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 of relative strains on fan belts for different engine models, including a graph.
| Identifier | ExFiles\Box 178\1\ img035 | |
| Date | 15th February 1926 guessed | |
| - 19 - the Phantom fan belt having to transmit almost twice the power of that of the Hispano, the Silver Ghost more than three times. It is quite clear that no normal fan belt can be expected to transmit much more than three horse power. The result is that unless some special drive is provided, the Silver Ghost fan attains its maximum revs. at a car speed of 60 m.p.h. and at anything above this speed the belt slips, so burning the leather, GRAPH VII RELATIVE STRAINS ON FAN BELTS SILVER GHOST v HISPANO RELIEF ON PHANTOM------- H.P. TO DRIVE FAN ENGINE R.P.M. SILVER GHOST HISPANO and stretches, which necessitates constant adjustment. The difficulties of providing a positive drive are considerable. To mention two - Silence is one problem and allowing the drive to slip at high speeds is another. Nobody wishes to lose 9 H.P. driving their fan when travelling at 70 m.p.h. There is a tendency on modern overhead camshaft engined contd. | ||