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).
Memo comparing the engine smoothness and specifications of a Hudson Terraplane with a Rolls-Royce 20/25.
| Identifier | ExFiles\Box 173\2\ img071 | |
| Date | 19th February 1934 | |
| AG SGW OR EBy D9 HDY{William Hardy} / HS{Lord Ernest Hives - Chair} / Rm{William Robotham - Chief Engineer} 14 / NW{N. Walker - Patents} 73.2.34 EV{Ivan Evernden - coachwork} BN{W.O. Bentley / Mr Barrington} 19/2/34 Hs.{Lord Ernest Hives - Chair} Yesterday I spent at the Hudson Essex Plant. Since we have had a Terraplane at Derby it was interesting. ENGINE SMOOTHNESS This of course was the outstanding characteristic of the Terraplane, to investigate which it was purchased. I tried one of their 1934 eights which had substantially the same feel as the car we bought. After this I found that they were making the six which was as close as possible to our 20/25 unit both in dimensions and output - though it had a better tape ratio being 3" bore and 5.0" stroke. The displacement is 212 cu. ins and the H.P. output is 80 at 3600 R.P.M. with 5.75 c/r.{Sir Henry Royce} or tabulated R.R. 20/25 Terraplane 6 cyl. Bore & Stroke 3 1/4 x 4 1/2 3" x 5" Displ. 224 Cu. ins. 212 cu. ins Tax £ 26 £ 22 Comp Ratio 5.75 5.75 H.P. 77 (87 newcastle) 80 | ||