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).
Report from Cleveland Wire Spring Company on spring vibration characteristics and design.
| Identifier | ExFiles\Box 19\3\ Scan147 | |
| Date | 20th January 1930 | |
| - 2 - 950 R.P.M. Vibration steadily growing worse to a very bad peak at 990 accompanied by coil clash. Diminishing slightly to 1030, here again increasing to 1090 where there is a very bad peak with bad coil clashing and valve tossing. Diminishing from this point to 1130 where it increases to another bad peak at 1210 where there is also coil clashing. Out at 1220. 1290 R.P.M. Bad on upwards. The above are the characteristics of your present spring. The following is the chart made on the sample submitted:- 900 R.P.M. Slight vibration. 1000 R.P.M. Slight vibration increasing very slowing up to a bad peak at 1340 where there is clashing of coils and valve tossing. Bad on upwards. All speeds R.P.M. of Camshaft. The sample springs are very satisfactory from the standpoint of safe design, their stress at solid length being in the neighborhood of 100,100 lbs. per square inch, whereas we allow as a maximum 130,000 lbs. per square inch. We shall be interested in hearing the results of any tests which you might give these springs. Confident that you will adopt them as your production springs, we are Yours very truly, CLEVELAND WIRE SPRING COMPANY J.L. Whiteman Engineering Department. Copied Jan. 20/30 | ||