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).
Alterations and performance tests of an exhaust system.
| Identifier | ExFiles\Box 66\2\ scan0018 | |
| Date | 10th February 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -3- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/ACL/LG10.2.25 The expansion chamber nozzle - see diagm. - also distorted slightly. EXHAUST SYSTEM EXPERIMENTS CONTD :- The following alterations to the system have been made since the previous experiments. (1) The number of holes in the Intermediate Pipe have been increased by 50%. There are now 63 holes in this pipe. (2) The width of the 'fish tail' at the end of the swan neck has been increased from 6" to 9". The depth is still the same i.e. 1/4". Similar tests to the previous ones have been carried out. Curves giving the power output with the various parts and the power losses to each component are attached. From these curves it is seen that :- (a) The power difference between cutout open and closed has been reduced from 22.4 HP. to 13 HP. at 2500 r.p.m. At this speed we now get 99 HP. with the cutout closed instead of 90 HP. before the system was altered. (b) The power loss to the various component parts is now much more evenly distributed instead of as before confined chiefly to the Intermediate pipe and the 'Fish tail' of the swan neck. If during trials on the car it is thought that the system is not quiet enough, we could try decreasing the holes in the baffles contained in the silencer. Hs{Lord Ernest Hives - Chair}/ACL. | ||