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 cure drone issues and comparing expansion box sizes.
| Identifier | ExFiles\Box 93\1\ scan0100 | |
| 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 1 3/4" 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} | ||