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).
Chassis Alteration No. 7, proposing to replace the Klaxon horn with a Sparton S-O-S DeLuxe and relocate its mounting to the cylinder head.
| Identifier | ExFiles\Box 64\3\ scan0297 | |
| Date | 6th February 1929 | |
| H/S X7550 thor [crossed out] OY7- February 6th, 1929. Mr. A.F. Sidgreaves, Rolls Royce Limited, London, England. [crossed out] cc - Mr. Royce Derby Works ✔ Dear Mr. Sidgreaves: Report on Chassis Alteration No. 7 RE Horn on Cylinder - Section 7360 Cause for Alteration. Of recent years the "tone" of the rotary Klaxon horn and its failure to clear the road in emergencies (particularly in winter when the shutter is wholly or partly closed) has been a source of considerable complaint. After trying various types of horn including the Robert Bosch, American Bosch, Klaxon "buzzer", etc. we found that the Sparton "S-O-S DeLuxe" gave results most acceptable to the Sales Department and customers. A number of these have been fitted and have been well received by the public. Alteration. In the course of these tests horns were several times fitted to be carried off the cylinder head bolts instead of the dashboard. It was found in every case that the noise within a closed car when the horn was sounded was very much less in the former position. It is therefore proposed to carry the horn off the cylinder head as shown in attached photographs. The horn there shown is the Sparton S-O-S DeLuxe. In order to show the mounting clearly this has been mounted on an unfinished engine with aluminum head not enamelled. -continued- | ||