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A small thing about Ki-93 that WG may seriously consider...

Japan Heavy Fighter Attack Aircraft

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vcharng #1 Posted 16 October 2019 - 05:38 AM

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Basically I browsed through some data about Japanese planes, and found one thing that may worth noting:

The Ki-93 is known as an attacker in Japanese wiki, while known as a heavy fighter in English.

It's not a problem for Ki-45 or Ki-102 as they both have heavy fighter variants, but Ki-93 was actually exclusively an attacker.

 

Both Ki-93 and Ki-102B are both IJAAF's response to the failure in the Battle of Khalkhyn Gol, as the IJA failed to counter the Soviet's armor battalions. As such, they designed the aerial 57mm AT guns and these aircrafts to mount them.

 

I wouldn't go as far as suggesting to remove HF Ki-93 and change it into GAA Ki-93, but maybe when WG is trying to make a GAA line for Japan they can think about this.

 

Reference: http://ktymtskz.my.coocan.jp/J/JP/aki6.htm#3 , Japanese Wikipedia entry of Ki-93.



wylleEcoyote #2 Posted 16 October 2019 - 12:14 PM

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An interesting Idea.
A gun focused Army attacker line that could be a counterpoint to Navy torpedo/dive bombers.
Like the American Army/Navy Multirole lines

Fair warning. My success rate at speculative guesswork is much like my WinRate. Hit or Miss.
Usually I start on the right track and then a make a weird left turn and get lost in the weeds ... 
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Attack Aircraft: Hs 123, Ha 137, Hs 129 A, Ju 87 G, Me 265, Me 1099 B-2
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J311yfish #3 Posted 16 October 2019 - 02:44 PM

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View Postvcharng, on 16 October 2019 - 12:38 AM, said:

Ki-93 was actually exclusively an attacker.

 

Not true.  The first prototype was anti-bomber and stemmed from earlier notions of mounting 'the big gun' to a twin-engined aircraft capable of reaching the bombers at altitude (supercharged engines).  Ki-109 was the (ineffective) stop-gap to bring the idea to reality quicker.  If you have any doubt about that, look at the timeline.  The evolution of Ki-45, Ki-102, Ki-93 depicted in-game is correct, and you can see that quickly from notes under each plane in the Japan tech tree project.

 

The second prototype was developed as anti-shipping and featured a larger gun (75mm).  It has been said in the past (by a developer or representative several years ago) that there were no plans (at that time) to introduce 75mm guns.  If they do go that way then there are some great opportunities for U.S.A.


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qu33kKC #4 Posted 16 October 2019 - 10:14 PM

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B-25H WHEN????????

 

:playing:



vcharng #5 Posted 17 October 2019 - 12:36 AM

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View PostJ311yfish, on 16 October 2019 - 02:44 PM, said:

 

Not true.  The first prototype was anti-bomber and stemmed from earlier notions of mounting 'the big gun' to a twin-engined aircraft capable of reaching the bombers at altitude (supercharged engines).  Ki-109 was the (ineffective) stop-gap to bring the idea to reality quicker.  If you have any doubt about that, look at the timeline.  The evolution of Ki-45, Ki-102, Ki-93 depicted in-game is correct, and you can see that quickly from notes under each plane in the Japan tech tree project.

 

The second prototype was developed as anti-shipping and featured a larger gun (75mm).  It has been said in the past (by a developer or representative several years ago) that there were no plans (at that time) to introduce 75mm guns.  If they do go that way then there are some great opportunities for U.S.A.

That's definitely English data, eh?

I went through Japanese data and Ki-93 is attacker only, from start to the end.

 

The 57mm gun was envisioned (even before design) to be used for anti tank, the 75mm gun is for Ki-109, which was envisioned to take down B-29s from the beginning.

The second (and third) Ki-93 prototype was not finished. And the engine of Ki-93 was commented to be underpowered.

Also Ki-93 is nowhere faster than the Type 100 Command Recon (Tachikawa Ki-46) which came with a HF variant. Making Ki-93 a HF simply unreasonable.

 

And Ki 102B and Ki-93 was not "timelined", they happened at the same time (April 1943). Ki-93 is the Army First Aviation Technology Research Institute counterpart of Ki-102B, which was from Kawasaki, they were the same project for different manufacturers.

And actually there's only one Ki-102 between April and June 1943 bc HF variant was only requested in June, when the name Ki-102A (HF) and Ki-102B (GAA) came into existence.

And there wasn't such an order for a HF variant in June 1943 given to AFATRI, only to Kawasaki. (otherwise we will be seeing stuff like "Ki-93A" and "Ki-93B" in the documents)

 

 



J311yfish #6 Posted 17 October 2019 - 08:45 AM

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Which sources in English do you disagree with, and which sources in Japanese do you offer as proof that they are wrong?

