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).
The performance of a 12-cylinder Packard car engine, focusing on crankshaft vibration and compression.
| Identifier | ExFiles\Box 127\1\ scan0076 | |
| Date | 25th February 1920 | |
| X.435 To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to Bn.{W.O. Bentley / Mr Barrington} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} Hs{Lord Ernest Hives - Chair}1/LG25.2.20. X.435. 12-CYLINDER PACKARD CAR. We have run this car, with the small friction damper on the front end of the crankshaft, removed. We find that without the friction damper on there is a distinct crankshaft period at 33 M.P.H. on the top gear which is equal to 1250 engine revs. With the damper fitted one cannot pick out any distinct crankshaft period but one can feel an engine vibration especially at high speeds. The crankshaft on this car has only 3 bearings - one at each end and one intermediate. The friction damper is approximately 8" diameter, it also does duty as a fan pulley. The compression ratio of the Packard car is 5. to 1. The compression by gauge is 95 lbs. at 1500 revs. Unless the engine is kept clean the detonations on this car are bad. Hs.{Lord Ernest Hives - Chair} R R.{Sir Henry Royce} 255 A (100 T) (S.P) 816 6-S-19 G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2460 | ||