aircraft/loadouts Mitsubishi Ki-147 & Kawasaki Ki-148, "I-Gō"「イ号」- Japanese Guided Missiles!

[_qaz_ 675]

 

With the recent addition to the Fritz-X to War Thunder, I feel this is now more possible than ever. Here is my first suggestion ! 

 

I-Gō『イ号』Remote Guided Air-Surface Missiles

 

Mitsubishi Ki-147 (I-Gō Model 1 Kō) & Kawasaki Ki-148 (I-Gō Model 1 Otsu)

 

 

 

Contents

 

• Introduction
• History & Development
• Suggestion
• Specifications & Characteristics
  • Ki-147 / I-Gō Model 1 Kō
  • Ki-148 / I-Gō Model 1 Otsu
• Control Method & Mechanics
• Suggestion
  • Statcard (soon)
• Sources
  • Primary
  • Secondary

 

 

 

 

Introduction                                                                                                      Ki-147 (top) & Ki-148 (bottom) to scale

 

In the latest major update to the game, the German radio guided anti-ship bomb Fritz-X was implemented. This addition has effectively opened the door to early manually guided air ordnance. Because of this, I decided to gather information on Japanese guided munitions and form a suggestion for viable weapons.

 

In World War II, the IJA had developed two basic types of air-surface guided missiles, the *radio-guided I-Gō Model 1 (3 variants) & infrared-guided Ke-Gō (9 test variants). Because Ke-Gō is guided by infrared sensors and functionally "fire-and-forget" it is omitted from this suggestion, as these weapons systems do not appear in War Thunder yet.

 

*The third variant of I-Gō was developed in early 1945, I-Gō Model 1 Hei, and used an alternate guidance system of acoustic sensors. Due to the fire-and-forget nature of this system it is also omitted from the suggestion.

 

As a general rule of thumb, Kō = A, Otsu = B, Hei = C. 'I-Gō Model 1 Kō' & 'I-Gō Model 1 Otsu' are the subjects of this suggestion (designated Ki-147 & Ki-148 respectively).

 

History & Development

 

On September 8, 1943, Italy signed an armistice with the Allies and surrendered. On the 9th, the Italian fleet departed for Tunisia. To prevent ships from falling into Allied hands, the Luftwaffe dispatched 6 Do-217 bombers of KG 100, armed with Fritz-X guided bombs, to intervene. The battleship Roma, flagship of the Italian fleet, was struck by two of these new weapons and sunk after a catastrophic magazine detonation. The effectiveness of this attack shocked the world, and the IJAAF, with no dedicated anti-ship weapons, were inspired.

 

Early in 1944, the Army Bureau of Aeronautics began research on the design of guided missiles to attack surface vessels. By July, two specification proposals were finalized. The more ambitious I-Gō Model 1 Kō, and the smaller I-Gō Model 1 Otsu. Engineer Major Takeo Omori was tasked with preparing the preliminary radio-control and stabilization systems for these missiles. Mitsubishi was prompted to produce the design and construct the airframe of the I-Gō Kō (Ki-147), while I-Gō Otsu (Ki-148) was assigned to Kawasaki. Mitsubishi's Toku-Ro Mk. 1 liquid fuel rocket motor was the propulsion system of both models. Sumitomo Communicating Machine Company built the radio control systems.

 

Ki-147 was significantly larger than its brother, bearing a Navy Type No. 80 800kg bomb as the warhead, while Ki-148 was equipped with a 300kg

HEAT charge. The Type4 Heavy Bomber Ki-67-I was the designated mother

aircraft of Ki-147, Ki-148 was carried by Type99 Light Bomber Ki-48-II and Ki-102 Otsu.

 

Both models of the I-Gō had their first prototype completed in October 1944. The construction of the missiles consisted of wood for the wings and tail control surfaces, while the rest of the fuselage was made of galvanized sheet iron. By November, 10 prototype Ki-147 were delivered, and the number of prototype Ki-148 eventually amounted to 30. 

The initial experimenting of Ki-147 was held off the coast of Choshi, gliding and powered flight were tested. In the secondary stage of testing, with radio control, observed were issues with the servo motors near the end of powered flight. Missiles often fell in a range 30 meters short to 100 meters far of the target. In an unfortunate accident during testing in February, a missile lost control and veered off course toward the town of Atami where it struck an inn, killing a maid and injuring a bather.

 

When testing concluded, adjustments to the control surfaces and stabilization system were complete, but problems with the servos were still in the process of being amended.