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vcharng #7 Posted 18 October 2019 - 10:56 AM

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View PostJ311yfish, on 17 October 2019 - 08:45 AM, said:

Which sources in English do you disagree with, and which sources in Japanese do you offer as proof that they are wrong?

Any English source that said Ki-93 was a HF.

 

The source I offer is the non-wikipedia link I posted in the OP. Mind you, from what I saw it was written by someone who worked in the IJAAF back in WWII.

"筆者も教育のため昭和十九年三月から一年間設計を離れたが二十年四月には復帰、そして四月八日の初の試験飛行に立会うことができた。"

If you can read Japanese this means "I, the author, have left the design effort in March 1944 for education for an year, but I returned in April 1945, and I participated in the first test flight in 8 April"

In other words the author of the webpage was there when Ki-93 made its only test flight. In other part of the article he mentioned that he was new in the Army Aircraft Design department and he was in charge of the main wing's center section of the Ki-93.

 

In the article, he indeed did mention about Ki-102/93's shift from attacker to HF:

"最も、これらの機体が具体的な設計作業に入った昭和十八年には事情は一変し、目ざす相手はアメリカ、イギリスを初めとする連合軍であり、目標も戦車よりは地上施設、飛行場あるいは艦船に変り、さらには来襲する大型爆撃機へと変った。"

"However, these aircrafts' (Ki-102/Ki-93) situation have suddenly changed during 1943, when design work has already begun. The perceived enemy has changed (from Soviet Union) to the Allied starting from the US and UK, and the targets has changed from tanks to land installations, airfields or ships, and later changed to large bombers."

 

Despite that, Ki-93 never received a separate designation for HF variant and GAA variant (unlike Ki-102 which later became 102A and 102B), contrary of what English sources believed.

 

 

"Francillon, René J. Japanese Aircraft of the Pacific War. London: Putnam & Company, 1970. ISBN 0-370-00033-1."

This seems to be the book that claims Ki-93 had a HF variant, it said Ki-93-Ia is a 57mm gun HF while Ib is a 75mm anti shipping variant.

 

However, from the Japanese source we know the 57mm variant was NOT a HF. He stated earlier that:

"元々ソ連陸軍を目標としていた日本陸軍は、昭和十四年のノモンハン事件での苦い戦訓から、装甲の強固なソ連戦車群を撃破するには比較的装甲の薄い上面を空から攻撃するのが、最も効果がある、と考えるようになり、強力な地上襲撃機の構想が芽生えた。
その具体的な現われが、双発で五七ミリ対戦車砲を装備したキ93であり、キ102乙であった。"

"The IJA originally took the Soviet Union Red Army as its potential enemy, and during the Battles of Khalkhin Gol, they learned that the most effective way to handle Soviet tanks' armored battalion would be to shoot from above, and thus they envisioned an attacker for this purpose.

The actual design for this concept would be the twin-engine, 57mm-armed Ki-93 and Ki-102B."

 

In fact if you read Japanese Wiki, the 57mm Ho-402 was an air-to-ground gun, while the 75mm Ho-501 (to be carried by Ki-109) was an air-to-air gun.

Yeah I know this sounds weird, a smaller gun for ground targets, and a bigger one for air targets, but that's what the IJA did.

So the claims from Francillion's 1970 book was wrong in just about every way.

Ki-93 didn't have a 75mm variant, and even if it does, the 57mm would be anti-ground and the 75 would be anti-air. He clearly didn't check the nature of the Ho-402 and 501.

 

Also, Ho-402 has a recoil of 1.5 ton, Ho-501 has a bloody 4 ton. I don't think Ki-93 would be able to hold it, at all....



J311yfish #8 Posted 19 October 2019 - 03:08 PM

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Even supposing that everything above is 100% true with 0% lost in translation -- it is not unusual for an aircraft to change roles in the middle of development, or to be designed as suitable for more than one specific purpose.  There are many examples.

 

Also, even supposing that Wargaming had to rely 100%, or lean very heavily, on published work with authenticated sources only, it would not be unreasonable for them to emphasize, or deemphasize as needed, attributes or characteristics within the reasonable bounds of an imagined alternate history to create interesting or compelling gameplay.  Have they succeeded in doing that?  I think so.  Could they take it further along those lines to complete heavy fighters VIII, IX, X?  I think they can.  Would a ground attack aircraft for Japan also be interesting?  Of course I think so.  Could Ki-93 be a candidate for 'alternate configuration' that has been mentioned in developer posts?  Absolutely, so thank you for bringing it up.

