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).
Letter detailing engine pulsation issues, a dynamo failure, and a comparison with a Cadillac vehicle.
| Identifier | ExFiles\Box 5a\4\ 04-page172 | |
| Date | 13th December 1934 | |
| X5840 Rm{William Robotham - Chief Engineer} Hotel de France, Chateauroux, Indre. France. To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} From GWH.{George W. Hancock - Head Chateauroux} 13th December 1934. I have received your letter Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer}/7/KW-10.12.34. Re the daily report of the 7th instant. I am sorry a mistake has been made in the maximum speed given. It should have read 74.07 MPH. Re the pulsations of the engine. We have endeavoured to get the engine of 21 G 1V to run even at low speeds, but have not managed it. We have had it running fairly even, but after a days run it will not run even. We demonstrated the pulsations to Hs.{Lord Ernest Hives - Chair} and B. B. suggested fitting torque reaction dampers, but the Paris Depot do not keep stocks of them, so B. suggested that we should fit a damping device between the top of the cylinder block and the dashboard. This we have done, and the results are very promising. It has cured the torque reaction period, cured the pulsations felt in the seats and lessened the tendency of clutch jaggers. It has not brought up any roughness at low or intermediate speeds. At over 70 MPH. the engine has been very rough throughout the mileage, and we thought at first that a slight boom had been brought up by fitting the damper, but since, we do not think it has done so. We are, however, making sure of it. We note your remarks on petrol pumps having an influence on slow running and will verify it by fitting a temporary supply. We sent you a telegram from Paris saying we were taking the Cadillac to Chateauroux. We had a very good run down with this car, and as far as its running was concerned, it appeared to be quite alright. I decided, however, to have a look at one or two connecting rods after the run, and we do not like the appearance of the Cadillac bushes in the rods. Although they were smothered in oil, there is a tendency of the metal to drag. There are several spots that look as if the metal is pulled out, and we are definitely of the opinion that it will not stand thrashing. The bushes fitted by Dubonnet's are in good condition and do not show any tendency of the metal to drag. We are sending you one of the Cadillac bushes taken out. We asked you in our telegram to send a new armature for the 21 G 1V. The dynamo has completely failed. We located the trouble to the dynamo here, but could not say what it was, as we had not an instrument to detect the short. We had it tested upon arrival at Paris (having arrived there with dimmed lights). A brush holder was shorting direct to earth, and the coils of the armature are shorting behind the commutator. | ||