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).
Test results and comparison of a Packard Straight 8 engine against the company's own 6-cylinder designs.
| Identifier | WestWitteringFiles\P\2October1926-December1926\ Scan078 | |
| Date | 25th November 1926 | |
| TO R.J. FROM R.{Sir Henry Royce} C. to WGH. B.Y. HS.{Lord Ernest Hives - Chair} EP.{G. Eric Platford - Chief Quality Engineer} re. PACKARD STRAIGHT 8. X435/X634 test The test of the above car yesterday confirms some of our views. With the 8 cylinder in line scheme an engine for car work definitely eliminates 2 or 3 features which give the 6 cyl. engine a certain amount of imperfection. However the torsional deflection of the long crankshaft seems to be (as originally thought) a source of trouble, putting everything else in the shade. These were my early views of this type of engine. It has now been confirmed by the Isotta, and by the above car. Col Fell has also stated that this type of engine has given much trouble to the makers of larger size engines, and also HS.{Lord Ernest Hives - Chair} has received information from other sources suggesting the same results. We may therefore conclude that it will be more profitable for us at the present to go on improving the designs of our 6 cyl. engines rather than spend time in this new direction, unless some conclusion to the contrary arises. The trouble is that the crankshaft being so long and unavoidably flexible, appears to have its natural period of vibration, and master period, at a much used speed. This appears to set up a vibration throughout the car, which is most objectionable, at any rate it seemed so in the Packard specimen tested. We would infinitely rather have the whole of our 6 cyl. troubles than this one defect. It is however possible that owing to the low gear of the car resulting in a very high engine speed, an extremely small out of balance of any of the parts would shiver the whole car so that although we do not intend to give this scheme valuable time for the present, we must keep a serious lookout in case our conclusions are not true. Regarding the Packard car generally we did not consider it at all charming and restful, and we cannot believe that they have much to teach us. The riding, steering, and brakes, seemed poor. The starter motor was sparking and spread copper dust badly. Everything was of sheet metal, and rusting in our damp climate. It will be noticed that the English branch of this firm remove the spare wheels from the back, forward to the sides. This may have spoilt the riding somewhat, but at the back one could definitely feel the wanfering steerings. But being low priced, it will sell I fear. R.{Sir Henry Royce} | ||