Proposal to Adjust Ki-84 Performance Based on Historical Data
The Ki-84 is well-known as a late-war Japanese Army fighter aircraft. However, its performance in War Thunder (WT) is based on inaccurate facts, resulting in an overestimation of its capabilities.
Engine Performance and Limitations
Generally, the Ki-84 is equipped with the Ha-45-21 engine. The takeoff power (which became usable as War Emergency Power (WEP) only after December 1944) was prohibited for use in aerial combat until that time. Reference
More importantly, the Ha-45 engine was limited to an output of 1,860 horsepower due to extreme increases in cylinder temperatures caused by uneven fuel mixtures. This restriction remained in place until the end of the war, meaning the Ki-84 never actually operated at the 2,000 horsepower level depicted in WT for flight or combat scenarios.
Historical Performance Data
Historical performance measurements by the Japanese Army are well-documented and can be found here: Reference. These sources are based on primary documents, and for those who can read Japanese, the original sources are cited, confirming the reliability and accuracy of the information.
The U.S. estimates of 690 km/h at 6,000 meters are based on the engine’s “intended performance,” not on actual measured data. Moreover, the engine never achieved its intended performance in practice. Japanese military aircraft speeds are recorded based on nominal output (30-minute output) because takeoff power was not used during combat operations. While there are records of aircraft like the Zero at Lae bypassing regulations, demonstrating that higher outputs were physically possible, such instances were exceptions and not reflective of standard operational procedures.
Implications for War Thunder
The use of WEP in Japanese aircraft was delayed significantly, and particularly for the Ki-84, there is no confirmed evidence that wartime emergency power was used in combat or test flights. Therefore, implementing the current performance figures in WT is questionable. Adjusting the Ki-84’s performance in the game to reflect these historical limitations would provide a more accurate representation.
Further Considerations
This proposal calls for dramatic changes to the Ki-84’s specifications, warranting thorough discussion. Additionally, similar debates should be held for the Shiden Kai (紫電改, N1K2-J), which is equipped with the same engine, to ensure consistency and historical accuracy across related aircraft.
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