This was asked on another forum and, while it (supposedly -- I'm not a member) got little answer, it seems like a good question to ask. So, I'll put it here.
The High Speed Frontier: Chapter 2-3: Increasing the Critical Speed
By 1936, they had largely decided that they would not invent advanced aircraft, but largely provide designers with accurate high-speed component data, and set their sights on a 550 mph propeller-driven piston-engined aircraft as their ultimate goal of high-speed flight. It seemed a strange step to take, even though NACA definitely could, and did make great contributions to both military and civilian aviation, in that, even by 1935, there was some limited research on supersonic-flows, and a rudimentary base of knowledge on compressibility.
By 1938, some of their best minds had visited Europe and were made aware of newer aerospace developments and transonic flow-research, and were clearly aware of Germany's preparation for war (though were not aware of its developments), and were already doing tests to see where transonic flow would form on aircraft designs (admittedly a DC-3). It's strange that they didn't amend their goals to include transonic and supersonic research by 1939.
They already had the transonic research data behind them, there were some personalities in the aerospace field that had expressed concern that some new designs (i.e. P-38) would likely run into compressibility, including Ezra Kotcher, from the US Air Corps Engineering School, had already noted this and suggested to General Arnold, the initiation of a program aimed at transonic speeds/supersonic speeds, as well as the use of jet-propulsion (note, at this point in time, jet propulsion meant any engine that uses its thrust directly).
I'm not sure if we could have kept pace with the Germans, but I think we would have probably been closer paced with them.
The High Speed Frontier: Chapter 2-3: Increasing the Critical Speed
I've found that, in some ways, people are very logical and rational, and extremely crafty: They pick up things that surprise even those of decent intelligence; in other cases: Even sometimes very smart people, will fail to connect dots that their knowledge would seem to have allowed.
By 1936, they had largely decided that they would not invent advanced aircraft, but largely provide designers with accurate high-speed component data, and set their sights on a 550 mph propeller-driven piston-engined aircraft as their ultimate goal of high-speed flight. It seemed a strange step to take, even though NACA definitely could, and did make great contributions to both military and civilian aviation, in that, even by 1935, there was some limited research on supersonic-flows, and a rudimentary base of knowledge on compressibility.
By 1938, some of their best minds had visited Europe and were made aware of newer aerospace developments and transonic flow-research, and were clearly aware of Germany's preparation for war (though were not aware of its developments), and were already doing tests to see where transonic flow would form on aircraft designs (admittedly a DC-3). It's strange that they didn't amend their goals to include transonic and supersonic research by 1939.
They already had the transonic research data behind them, there were some personalities in the aerospace field that had expressed concern that some new designs (i.e. P-38) would likely run into compressibility, including Ezra Kotcher, from the US Air Corps Engineering School, had already noted this and suggested to General Arnold, the initiation of a program aimed at transonic speeds/supersonic speeds, as well as the use of jet-propulsion (note, at this point in time, jet propulsion meant any engine that uses its thrust directly).
I'm not sure if we could have kept pace with the Germans, but I think we would have probably been closer paced with them.