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).
Graph comparing the cooling efficiencies of different Phantom fans.
| Identifier | ExFiles\Box 14\7\ Scan069 | |
| Date | 18th May 1934 | |
| COMPARISON OF COOLING EFFICIENCIES OF PHANTOM FANS TOP TANK WATER TEMP. °C ENGINE IDLING IGNITION FULL RETARD SHUTTERS FULL OPEN ASYMMETRICALLY BLADED FAN Lec: 3748 SYMMETRICALLY BLADED FAN Lec: 3747 STANDARD PHANTOM FAN TIME - MINUTES 18.5.34 | ||