An Interesting NACA/NASA Article I found

[KJ_Lesnick]

I found this online while doing a research on a totally different subject: The information presented on this site was frankly incredible and helped answer a lot of questions I had regarding early research into transonic and supersonic flight as well as, to a degree, the state of affairs in multi-disciplinary research (for example why NACA kept obsessing on motorjets even after gas-turbines were being pursued by other nations, and why an axial-flow compressor concept was abandoned as the aerodynamic knowledge was not coupled with structural engineering knowledge)

I figure this is something that everybody here would find interesting.

The High-Speed Frontier
Table of Contents

Foreword

I. Introduction

II. The High-Speed Airfoil Program: Background and Origins (1745-1927)

A. The Quest for Understanding (1745-1927)
B. Increasing the Critical Speed (1928-1935)
C. Supercritical and Transonic Aerodynamics (1945-1956)
D. Supercritical Airfoils (1957-1978)

III. Transonic Wind-Tunnel Development (1940-1950)

A. The Choking Problem
B. The Re-Powered 8-Foot High-Speed Tunnel & Small-Model Techniques
C. Transonic Airfoil Facilities
D. The Annular Transonic Tunnel
E. Wing-Flow and Bump Methods
F. The Body-Drop and Rocket-Model Techniques
G. High-Speed Research Airplanes
H. The Slotted Transonic Tunnel
I. Comment on Management Methods

IV. The High-Speed Propeller Program

A. The Emergency Propeller Program
B. Full-Scale Propellers in the 16-Foot High-Speed Tunnel
C. Propeller-Blade Pressure-Distributions at High-Speeds
D. One-Blade Propeller-Tests
E. Sweptback Propellers
F. Transonic and Supersonic Propellers
G. High-Speed Flight-Tests of Propellers

V. High-Speed Cowlings, Inlets & Outlets, and Internal-Flow Systems

A. High-Speed Cowlings
B. High-Speed Air Inlets and Outlets
C. Internal-Flow Systems-Effects of Heat and Compressibility
D. The Ramjet Investigation

VI. Acknowledgements

VII. References

VIII. Appendix: List of Transonic Facilities

[kerick]

This looks very interesting thanks

[DogfighterZen]

This looks very interesting thanks

I'll second that, thanks KJ!

[KJ_Lesnick]

I posted this on Secretprojects.co.uk

[Captain Canada]

Thanks ! I'll print that one off interesting stuff cheers !

[KJ_Lesnick]

This commentary inspires some WHIF ideas

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. Even in 1936, it was predictable with certainty that within a few years the approach of improving the critical speed would reach a point of zero return, leaving the barriers still to be reckoned with.

I'm wondering why they felt that 550 mph was the maximum as they had clearly done very limited tests on supersonic flows.  I'm curious how quickly they could have switched from their 550 mph commitment to a faster speed, if not in 1936. 

This would have had interesting alternate history potential from the standpoint of supersonic test vehicles: I doubt we'd have built an M.52 because that was based on misguided intelligence.  There was a proposal in 1939 for a supersonic test-program based on issues with the P-38 at the very least.