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 engine performance, smoothness, and features against a Terraplane unit.
| Identifier | ExFiles\Box 173\2\ img072 | |
| Date | 19th February 1934 guessed | |
| II Therefore in spite of having side valves this engine gives a higher specific output - than the present 20/25 and about the same as the 20/25 with the new carburetter. On the other hand the Terraplane unit gives 15% more power for the same tax. This being considered, and also the price, one might have expected it to be considerably rougher than our product on the road! However in actual practice it was indistinguishable for in smoothness from the 8 cyl up to 60 M.P.H. Above that speed roughness could definately be felt on the gear lever and as on our own cars but there was otherwise little evidence of it in the driving seat until 4000 R.P.M. had been attained. The master crankshaft period seemed to begin at about 5400 R.P.M. allowing for speedo error etc but the valves floated before this. The intake and exhaust silencer was probably not quite so good as on the eight and the fan was noisy but the impressive feature was the uncanny smoothness at speeds up to 60 M.P.H. The engine had a three bearing crankshaft. | ||