 

Regarding details and narrative -- there is yet another source on the Ki-93 in French by Bernard Millot (1982), and some clues may be offered by Mikesh (2004) on specific discussion of each gun.  Will investigate.

 

 


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vcharng #9 Posted 19 October 2019 - 03:38 PM

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View PostJ311yfish, on 19 October 2019 - 03:08 PM, said:

Even supposing that everything above is 100% true with 0% lost in translation -- it is not unusual for an aircraft to change roles in the middle of development, or to be designed as suitable for more than one specific purpose.  There are many examples.

 

Also, even supposing that Wargaming had to rely 100%, or lean very heavily, on published work with authenticated sources only, it would not be unreasonable for them to emphasize, or deemphasize as needed, attributes or characteristics within the reasonable bounds of an imagined alternate history to create interesting or compelling gameplay.  Have they succeeded in doing that?  I think so.  Could they take it further along those lines to complete heavy fighters VIII, IX, X?  I think they can.  Would a ground attack aircraft for Japan also be interesting?  Of course I think so.  Could Ki-93 be a candidate for 'alternate configuration' that has been mentioned in developer posts?  Absolutely, so thank you for bringing it up.

 

Regarding details and narrative -- there is yet another source on the Ki-93 in French by Bernard Millot (1982), and some clues may be offered by Mikesh (2004) on specific discussion of each gun.  Will investigate.

 

 

Well, the reason why I said I'm not against putting Ki-93 as a HF is because I have no doubt that if it was actually put into service, it would eventually be also used as an HF anyway.

As for changing roles during development, that's what happened with Ki-102 becoming 102A and B.

 

WG "decided to make Ki-93 a HF after knowing it's a GAA" is one thing, but from what's happening here I think it's more like "WG simply took the non-Japanese misunderstanding and made Ki-93 accordingly".

That's why I hope they can know about this.

 

Ki-109 would be an obvious choice for Tier 8, after that... probably Kikka and a hypothetical "super Kikka".

Though... Kikka, being a smaller Me-262 replica, shouldn't really be put at a higher tier than the 262.....



Reitousair #10 Posted 20 October 2019 - 05:06 PM

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View Postvcharng, on 19 October 2019 - 08:38 AM, said:

Well, the reason why I said I'm not against putting Ki-93 as a HF is because I have no doubt that if it was actually put into service, it would eventually be also used as an HF anyway.

As for changing roles during development, that's what happened with Ki-102 becoming 102A and B.

 

WG "decided to make Ki-93 a HF after knowing it's a GAA" is one thing, but from what's happening here I think it's more like "WG simply took the non-Japanese misunderstanding and made Ki-93 accordingly".

That's why I hope they can know about this.

 

Ki-109 would be an obvious choice for Tier 8, after that... probably Kikka and a hypothetical "super Kikka".

Though... Kikka, being a smaller Me-262 replica, shouldn't really be put at a higher tier than the 262.....

 

Ki-93 uses the Ho-402 which is... around three times the length of the Ho-401, iirc. Definitely looks like an anti-tank gun.

 

Ki-109 uses a modification of the Type 88 AA gun, but, as a tier 8? No. The Ki-109 is based on the Ki-67, a bomber, which had weaker engines than the Ki-93. It would be extremely slow for tier 7, let alone tier 8. I don't know a good tier 8 Japanese HF but I'm pretty sure the big gun concept will die after tier 7, however.

 

I expect the Ki-201 to appear for high-tiers though which is an IJA copy of the Me-262, not the J9N Kikka. Maybe we'll get something like Ki-201 (the only one with any basis in reality,) Ki-201-II , Ki-201-III.


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vcharng #11 Posted 21 October 2019 - 01:06 AM

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View PostReitousair, on 20 October 2019 - 05:06 PM, said:

 

Ki-93 uses the Ho-402 which is... around three times the length of the Ho-401, iirc. Definitely looks like an anti-tank gun.

 

Ki-109 uses a modification of the Type 88 AA gun, but, as a tier 8? No. The Ki-109 is based on the Ki-67, a bomber, which had weaker engines than the Ki-93. It would be extremely slow for tier 7, let alone tier 8. I don't know a good tier 8 Japanese HF but I'm pretty sure the big gun concept will die after tier 7, however.

 

I expect the Ki-201 to appear for high-tiers though which is an IJA copy of the Me-262, not the J9N Kikka. Maybe we'll get something like Ki-201 (the only one with any basis in reality,) Ki-201-II , Ki-201-III.

Ho-402: 2500mm barrel

Ho-401: 800mm barrel

So yes, 3 times the length.

 

Ki-109 is designed to take down B-29s, since B-29's contender B-32 was in Tier 7, I can totally imagine B-29 being in T8.

