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 an exhaust system to reduce booming noise on chassis B.162.LS.
| Identifier | ExFiles\Box 131\2\ scan0196 | |
| Date | 11th June 1938 | |
| To By.. from GWH.{George W. Hancock - Head Chateauroux} c. Rm.{William Robotham - Chief Engineer} c. Hd.{Mr Hayward/Mr Huddy} c. H.{Arthur M. Hanbury - Head Complaints} c. Hs.{Lord Ernest Hives - Chair} Re: Chassis B.162.LS - A.Hartley,Esq., At the request of H.{Arthur M. Hanbury - Head Complaints} who has been in communication with Hd.{Mr Hayward/Mr Huddy} and Messrs.H.R.Owen, re the above car I again tried the car on June 4th. This was to get an impression of reduced booming by the fitting of an exhaust fish-tail knocked up by Messrs.Gurney Nutting. The fish-tail was made of a piece of piping the same size as the present snout, with the end flattened out to an aperature of approximately 1¾" x ¾", the end coming to just beyond the bumper bar. The result of this snout was a distinct improvement in the reduction of the boom right up the scale, but on the over-run there was a deep boom at 50 m.p.h. Having agreed that the boom was considerably reduced, I came to the conclusion that it was not due to the shape of the snout, so much as getting the beat of the exhaust away from the body. I therefore fitted an extra standard snout extension which brought the tail pipe approximately level with the rear bumper bar. This gave the same effect as Gurney Nutting's mock up fish tail. The reduction of boom being 50%. If this is satisfactory to the Owner, a standard extension snout of increased length can be fitted.(The present arrangement is hardly noticeable). With regard to the assumed axle noise, there is no axle noise that anyone could take objection to. I satisfied myself that by reducing the rear tyre pressures to 20 lbs. the noise was doubly increased, and by making the tyre pressures 32 lbs. decreased the noise considerably. The car has been returned to Messrs.H.R.Owens, and we are awaiting their comments. GWH.{George W. Hancock - Head Chateauroux} | ||