Avro 504R Gosport with Avro Alpha motor NACA Aircraft Circular No.49
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
1927-07-01
<a rel="nofollow" class="external free" href="https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930090626.pdf">https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930090626.pdf</a>