The second prototype of Ki-109 was planned to have turbo compressor, but it was left it tests only. WG can do something about that here.

 

The 22 mass (kinda) produced Ki-109s were preserved for use against American landing crafts, so making them GAAs is also an option.



J311yfish #12 Posted 22 October 2019 - 11:14 PM

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Here are the two published sources in English.  They happen to agree with each other, even though Dyer adds some more detail:

 

Ki-93

 

Rene J. Francillon, Japanese Aircraft of the Pacific War, 1987 Putnam Aeronautical Books, reprinted 1988 -- ISBN 0-87021-313-X -- p.244-245

 

-- "The Ki-93 was the last heavy fighter and ground attack aircraft built in Japan during the war and the only design of the Rikugun Kokugijutsu Kenkyujo (Army Aerotechnical Research Institute) to be flown.  Powered by two 2,400 hp Mitsubishi Ha-214 eighteen-cylinder air-cooled radials driving six-blade propellers, the Ki-93 was designed specifically to carry large caliber cannon in its under-fuselage gondola.  From its inception the aircraft was designed to perform as a high-altitude heavy bomber destroyer as well as a low-altitude anti-shipping aircraft.  In its bomber destroyer form (Ki-93-Ia) the aircraft carried offensive armament comprising one 57 mm Ho-401 cannon and two 20 mm Ho-5 cannon, while for the anti-shipping missions (Ki-93-Ib) its offensive armament comprised one 75 mm Type 88 cannon and two 250 kg (551 lb) bombs.  In both instances defensive armament consisted of a single hand-held 12.7mm Type 1 machine gun.  The cockpit and engine nacelles were heavily armoured, and all fuel tanks were self-sealing and had an automatic fire-extinguishing system."

-- "Production of the Ki-93 was entrusted to the Dai-Ichi Rikugun Kokusho (First Army Air Arsenal) at Tachikawa, and the first prototype, fitted with the armament intended for the Ki-93-Ia, was completed and flown in April 1945.  The chaotic conditions prevailing in Japan at this late stage of the war delayed the flight trial programme and tests were not completed prior to the Japanese surrender.  A second prototype, in Ki-93-Ib ground attack configuration, was completed but not flown before the final collapse."

 

Armament

-- One 57mm Ho-401 cannon and two 20mm Ho-5 cannon in a ventral gondola and one flexible rear-firing 12.7mm Type 1 machine gun (Ki-93-Ia)

-- One forward-firing 75mm Type 88 cannon and one flexible rear-firing 12.7mm Type 1 machine gun (Ki-93-Ib)

 


 

Edwin M Dyer, Japanese Secret Projects - Experimental Aircraft of the IJA and IJN, 1939-1945 (Book 1), 2009 Midland, reprinted 2010 -- ISBN 978-1857803-174 -- p.38-39

 

-- "When Rikugun Kokugijutsu Kenkyujo began the design research for the Ki-93, the goal was to provide an aircraft that could provide a platform for anti-bomber operations and anti-shipping missions.  In both cases the aircraft had to be able to absorb damage when flying in the face of interceptors, the defensive machine guns of bombers, and the anti-aircraft weapons of ships."

-- "Two versions of the all-metal Ki-93 were to be constructed.  The first, the Ki-93-I Ko, was the heavy fighter that would combat bombers.  The second was the Ki-93-I Otsu and this was the anti-shipping model.  The Mitsubishi Ha-211 radial engine was considered at first to power the Ki-93 but both models were ultimately powered by two Mitsubishi Ha-214 18-cylinder, air-cooled radial engines, each providing a maximum of 2,400 hp.  In order to give the aircraft a measure of survivability in the face of enemy fire, armour plating was used.  The pilot was provided with five armour plates, each 12 mm thick.  Two plates were placed just forward of the cockpit in the nose, one on each side of the pilot and the fifth would protect his back.  The front glazing was composed of 70mm thick bullet proof glass.  The rear gunner was also protected by a 12mm armour plate, offering defence from rounds being fired at the Ki-93 from behind.  Likewise, the fuselage fuel tanks were given a measure of protection from incoming fire via an 8mm thick armour plate.  Each engine was also provided with armour plating in the nacelles.  Should the armour protecting the fuel tanks be penetrated, each tank was self-sealing and, to prevent fuel fires, had an automatic fire extinguishing system.  Finally, a defensive armament, consisting of a single 12.7mm Ho-103 machine gun was fitted in a rear firing position to be operated by the second crewman."

