Ki-61/Ki-100 discussion

[Wmaker]

A discussion in in a thread about the Ki-84-Ib (http://bbs.hitechcreations.com/smf/index.php/topic,297441.0.html) in the wishlist forum got a little derailed so I thought it is best to continue the discussion about the Ki-61/Ki-100-topic in here.

Thank you Wmaker, I'm sorry to differ with you but you have stated one thing incorrectly. I actually didn't find any data regarding the Ki-61-II. The weights I found pertained to the Ki-61-I-KAIc. I do not know how similar this is to the KI-61-I-Tei we have in Aces High.

Well, I was referring to the above discussion about engine weights. You were talking about Ha-140's weight which powered the Ki-61-II, not the Ki-61-I series. And you were talking about how radial made Ki-100 lighter. Yes, it did make the Ki-100 lighter than the Ki-61-II but not lighter than the Ki-61 we have in AH. That was my point.

I have some stuff about the Ki-61. And I have that Francillon's book available.

Scans from Francillon's book:










Scans from Monografie Lotnicze No 5 handling the Ki-61:



Engine data:


Have fun!

[Wmaker]

Currently the AH model for the Ki-61 is off... It should turn as well as the wildcat, but does not.

It has been stated several times on this BBS by several people that AH's Ki-61 should have as small turn radius as the FM-2 because wartime combat testing suggested it to be so. The problem is that the Ki-61 tested for that particular report was earlier Ki-61 variant than what we have in AH. Based on armament and weight it seems to be what has been called as "Ki-61-Ib" in the west. AH's Ki-61 weight 7650lbs with full internal fuel and ammo. "Combat weight" mentioned in that report for the earlier variant is 6150lbs. That is less than the normal take-off weight of the Ki-61-Ib which is 6504lbs (Monografie Lotnicze suggests 6900lbs) but the difference between the take-off weights is still between 750lbs and 1146lbs. So it really isn't any wonder if an FM-2 in the game happens to turn with a tighter radius.

Link to the report: http://www.wwiiaircraftperformance.org/japan/Tony-I.pdf

That said, I'd really like to see Ki-61-Ib added when the Ki-61 in AH gets redone. I really loved that plane in WarBirds. A lot better power loading and wing loading but lighter armed.

[nrshida]

Thank you Wmaker for sharing that resource. I will read it carefully.

Where does the KI-61-I-Tei (AH version) fit in, for instance relative to the Ki-61-I KAIc? Or is it listed under a different designation in that list and I missed it?

Many thanks

[nrshida]

Err, ahem, what language is that please?

I'm guessing that:-

Masy = mass or weight?

Wlasna = empty or unloaded?

Normala startowa = normal operation / takeoff?

Maksmaina = maximum?

[Wmaker]

As far as I understand it, the Ki-61-I-KAIc is a designation used in the western literature while the correct designation for the same variant the Japanese used was Ki-61-I-Tei. Hence the name change by HTC. Only the name was changed by HTC, the plane itself didn't change at all.

The language is Polish. Don't speak Polish myself either but most of the figures are pretty self-explanatory. If you have more questions just ask.

Masy = mass or weight? Yep

Wlasna = empty or unloaded? Yep

Normala startowa = normal operation / takeoff? Normal take-off weight I think

Maksmaina = maximum? Yeh

[EDO43]

It's been awhile since I've delved into the research on the Ki-61 Hien but IIRC, the term Kai (short for Kaizo) meaning modified, is a term used to describe the Ki-61-I Hei fitted with Mg151 Mauser cannon.  The Ki-61-Ic is normally fitted with 2 x 20mm Ho-5 cannon in the wings.  Germany shipped 150 (sets, I believe) of the MG151's to Japan for usage.  Since the installation required some altering of the wing, I think the term Kaizo was used to differentiate between the Ho-5 machines and the MG151 equipped machines.  If you see a Ki-61-I with long barrels protruding from the wings, that would be a Hei Kai.  Now this is what I've distilled from the information I have been able to discover.  I believe it to be accurate but I do not speak or read Japanese so I have to rely on what those that can, tell me. 

