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).
Tests on a Phantom II model to address a 'boom' noise by trying a stiffer flywheel and crankshaft flange.
| Identifier | ExFiles\Box 137\4\ scan0237 | |
| Date | 2nd March 1931 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to Sg.{Arthur F. Sidgreaves - MD} Mor. c. to E.{Mr Elliott - Chief Engineer} Ds. c. to By.{R.W. Bailey - Chief Engineer} x634 Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}15/KT.2.3.31. x634 r°300 BOOMS ON P.II. Replying to your R.3/M23.2.31., we are going to try a stiffer flywheel back plate and crankshaft flange as soon as possible. Before receiving the LeC. scheme for this in conjunction with 4 balance weights, we decided to do it to the accompanying Hs.{Lord Ernest Hives - Chair} drawings, parts for which are now being made. We shall therefore try a stiffer flywheel by itself and also fixed to a stiffened crankshaft flange. We have carried out some tests to your suggestion of using an Electric Motor with an out-of-balance shaft to find the periodicity of the boom at 30 M.P.H. We did this on the road by driving the car continuously at 30 M.P.H. in 2nd gear and then running up a 20 HP. starter motor with an out-of-balance mass on its shaft, until we got a beat note with the car's boom. These beat notes occurred at 1 1/2 times and twice engine speed. A considerable difference of opinion exists as to which was the more pronounced. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||