Ki-43 Hayabusa Engines

[Laurelix]

So there are conflicting values even if we ignore the US figures completely and go by the Japanese values.

So this is from Bunrindo - Famous Airplanes of the World - Type 1 Fighter

Ha-25 / Sakai 12 engine - Listed as 950hp engine (Ki-43-I)
870hp at Sea Level (Military Power)
*990hp* at Sea Level (Combat Power)
-
**970hp at 3400m (Military Power)**

*It however states that Nakajima engine data states 940hp whilst Ando with the 1st Aeronotical technology Research Institute at the end of the war claims 980hp, a table created by Colonel Naruo*

**Nakajima states 950hp at 4200m**

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Ha-115 / Sakai 21 - Listed as 1150hp engine (Ki-43-II / A6M3 / A6M5)
???hp at Sea Level (Military Power)
*1120hp* at Sea Level (Combat Power)
-
**1020hp at 2800m** (Military Power)
-
***980hp at 5600m*** (Military Power)

*Nakajima side and Ando table figures state 1130hp*
**Nakajima side claims 1100hp at 2850m**
***Kouki Engineering Department states 990hp at 5600m whilst Nakajima and Colonel Ando numbers are 980hp at 6000m***

----------------------------------------------------------

Ha-115-II / Sakai 31 - Listed as 1150hp engine (Ki-43-III / A6M6?)
???hp at Sea Level (Military Power)
*1190hp* at Sea Level (Combat Power)
-
**1230hp at 2800m** (Military Power)
-
***950hp at 6800m*** (Military Power)

*Nakajima states 1150hp whilst Colonel Ando's Table claims 1190hp*
**Nakajima states 1100hp at 2850m**
***Nakajima states 980hp at 6000m***


====================================

Lets debate this...
I think it is probably like this...

Ha-25 (Hayabusa 1 / Oscar 1)
870hp at Sea Level (Military Power)
940hp at Sea Level (Combat Power)
-
950hp at 4200m (Military Power)

Ha-115 (Hayabusa 2 / Oscar 2)
1020hp at Sea Level (Military Power)
1130hp at Sea Level (Combat Power)
-
1100hp at 2850m (Military Power)
-
980hp at 6000m (Military Power)

Ha-115-II (Hayabusa 3 / Oscar 3)
???hp at Sea Level (Military Power)
1190hp at Sea Level (Combat Power)
-
1230hp at 2800m (Military Power)
-
950hp at 6800m (Military Power)

 

[Laurelix]

US Data:

Ha-115 - from Ki-43-II TAIC
997hp at Sea Level (Military Power)
1105hp at at Sea Level (Combat Power)
-
1085hp at 2800m (Military Power)
-
965hp at 6000m (Military Power)


Ha-115-II - from TAIC 2 for Oscar 3
???hp at Sea Level (Military Power)
1150hp at Sea Level (Combat Power)
-
950hp at 6600m (Military Power)
-

 

[wells]

TAIC engine data is Japanese data, translated, with the exception of WEP estimates. Given boost and RPM figures, everything makes sense, except that power at 3400 m is probably closer to 930 US hp ( 940 metric HP ). The Sakae 12 is not the same, as the supercharger ratio is different ( 7.53 vs 7.125 ), manifold pressure is higher and RPM is lower, thus the power of 950 HP @ 4200 m makes sense for that engine.