During its existence, NACA [National Advisory Committee for Aeronautics ] produced thousands of (technical) reports, many of which still have relevance to today’s researchers and engineers in aeronautics and aerodynamics. While many of the reports are only available in hardcopy, in the last decade or so, a substantial number of the reports - over 14,000 - have been digitised and made available online.
These digitised reports are still available despite the demise of the NACA Reports Server. They can now be accessed from the NASA Technical Reports Server (NTRS). http://ntrs.nasa.gov/search.jsp (Princeton University Library also houses a very substantial number of these reports in print or on microfiche.) Resource (below), via docuticker http://www.docuticker.com http://aerade.cranfield.ac.uk/newsletter0207/page3.html
The UK also maintains a searchable database of NACA reports: http://naca.central.cranfield.ac.uk/
AERADE Reports Archive http://aerade.cranfield.ac.uk/reports.html AERADE is “Your quality portal to aerospace and defence resources on the Internet.” The Aerade Reports Archive incorporates more than ten thousand, historically significant, digitised reports from:
The Aeronautical Research Council (ARC) - the principal agency in Great Britain with a major output of reports on matters aeronautical, which existed from 1909-1979, and published reports until 1980.