the Racoon resin model is excellent.

Ken Glass

R. Vieira said...

Hello Nick,

Thanks for the comprehensive post, with so many interesting details on the Ki-119 development process.

Please congratulate Mr. Koyama also on my behalf. I fully agree with you and Mark Smith on the excellent finish and overall convincing appearance of the model.

R. Aballe

Ronnie Olsthoorn said...

Interesting article, Nick! I always liked this plane for no particular reason. I nearly made some artwork for it for Japanese Secret Projects, but it was scrapped from the book due to lack of space.