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).
Test report on running a 12-cylinder car on 6 cylinders, comparing performance and crankshaft weights.
| Identifier | ExFiles\Box 127\2\ scan0033 | |
| Date | 12th December 1933 | |
| To Sg.{Arthur F. Sidgreaves - MD} From Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. By.{R.W. Bailey - Chief Engineer} Rn.{Mr Robinson} RUNNING A 12 CYLINDER CAR ON 6 CYLINDERS. We arranged with Rn.{Mr Robinson}, at the request of E.{Mr Elliott - Chief Engineer}, to make a test running a Lincoln car on six cylinders. The car was the same as we tried previously. We found that it was geared 4.23/1 on top which is equivalent to just over 65 M.P.H. at 3000 R.P.M. Running on six cylinders we attained 55 M.P.H. on top which is equivalent to about 2500 R.P.M. On running downhill we managed to reach 55 M.P.H. on second speed, which represents about 4500 engine R.P.M. At no time during the test were we able to pick out a crankshaft period of any magnitude, in fact the engine was almost as smooth on 6 cyls. as on 12 cyls. It is difficult to believe that we reached the master period; on the other hand, since on a 12 cylinder engine the disturbing influences are due to the gas torque only, it might possibly be that this is of no appreciable magnitude when running well over the power peak, and with six idle pistons assisting in damping it. We have to observe, however, that we do not know what percentage balance there is on the Lincoln shaft. We are assured that it is balanced by the London agents. The crankshaft weights, which give some indication as to the possibility of balance are as follows. Present P.II. Standard Shaft Balanced. 100 lbs. SpectreCodename for Phantom III. Estimated Weight. 70 lbs. Lincoln Weight. 93 lbs. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||