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 reduce heat and noise, such as a double dashboard, rubber floor mats, and a shorter gearbox undersheet.
| Identifier | ExFiles\Box 74\3\ scan0146 | |
| Date | 30th July 1925 guessed | |
| -5- Oy5-W-78023 (3) (Continued) at a point closer to the wheel than formerly, leaving the circulation of air around the crankcase unobstructed for the sake of keeping the oil cool and the engine accessible. (4) A double dashboard built up of two plates with a 5/16 air space between with an entrance for cool air near the top. We have carried out this scheme on a car owned by a Californian owner who complained of heat in the cowl. This was a very early car which has been driven across the continent three times. The effect of the double board is very satisfactory, the dashboard in the cowl only getting comfortably warm in the hottest weather. Sketch enclosed. (5) One piece rubber mat in front compartment Several owners have fitted these on their own initiative and report excellent results in reducing heat. We are shortly going to try this out in a closed car. The mat will be corrugated transversely and clipped to the floorboards; the rubber can be obtained at least 3/16 thick, beaded with leather at the edges. We think this will (a) Keep the front floorboard much cooler. (b) Stop hot drafts from the joints of the boards. (c) Reduce transmission noise considerably. (This is the chief function of the one piece floor mat on cheaper cars). (d) Help to prevent dirt entering clutch trunnion thrust bearing when floorboards are lifted. (e) Improve appearance and reduce cost of fitting front boards. Sketch is enclosed. (6) Reducing the length of the gearbox undersheet We have the impression, which is so far confirmed by trial, that the protection of the reartor, etc., comes more from the depth of the undersheet than its length. We have for a trial cut the rear 17" off the gearbox undersheet and find (a) no appreciable increase of mud on the sphere, (b) a decrease in booming and transmission noise, (c) a decrease in heat under the floorboards. [Stamped over section 5 in red ink: COPY] | ||