 

Nonetheless, Ki-147 had achieved a significant result. 50 missiles were ordered for production, but only several were completed. It was believed that Ki-147 would be perfected on the basis of experiments with Ki-148.

Ki-148 was tested extensively from November 1944 to February 1945. During testing, adjustments to the machines were constantly made to improve the missile. 

 

The last test series was conducted in July from Yokaichi Army Air Field, and the missile's control systems were heavily improved. The Shiraishi Rock in Lake Biwa was used as a target. These tests confirmed the perfection of the radio-guidance and flight control systems. In combat scenarios vs. enemy ships, an accuracy of 75% was estimated. In April, mass production had begun with 150 missiles, and they were all completed before the war ended.

 

In reality, neither Ki-147 nor Ki-148 would ever see combat use, due to several factors. It was believed that the mother plane would be too vulnerable to attack during the launch of the missile. Incessant air raids in prevented further testing in the summer of '45. All completed

I-Gō missiles were reserved for defense during the perceived mainland invasion.

 

Prior to the arrival of the US forces to occupy Japan, all ~200 I-Gō missiles had been destroyed. In postwar questionings, the Japanese were adamant that they received no German assistance in developing guided munitions.

Specification & Characteristics

 

Ki-147 / I-Gō Model 1 Kō

 

• Span: 3.6m
• Length: 5.77m
• Height: 1.0025m
• Wing Area: 3.6m²
• Weight (Empty): 1266kg
• Weight (Loaded): 1472kg
• Drop Altitude: 500-1000m
• Drop Speed: 360km/h
• Top Speed: 550-560km/h @ SL
• Propelled Range: ~11km
• Armament: Navy No. 80 800kg Bomb
• Engine: Toku-Ro Mk. 1 Model 3 (240kgf for 75s)
• Mother Aircraft: Ki-67-I
• Observation Scope: Type94 Aerial Surveillance Glasses

 

Ki-148 / I-Gō Model 1 Otsu

 

• Span: 2.6m
• Length: 4.09m
• Height: 0.90m
• Wing Area: 1.95m²
• Weight (Empty): 550kg
• Weight (Loaded): 680kg
• Drop Altitude: 500-1000m
• Drop Speed: 330km/h
• Top Speed: 550km/h @ SL
• Propelled Range: ~11km
• Armament: 300kg HEAT warhead
• Engine: Toku-Ro Mk. 1 Model 2 (150kgf for 80s)
• Mother Aircraft: Ki-48-II, Ki-102 Otsu
• Observation Scope: Type94 Aerial Surveillance Glasses

Control System & Mechanics                                                                      Useful I-Gō missile flight diagram, drawn by a test pilot of I-Gō Model 1 Kō

 

Ki-148 utilized an electric system for gyro and control surface power. One minute prior to dropping, current was applied to filaments in the receiver tubes of the bomb. Moments before launching, the gyros were started electrically and reached ten thousand RPM in four seconds. This translated to about 2 minutes of useful control sensitivity after launch until the gyros tumbled, as they were unpowered in flight. During flight, the servos were powered by a series of dry cells supplying 6A @ 24V for 5 minutes. 

 

Ki-147 used an alternate pneumatic method of providing power to its gyro and servos, manufactured by Tokyo Aircraft Instrument Company, which proved

problematic as the same power source was used to feed propellant into the combustion

chamber. The air pressure to actuate the servos dropped sharply as the rocket propelled flight neared finish.

 

At approximately 11km from the target, the rocket engine was fired for 1 second before the electromagnet is disengaged and the missile dropped. The missile was lowered to an altitude between 30 and 100 meters, and leveled off at about 5km to target. Ki-147 & Ki-148 were both controlled identically. Control is done by shifting the gyro centering point, which causes the servos to move the missile until the gyro is re-centered. The bombardier observed the missile with an optic, and visually guided it to target using an equivalent to an aircraft control stick. Though the missile had no flare or indicator other than the smoke of the exhaust, it is said that it was uncommon to lose sight of it, even at distances of 3 kilometers.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The following pitch angles are available:

• 5° Climb
• 25° Descent
• 25° Left
• 25° Right

 

When the stick is pressed and held in a direction, the missile adjusts to its maximum pitch angle in the applied direction. When released, the missile rights itself back to its predisposed heading. This results in a zig-zag path as adjustments are made to get the missile on course with the target. Vertical adjustments are accomplished by the elevator, to adjust horizontally the rudder and aileron are effected. Suppose that the control stick is fully shifted horizontally:

 

• The rudder adjusts 10° in the applied direction.
• The respective wing drops down 5° in the applied direction.
• The missile turns horizontally until 25° heading is achieved, and the missile rights itself to maintain this course
• When the stick is returned to neutral, the missile returns to its default heading.

