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Piper106,
r
Information for the La-7 came from the NII-VVS test trials of A/C No. 452132-76. Information for the Ki-84-1a is from TAIC 156A report.
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Similarely, TAIC records for Ki-84 were done on a machine specially prepared and tuned, run on higher than usual grade fuels. Japanese trials were lower than that.
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Seems like the A8 data is with over-boost (when applicable).
Where does this datasheet come from? I've never seen an original datasheet from any German plane dated during WWII in English. Unlikely that this paper was provided by the Focke Wulf Company.
cimmex
Where does this datasheet come from? I've never seen an original datasheet from any German plane dated during WWII in English. Unlikely that this paper was provided by the Focke Wulf Company.
cimmex
Sure, the sheet was translated from an original document and the data seems correct. But why it is not mentioned translated and by whom and done to give a lookalike as an original. Credible sources should always provide the original document together with the translation otherwise there is always a bad smell.
cimmex
RG mentioned various modifications on the fuel lines, the cylinders and mixture controll with replacement parts beeing specifically manufactured in the US in context with the Ki-84 tested in the US.
He went so ar to suggest that the modifiations in connection with the 100/150 grade fuel allowed higher than usual boost pressures beeing utilized in the A/C, resulting in appreciably better performance than with 75/85 octane fuels used by the japanese.
In fact, the US Ki-84 trials used forced WEP on 10 minutes to develop max. speed, something the A/C was never cleared for operation in japanese airforces.
Japanese data only give military rating for their A/C. This is understandable, as the fuel grade wouldn´t allow for max boost levels to be utlilised for more than 60 sec. at anything else than SL+1000m.
Certainly sure is that the Ki-84 was rated at 345mph on the deck and 388 to 392 mph at +250 boost in optimum altitude (military rating).
It has been suggested that speed on WEP would be temporarely higher had the Ki-84 made use of Water injection on the Ha-45-11 engine or forced on better fuel grade. However, note that it appears from various sources that the engine had restrictions preventing it from using WEP until late in the war (and even then for only 1 minute rather than 5 on the La-7 or 10 on the Fw-190A) due to low grade fuels and water injection was never implemented.
My guess? The engine was producing 1600hp at +250 (military rating), resulting in ~390 mph. On 1 minute WEP it could be forced to 1800 hp @ + 350 boost, providing it was cleared for this in 45. Assuming the WEP could be engaged long enough to stabilize on a new max. speed (1 minute is to short for this, but the US trial may have been long enough), the cube root rule from 1800/1600 allows the estimation of a top speed of roughly ~405mph, not accounting for ram effects and increased full pressure height.
RG mentioned various modifications on the fuel lines, the cylinders and mixture controll with replacement parts beeing specifically manufactured in the US in context with the Ki-84 tested in the US. He went so ar to suggest that the modifiations in connection with the 100/150 grade fuel allowed higher than usual boost pressures beeing utilized in the A/C, resulting in appreciably better performance than with 75/85 octane fuels used by the japanese. In fact, the US Ki-84 trials used forced WEP on 10 minutes to develop max. speed, something the A/C was never cleared for operation in japanese airforces.
Interesting; were those modifications made because the specific engine (engines?) have malfunctions, being worn-out war-time ones, or all Homares needed specified treatment?