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).
Performance comparison test between two Wraith models, focusing on acceleration and engine smoothness.
| Identifier | ExFiles\Box 108\2\ scan0231 | |
| Date | 28th March 1939 | |
| 600 S/W Rm{William Robotham - Chief Engineer} Sgr c. to C. c. " Hs.{Lord Ernest Hives - Chair} c. " BY.{R.W. Bailey - Chief Engineer} c. " Rm.{William Robotham - Chief Engineer} c. " Mx.{John H Maddocks - Chief Proving Officer} Wraith Performance. Cx{Major Len W. Cox - Advertising Manager}12/KW28.3.39. I took the opportunity again to-day of making a second test of your car, and on this occasion took another Wraith with me for comparison. I found I had to add 1 cwt of ballast to your car to bring it up to the weight of our Trials Wraith with division. In spite of this, and with two passengers in each car, your car showed definite superiority in acceleration on top gear from 20 and again from 30 m.p.h. Whilst the difference on paper looks very small, the actual difference on the road is naturally pleasing because it gives one car a definite superiority over the other. There is, I consider, a slight difference in smoothness of the engines between our Trials Car and your car, but it really is so slight that without comparing the two cars very closely it could be considered almost negligible. I think the benefits derived from the changes are well worth having, although I doubt whether it would be worth while going to the expense of scrapping material because of the changes. I do feel, however, that they should be introduced at the earliest point on production where scrap is not involved or extra costs do not arise. Cx.{Major Len W. Cox - Advertising Manager} | ||