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 discussing various engine development points including bearings, hydraulic tappets, and a 12-cylinder unit.
| Identifier | ExFiles\Box 140\4\ scan0300 | |
| Date | 11th May 1939 | |
| -2- for energy absorption at the time of gear shift. I think you will be aware of the desirability of some fluid cushioning device between the oil engine and the transmission, but this, of course, is only a long range experiment. On the subject of copper-lead bearings, we have noted your remarks in regard to the condition of the Babbitt flashed copper-lead, which you claim has reached the limits of capability. We are, however, carrying out destruction tests at some later date, and also have arranged for a certain number of vehicles to be fitted with "Tri-metal" and copper-lead bearings for the purpose of comparative test under road service conditions. When you were examining the 12-cylinder O.E. unit you commented on the hydraulic tappet arrangement fitted and the reasons why this was adopted. This goes back to some discussion we had at the time of inception of the design, when it was stipulated that tappet adjustment should be taken out of the hands of the inexperienced fitters who handle these units in the field, and also that there should be no doubt that tappet adjustment would not be required while the unit was installed in the tank, where adjustment was virtually impossible. We have not had the time fully to investigate the reason for the pumping up of the hydraulic tappets on this engine, as we must progress with other parts of the development work, but if you could let us have details or a sample of the rocker type hydraulic adjuster, it would be well worth while considering fitting a set of these at a later date. As we carry out the modifications to the timing gears we will let you know what the results of the various steps are, and particularly in regard to any damper experiments which are carried out. We will certainly be interested to receive your criticism of the critical speed of the 12-cylinder shaft, based on information which you have available. Fuel pumping under high temperature conditions in tanks is a problem which I think we will have to face, and we should be glad to have an opportunity of seeing the electrical curve for the delivery pump which you told us about during your visit. I think the above covers the points on which you required information, and perhaps at a later date you will be able to come to the Works and discuss more closely the question of the 12-cylinder unit. Kind regards, Yours sincerely, | ||