Suggestion (WIP Section)

 

I am suggesting Ki-147 & Ki-148 as ordnance options for Ki-67-I & Ki-102 Otsu respectively. I personally feel that these missiles would be a welcome addition to the meager bombloads of the Ki-67s, and even more so the Ki-102 Otsu, which is an attacker-type currently lacking any ordnance. When Japanese Navy is introduced, these could be quite useful aircraft. With Fritz-X introduced, it's inevitable that we see guided bombs for other nations.

 

Now to the control system + flight path and how it can translate into the game.  As the attack angle is shallow, an alternate camera angle to Fritz-X will be necessary (perhaps an observation from the bombardier position). Luckily, I-Gō's control method itself is very simple and is perfect for arrow key / WASD control, while staying more or less accurate to how the weapon was guided in reality:

 

Now, for the balance question.

 

Q: 11km range ? How can that be balanced ?

A: The vulnerabilities of the mother aircraft during guidance must be considered. The missiles are designed to be dropped from an altitude of 1500m or less. In addition to that, the launch speed is ~345km/h for either mother aircraft. The missile is followed very closely by the mother aircraft after launch as to be guided effectively, with the maximum separation being 3km at the point of the bomb's impact. Trailing the bomb in this vulnerable state lasts over a minute at maximum range. To encourage historical use, a torpedo-like drop limitation could be enforced, to keep the missile's use under 2000m.

 

Depending on how the camera view would be done for guidance, hitting a target at the maximum separation range could also be very difficult.

 

Q: What is preventing this missile from being used against the wrong vehicles (planes, tanks) ?

A: Hitting an aircraft with this missile would be nearly impossible, due to many factors like the guidance limitations, poor ascent angle, and the fairly slow maximum speed of 560km/h. As previously mentioned, a torpedo drop limitation could be enforced on this bomb to prevent it from being used in questionable manners. As a more historical limiter, the experimental radio-altimeter could be implemented, which automatically lowered the bomb to skim above sea level, though it was poorly functional in reality.

 

As for tanks, there is little preventing the killing of a stationary or slow moving vehicle. However, it's scarcely more practical, and certainly more time consuming than attacking with conventional bombs. It's worth mentioning that Fritz-X is more than capable of the same.

Primary

 

Spoiler

 

 

 

 

 

 

 

 

 

 

 

 

 

U.S. Naval Technical Mission to Japan - Japanese Guided Missiles. Cover, Page 11-15, 20-25.

 

Spoiler

 

 

 

 

 

 

Japanese Aircraft Relative Performance, Serial No. 436, Report No. 2-T. Cover (Page 1), Page 1-5.

 

Spoiler

 

 

 

Specification and Performance Tables, Report No. 16B(5). Cover, Page 19.

 

Spoiler

 

 

 

 

 

Japanese Air Weapons and Tactics (Final Report And Original Draft), Report No. 63. Cover, Page 59-60.

 

Spoiler

 

 

 

 

 

Technical Data, Report No. 16A(9). Cover, Page 22-23, 25.

 

Spoiler

 

 

 

 

 

 

 

Mitsubishi Heavy Industries Aircraft History. Cover, Page 699-703. (Thanks @Lineins !!)

 

 

Secondary

 

 

Spoiler

 

 

 

 

Famous Airplanes of the World No. 98, Army Type 4 Heavy Bomber "Hiryu". January 2003. Cover, Page 33-34, 81.

 

Spoiler

 

 

 

 

Japanese Military Aircraft Dictionary 1910-1945 Army Version. Written by Shigeru Nohara. October 2005. ISBN-13: 978-4871497329. Cover, Page 156-157. (Thanks @*tester188 !!)

 

Spoiler

 

 

 

 

 

 

 

 

An Illusionary New Plane. Written by Toshihiko Ogawa. August 2003. ISBN-13: 978-4769821427. Cover, Page 294-299. (Thanks @*tester188 !!)

 

Spoiler

 

 

 

 

Mechanism of Military Aircraft No. 2, Type 3 “Hien” & Type 5 Army Fighter/Type 99 Light Bomber. February 2000. ISBN-13: 769809115. Cover, Page 80-81.

