Data Base: Japanese Aircraft Engines

[MiTasol]

How come US and Japanese power curve for Ha-45-21 differs?

Japanese state
1990hp at SL with WEP
1625hp at 6100m with Military Power

US on the other hand state 1970hp at SL with WEP
1675hp at 6100m with Military Power

Probably because each country has its own testing standards and processes.
Identical standards/processes should produce the same results.
Different standards/processes will almost certainly produce different results.

Also Japan used metric measurements and the USA used exclusively inferial during ww2 so conversion from metric to inferial would provide further errors in rounding and the US was almost certainly testing an engine repaired in the US with US fuel instead of as built with Japanese fuel

I would trust the Japanese figures more than any other

 

[warbirdperformance]

How come US and Japanese power curve for Ha-45-21 differs?
Japanese state
1990hp at SL with WEP
1625hp at 6100m with Military Power

US on the other hand state 1970hp at SL with WEP
1675hp at 6100m with Military Power

In the Japanese data, at first Ha-45-21 was expected to perform
2000PS @ S.L. for take-off power
1900PS @ 1800m
1700PS @ 6400m for rated power

I guess the U.S. intelligence seized some documents using this performance data and just converted it from metric to imperial.
1970HP×1.01387=1997.3239≒2000PS
1875HP×1.01387=1901.00625≒1900PS 5900ft×0.3048=1798≒1800m
1675HP×1.01387=1698.23225≒1700PS 19600ft×0.3048=5974≒6000m(?)
I don't know why 2nd speed supercharger altitude does not correspond to the Japanese one.

However, Ha-45-21 output didn't reach its expectation due to some reason and was re-defined as below.
1990PS @ S.L. for take-off power
1860PS @ 1750m
1625PS @ 6100m for rated power

That's what I think recently.

 

[Vincenzo]

Hello All,

From Famous Airplanes of the World and other sources, I have the following data:
Ha-40
Take-Off Boost Pressure +330 mm
Take-Off Power 1175 - 1180 HP @ 2500 RPM

Sea Level Military Boost: +240 mm
Military Power 1040 HP @ 2400 RPM @ Sea Level
Military Power 1100 HP @ 2400 RPM @ 4200 Meters altitude


Ha-140
Take-Off Boost Pressure +380 mm
Take-Off Power 1500 HP @ 2750 RPM

Sea Level Military Boost: +380 mm <-------- I am certain this must be a misprint.
Military Power 1350 HP @ 2650 RPM @ Sea Level
Military Power 1250 HP @ 2650 RPM @ 5700 Meters altitude

Does anyone here have the correct military boost pressure for the Ha-140 engine?
I believe it should be a lot lower than the take-off rating.

Thanks.
- Ivan.

i found this 2019年9月6日 : WW2航空機の性能:WarbirdPerformanceBlog
for the Ha 40 give nominal power Boost pressure a +230mm Hg

 

[warbirdperformance]

Hello All,

From Famous Airplanes of the World and other sources, I have the following data:
Ha-40
Take-Off Boost Pressure +330 mm
Take-Off Power 1175 - 1180 HP @ 2500 RPM

Sea Level Military Boost: +240 mm
Military Power 1040 HP @ 2400 RPM @ Sea Level
Military Power 1100 HP @ 2400 RPM @ 4200 Meters altitude


Ha-140
Take-Off Boost Pressure +380 mm
Take-Off Power 1500 HP @ 2750 RPM

Sea Level Military Boost: +380 mm <-------- I am certain this must be a misprint.
Military Power 1350 HP @ 2650 RPM @ Sea Level
Military Power 1250 HP @ 2650 RPM @ 5700 Meters altitude

Does anyone here have the correct military boost pressure for the Ha-140 engine?
I believe it should be a lot lower than the take-off rating.

Thanks.
- Ivan.

i found this 2019年9月6日 : WW2航空機の性能:WarbirdPerformanceBlog
for the Ha 40 give nominal power Boost pressure a +230mm Hg

Let's answer the 7-year-ago question.
Yes, nominal(military) power boost pressure for Ha-40 is +230mmHG.
Ha-140's take-off power boost is +480mmHG and military power boost is +380mmHG.

 

[Vincenzo]

So i found your blog

 

[Shinpachi]

Let's answer the 7-year-ago question.
Yes, nominal(military) power boost pressure for Ha-40 is +230mmHG.
Ha-140's take-off power boost is +480mmHG and military power boost is +380mmHG.

おお日本の方でしたか。
今後共宜しくお願いします。

My best regards to new Japanese member.

 

[warbirdperformance]

おお日本の方でしたか。
今後共宜しくお願いします。

My best regards to new Japanese member.

こちらこそ宜しくお願いします。
Thank you very much!!

 

[islandee]

According to locals south of Chiang Mai City, this engine (photos attached) came from an IJAAF aircraft which crashlanded on a river plain probably in late 1941 or early 1942. Most of the aircraft was intentionally burned / destroyed by the Japanese military, but the engine block was simply buried in a river bank. Many years later, the river changed course exposing the block. Eventually it found its way to a display in a local schoolyard.

In the Year 2000, two Japanese apparently hoping to find a Zero engine, examined the block, judged it of Nakajima manufacture, and walked away.

At this later date, interested in the history of the engine and its possible role in the war, I would like to further identify it. This forum / this thread would appear to be a likely resource. Obviously I can measure bore and estimate stroke and photograph details which might allow a general identification of the block / engine (perhaps the attached photos will suffice). But I'm wondering if I should be looking somewhere specific on the block, for either characters punched into the block proper, or an attached metal tag (if such has survived), or other characteristic(s) which might better identify the engine and, perhaps, the aircraft in which it had been installed. If so, where might that / those be? (Or is it even worth the effort?)

