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[0039902] Ki-27 Otsu: wrong model, incorrect configuration

Hello. I am currently reading up on Japanese aircraft of ww2 and found out that the Ki-27 Otsu is represented incorrectly in game.

The way the plane is in game right now, it's portrayed as having two fixed gas tanks beneath the wings (them boobies).

While it is true that those tanks were used for long range sorties, they weren't actually used in regular sorties. And even when they had to be used, they were not fixed at all, but drop tanks. This is why, when looking for Ki-27b pictures or Ki-27 pictures in general, you will most likely never see those tanks there. Like at all.

 

In Francillon, René J.: Japanese Aircraft of the Pacific War (1979), pp. 196-203 it is stated, however, that usually, there would be up to 4x25kg bombs there instead.  This ability, to stack either those 4 bombs or the drop tanks for more range was the key difference to the older model, the Ki-27a (or Ki-27 ko if you will).
In other words, the loadout specs would be correct (though without the tanks) for the model Ki-27a (or Ki-27 ko if you want), but not for the Ki-27b model, which is currently portrayed in game. Model A would have not have the clear vision rear canopy and would lack the antenna. It would also have a different oil cooler, but I don't seem to have more precise data on that.

 

Differences (externally) between Model a and Model b

ICM_Ki-27a_review_in_box_box_top.jpg
Ki_27_2s.jpg

Note the part-metal rear end of the canopy and the lack of radio antenna
 

 

Ki-27b/Ki-27 otsu

ki_27b.jpg
[attachment=185709:IMG_20160202_0004.jpg]
 

Note the clear rear canopy and antenna and the absence of drop tanks,

[attachment=185710:oIMG_20160202_0005.jpg]
Note the dotted lines, furtherly indicating the optionality of those tanks

My case:

The extra tanks should be removed from the model and the ability to equip the plane with 4x25kg bombs should be added to the modifications.

I do understand this is probably meant to reflect the plane's long range fighter configuration, but I think it should be changed.

 

My reason:

1. It's historically correct and reflects the fighter's abilities and configurations correctly.

2. Especially as long as we don't have the Japanese light bombers represented, this could help fill the gap on historical lineup Khalkhin Gol at least a bit.
3. This goes especially for HLEC Khalkhin Gol, where the Japanese currently lack any easily available bombers (which also isn't historically accurate).

 

My source:

Francillon, René J.: Japanese Aircraft of the Pacific War (1979), pp. 196-203.
ISBN-13: 978-0870213137
http://www.amazon.com/Japanese-Aircraft-Pacific-Rene-Francillon/dp/087021313X

Techs'n specs:

[attachment=185711:IMG_20160202_0005.jpg]

  • Upvote 8

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Thank you for improving the game.

 

Excellent start to the topic, however we require 2 sources.

An image of the 27 with bombs mounted will be excellent.

 

We still require in game screen shots and CLOG, use Test Flight for this (start and finish game just to make the CLOG).

 

P51

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Great! :good:

 

Will this suffice?
This site confirms Francillon's data of a total bomb load of 100kg for the Ki-27b and cites another source:
Wieliczko, Leszek A. and Zygmunt Szeremeta. Nakajima Ki 27 Nate (bilingual Polish/English). Lublin, Poland: Kagero, 2004. ISBN 83-89088-51-7.
Page 99.

 

I would have absolutely loved to have a picture of a Ki-27b with bombs attached to it, but unfortunately I could not find one. So I'm afraid the stats will have to do for now. Sorry :dntknw:

I'll keep my eyes peeled though. Should I come across a picture of a Ki-27b with bombs attached, I'll post it immediately

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New information!

 

I furiosly searched the internet for pictures of Ki-27bs with bombs. I found drawings and a picture of a Ki-79 two-seater with bombs (= kamikaze sortie) and even a drawing of a Ki-27a with a bomb.. which is just wrong.

There is also one surviving Ki-27b in Tachiarai, which used to be presented with a fake bomb down the fuselage:
[spoiler]

0993639.jpg

blog-tachiarai_mg_7669_edited-1.jpg

[/spoiler]

But this is also wrong according to my information

Not only are the drop tanks still attached together with the bomb, but it's also the wrong kind of bomb alltogether.

 

And then I hit the jackpot.
Wieliczko, Leszek A. and Zygmunt Szeremeta. Nakajima Ki 27 Nate (bilingual Polish/English). Lublin, Poland: Kagero, 2004. ISBN 83-89088-51-7.