 

Many thanks to @B000B !

 

Spoiler

 

 

 

 

 

 

 

Prototype and Planned Aircraft of Japanese Army 1943 - 1945. Written by Akira Sahara. April 2006. ISBN-13: 978-4871498012. Cover, Page 193-197.

 

Spoiler

 

 

 

 

 

 

 

Senshi Sōsho, Development, Production, Supply of Army Aviation Weapons. January 1975. Cover, Page 458-459, Page 527-529.

 

Spoiler

 

 

 

 

History of Kawasaki Heavy Industries, Ltd. 1959. Page 889, 893-894.

 

Spoiler

 

 

History of Mitsubishi Heavy Industries, Ltd. 1956. Page 643.

 

Several additional books of my own will be scanned & included in the next few weeks:

 

Japanese Aero-Engines 1910 - 1945. Written by Mike Goodwin. April 2017. ISBN-13: 978-8365281326.

Japan’s First Rocket Fighter “Shūsui” - Birth of the Liquid Rocket Engine Plane. Written by Hisamitsu Matsuoka. March 2004. ISBN-13: 978-4895223928.

All the Experimental Aircraft in Japanese Army. Written by Minoru Akimoto. January 2008. ISBN-13: 978-4873572338.

Japanese Naval Aircraft Bombs till 1945. Written by Hyodo Nisohachi. November 2010. ISBN-13: 978-4769826644.

Japanese Guided Missiles, Journal of Jet Propulsion, August, Vol. 26, No. 8. By Martin Caidin. August 1956. No Cover, Pages 691-692.

Special thanks to:

 

@*tester188 for providing 2 book sources verifying Ki-102 Otsu as a mother plane for Ki-148!

 

@B000B for for providing an abundance of information and sources from his own research!

 

@Lineins for finding additional primary documentation on Ki-147!

 

 

Edited January 23, 2019 by ARADO_AKBAR

[leroyonly 4,311]

Open for discussion. 

[Z3r0_ 4,128]

Well, it's definitely less controversial than the Ohka.

[aizenns 3,591]

This is infinitely better than Ohka.

We need these one!

[Orlunu 6,863]

Just an aside, but, look, yet more confirmation that the Ki-109 retained it's bomb load!

[tester188@psn 1,413]

Nice suggestion. +1

 

2 hours ago, Orlunu said:

Just an aside, but, look, yet more confirmation that the Ki-109 retained it's bomb load!

I'm sorry I can derail from the suggestion, are there any documents about the bomb load of Ki-109 mixed up? I would like to submit a bug report.

[Orlunu 6,863]

18 minutes ago, *tester188 said:

I'm sorry I can derail from the suggestion, are there any documents about the bomb load of Ki-109 mixed up? I would like to submit a bug report.

I'll do it in a bit, haven't previously because of how pointless it is bug reporting things to Gaijin.

 

 

As to the suggestion, do we have any details on the composition and shape of the warheads?

[Goldkoron 109]

+1

[Guest]

More smart bombs? I'll support that.

[Tasty95215 2,099]

Would the Funryu 1 work as another Air-to-Surface missile? While it was cancelled in favor of Surface-to-Air versions and the aiming system was kinda unreliable, it could be carried by the G4M and had a 400 kg warhead. I don't know much about it, though.

[IOC_000 924]

If it was built, tested and we have specs on it i see no reason for this not to be in-game.

+1

[B000B 26]

I researched about this project and posted yeaterday in JST. But it seems that you posted earlier than I.

Anyway, yours is more wonderful suggestion than mine!

 

 

14 hours ago, ARADO_AKBAR said:

The initial experimenting of Ki-147 was held at Point Manazuru,

And this would be wrong. According to Senshi-Sōsho, first test flight was conducted off the coast of Choshi.

 

Source

防衛庁防衛研修所戦史室(1975), 戦史叢書87 陸軍航空兵器の開発・生産・補給, 朝雲新聞社, P458-P459

The Defense Agency, Training Institute of Defense, Office of History of War, Senshi Sōsho 87 Development, Manufacture and Supply of Army Aeronautical weapon, Japan; Asagumo-shimbunsha; 1975, P458-459

 

I can’t post images of the book. Because it’s still under copyright.... Sorry 

If you need, please contact me on Twitter @ImB000B or Discord.