-- "The difference in the two versions was in the offensive weapon fits, both mounted in ventral gondolas.  The Ki-93-I Ko was equipped with a powerful 57mm Ho-401 cannon and this was backed up by two 20mm Ho-5 cannons (although one initial design did away with the two Ho-5 cannons and used a single 37mm cannon with 40 rounds of ammunition).  It was anticipated that the Ho-401 cannon would inflict enough damage with a single hit to cripple or shoot down a B-29.  The Ho-401 could fire 90 rounds per minute with a muzzle velocity of 518.2 m/s (1,700 ft/sec).  For the Ki-93-I Otsu, the large 75mm Type 88 cannon was fitted.  The weapon was an adaptation of the Type 88 anti-aircraft gun that had been modified for use on aircraft.  Besides the Ki-93, this weapon was also used operationally in the Mitsubishi Ki-109 (flown by the 107th Sentai).  The Type 88 had to be hand loaded by the second crewman.  In addition to the cannon the Ki-93-I Otsu would carry two 250kg (551 lb) bombs."

-- "Rikugun had Dai-Ichi Rikugun Kokusho, located in Tachikawa (which is about 24 miles from the centre of Tokyo), construct the Ki-93.  The first prototype in the Ki-93-I Ko configuration was completed by April 1945.  In the same month the aircraft successfully took to the air making it the first Rikugun aircraft to be built and flown.  However, further flight testing was hampered by the war situation, so much so that the test program was never completed.  Despite the worsening conditions in Japan and delays with the flights of the first prototype the second aircraft in the Ki-93-I Otsu configuration was completed.  However, it would never fly."

-- "With the surrender of Japan, the Ki-93 would become the last heavy fighter and ground attack aircraft to be built during the war."

 

Armament

-- One 57mm Ho-401 cannon with 20 rounds of ammunition, two 20mm Ho-5 cannons with 300 rounds of ammunition per gun and one 12.7mm Ho-103 machine gun with 400 rounds of ammunition (Ki-93-I Ko).

-- One 75mm Type 88 cannon, one 12.7mm Ho-103 machine gun and two 250 kg (551 lb) bombs (Ki-93-I Otsu).

 

Note that while Francillon and Dyer mention the amount of rounds available per gun, neither has anything to say about ammo available for the 75mm Type 88.  Francillon claims that the Ki-109 carried 15 shells for the 75mm Type 88, while equipped with two 1,900 hp Mitsubishi Ha-104 radials, and that it was capable of 550 km/h at 6090m (342 mph at 19,980 ft) with a range of 2,200 km (1,367 miles), but no technical information is provided for rate of climb, only narrative that it was found lacking, and that weight reduction was a priority, and even RATO was tried and abandoned.  This gives cause to wonder -- if the 75mm Type 88 was truly to be used against bombers, and not shipping, as (you and/or website) claim, then one way to substantiate that would be to look at the practical realities of climb rate, performance at altitude, and ammo available as used on Ki-93.

 

As for smaller points about the intended use for the 57mm or 75mm, it should be possible to eliminate any ambiguity by referencing also:

 

Robert C. Mikesh, Japanese Aircraft Equipment: 1940-1945, 2004 Schiffer Publishing -- ISBN 978-0764320972

 

and 

 

Anthony G. Williams & Dr. Emmanuel Gustin, Flying Guns of World War II - Development of Aircraft Guns, Ammunition and Installations 1933-1945, 2003 Airlife Publishing, reprinted 2014 -- ISBN 978-84037-227-4

 

From Williams & Gustin:

-- "The IJA made some use of a 37mm Type 94 tank gun (37 x 134 R case) and a 75mm cannon, the high-velocity Type 88 AA gun, firing a 75 x 497R cartridge.  It appears that the loading cycle for these weapons may have been partially automated.  One of the largest airborne guns to be tested in flight was, somewhat improbably, a 102mm Italian naval gun installed in some Piaggio P.108A bombers for anti-shipping purposes.  This is sometimes incorrectly described as the Ansaldo 90/53 (that was a high-velocity 53-calibre 90mm AA gun), but was in fact a 35-calibre WWI vintage piece made by either Schneider-Armstrong or Terni (both made guns to the same specification).  The gun used a 102 x 632 cartridge, firing a 13.74 kg shell at 750 m/sec, and weighed 1,220 kg." (p.34)

 

From Williams & Gustin:

-- "The Japanese made some use of several different large-caliber cannon, although in this case they were all developed for the IJA.  The Ho-203 was a Kawamura-designed long-recoil gun, firing a low-velocity 37 x 112R cartridge (taken from the 37mm Type 11 infantry gun) from a hoop-shaped 15-round 'captive belt', very similar to the 30-round magazine used with the US 37mm M4 (magazine sizes of 18 and 25 rounds were also reported). Rate of fire was only 120 rpm.  The H0-401 was essentially the same design, scaled up to take a 57 x 121R cartridge (from a tank gun) and with a similar type of 17-round magazine, but rate of fire further reduced to 80 rpm.  The Ho-204 was a different weapon altogether; it was the biggest of the Browning-pattern short-recoil designs and fired 37 x 144 ammunition at 300-400 rpm from a belt feed." (p.34)

