# Pre-War NACA Visions for High-Speed Flight.



## Zipper730 (Jul 13, 2019)

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


> In the light of later events, NACA's 1936 vision of the "550-mph" propeller-driven piston engine airplane as the ultimate goal of high-speed aeronautical research was obviously too shortsighted and restrictive. Focusing the effort totally on the immediate problem of increasing the critical Mach number of conventional aircraft components denied consideration of the broader and far more important "barrier" problem areas of transonic flight, including new propulsion concepts, radical configurations, transonic facilities, etc. A small cadre of the more imaginative thinkers could have been separated from the main effort to provide high-critical-speed data for industry, and encouraged to look beyond the speed range of the existing high-speed tunnels at these "barrier" problems.


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.


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## thunderbird (Jul 18, 2019)

Look at the Lockheed L-133 concept proposed in 1939. 

Lockheed L-133 - Wikipedia

One can see with modern eyes it’s weaknesses. Intakes look a little small for the engines. No sweepback and no area ruled fuselage. Lockheed has probably not yet developed the manufacturing skills to produce a sufficiently aerodynamically clean shape. 

And the Army passed on it completely anyway.

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## Zipper730 (Jul 31, 2019)

thunderbird said:


> Look at the Lockheed L-133 concept proposed in 1939.


Amazing design, that said: It doesn't appear as if it would have been capable of going supersonic. Regardless, that could be overlooked as many early jets couldn't. The engine was too complicated though.


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