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).
Note from the U.S.A. detailing performance feedback and test results for the 25-EX car model.
| Identifier | ExFiles\Box 19\4\ Scan231 | |
| Date | 22th December 1930 | |
| 8777 22.12.30. x777 x7941 Copy of note received from Hs.{Lord Ernest Hives - Chair} in U.S.A. To R.{Sir Henry Royce} c. Sg.{Arthur F. Sidgreaves - MD} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} Hy.{Tom Haldenby - Plant Engineer} 25-EX. in U.S.A. We have now run almost 3,000 miles and the criticism of this car has resolved itself to three points. None of these points are effected by the L.H. version they are a criticism of P.II. Acceleration. We have made a number of side by side tests with cars of the same weight. The springfield cars from 10 to 40 m.p.h. will gain from 1 to 2 car lengths in that distance, on time they run from 10 to 50 m.p.h. in 17 secs.. on the same road we take 18 secs. From the records of power curves of the engine they show an increase in power up to 12.50 R.P.M. They have bench test running now so that I have not been able to check that figure. The compression space on their cars is exactly the same as on 25-EX. They gain, I believe, on their inlet timing, they use the standard P.I. cams. The offset of the tappet is opposite to our P.I. that is, they made no correction for L.H. I am trying to get a valve lift diagram to bring back. The feeling of acceleration on the U.S.A. P.I. is greater than the measurements show. I have increased the amount of heat to the hot spot on 25-EX but it has made no appreciable gain on these tests but it is a gain on average conditions. I am getting hold of another R.H. P.II. to check up the results. The axle ratio and the wheel sizes are the same. At speeds above 40 M.P.H. 25-EX gradually gets away. I will not confuse this report with comparisons we have made against other makes of U.S.A. cars. Steering. The steering was criticised for joggling. it was appreciated, however, that it was very light, much lighter than P.I. U.S.A. cars. We have since fitted | ||