Ki-83 test performance

[Graham Boak]

Just filling the tanks with 100 octane will not make any individual aircraft go any faster unless the engine is rated at a higher boost than it previously could achieve on the design petrol. This seems a curious design trait.

I've seen, earlier on this site, postings describing a Japanese habit of quoting a maximum speed at something less than the absolute maximum power setting. I don't recall the details, or even whether this was confirmed.