 

The whole book is filled with pictures of Ki-27bs (and other models), with not a single one showing them bombs.

There is an explanation for this.

The capability of loading four  25kg bombs instead of the two drop tanks is confirmed several times in this book and is also included in the technical parameters section on page 97 (not 99, as the wiki stated). So anyway, here's the explanation:
[attachment=185859:ki27bomb1.PNG]

(taken from Wieliczko,Szeremeta 2004:23)

More confirmation of the bomb load:
[attachment=185860:ki27bomb2.PNG]
(Wieliczko, Szeremeta 2004:21)

[attachment=185861:ki27bomb3.PNG]
(Wieliczko,Szeremeta 2004:97)

conclusion
As it stands, it would seem that the Ki27b were indeed capable of carrying bombs, but it is unclear whether this was used, as the four bombs would considerably worsen the performance of the plane. If it were to be implemented, this should absolutely be reflected in game as well. It's most likely the bombing capabilities of the Ki-27b were not used because there were machines around which were better suited for the job without decreasing their own performance as much. In Khalkhin Gol these were not only the Fiat BR.20 and Ki-21, but also LIGHT bombers like the Ki-30 and the Ki-32. Of which atm only the Ki-21 is represented in game. You know what I'm aiming at ^^

 

recommendation-suggestion

I would recommend getting rid of those drop tanks and temporarily enable the bomb load of four 25kg bombs for the Ki27b, as long as planes like the Ki-32 (it's on the release tree) and ki-30 are not included. At least for the fuel tanks, there's plenty of photographical evidence they were not permanently fixed to the fuselage. I can provide such pictures if required.

 

Reasoning

The japanese light bombers which were historically used are currently not represented in the game.These could be temporarily represented by bomb-carrying Ki-27b. Gameplay-wise bomb-carrying Ki27bs in Khalkhin Gol EC events would make for more varied and better balanced gameplay as well, helping the japanese counter the Soviet reserve planes (all of which can be equipped with small bombs as well). It would also give Japanese players more to do and take the initiative without having to wait ages for players to be able to spawn one ki-21 (BR 2.0).

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Sorry for delay, but it is submitted.

 

Carrying bombs may be acceptable to the game, so forward any data for Dev's to decide.

 

I see the image and you mention the 100kg bomb not "correct", however it may indeed be true that 100kg bombs where an option.

 

Please keep looking for anything that will support the hypothes.

 

Suggest:

1.  Find all the bombs the Japanese used (there many be a post-war USAAF report on it, like for the Luftwaffe).

2.  When where the 100kg or similar bombed used in service.  What is available same time as Ki 27?

3.  Check/ask our Japanese visitors for help.

 

I will keep this thread open for 7 days for any additional info.

 

Thanks for your help!

 

P51

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Hello again.

 

I consulted Francillon and Wieliczko/Szeremata again in order to check on what kind of bombs were used.

They both state that up to four 25 kg bombs could be mounted on a rack underneath the center of the wings (Wieliczko/Szeremata 2004:97; 21; and Francillon 1979:199;203).

What they don't mention however is the type name or other details concerning these bombs. They're instead just called "light 25kg bombs" (Wieliczko/Szeremata)  or "four 25 kg (55 lb) bombs" (Francillon). I checked around a bit and there's two books which contain detailed information about japanese bombs:

*:not sure if this deals with IJNAF and IJAAF or just IJNAF

Unfortunately I don't have access to either of those (I only managed to find TM 9-1985-5, but it doesn't have info on bombs).
If somebody here has access to one or both of these books, please feel free to check them out and share the information!
There is however two lists of bombs used by the IJA on wikipedia, in reference to TM 9-1985-4:
 
I am assuming this list leaves out some details, as e.g. the Name Type 99 No.3 Mod. (list 1) suggests that there were more types of that bomb used (like No. 1 and No. 2?) and that this is a modification of a different bomb. The second list is even more general and calls this bomb just Type 99.
I do think however that these are most likely bombs which could have been used on the Ki-27b. The Type 99 was introduced in 1939, according to the first list. Obs: Not to be confused with the IJNAF type 99 bombs!
Another possible bomb would be the Type 92 No. 1 bomb, introduced in 1932, with 15 kg.
 