-- "Experimental Japanese weapons which did not enter service included the 57mm Ho-402, a large cannon weighing 400kg and firing its 2.7kg projectiles at 700 m/s and 80 rpm, and the 75mm Ho-501 which weighed 450 kg, had a muzzle velocity of just under 500 m/s and an RoF of 80 rpm." (p.34)

 

Data per Williams & Gustin:

-- 75mm M4, M5 (75 x 350R) -- United States of America -- High Explosive, weight 6,670 grams, muzzle velocity 600 m/s, muzzle energy 1,200K Joules

-- 75mm Type 88 (75 x 497R) -- Imperial Japanese Army -- High Explosive, weight 6,490 grams, muzzle velocity 720 m/s, muzzle energy 1,680K Joules

-- 75mm PaK 40, BK 7.5 (75 x 714R) -- Germany -- Armor Piercing, weight 6,800 grams, muzzle velocity 790 m/s, muzzle energy 2,120K Joules

 

^ a comparison of three 75mm's.

 

There is still the 3rd source, in French, by Bernard Millot.  I'm not super fluent in French but with some help from Google/Bing translators line-by-line it should be possible to corroborate or refute the sources in English.


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vcharng #13 Posted 23 October 2019 - 01:17 AM

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Ki-109's Ho-501 carries 15 rounds, Ki-93's Ho-402 carries 20.

It would seem to me that Ki-93's nacelle is simply too small to carry the Ho-501.

Also: Ho-501 is manually loaded. To be carried in Ki-93 it has to be automatic (because nacelle, the crew has no access to the gun)

 

" "The IJA made some use of a 37mm Type 94 tank gun (37 x 134 R case) and a 75mm cannon, the high-velocity Type 88 AA gun, firing a 75 x 497R cartridge.  It appears that the loading cycle for these weapons may have been partially automated."

37mm yes, 75mm no. Japanese data states Ho 501 to be manually loaded and have a ROF of 20 rounds per minute, same as the Type 88 AA gun when mounted on the ground.

 

Also: Japanese wiki page for Ho-501 stated a very detailed test in 1944 about the performance of the gun in subzero conditions.

I would say this means it's meant for high-altitude, and therefore anti-bomber usage.

 

During May 10-13 1944, Ho-501 underwent subzero shooting test in Tokyo. The viscosity change for the recoil buffering liquid (not sure how it's called in English) is as follows:

10C : 8.636 centipoise

0C: 14.844

-10C: 27.606
-20C: 54.217
-30C: 118.110
-40C: 296.317

 

I think this can prove that it is for high-altitude (and therefore anti-aircraft) use.

 

It would seem to me that the non-Japanese sources are referencing one another, and end up having similar mistakes...


Edited by vcharng, 23 October 2019 - 01:19 AM.


J311yfish #14 Posted 23 October 2019 - 08:36 AM

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View Postvcharng, on 22 October 2019 - 08:17 PM, said:

Ki-109's Ho-501 carries 15 rounds, Ki-93's Ho-402 carries 20.

It would seem to me that Ki-93's nacelle is simply too small to carry the Ho-501.

Also: Ho-501 is manually loaded. To be carried in Ki-93 it has to be automatic (because nacelle, the crew has no access to the gun)

 

"The IJA made some use of a 37mm Type 94 tank gun (37 x 134 R case) and a 75mm cannon, the high-velocity Type 88 AA gun, firing a 75 x 497R cartridge.  It appears that the loading cycle for these weapons may have been partially automated."

37mm yes, 75mm no. Japanese data states Ho 501 to be manually loaded and have a ROF of 20 rounds per minute, same as the Type 88 AA gun when mounted on the ground.

 

Ki-93's 75mm may be Ho-505, which Mikesh believes is the Ho-501 modified to have a recoil-operated automatic loader.  

 

View Postvcharng, on 22 October 2019 - 08:17 PM, said:

During May 10-13 1944, Ho-501 underwent subzero shooting test in Tokyo. The viscosity change for the recoil buffering liquid (not sure how it's called in English) is as follows:

10C : 8.636 centipoise

0C: 14.844

-10C: 27.606
-20C: 54.217
-30C: 118.110
-40C: 296.317

 

I think this can prove that it is for high-altitude (and therefore anti-aircraft) use.