The lineage for the -I goes something like this:

Ki-61-I Ko (version a)  4 x 7.7mm machine  guns
Ki-61-I Otsu (version b)  2 x 7.7mm and 2 x 12.7mm machine guns
Ki-61-I Hei (version c) 2 x 12.7mm machine guns in the nose and 2 x 20mm Ho-5 cannon in the wings
Ki-61-I Hei Kai  (modified c)  same as Hei but equipped with Mauser 20mm MG151 in wings
Ki-61-I Tei (version d) 2 x 20mm Ho-5 cannon in nose and 2 x 12.7mm machine guns in the wings.

[Krusty]

Let me preface with saying I'm open to being convinced, I simply wasn't up to date.

I was up til now just comparing what we HAVE vs what was requested... After the recent posts in the other thread I realized I didn't know exactly WHICH version of Ki-61 we have.

Seems we have a bit of a frankenstein.. The speed and climb of a Ki-61-II (the 140 engine, a DB603 knockoff), the weight of a Ki-61-I, the turn performance of neither (or maybe that's why it turns so bad, that's modeled off the -II?), and the weapons of a Ki-61-Id (aka Ki-61-I Tai).

[EDIT: typo fix, changed "-I?" to "-II?" in the previous sentence]

The Ki-61-II With the Ha140 engine was rare... About 100 and change were made, out of 3000 or so Ki61s total. If we had a true Ki-61-II I'd say there's almost no need for a Ki-100.... BUT...

Follow me for a second....


IF the Ki-61 gets redone I would like to have a true Ki-61-I, even if it means it's a bit slower. That would open up a couple of other guns options too.

In THAT case it would be also nice to see a Ki-100 or Ki-61-II (either one) as a limited use plane for scenarios. There were only 100+ of the latter and only a few hundred of the former.


The Ki-61-I began with little or no armor plating and it was increased several times, including 8mm in the radiator, and the fuel loads changed with various models.

Reference with some values on the fuel loads and the armor plating.
http://78sentai.org/forum/viewtopic.php?f=4&p=1934
(also discusses no 250kg bombs, removable wing racks...)

As the Ki-61-I (as we call it) was enhanced, it became tougher to shoot down, and harder hitting.

Japanese Name = Kitai No. = English Designation = (what it was)

Type 3 Fighter = Ki-61-I = Ki-61 (prototype)
Type 3 Fighter, Model I Ko = Ki-61-I Ko = Ki-61-1a = (first released version)
Type 3 Fighter, Model I Otu/Otsu = Ki-61-I Otu/Otsu = Ki-61-1b = (second armament version)
Type 3 Fighter, Model I Hei = Ki-61-I Hei = Ki-61-1c = (third armament version)
Type 3 Fighter, Model I Kai/Tei = Ki-61-I Kai = Ki-61-1d = (Considerably changed version)
Type 3 Fighter, Model II = Ki-61-II = Ki-61-2 = (New Prototype)
Type 3 Fighter, Model II Kai= Ki-61-II Kai = Ki-61-2 = (Newer Prototype)
Type 3 Fighter, Model II Kai = Ki-61-II Kai = Ki-61-2a = (First production model, none further made so "Ko" not used)

It began life with 2x 7mm and 2x 12mm guns. These were upgraded to 4x 12mm. The Ho 5 cannon was either delayed or slow to produce in numbers, so 800 Mauser MG151/20 cannons were shipped to Japan via submarine. These were installed on about 400 planes of the Ki-61-Ic model if I read some of these webpages correctly. They were actually in the WINGS. When the Ho 5 cannon were available, they were larger and different, and would not fit in the wings without significant work. They were placed in the NOSE and the 12mms left in the wings. That would be the guns setup we have (Ki-61-Id or kai or tai)

Although it seems that none of these planes carried bombs. They were fighters. They did try some phosphorous air bursting bombs to use on bomber formations, but according to one fairly reputable person (not sure if she's an author, but she hobknobs with some noted ones) they did not ever carry 250kg bombs.