Edited June 25, 2018 by B000B

[B000B 26]

12 hours ago, ARADO_AKBAR said:

• Span: 3.6m
• Length: 5.77m
• Height: 1.0025m
• Wing Area: 3.6m²
• Weight (Empty): 1266kg
• Weight (Loaded): 1472kg
• Drop Altitude: 500-1500m
• Drop Speed: 360km/h
• Top Speed: 550-560km/h @ SL
• Propelled Range: ~11km
• Armament: Navy No. 80 800kg Land Bomb
• Engine: Toku-Ro Mk. 1 Model 3 (240kgf for 75s)
• Mother Aircraft: Ki-67-I 

And Armament is Navy No.80 800kg armor-piecing bomb according to following book.

 

佐原晃(2006), 陸軍航空技術開発の戦い日本陸軍の試作・計画機1943-1945, イカロス出版, P193-P197

Akira, Sahara, Struggles in Development of Aeronautical Technology by Army, Prototypes and Plans of Aircraft by Imperial Japanese Army; Japan; Ikaros Publishes; 2006, P193-P197

[_qaz_ 675]

3 hours ago, B000B said:

And Armament is Navy No.80 800kg armor-piecing bomb according to following book.

 

佐原晃(2006), 陸軍航空技術開発の戦い日本陸軍の試作・計画機1943-1945, イカロス出版, P193-P197

 

Thank you for improving the suggestion, I will amend the history section;

 

Is it possible to attach a scan of this book? I don't mean to be troublesome.

Also, do you have the exact name of the bomb? I had found only limited (primary) data on the bomb, naming it broadly as "No. 80 bomb", and standard "No. 80" (八〇番、八〇番一型) bombs are Land or Ordinary Bomb. However, AP bomb is more logical as an anti-ship weapon. Could it be "No. 80 Mk. 5" AP (八〇番五号) ?

Edited June 25, 2018 by ARADO_AKBAR

[B000B 26]

57 minutes ago, ARADO_AKBAR said:

Is it possible to attach a scan of this book? I don't mean to be troublesome.

Yes. Are there any way to contact you in private?? I have Twitter or Discord.

 

57 minutes ago, ARADO_AKBAR said:

Also, do you have the exact name of the bomb? I had found only limited (primary) data on the bomb, naming it broadly as "No. 80 bomb", and standard "No. 80" (八〇番、八〇番一型) bombs are Land or Ordinary Bomb. However, AP bomb is more logical as an anti-ship weapon. Could it be "No. 80 Mk. 5" AP (八〇番五号) ?

Probably it’s right, No.80 Mk.5 AP.

It’s just written “海軍で使用していた80番800kg徹甲爆弾”, “Navy’s No.80 800kg AP bomb”, in the book.

I don’t know either type99 or type2.

 

 

Edited June 25, 2018 by B000B

[xxkvasirxx 321]

+1

 

[B000B 26]

Here's the content of suggestion I posted. I hope this make your suggestion better than better.

I know my English is so ugly. Please manage to read it....

 

Thanks to @leroyonly

 

イ号I型無線誘導弾,I-Go type I guided bomb:The Guided Bomb called HENTAI-Bomb

Model Ko from source.5

Model Otsu from source.5

 

Thanks to @Phosphophyllite!

He helped me write some sentences! 

 

When Fritz-X came into WarThunder, one bomb came of a topic in a part of Japanese WarThunder community. So, today, I will introduce the bomb with guide system and rocket which was developed by the Imperial Japanese Army.

 

OUTLINE for busy people.

Quote

What’s this?

->It’s anti-ship guided glider missile dropped from aircraft, have three model. The war was over before one of three was tested. So I didn’t explain the model.

How is the power?

->They were mounted Ta-Dan 300kg sharped charge bomb or Navy No.80 800kg armor-piecing bomb; I don’t know either type 99 or type 22.

How to fly?

->It’s by a rocket motor like Ki-200.

How fast and how long to fly?

->It’s about 500km/h-600km/h and over 10000m.

Was it produced?

->Yes, 190 ones including 40 prototypes were done.

What’s the war experiences?

->Fortunately, the war was over while considering the most effective way to use.

 

History

Quote

HISTORY

After half of May 1944, Technical Major Jobu Ōmori, who is a member of 1st Army Aeronautical Tech Lab, and Technical Major Mitsuharu Kogasa, who is a member of 2nd Army Aeronautical Tech Lab, heard a news that some pilots in 5th Imperial Japanese Army Air Service had hurled at enemy ships. They concluded that the fact such a suicidal operation was put into action caused by engineers’ negligence and is so dishonorable for engineers and suggest “Parent-Child Aircraft Plan”.

