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).
Visit to the Hudson Essex Plant, comparing the Terraplane 6-cylinder engine to the 20/25 unit.
| Identifier | ExFiles\Box 178\2\ img200 | |
| Date | 23th February 1934 | |
| COPY OF REPORT RECEIVED FROM Res. IN U.S.A. DATED 11.2.34. To. Mr. [Redacted] Mr. [Redacted] Mr. [Redacted] Mr. [Redacted] Mr. [Redacted] c. to EV.{Ivan Evernden - coachwork} Mr. [Redacted] EV{Ivan Evernden - coachwork} 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 a six which was as close as possible to our 20/25 unit both in dimensions and output, though it had a better tax 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 and Stroke. 3¼ x 4½" 3" x 5" Displ. 224 cu.ins. 212 cu.ins. Tax. £26. £22. Comp.Ratio. 5.75 5.75 H.P. 77 (87 new carb.) 80 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 will 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. | ||