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).
Modifications to the exhaust system to resolve an exhaust drone and questioning the sizing of the front expansion box.
| Identifier | ExFiles\Box 86\3\ scan0212 | |
| Date | 15th October 1937 | |
| -2- Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager}3/JH.15.10.37. complained of by LA.{L. A. Archer}, we have now been able to effect a 50% improvement by the following methods, (a) Increase length of front expansion box from 19" to 27". -------------------- To By.{R.W. Bailey - Chief Engineer} c. Sg.{Arthur F. Sidgreaves - MD}Wor.{Arthur Wormald - General Works Manager}Hs.{Lord Ernest Hives - Chair}Roy.{Sir Henry Royce}Sft.{Mr Swift}Mx.{John H Maddocks - Chief Proving Officer} Hs{Lord Ernest Hives - Chair}/Wym.{G. Harold Whyman - Experimental Manager} E.1/HP.13.10.36. re Exhaust System. To cure the exhaust drone at 30 miles per hour on Phantom III we wish to introduce a modification as soon as possible which involves lengthening the front exhaust box by 8", and using 1¾" dia. tail pipe instead of 2" long from the rear crossmember with a rubber link instead of the present device. ------------ We would also like to point out to the Design Dept. that we have steadily increased the size of our front expansion box during the last few years, for example :- The 20/25 car had an expansion box 8¼" x 4¼". The 25/30 car had an expansion box 12¾" x 4¼" x 3". On the Wraith we have gone to a still larger box 18" x 4". It is really past our comprehension why the design should suddenly consider that we should be happy with a box smaller than anything we have had for many years. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} | ||