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).
E.A.C. performance tests with associated graphs for a New Phantom.
| Identifier | ExFiles\Box 29\3\ Scan135 | |
| Date | 12th October 1925 | |
| R.R. 493a (50 M) (D.D. S1. 12-6-25) J.H.V. EXPERIMENTAL REPORT. Expl. No. REF. Hs{Lord Ernest Hives - Chair}/Rml/LG12.10.25. E.A.C. PERFORMANCE TESTS. These graphs are more or less self-explanatory. The tests were carried out with hood and side curtains up to protect the Chronograph. Also cutout closed as being the normal driving condition in the British Isles. Graph 1. This gives the road wheel H.P. curve of the car on the dynamometer with cutout closed and cutout open taken before the test. It also gives the H.P. required to drive the car at any road speed. This is calculated from the tractive resistance curve in Graph 1V, which was obtained by means of the Chronograph. Where curve C. meets curve A.{Mr Adams} or B. will be the max. speed of the car if its tractive resistance has been correctly estimated. In this case it is 71.3 m.p.h. with the cutout closed which agrees fairly well with the max. lap speed registered by stop watch, actually it is just over 1 m.p.h. low. Graph 111. These give New PhantomCodename for PHANTOM I acceleration on direct drive and low gears. We have superimposed a curve (R) we obtained some considerable time ago on an old Silver Ghost. The curves are not directly comparable because the Silver Ghost was driven with the cutout open and the hood down. They shew however, the extent to which the low speed acceleration of the Phantom has suffered due to its increased weight (19%). The curve 2 up to 20 m.p.h. is not as good as we anticipated it would be. It will be realised that acceleration up to this speed is almost entirely a matter of carburation; contd :- | ||