(Credit Ben Svasti for the photos, taken April 2018.)

I thank you.

Hak Hakanson
Chiang Mai

 

[Shinpachi]

Metal tag is on the front gear case.
For your preliminary knowledge, if the engine diameter is 1,280 mm with 9 cylinders of bore/stroke 146/160mm, the engine will be Nakajima Type 97 650hp engine (Ha-1-otsu for the army or Kotobuki model 41 for the navy) which was still popular in the early stage of Pacific War.

Cross section: Nakajima Type 97 650hp engine.

 

[MiTasol]

Hi Hak

Now that Shinpachi has identified the engine type you will find a link to a manual for one model of that engine here Japanese engine manuals and technical drawings (blueprints)

According to wiki that engine was used in these aircraft

• Mitsubishi A5M
• Mitsubishi Ki-18
• Nakajima A1N2
• Nakajima A2N
• Nakajima Ki-8
• Nakajima Ki-27
• Nakajima E4N
• Nakajima E8N
• Nakajima Ki-34
• Nakajima Type 91

Incidentally all "Zeros" had engines with two rows of cylinders and a 3 blade propeller.

 

[islandee]

Shinpachi: Thank you. And Mitasol, thank you.

In reviewing the aircraft in which the engine was installed, I see the Ki-27 is the obvious candidate.

I gather from the information provided by the photographer that there is no longer a metal tag attached to the front gear case. Even if that information were available, is it accurate to state that there is no master list available tying Nakajima engine serial numbers, or equivalent, to individual aircraft which would allow identification of IJAAF unit assigned, pilot, etc?

With the assumption that there is no master list, I will guess that the aircraft was involved in the early attacks on Burma from bases in Thailand. I've got Hiroshi Umemoto's book(s) and Google Translate and I can make, at the least / at best, a list of candidates; and leave it at that. Does that seem realistic?

 

[MiTasol]

I think that when you get into it you will either find some good information that provides a solid conclusion or get totally frustrated. I can certainly promise frustration at times and predict great joy at other times

I am involved with two similar projects and the results of both are slowly coming together and in both cases the official history is very much in question. In one case the military swore legal statements for the police and for the coroner that are demonstrably untrue (from official records released months before the statement was sworn) in three key statements, the date, where he was flying to, and the serial of the aircraft. The question is why. Then the head of the responsible unit went to press and made what appear to be wild claims linking the same crash to a totally different date. Why were these people deliberately muddying the waters? Why did they confiscate all the Police records on the accident? And why do they currently insist that the statements to the coroner were correct and that the wartime records proving they are lying are of no consequence?

 

[Shinpachi]

Shinpachi: Thank you. And Mitasol, thank you.

In reviewing the aircraft in which the engine was installed, I see the Ki-27 is the obvious candidate.

I gather from the information provided by the photographer that there is no longer a metal tag attached to the front gear case. Even if that information were available, is it accurate to state that there is no master list available tying Nakajima engine serial numbers, or equivalent, to individual aircraft which would allow identification of IJAAF unit assigned, pilot, etc?

With the assumption that there is no master list, I will guess that the aircraft was involved in the early attacks on Burma from bases in Thailand. I've got Hiroshi Umemoto's book(s) and Google Translate and I can make, at the least / at best, a list of candidates; and leave it at that. Does that seem realistic?

I think your direction for research is realistic and correct.
Hoping this may help, according to my quick research based on several official records, the 77th Sentai was the sole army fighters unit which was equipped with the Ki-27 fighters during the period from December 8, 1941 to January 21, 1942. Through the operation in Burma, the unit had 3 crashlanded cases on December 25, 1941, February 7 and March 6, 1942. The case of December 25 by Sgt. Ono on his way back from Rangoon looks not only matching the period but he crash landed near the Thai-Burma border to be rescued.

 

[islandee]

Shinpachi:

Ah, many thanks: I was still working my way through the first two pages (pp 448, 449) of Umemoto's listings and quit with a headache last night after a long search to find 藤 in Nelson when my OCR couldn't reproduce it.

Okay, with your guidance, I can now see Sergeant Ono on p 450, last one listed of the four Ki-27 pilots in the 77th downed on 25 Dec 1941 on missions over Rangoon. Yes, local folk said he flew it into the ground. And the location is about 30 km from the Thai-Burma border.

Needless to say, had I gotten to this item in Umemoto's compilation in my translation effort, I probably wouldn't have recognized its relevance. Again, many thanks, Shinpachi!

Can I credit you as "Shinpachi" when I add this information to my website, or would you prefer something else?

 

[islandee]

In skimming Umemoto's commentary, I don't find much more information: Google Translate seems to indicate that Sgt Ono apparently had his fuel tank punctured, so that he simply ran out of fuel. If correct, Ono was lucky that the fuel tank didn't catch fire. And there is a comment about statistics apparently being somewhat muddled as to Sgt Ono's fate.

 

[Shinpachi]

Can I credit you as "Shinpachi" when I add this information to my website, or would you prefer something else?

I have advised as Shinpachi of ww2aircraft.net.
Thanks.

 

[islandee]

MiTasol: can I reference you in a similar manner; ie, MiTasol of ww2aircraft.net?

 

[MiTasol]

MiTasol: can I reference you in a similar manner; ie, MiTasol of ww2aircraft.net?

I will leave the decision to you.
I do not provide information to obtain recognition but appreciate the honour you ask to bestow

 

[islandee]

Forum: thank you for your assistance. My writeup for this crash is at 25 Dec 1941. I would appreciate comments / criticisms, particularly with regard to those areas for which I must rely on Google Translate.

 

[MiTasol]

Congratulations. A nice tight summary and good maps.