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 conducted to understand power losses in the Phantom II exhaust system.
| Identifier | WestWitteringFiles\W\September1931-November1931\ Scan066 | |
| Date | 2nd November 1931 | |
| ORIGINAL To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. to By.{R.W. Bailey - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}1/KT.2.11.31. LOSSES IN P.II. EXHAUST SYSTEM. Handwritten notes: X7^30, X5^30 With a view to getting some information with the minimum of delay as to the relative importance of various items in the exhaust system, we carried out a test with an expl. camshaft which approximately gives the same R.H. as the 114° W.W. shaft, none of the latter being available at the time. We shall repeat the tests with a 114° shaft as the first opportunity. Rn.{Mr Robinson}P33. shows that 10 HP. is lost between C.O. open and open exhaust. Rn.{Mr Robinson}P35 shows that this is mainly due to the front expansion box, downtake and intermediate pipe. These pieces "grew up" when we were originally working on the 50 - 60 M.P.H. boom, they may be necessary but we are now going back to a "straight through" from the manifold to the main silencer to see if it as bad as we originally thought before the diamond mounting. was evolved. The other item, which was not altogether expected, was the loss in the fish tail; recent tests on the 25 HP. have confirmed that the P.II. fishtail does not seem much too large for this unit. One thing we noted during these tests was that the exhaust valves disliked the full exhaust system at full throttle. We hope to be much happier in this respect on 18.C.IV. the next 10,000 miles car, with the new design of exhaust valve and the reduced exhaust back pressure. The fact that 25-EX was not fitted with a cut-out, on the last 10,000 miles, may have increased our exhaust valve difficulties. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||