This plan was aimed to drop a child-aircraft such as a glide bomb or missile instead of a normal bomb from a parent aircraft such as a heavy or light bomber and guide a child-aircraft to the target like a radio-controlled model car. But it had a danger that a parent-aircraft may have been shoot down before the hit because the shortcoming that a guider can’t control the bomb from far away forced a parent-aircraft to head for the target while guiding.

Finally, this plan was judged it’s better than the missions which absolutely provides death to pilots and given a green light.

This is the start of the project.

The project took over the development of guided bomb from Sa-Gō project; aimed to shoot down B-29 with a weapon like AA missile, and named I-Gō. And the project members were the excellent in 1st or 5th Army Aeronautical Tech Lab. These makes the progress of development more quickly.

I-Gō guided bomb was planned three models, Kō, Otsu and Tei. The Kō, which was named “Ki-147”, mounted Navy No.80 800kg armor-piecing bomb which was equipped by Ki-67 light bomber. The Otsu , which was named “Ki-148”, mounted Ta-Dan 300kg sharped charge bomb which was equipped by Ki-48 or Ki-102. Tei is a model like Fliz-X mounted auto control system. But it was not tested with auto control system by the end of war. So, in this post, I don’t explain about Tei.

Army ordered prototype of Kō from Mitsubishi heavy industries in after period of July 1944, at the almost same time, ordered prototype of Otsu from Kawasaki heavy Industries. They finished to design by September. First produced Kō prototype was completed in October, in a month, ten prototype was completed. First Otsu was completed in October. And more 29 Otsu prototypes were made in a month.

The test fright was conducted from November at off Chōshi, Chiba prefecture at first, and later, at surrounding Manazuru, Kanagawa prefecture.

Then!!!! The accident was happened!!!!!

At the test fright of model Ko, the target was Mitsuishi, locating the end of Manazuru-Misaki cope, and it was dropped from the detection of Ito. Unfortunately, the dropped one had a malfunction in the remote control system. What was worse, it changed the course to wrong one and just hit a bathroom for women in a hotel, Tamanoi-Ryokan, in Atami. This is the reason why Japanese calls this bomb “ero-bomb” in Japanese, saying in English, “Hentai Bomb”. Sadly, the bomb killed some civilians.

This is a photo of Mitsuishi.

Spoiler

From the website of Manazuru town Tourism Association: https://www.manazuru.net/discover-manazuru/

I cant understand why IJA selected this beautiful palce as a target.... 

After the accident, the test, of mostly Otsu, was conducted over Biwa-Ko lake. The test flight was conducted by May 1945. Finally, hit rate became 50% or 75% to an enemy huge ship. IJA executives organized a company for I-Go in Yōkaichi to deploy the Battle of Okinawa and started trainings. But someone claimed the objection about the way to use effectively in real battle. Eventually, while considering about it, the war was over*.

*Some books written in recent years insists that the project was cancelled in July 1945. Because there were high opportunities that soldiers in parent-aircraft would be killed before the hit. But it’s strange that the cancelled reason is an objection to a reason which made the project start. And a source of description, “The war was over while considering the way to use effectively.”, in Senshi-Sōsho, the series of war history, is the book “History of Aeronautical Technology by Army”. This is a book written in 1947 by the 1st demobilization bureau; 1st demobilization bureau is an organization in the Ministry of Health and Welfare which was the the Ministry of Army. (The Ministry of Army > The 1st Ministry of Demobilization > The 1st Demobilization Agency > 1st demobilization bureau in the Ministry of Health and Welfare) I think this have high-reliability as a source.

Considering with all books and production state, both of the model were completed but cancelled to the production in July 1945. And they considered the effective way to use 150 pre-produced model Otsu by the end of war.

 

Body

Quote

Body

In both of the model, the metal frame was covered with galvanized iron sheets. And the wing was made from wood. A receiving set, a gyrostabilizer and a drive were in the cylindrical part which was on the top of the body. In model Otsu, a gyrostabilizer and a drive were worked by servo motors but, in model Kō, by compressed air which was used not only a gyrostabilizer and a drive but also to apply pressure on a propellant. So, as model Kō fried for a long distance, its rudder were getting not to work well. Ko’s bodies were ordered from Mitsubishi heavy industries factory in Nagoya. Otsu’s bodies were ordered from Kawasaki Heavy Industries. Size is in a topic “Specification”.