Concerning the 3D model of the plane, something else has come to my attention. Aside from the drop tanks, Wieliczko/Szeremata have included four, rod-like attachments, which I underlined blue.
[attachment=187919:ki27bomb5.PNG]
(Wieliczko/Szeremata 2004:Sheet A)

Could these be the bomb racks? They're missing on the Ki-27a, as well as the drop tanks:
[attachment=187920:ki27bomb6.PNG]
(Wieliczko/Szeremata 2004:Sheet A)

Some model kits have them included on one side of the wings:
680gncs02u_large.jpg
7dtjl8a4vv_large.jpg

I re-checked the model in game and also noticed that these rods or racks or whatever they are, are also currently included on the model on one side only too, just like the model kit:
[attachment=187921:ki27bomb7.PNG]

On actual photographs though I could not find those almost entirely.
There's only one photograph hinting at them:
[attachment=187929:ki27bomb8.PNG]
(Wieliczko/Szeremata 2004:23)

Francillon mentions that a special gun could be mounted on the wing on the portside and near the root (Francillon 1979:199) and I briefly thought that's what those two rods could have been used for too. However, they're not on the portside of the models, thus ... those four rods might well be the bomb racks?

2.  When where the 100kg or similar bombed used in service.  What is available same time as Ki 27?

I still think the museum display is incorrect since the books both explicitly mention that it was 4x25kg bombs instead of 1x100kg bomb and they also agree that the bombs would not be used together with the drop tanks.There's about 4 or 5 different types of 100kg bombs used by the army (according to the list #1 from above) and there's 2 which had been in service since 1934 and one type was introduced in 1941. The other two types were introduced in 1943 and 1944 respectively but at this time the Ki-27b was already absolutely obsolete and only used as a reserve and trainer aircraft afaik.

 

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Hello again.

 

I consulted Francillon and Wieliczko/Szeremata again in order to check on what kind of bombs were used.

They both state that up to four 25 kg bombs could be mounted on a rack underneath the center of the wings (Wieliczko/Szeremata 2004:97; 21; and Francillon 1979:199;203).

What they don't mention however is the type name or other details concerning these bombs. They're instead just called "light 25kg bombs" (Wieliczko/Szeremata)  or "four 25 kg (55 lb) bombs" (Francillon). I checked around a bit and there's two books which contain detailed information about japanese bombs:

*:not sure if this deals with IJNAF and IJAAF or just IJNAF

Unfortunately I don't have access to either of those (I only managed to find TM 9-1985-5, but it doesn't have info on bombs).
 
 
 

I still think the museum display is incorrect since the books both explicitly mention that it was 4x25kg bombs instead of 1x100kg bomb and they also agree that the bombs would not be used together with the drop tanks.There's about 4 or 5 different types of 100kg bombs used by the army (according to the list #1 from above) and there's 2 which had been in service since 1934 and one type was introduced in 1941. The other two types were introduced in 1943 and 1944 respectively but at this time the Ki-27b was already absolutely obsolete and only used as a reserve and trainer aircraft afaik.

 

 

Great work!

 

Yes, I also turned up empty on https://archive.org/details/TM9-1985-4, but the document exists in some library somewhere.  Just need a trip.

 

Those tubes are on the flap and would not be at all related to weapons, bombs, or drop tanks.  

It is a mystery, at a guess colored smoke canisters for signaling ground and/or air?

 

 

About books:  Every book I have read has at least a few minor errors, and some are full of mistakes.  There is also a habit of repeating errors others have published as canon despite some absurd claims!

 

I judge it likely a rack for 100kg was made since the 27 could carry it and the bomb was available.

Proof is still needed, and trust me it can take a lot of searching to find that.   You may have to search in different ways.  For example in Germany the pylons have special designation (I think you know).  If Japan used similar, find the name for the rack, and see if it was used on Ki27.

 

As to fuel + bombs, that is correct.  Fuel adds weight.  20 gallons of fuel = 120 lb, or 55kg, which means that is 2 small bombs.  

Besides, why use long range tanks to drop bombs, better have a real bomber do that, they will have more.

 

Good luck finding the answer!

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I'm afraid I've reached my limits here. I unfortunately do not have access to such specific data and I will ask around.
But I'm guessing finding answers on these questions will take more than seven days.I'll contact you via PM once I've got new information.

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I'm afraid I've reached my limits here. I unfortunately do not have access to such specific data and I will ask around.
But I'm guessing finding answers on these questions will take more than seven days.I'll contact you via PM once I've got new information.

 

Thank you for your great effort.  I know how hard it is to find such details.

 

Topic will be open till 26, and should you find something you can PM me, or open a new topic (add the ID number in explanation) with the supporting information.