 

Testing in 05/1944 at sub-zero temperatures indicates and interest but does not necessarily prove anything.  The first prototype Ki-109 was completed 08/1944, second prototype 10/1944, 107th Sentai formed 11/1944 to operate Ki-109's, final delivery of 22 Ki-109's 03/1945.  Ki-109 program considered ultimately to be useless due to U.S. bombers flying high by day, low by night.  Ki-109-II production program (more powerful engines at altitude) cancelled and 107th Sentai dispersed sometime after 03/1945.

 

"Some of the Ki-109 aircraft were taken to the IJA's Air Examination Division to see if they could be utilized to attack ground targets and ships in preparation for the Allied invasion of Japan, which Japanese military planners foresaw as happening." (Dyer, 116)


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Stygian_Alchemist #15 Posted 23 October 2019 - 12:37 PM

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Sub zero testing may have had nothing to do with altitude. Anyone in a war with Russia is going to need the ability to fight during their winter.

 

That said, if the Japanese article can be proven to have been written by someone who actually worked on the project, it would supersede any post war western dissection and would not be the first time such a historical misunderstanding was ever present in English language documentation while the documents of the people who actually were involved disagree. Language and the... Emotional issues of the west post ww2 both frequently caused issue. Especially the U.S. Propaganda machine trying to show everyone else was weaker somehow and that the US was destined by God to be a superpower. 



vcharng #16 Posted 23 October 2019 - 04:22 PM

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View PostJ311yfish, on 23 October 2019 - 08:36 AM, said:

 

Ki-93's 75mm may be Ho-505, which Mikesh believes is the Ho-501 modified to have a recoil-operated automatic loader.  

 

 

Testing in 05/1944 at sub-zero temperatures indicates and interest but does not necessarily prove anything.  The first prototype Ki-109 was completed 08/1944, second prototype 10/1944, 107th Sentai formed 11/1944 to operate Ki-109's, final delivery of 22 Ki-109's 03/1945.  Ki-109 program considered ultimately to be useless due to U.S. bombers flying high by day, low by night.  Ki-109-II production program (more powerful engines at altitude) cancelled and 107th Sentai dispersed sometime after 03/1945.

 

"Some of the Ki-109 aircraft were taken to the IJA's Air Examination Division to see if they could be utilized to attack ground targets and ships in preparation for the Allied invasion of Japan, which Japanese military planners foresaw as happening." (Dyer, 116)

Ho-505 didn't exist. Don't try to use a fictional designation to make a point.

Western historians made up quite a number of fake designations for Japanese stuff, like Kikka being either J9Y J9N J10N M7N M8N etc. None of which existed. It's just Nakajima Kikka.

 

Also all 75mm+ aerial guns at the time, whether it's the German BK 7,5 or the American M4 75mm cannon, were manually loaded, I have zero reason to believe that Japanese, who can't even make a decent turbocharger, were ahead of everyone else in terms of the technology to make huge automatic guns AND to control the mass and size to be small enough to fit it into Ki-93's tiny nacelle without breaking the proven-to-be-fragile landing gear (which snapped on the only test flight, when not even the 57mm was mounted).

Hell, even modern AC-130's 105 howitzers are manually loaded.

 

Plus, Ho-501, with a full length of 3.89m, has at least 1.39 meters (tested under -40 degree) of recoil stroke. I.e. it takes up >5.3 meters in total. I checked the blueprint of Ki-93, the nacelle is significantly shorter than that. Even exposing much of Ho-501's barrel (neglecting center of mass issue) won't fit it in. And where're you supposed to fit the belt/magazine for the alleged "Ho-505"? the cabin is a no-go because Ki-93's cabin literally don't have space for anything beside the two crew members.

 

Does not necessarily prove anything? That test was just 2 months after the beginning of the project. (Ho-501 project started at 6 March 1944, subzero test was in May).

It proves that the gun (and the aircraft that carries it) was meant for high altitude usage from the beginning (as for cold areas, check the comment below). And unless you're going to fire at tanks near Tibet, otherwise high-altitude means air-to-air.

Yes, Ki-109 was indeed later kept for anti-shipping purpose, but that's only after they proved useless against B-29s due to their speed and altitude performance. The 2nd prototype with a turbocharger was not mass produced, that's probably why.

 

View PostStygian_Alchemist, on 23 October 2019 - 12:37 PM, said:

Sub zero testing may have had nothing to do with altitude. Anyone in a war with Russia is going to need the ability to fight during their winter.

 

That said, if the Japanese article can be proven to have been written by someone who actually worked on the project, it would supersede any post war western dissection and would not be the first time such a historical misunderstanding was ever present in English language documentation while the documents of the people who actually were involved disagree. Language and the... Emotional issues of the west post ww2 both frequently caused issue. Especially the U.S. Propaganda machine trying to show everyone else was weaker somehow and that the US was destined by God to be a superpower. 

