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).
Experiment to fit a Terraplane engine into a 20/25 car and considerations for future engine designs.
| Identifier | ExFiles\Box 21\6\ Scan133 | |
| Date | 6th February 1934 | |
| To E.{Mr Elliott - Chief Engineer} from Sg.{Arthur F. Sidgreaves - MD} Hs.{Lord Ernest Hives - Chair} about the whole idea, he mentioned conducting an experiment of putting the Terraplane engine into a 20/25 experimental car. I think this is a fine idea as it would show us very quickly what the car would then be like and whether the Terraplane engine is really obtaining some of its virtue from the rigidity of its chassis frame. If so, I presume there is no reason why we should not design our frame on similar lines. I note that for the reasons given in your letter the 8-cylinder "Vee" type of engine is out of the picture. I agree that possibly a small 12 of about the size previously discussed might have certain advantages over a straight-8 but we have got to look at the matter as a whole and the disadvantages of a small double-6 are first and perhaps foremost - its expense. I think we can say fairly safely that a small double-6 will cost as much to produce as the large double-6. We cannot possibly contemplate increasing the price of the 20/25 HP. Car and the margin of profit on that model to-day with its 6-cylinder engine is painfully small. The other disadvantages of the double-6 are the ones of policy referred to in my Sg{Arthur F. Sidgreaves - MD}7/E31.1.34. Then there is the disadvantage of inability to fit a completely dual ignition referred to in your memo. Then there is the further disadvantage of increased taxation because of the number of cylinders. I see from your E.3/HP.6.10.33 that a 12-cylinder of the same litre capacity as the present 25 HP would work out at a £30 tax. The Terraplane comes out at about £28 and I certainly do not want to go to more than that. I should like you and Hs.{Lord Ernest Hives - Chair} to speak to me to-morrow about the experiment referred to above with a view to seeing how soon it can be carried out. | ||