Sketch of bomb

Spoiler

Model Ko from source.4

Model Otsu from source.4

 

 

Rocket

Quote

Rocket

Both of the model mounted one Toku-Ro.1 rocket motor. As you know, this rocket is same series as one of Ki-200, Toku-Ro.2.

Toku-Ro.1 was developed near end of 1944. It had a simple mechanism which utilized high-pressure and high-temperature gas which is provided when one liquid propellant, hydrogen peroxide, reacted violently with one catalyst, potassium permanganate.

Ko mounted Toku-Ro.1 type3, Otsu mounted Toku-Ro.1 type2.

Both of the model was ordered from Mitsubishi heavy industries weapon factory in Nagasaki.

Rocket power is in a topic “Specification”.

 

System

Quote

System

Both of models were designed to dropped 10km away from target and a controller guide it with heading to 4km away from the target.

Passed 0.5 second after dropping, stability device is activated, and 1.5 second later, the rocket motor starts boosting.

While flying, auto keeping altitude device which was applied a radar altimeter kept it at 7m.

 

Guiding

Quote

Guiding

A controller guide from the nose of aircraft in the case of Ki-48 and Ki-67 or from the backseat in the case of Ki-102 Otsu by an optics sight.

Optics sight was a device used the method for guiding called Manual Command to Line of Sight and it was made by Sumitomo Telecommunication Equivalents.

 

Production

Quote

Production

The factory which was planed to produce model Kō was Nippon Sharyo in Atsuta.

Model Otsu was pre-produced in Kawasaki Aircrafts factory in Akashi from April 1945. But production line was destroyed by U.S. Military bombing in July. So the production stopped in effect. By June, 150 Otsu’s were produced in total.

 

Spectification

Quote

SPETIFICATION

Model		Kō	Otsu
Prototype name		Ki-147	Ki-148
Warhead		Navy No.80 800kg armor-piecing bomb	Ta-Dan 300kg sharped charge bomb
Size	Length(m)	5.77	4.090
	Span(m)	3.60	2.600
	Height(m)	1.055	0.90
	Wing area(m^2)	3.60	1.95
Max Weight(kg)		1400	680
Rocket	Name	Toku-Ro.1 type 3	Toku-Ro.1 type 2
	Maker	Mitsubishi	Mitsubishi
	Thrust(kg)	240	150
	Flight Time(s)	75	80
	Number	1	1
Guiding method		MCLOS	MCLOS
Max-Speed(km/h)			680
Drop-Speed(km/h)		360
Hit-Speed(km/h)		550
Drop-Altitude(m)		500-1000	500-1000
Max-Flight-Distance(m)		11000	11000
Product	Maker	Mitsubishi	Kawasaki
	Term	Oct 1944	Oct 1944 Apr-Jun 1945
	Number	10	180
Notes		Only prototypes	Including 30 prototypes

 

 

Sources

Quote

Sources

I can’t post photos of source because there is a limit to uproad and source 1,4,5 are still under copyright. If you need to read, please Contact me on Twitter @ImB000B!!!, buy them, go to libraries or order remote copy service from the National Diet Library in Japan, from here: http://www.ndl.go.jp/en/index.html

 

1.防衛庁防衛研修所戦史室(1975), 戦史叢書 87 陸軍航空兵器の開発・生産・補給, 朝雲新聞社, P458-P459

1.The Defense Agency, Training Institute of Defense, Office of History of War, Senshi Sōsho 87 Development, Manufacture and Supply of Army Aeronautical weapon, Japan; Asagumo-shimbunsha; 1975, P458-459

 

2.三菱重工業株式会社社史編纂室(1956), 三菱重工業株式会社社史, 三菱重工業株式会社, P643-P644,P659

2.Mitsubishi heavy industries inc. company history editor office, The Company History of Mitsubishi Heavy Industries; Japan; Mitsubishi Heavy Industries; 1956, P643-P644, P659

 

3.川崎重工業社史編さん室(1959), 川崎重工業株式会社社史, 川崎重工業, P889,P893-P894

3.Kawasaki Heavy Industries inc. company history editor office, The Company History of Kawasaki Heavy Industries; Japan; Kawasaki Heavy Industries; 1959, P889,P893-P894

 

4.小川利彦(2003), 逆転を掛けた傑作機 幻の新鋭機, 光人社NF文庫, P294-P299

4.Toshihiko, Ogawa, Excellent aircrafts for a victory from behind, Rookies in a vision; Japan; Kojinsha NF books; 2003, P294-P299