 

Cheers!

 

P51

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Sometimes, obvious answers are the best answers.

I was able to find out two more things:

  1.  By asking the experts in the community, we were able to determine the exact nature of those rods. As you already said, they were indeed used for flare signals. Mixu83 totally won that thread and a lot of respect (in my book) for coming up with a link to detailed plans of the plane and solving this riddle.
  2. By asking the war thunder live community someone pointed out the obvious: The museum shows a suicide attack-style setup for the Ki-27. Thus, the bomb is not 100kg heavy, but 500kg.

Not only does this make a lot of sense, but I was able to find a japanese website confirming this:
http://www.geocities.jp/ramopcommand/_geo_contents_/97/97.html
states:

九十七式戦闘機爆弾懸架装置及び爆弾 本来は爆装をしな 九十七式ですが、展示機はすでに特攻機として使用が予定されたため、この懸架装置を取り付けた形に改修されたそうです。

rough translation

Type 97 fighter and bomb rack. The Type 97 fighter, originally not intended  to be outfitted with bombs, was planned to be shown in the special suicide attack type configuration in the exhibition (of the museum). It appears this bomb rack has been remodelled in order to install it onto the plane

I don't know if this suffices as proof, but imo it seems legitimate.

Note: Even though this one states that "The plane was originally not meant to be outfitted with bombs", this does not mean the data above (4x25kg) is wrong. The original Ki-27 fighter model A (or Ko) could indeed not be outfitted with bombs - in contrast to Model B (or Otsu).

I can't believe I did not think of suicide attacks. It's so obvious! :facepalm:

I will continue to look for more information.

 

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Excellent work!  Progress!

 

Not sure if GJ will approve a suicide load-out, but now we know it could carry a heavier load!

 

 

The movie Jurrasic Park, the 5 foot tall "velocoraptors" where invented for the movie because fossilized examples where only about 1 foot tall.

But just before the movie was released, a much larger fossil was found.

 

Although we do not have a proof yet, maybe it will be discovered a 100kg load-out is fact after all!

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No! Please no suicide loadout xD
Please, no! I don't think such things belong in game. They certainly would not improve gameplay either. So please. No.
But we do know now why the museum ki-27 has such a large bomb put on it etc. It's not like those kamikaze loadouts weren't mentioned in the books too... somehow I just didn't think of it before -_-

 

 

I am currently in contact with another user who was able to give me further and more detailed information but it's not so easy to get access to the actual source material.
If what he says is true, then the 25 kg  type 99 bombs were only produced only between 1937 and 1939, which is why they are not to be found on wikipedia for example and, by extension not in the US reports about japanese ordnance. This is  already hinted at by the "mod.2" or "mod 3" in the bomb's name actually.
It's also said now that those bombs were in fact highly unpopular with the pilots because they were highly unreliable and were finally drawn out of service as there had been cases of bombs exploding in flight, killing japanese pilots.
This bit of information is based on memoirs, I am told, but I can't (yet) say which ones or in which collection they can be found.

 

So while all of this sounds pretty reasonable and does confirm and expand what was found in the books already, I am currently not able to give any links or scans or pictures of actual source material. Yet. I am hoping to be able to change this.

I can only say that the "ask the experts" section in this forum is worth gold.

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I can only say that the "ask the experts" section in this forum is worth gold.

 

Heroic effort!

 

Try expanding to other forums, like "12 oclock high"!

http://forum.12oclockhigh.net/index.php

 

 

(and no suicide load-outs :) )

(Did not realize they 27 in use that late in war)

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Hello.

The topic will now be closed and moved to the appropriate section.
If you believe there is still information that needs to be passed on, please PM a Senior TechMod.

Greeting
FredericusRer
medal medal medal medal medal medal medal

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Lufthans found some additional data.

 

Concerning the Ki-27 and its loadout data. I believe I have found some relevant new information in documents I had not priorly had access to.

The info is as follows:
In TM 9-1985-4, there is a drawing and some data for a "12th year" 25kg bomb, used by the IJAAF. The 12th year of Shôwa was 1937. The bomb I mentioned before was first produced in 1937, the 12th year. However, it was discontinued after 1939 - which explains why the US document states "No specimens found, but reported in documents". It's the bomb on the bottom of page 40:
https://www.scribd.com/doc/67628319/TM-9-1985-4

TL;DR: IJAAF 25kg bomb used for Ki-27 confirmed through US documents on Japanese bombs of ww2

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