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 from Rolls-Royce of America to the UK discussing valve spring surge, referencing external papers, and requesting harmonic analysis of a cam layout.
| Identifier | ExFiles\Box 56\2\ Scan076 | |
| Date | 2nd May 1929 | |
| ROLLS-ROYCE OF AMERICA, INC. SPRINGFIELD, MASS. Y290 OY 6 May 2nd, 1929. Mr. Robotham, Rolls Royce Ltd., Derby, England. Dear Mr. Robotham: VALVE GEAR - SECTION 5060 I attach a copy of Donkin and Clark's paper on valve spring surge which was published in S.A.E. journal for March 1929, and Jehle and Spiller's paper from the February journal. The Cleveland Wire Spring Co. have been making valve springs for us, and they have not been successful as regards silence. Donkin has now asked us to send them a set of valve gear so they can run it on their telemeter testing rig and give us a spring such as they could recommend with full knowledge of the conditions. They are not asking us for our cam form which I should not want to give them anyway. CAM. If you will notice the two papers, Jehle gives more attention to cam-form, and Donkin to spring design. Both however insist on the necessity of making an analysis of the cam-layout from peak to peak, to determine the harmonic series, and to find which of the harmonics are dangerous and whether any of them can be reduced. It strikes me that it would be extremely useful to have one of your mathematical wizards make such an analysis of our present valve lift form, giving the components up to say the 30th harmonic. I do not know how to go about it. In making this please note that, as pointed out to By.{R.W. Bailey - Chief Engineer} some time ago, our master cam layouts are not accurate, and instead of them one should presumably take the basic acceleration figures given in By/Cgh{W Clough}9/H.17.6.26. -continued- | ||