From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Comparison table of drag and maximum speed for an existing car and various experimental tail designs.
| Identifier | ExFiles\Box 90a\4\ Scan010 | |
| Date | 13th January 1936 guessed | |
| " DRAG lbs. AT. 100 M.P.H. MAXIMUM. SPEED ON SMOOTH HARD SURFACE. MILES/HOUR. EXISTING CAR. (GREEN MODEL) 160. 115. EXPERIMENTAL BODY. TAIL No. 1. 137. 120. 2. 141. 119. 3 147 117½. 4. 143 118½. 5 142. 119 6. 139. 119½. | ||