Link to designation discussion which also includes several Ki-61 weapons:
http://www.j-aircraft.org/smf/index.php?topic=627.0

Link that also discusses MG151/20s vs Ho5s:
http://www.j-aircraft.org/smf/index.php?topic=2246.0

Another discussion of Ki-61-II v. Ki-100
http://www.j-aircraft.org/smf/index.php?topic=3579.0

Apparently only the early models had blue interior:
http://www.j-aircraft.org/smf/index.php?topic=3381.0



Food for thought!!

Now that I think about it I would really like a middle or later -I model with options for:

1) 7mm and 12mm
2) 4x 12mm
3) wing 20mms (did they have more rounds storage?)
4) nose 20mms (as now modeled)

[Wmaker]

Let me preface with saying I'm open to being convinced, I simply wasn't up to date.

I was up til now just comparing what we HAVE vs what was requested... After the recent posts in the other thread I realized I didn't know exactly WHICH version of Ki-61 we have.

We have Ki-61-I-Tei, just as it says.

Seems we have a bit of a frankenstein.. The speed and climb of a Ki-61-II (the 140 engine, a DB603 knockoff), the weight of a Ki-61-I, the turn performance of neither (or maybe that's why it turns so bad, that's modeled off the -II?), and the weapons of a Ki-61-Id (aka Ki-61-I Tai).

Before you start these frankestein/hybrid talks again, why don't you compare the performance of the AH Ki-61 against primary source material? Yes, I've seen data points in the literature which suggests that AH's Ki-61 is a tad on the fast side and posted some on this thread even but I have no idea about the primary source material where these data points are from. Maybe a bit more rational approach should be in order instead of hybrid this frankenstein that? And no, Ha-140 wasn't a "DB603 knockoff".

Also, there's no such thing as "weight of the Ki-61-I". Just as I posted above, there were drastic differences in weight just inside the I-series alone between subvariants. The early subvariants of the I-series weighed considerably less than the later ones. The weight of the AH Ki-61 is correct.

[Krusty]

As you mention the weight varies, but the weight significantly jumps when you consider the stats for the Ki-61-II with the Ha140 engine.

As for "knock-off" I mean "clone" "copy" or "descendant"...

The Japanese had almost no in-line experience. They copied the Ha40 fairly closely off the DB601A, this is no secret. Their uprated engine looks and performs a LOT like the DB603, and also a lot like the C205's DB603 derivitave engine as well. It's no stretch of the imagination to say without help from German designs the Ha140 probably would never have been built.


Further, it's well documented in the many early "generation 1" models that AH has that many of these planes combine features of multiple versions. Often they can have the weapons of one version, the graphics of another, and the performance of yet another (the old-style typhie spawned quite a few debates). At the time it was understandable. Even though they don't seem to do that with newer craft, we must contend that this is a very real possibility when discussing these first-generation craft that still have the old-style graphics and/or flight and damage models.


I did read your post. I did also read other resources on the Internet. The K2 / Kelly individual seems to be going off primary sources, as well as (in some discussions I've browsed) direct japanese translations of primary sources.

Our Ki-61 in AH has the weight and weapons of a Ki-61-Ic (to use the western designation), but the power chart seems to be close to the top speed of the Ki-61-II. Our Ki-61 just about touches 375 mph on the performance chart, which is significantly higher than the -Is ever got to. However, it is just about right for a -II. On top of that the turn performance is rather bad compared to most US planes... It's barely under the F6F's turn radius. Even the -I models that gained some weight were still more manuverable than all but the FM-2 by a noticable amount. Too bad both the Ki-61-Ic and Ki-61-II had similar climb rates, or I'd be able to also see which model that fits. As-is it's about the same (which is interesting, in itself).

