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).
Test report on a Phantom II type front expansion box, clutch performance, engine rattles, and various exhaust system configurations.
| Identifier | ExFiles\Box 5a\3\ 03-page086 | |
| Date | 4th November 1931 | |
| (2) (4) P.II. type of front expansion box fitted with lagged box downtake and intermediate. Critical crankspeed 62 m.p.h. on 3rd. Clutch slips badly. ? type of fabric. Engine gear rattles at 20 m.p.h. ----- 4.11.31. Tests on exhaust systems continued. - (5) 1 1/4" manifold fitted with straight through pipe. This system is perfectly all right except for a marked period which is like a roar at 30 m.p.h. on the pick up and a boom at 60 m.p.h. on top gear. The boom at 60 m.p.h. is not very bad and may be partially due to the engine. There is a slight boom between 40 - 50 m.p.h. but we believe this to be mainly engine. (6) 1 1/4" manifold fitted with small front expansion box and small intermediate pipe. With this expansion box the period at 30 m.p.h. has completely disappeared and with the box- lagged there is little or no tinniness. The worst feature of this arrangement is a roar at 60 m.p.h. as in test (5) but slightly less pronounced. On the whole this system is passable for noise but there is a distinct feeling of loss of power. To improve slipper wheel rattles the spring drive damping load is reduced from 19 lbs to 13-14. (six springs removed). | ||