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).
Packard engine tests, crankshaft specifications, and balancing procedures.
| Identifier | ExFiles\Box 173\1\ img413 | |
| Date | 6th February 1934 guessed | |
| IV This parallels Packards who run 100 hour full throttle engine tests at 4250 R.P.M. successfully. Packards have their own proving ground, they spend 1,000,000 p.a on experimental work but this includes bodies which probably account for 1/3 of the total. - They are absolutely meticulous on balance in the works, I have not seen so much trouble taken elsewhere. Crankshaft 12cyl. Pins 2 1/2 dia. 2 1/4 long Journals 2 3/4 dia. Central mains 1 3/4 long 80% balanced. Shaft length flywheel to termination of front bearing 33 11/16" 4 Bearing Shaft 80% Total balance Balancing. Shaft, flywheel etc all held to 2/10 inch oz. out of balance (Dynamic) Selective assembly of flywheel on crankshaft flange. Con rods, no final machining, held to 1/32 oz for weight. Packards say that they were forced to these close limits on out of balance | ||