The "entire package" of what we have in AH seems like a mixed basket of features between 2 models of Ki-61. Hence my loose use of the "frankenstein" phrase that has specific meaning in AH.

No different than the frankenstein 109G-6 we used to have, or the frankenstein typhie we used to have, or the bit of a frankenstein P-40E we have, or the just plain weird Hurricanes we have....

There's nothing derogatory in the term. Don't misunderstand me. It's more a colorful euphamism for "having mixed lineage" (to put it politely).

[Wmaker]

The Japanese had almost no in-line experience. They copied the Ha40 fairly closely off the DB601A, this is no secret. Their uprated engine looks and performs a LOT like the DB603, and also a lot like the C205's DB603 derivitave engine as well.

Ha-40 is a licence-built DB601A. You must be talking about the DB605 when you say DB603. C.205 was powered with licence-built DB605A-1. Japanese never licence-built the DB605. They developed Ha-40 (DB601A) further on their own. Ha-140 isn't a licence built DB605 but a Japanese development of the DB601A/Ha-40. It is clear that the general technology used originates from Germany but it's still neither a licence built DB605 nor is it a DB605 "knock off". It is more of a uprated, licence built DB601A.

Further, it's well documented in the many early "generation 1" models that AH has that many of these planes combine features of multiple versions. Often they can have the weapons of one version, the graphics of another, and the performance of yet another (the old-style typhie spawned quite a few debates). At the time it was understandable. Even though they don't seem to do that with newer craft, we must contend that this is a very real possibility when discussing these first-generation craft that still have the old-style graphics and/or flight and damage models.

I just wish that if somene sees something out of place in the any AH aircraft compared to the designation that reads in the Hangar-list they wouldn't go comparing it to other variants of the same aircraft as I personally think that just adds the confusion in cases/discussions like these, but that's just my opinion.

Our Ki-61 in AH has the weight and weapons of a Ki-61-Ic (to use the western designation)

Well if we use those western designations found from your first post to this thread, then no. AHs KI-61 is not Ki-61-Ic but Ki-61-Id (ie. -Tei aka -KAIc). It was the first variant that was significantly different and heavier than the previous Ki-61 variants. It's production started as late as January 1944. It is a different aircraft compared to the earlier variants.

The earlier variants never had nose mounted cannons for example as you suggested but the other load out options you mentioned were found. Yes, that is the variant I'd like to have. Significantly lighter and equipped with the same engine as the -Tei we have in AH.

Ki-100 on the other hand would weigh the same as AH's current Ki-61 but would have 320hp more power and twice the Ho-5 rounds. I think with the existing variant, the -Otsu and Ki-100-Ib would make a nice and complete line-up for this airframe when the time comes to redo it.

There's nothing derogatory in the term. Don't misunderstand me. It's more a colorful euphamism for "having mixed lineage" (to put it politely).

I totally understand. I didn't think of it as derogatory, just as a totally incoherent way of having a discussion about this particular topic. Still do.

[phatzo]

. I really loved that plane in WarBirds.

Yes it was my favorite, especially when I first started.

[nrshida]

Wmakker,

You are right about the Ha-140's weight. The Wikipedia article does state at the top that a Ki-61-II-KAI fighter was adapted to carry the Mitsubishi radial engine. Hence my citing the comment about the engine itself being 45 kgs lighter.

However the specification (including weights and measures) at the bottom of the Wikipedia article is for the Ki-100-1a/b Goshikisen. Which would correspond to the data in the first column of the third and forth scans you kindly uploaded. Assuming that the Ki-100-1a/b Goshikisen is the same model or similar to the Ki-100-I?

That gives the empty weight at 2,525 kgs, which all seems consistant so far.

