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).
Recurring crack in a Phantom engine crankcase during test bench runs.
| Identifier | WestWitteringFiles\P\2July1926-September1926\ Scan213 | |
| Date | 24th September 1926 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. to BJ. Wor.{Arthur Wormald - General Works Manager}✓ c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer}✓ c. to DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer}✓ ORIGINAL HS{Lord Ernest Hives - Chair}/ACLL/LG24.9.26. RE. CRACK IN PHANTOM CRANKCASE. X8000 A crack has developed in the upper half of the crankcase of a Phantom engine (test bench). It is at each end of the web carrying the centre main bearing and on one side passes through the bore for the oil pump drive (see appended sketch). We have experienced this trouble before on Phantom test engines after severe running and the crack is always near the same place. This particular engine has done about 750 hrs. on the test bench and it was only after approximately 30 hrs. full throttle piston and bearing tests at 2800 to 2900 r.p.m. that the crack was detected. The last part of the running has been at speeds above 3000 r.p.m. and under these conditions the crack increased. The test engines are carried by the normal three point suspension on the test beds and it seems to be the result of high speed work that causes the trouble. The cylinder blocks would tend to stiffen the crank-case, except at the centre over the main bearing, also the cyl. head. It would be imagined however that considerable more rigidity would be possible with the cylinders in one block like the 20 HP. This would mean it would be more difficult to handle due to the weight but once fitted there is contd :- | ||