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).
The investigation and resolution of a 30 m.p.h. exhaust boom issue on a trials car.
| Identifier | ExFiles\Box 104\2\ scan0143 | |
| Date | 26th September 1935 | |
| X523 To Gg. & Nor. a.{Mr Adams} to H.{Arthur M. Hanbury - Head Complaints} b. to By.{R.W. Bailey - Chief Engineer} c. to CX.{Major Len W. Cox - Advertising Manager} d.{John DeLooze - Company Secretary} to Dr. e.{Mr Elliott - Chief Engineer} to JLL. f.{Mr Friese} to Hd.{Mr Hayward/Mr Huddy} HS{Lord Ernest Hives - Chair}/Rn.{Mr Robinson}H/KN.{D. G. McKechnie - Sales}26.9.35. 30 m.p.h. Exhaust Boom, H.{Arthur M. Hanbury - Head Complaints}/25's. It will be remembered that this complaint was raised at the last Conference at Derby and we agreed that if a Trials car could be found with the trouble we would go down and investigate it at Cricklewood. It will be recalled that when the problem was first mentioned a little time ago, we pointed out that we had a modification in the shape of a small extension at the end of the tail pipe, which in our opinion greatly reduced the boom, and asked that this should be tried. As a result of the tests made in London it was decided that the modification did not make any appreciable difference. We found that GSP-4 was a typical example of the exhaust boom as we know it. The boom was distinctly audible in the front seat at the correct throttle opening over a range of about 2 m.p.h. It was barely detectable in the back seats at all. Without wishing to belittle the complaint, an indication of its magnitude is given by the fact that the driver of GSP-4 had carried out over a 100 trials runs and had never had a case where anybody had previously noticed it. We agree, however, that once it had been noticed it might be considered very annoying. We have fitted the extension to the tail pipe and in our opinion the improvement effected was something more than 50%. We demonstrated the result both to the driver of GSP-4 and Messervy of Cricklewood. We are having two or three of these extensions made and plated so that they can be tried on customers' cars. | ||