By the time the subzero test took place, war against Russia was no longer envisioned by the IJA. So no, using them against USSR will be a very far guess.

 

Seriously, just recognize that Western historians made up a bunch of crap regarding Japanese technology, and trust the actual Japanese sources instead.

Ho-501 was an anti-air gun, 402 was an anti-tank gun, and Ki-93 was purely designed as a GAA. That's as simple as it can be.



Stygian_Alchemist #17 Posted 23 October 2019 - 07:14 PM

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First, I already agreed you were probably right. So coming at me like that? K. 

 

Second.. That war with the Russians was not going to happen? You're serious? The Americans and Russians were in a race to see who could Conquer or force the Japanese to surrender. Flying against the troop and etc. Ships of the soviets would have required sub zero capabilities even if it were say.. Thirty degrees out.. Due to windchill from the plane simply moving through the air. 

 

But.. Sure.. Let's not look at the actual simplest answer about subzero testing . Which is just that they wanted to make sure the gun would fire right in cold Temps And that that likely had several purposes...



J311yfish #18 Posted 23 October 2019 - 10:42 PM

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Well, I do not make things up, I have named all sources above for transparency, which I believe is valuable in these kinds of discussions, which I do enjoy so long as they remain reasonable -- and because I am finding that absent, I'm out.

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vcharng #19 Posted 23 October 2019 - 11:38 PM

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View PostJ311yfish, on 23 October 2019 - 10:42 PM, said:

Well, I do not make things up, I have named all sources above for transparency, which I believe is valuable in these kinds of discussions, which I do enjoy so long as they remain reasonable -- and because I am finding that absent, I'm out.

You didn't, but you referenced a source that definitely did.

Ho-505? Seriously? That thing doesn't exist and couldn't exist.

The whole "Ki-93 as a HF with a 75mm gun" thing was made up, not by you, and all you need to do is to recognize that your sources made it up.

 

And let me remind you that the website I referenced came from a guy who actually participated in the design effort of Ki-93.

Even if your Western sources didn't show these clear symptoms of being entirely fake, they still won't outweigh him.



vcharng #20 Posted 23 October 2019 - 11:59 PM

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View PostStygian_Alchemist, on 23 October 2019 - 07:14 PM, said:

First, I already agreed you were probably right. So coming at me like that? K. 

 

Second.. That war with the Russians was not going to happen? You're serious? The Americans and Russians were in a race to see who could Conquer or force the Japanese to surrender. Flying against the troop and etc. Ships of the soviets would have required sub zero capabilities even if it were say.. Thirty degrees out.. Due to windchill from the plane simply moving through the air. 

 

But.. Sure.. Let's not look at the actual simplest answer about subzero testing . Which is just that they wanted to make sure the gun would fire right in cold Temps And that that likely had several purposes...

Right, I need to make it clear, that last paragraph was meant for both of you, not just you.

 

"

Seriously,(the two of you should) just recognize that Western historians made up a bunch of crap regarding Japanese technology, and trust the actual Japanese sources instead.

Ho-501 was an anti-air gun, 402 was an anti-tank gun, and Ki-93 was purely designed as a GAA. That's as simple as it can be."

 

That's what I meant. It was past midnight here and I was in a haste to complete the reply, I won't lie about it not being arranged in the best way.

I would also not lie about losing patience after seeing people bringing up entirely fictional stuffs like the so-called "Ho-505".

I mean, how can you use something that didn't exist to prove the existence of some other thing that also didn't?

 

As for whether a war against Russia was to happen, let me remind you that it indeed didn't. Russia never seriously invaded Japan.

My original claim was "IJA no longer envision fighting against Russia". In other words, they now envision fighting sb else more.

They may or may not still consider Russia as a potential enemy, but they definitely put it as less of a priority.

Hell, they even "forgot" to make peace with the USSR after the war (it was only done a few years ago)

 

The most simple answer about subzero testing on an aircraft gun would always be high-altitude. It happens far more often then being used in cold weather.

Russia has subzero for half of the year, not the whole year, but if you fly high, you get subzero every day.

Plus, the subzero test also concluded that "when the gun was returned to room temperature from subzero conditions, the gun suffers icing, causing the firing mechanism to show slightly less reliability".

(しかし低温から常温へ砲を戻すと大量の氷結が生じた。撃発機の作動がやや不良となった。-----from Japanese wiki entry for Ho-501)

You won't be able to return the gun into room temperature in winter Russia, you know.

As for windchill, returning to room temp from windchill-induced subzero conditions only happens when you land the plane and stop it, and by then, icing and firing unreliably are obviously no longer important.






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