If the Aces High Ki-61 is the KI-61-I-Tei, and that is the same actual model as the Ki-61-I-KAIc, as you stated, then the empty weight is listed at in the middle column of the second scan as 2,630 kgs.

So it is actually true then, that the Ki-100-1a/b Goshikisen was indeed lighter than the version of the Ki-61 we currently have in Aces High?

105 kilos or 231 pounds lighter, as well as the additional power?

Help me out Wmaker, I know you have an eye for data & I am now confused about the model types so I even suspect I am reading the data wrong?

Krusty, I apologize to you sir for getting offhand about being absolutely certain I was right and you were wrong. Regardless of who was right or wrong, one thing I have learned from these discussions is just how difficult it is to even find consistent data. Nevermind discussing different names for the same exact aircraft, or comparing unloaded / loaded weights.



Am I right in thinking that the KI-61-I-Tei we have in Aces High is an AH1 3d model? The interior reminds me a little of the N1K we had before the revision. So you fellows are proposing an earlier version of the Ki-61 also be included if and when the model gets updated?

  I just want the Ki-100-1 (one day) to feel an almost direct comparison of less weight and more power on the same wings and airframe.

Does seem like a unique opportunity to add two more Japanese aircraft to the plane set in one go (Ducks as the J2M and Ki-43 fans respond). 

[Masherbrum]

Krusty, for the last time, the Ki-61 was basically a license built and re-engineered He-100.   It had NOTHING to do with the 205.   As possibly the Ki-61's biggest fan in the game, I have to applaud Wmaker's posts.   He's saved me a ton of typing.   The Ki-61 we have in game, is indeed closest to the Id (performance wise).   

I have the common Bueschel book, the rare http://www.arawasi.jp/salebook.hp/244.html and various books not strictly dealing with the Hien.

The Ki-100 is NOT similar in performance to the Ki-61.   You can argue the point all day long until the carcass rots, but in the end, you're wrong.   The 100 fuselage implemented the FW-190 A5's engine mounts in order to "narrow the already wider nose due to the radial".   The 100's optimum altitude in WWII was around 20k.   Which contrary to popular criticism in here, was perfect for making mincemeat of the 20k B-29 raids.   The goal of the -100 was to get to the bombers easier and the radial accomplished that easier than the -61. 

Some 100 squadrons (starting with the 111th Regiment) didn't load the 12.7mm ammo, making the -100 even more maneuverable at altitude.   But this became more common after the characteristics were noted.   

I am NOT talking about implementing -100's into the game.   I am merely defending the very relevant -100 in WWII.   It was more than a match for the Hellcat and Mustangs in the hands of a capable pilot.   To discredit this, is nothing more than ignorance.   While only roughly 275 -100's were built, the Japanese were forced to rethink the propulsion of the -61's.   They had to make due and basically modified the A-5's fuselage from the cockpit forward and even utilizing the 801D's exhaust, which were modified to fit as well.   The 244th Sentai were feared by USAAF and USN pilots alike.   

[Wmaker]

Krusty, for the last time, the Ki-61 was basically a license built and re-engineered He-100.   It had NOTHING to do with the 205.   As possibly the Ki-61's biggest fan in the game, I have to applaud Wmaker's posts.   He's saved me a ton of typing.   The Ki-61 we have in game, is indeed closest to the Id (performance wise).

Actually Krusty wasn't saying C.205 had anything to do with Ki-61. He was talking about the powerplants alone. And no, Ki-61 isn't a licence-built He100. This is easily seen just by looking at the external dimensions and 3-views of the said planes. I'm sure Kawasaki engineers got inspiration from both Bf109E and He100 while design studies for the Ki-61 were made. After all both aircraft were exported to Japan. But saying that Ki-61 is a licence built re-engineered He100 is simply incorrect. There were no licence contracts signed and the planes are completely different designs, a fact that is easily seen with a naked eye. Also, range and initial wing-loading that the basic design philosophy behind Ki-61 is different from the 109E and He100. Ki-60 is closer to the design philosophy of the 109E and He100 than Ki-61. The airframe of the Ki-61 was 100% in-house Kawasaki design.