 

5.佐原晃(2006), 陸軍航空技術開発の戦い 日本陸軍の試作・計画機 1943-1945, イカロス出版, P193-P197

5.Akira, Sahara, Struggles in Development of Aeronautical Technology by Army, Prototypes and Plans of Aircraft by Imperial Japanese Army; Japan; Ikaros Publishes; 2006, P193-P197

 

Edited June 25, 2018 by B000B

[tester188@psn 1,413]

The warhead may be Navy No. 80 ordinary bomb. IJAAF used the Navy No. 80 ordinary bomb to attack the ship. The ordinary bomb is a semi-armor-piercing bomb with 70 mm penetration by kinetic energy. The bomb was designated 800 kg Navy bomb or 800 kg anti-warship bomb. It was transferred from the Navy or was produced by the Army.

Spoiler

 

https://forum.warthunder.com/index.php?/topic/410555-1772149-ki-67-missing-800-kg-navy-bomb/

 

http://dl.ndl.go.jp/info:ndljp/pid/8818497/9?itemId=info%3Andljp%2Fpid%2F8818497&contentNo=9&__lang=en

 

[B000B 26]

4 hours ago, *tester188 said:

The warhead may be Navy No. 80 ordinary bomb. IJAAF used the Navy No. 80 ordinary bomb to attack the ship. The ordinary bomb is a semi-armor-piercing bomb with 70 mm penetration by kinetic energy. The bomb was designated 800 kg Navy bomb or 800 kg anti-warship bomb. It was transferred from the Navy or was produced by the Army.

  Reveal hidden contents

 

 

Well...I’m not familiar with types of bomb...

 

Can it penetrate the side armor of warship?

[_qaz_ 675]

@B000B , Thank you for sharing your wonderful research and information! It is very crucial! After reviewing the sources I will properly update the post information when possible. 

I am sorry that my suggestion caused yours to be not approved. But with the material of both, we can make this a sort of co-suggestion, and the best it can be! 

 

@*tester188 , Thank you for providing these documents. I was wondering myself if perhaps it is a No. 80 (non-AP) considered to be somewhat armour-piercing. I read that standard No. 80 bomb can penetrate 400mm of reinforced concrete. "Navy No. 80 800kg armour-piercing bomb" is not a precise name, and I find it odd that in the (limited) primary data, it is only named as "Navy No. 80 bomb" or "type bomb No. 80"  without a clarified modification number, if there is one.

 

 

 

Do you know if the Army received No. 80 Mk. 5 AP bombs?

 

At the moment, I will name it broadly as "No. 80 bomb" until an exact type can be confirmed. I will do my best to locate more information. 

 

---

 

On 25/06/2018 at 12:13, xxkvasirxx said:

+1

 

On 24/06/2018 at 19:18, IOC_000 said:

If it was built, tested and we have specs on it i see no reason for this not to be in-game.

+1

 

On 24/06/2018 at 18:03, Invader9908 said:

More smart bombs? I'll support that.

 

On 24/06/2018 at 17:55, Goldkoron said:

+1

 

On 24/06/2018 at 13:31, Z3r0_ said:

Well, it's definitely less controversial than the Ohka.

 

On 24/06/2018 at 14:24, aizenns said:

This is infinitely better than Ohka.

We need these one!

 

On 24/06/2018 at 17:19, *tester188 said:

Nice suggestion. +1

 

Thank you everyone for your support of the suggestion! 

Edited June 27, 2018 by ARADO_AKBAR

[CherryBlossom 4,210]

excellent suggestion, love the layout as well to enable easy read. 

 

Obviously this is a better alternative to the Ohka, but still, id welcome both. 

[Optical_Ilyushin 5,554]

yes please! +1

[Orlunu 6,863]

On 26/06/2018 at 10:25, B000B said:

Well...I’m not familiar with types of bomb...

 

Can it penetrate the side armor of warship?

As a part of the missile? Attack proflie seems to involve a top-down attack striking at significantly below the terminal velocity of a similar bomb. While I don't know the characteristics of the drop test, I'd be very comfortable in saying that just using that bomb striking at the velocity and angle of the missile, we're looking at substantially lower than 7cm of penetration in a plunging orientation. Rough translation, it'll punch holes in anything short of a battleship or a British aircraft carrier, but those will laugh off a hit from it.

[onemax9000 1,243]

.

Edited January 2, 2019 by onemax9000

[Borotovas 4,500]

+1