I'll quote Francillon on the matter:

"While negotiating with Daimler-Benz, Kawasaki had approached the Army with initial design studies for various fighter aircraft making use of this engine. As reports from the air war in Europe were showing the apparent superioiry of aircraft powered by liquid-cooled engines, the Koku Hombu instructed Kawasaki in February 1940 to proceed with two aircraft of this type: the Ki-60, a heavy interceptor, and the Ki-61, a lighter all-purpose fighter, priority being given to the heavier aircraft. In December however the emphasis shifted to the Ki-61 for which Takeo Doi and Shin Owada responsible. The aircraft, powered by a Kawasaki Ha-40, showed in its design the strong influence left by Dr Vogt on his Japanese pupils."

As can be seen the Ki-61's air frame is 100% new design, but powered with a German powerplant licence-built by the Japanese.

The 100 fuselage implemented the FW-190 A5's engine mounts in order to "narrow the already wider nose due to the radial".

No, Ki-100 didn't use Fw190A-5's engine mounts directly. The Focke-Wulf design was indeed studied for the purpose of mating Ha-112 to the Ki-61 fulselage but Fw-engine mount obviously couldn't be used "as-is".

Francillon:

"It soon appeared that the only powerplant combining availability and reliability with a suitable output was the 1,500hp Mitsubishi  Ha-112-II fourteen-cylinder double-row radial. As this engine had a diameter of 1.22m (4ft) it appeared at first difficult to install it in the Ki-61-II KAI airframe with its fuselage width of only 0.84m (2ft 9 1/16in). However, the Kawasaki engineers were able to study the engine mounting of an imported Focke Wulf Fw 190A, an aircraft in which a radial engine had been succesfully fitted to a slim fuselage, and call on the experience of the Imperial Japanese Navy which had fitted the same Mitsubishi  Ha-112-II to the Aichi-built D4Y3, earlier versions of this aircraft also being powered by an inverted-vee liquid cooled engine."

The 100's optimum altitude in WWII was around 20k.   Which contrary to popular criticism in here, was perfect for making mincemeat of the 20k B-29 raids.   The goal of the -100 was to get to the bombers easier and the radial accomplished that easier than the -61.  

Some 100 squadrons (starting with the 111th Regiment) didn't load the 12.7mm ammo, making the -100 even more maneuverable at altitude.   But this became more common after the characteristics were noted.  

I am NOT talking about implementing -100's into the game.   I am merely defending the very relevant -100 in WWII.   It was more than a match for the Hellcat and Mustangs in the hands of a capable pilot.   To discredit this, is nothing more than ignorance.   While only roughly 275 -100's were built, the Japanese were forced to rethink the propulsion of the -61's.   They had to make due and basically modified the A-5's fuselage from the cockpit forward and even utilizing the 801D's exhaust, which were modified to fit as well.   The 244th Sentai were feared by USAAF and USN pilots alike.  

Saying that Ki-100 incorporated a modified A-5's fuselage is basically nonsense. Easily seen when looking that the two planes. Francillon's quote above.

The massive lack of speed alone compared to the 1945 fighters of the USN/USAAF make the Ki-100 utterly inferior compared to them. The speed difference between P-51D and Ki-100 at 20k is roughly ~60mph.

Personally, I think that the Ki-100 would still be a cool and interesting dogfighter in the AH planeset as it doesn't have to worry about the realities of the actual war in the Late War Main arena.

nrshida, I'll get back to your post a little later. <S>

[Masherbrum]

I never said they used the "A-5 nose".  They looked at the design of the engine mounts, and exhaust.  They obviously made tweaks.  Also, the 61 handles NOTHING like 205 or a 109, so you can pretend the He-100 that was sent to Japan, wasn't used as a platform.