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).
Summary and conclusion of cooling tests for the Phantom III car, proposing improvements such as a new radiator matrix, louvred bonnets, and a flexible fan.
| Identifier | ExFiles\Box 155\1\ scan0230 | |
| Date | 10th June 1936 | |
| -2- Hs{Lord Ernest Hives - Chair}/Std.13/KW.10.6.36. (4) The "lamp-post" float chamber vent scheme as on 20/25 works perfectly well on Ph.III, no difficulty being experienced in starting after switching off and waiting for 3-4 minutes after a full throttle run. Summary. The Ph.III car as it stands at the moment is definitely under-cooled; especially at low speeds, but we do not think that the matter is as serious as the test results indicate at first sight - see remarks at end of report. The Mark VI matrix should be standardised at the earliest possible moment and louvred bonnets should be available for Continental conditions, the only objection to the Mark VI matrix being that it may increase our fuel starvation troubles. On the track, the starvation was definitely worse with the Mark VI radiator than with the Mark V one. We propose to attempt to develop a flexible blade type of fan of either larger size or higher speed, with a view to improving low speed cooling while retaining a reasonable degree of silence. The 20/25 scheme of float chamber vent works perfectly well on the Ph.III carburetter. In conclusion, we would point out that the track cooling tests represent an extremely arduous condition which would never be met in this country, and that although we were unable to obtain actual test figures as explained previously, we estimate that the critical air temperature with the Mark VI radiator and standard flip-flap bonnet, under full speed conditions, would be approximately 30°C. Further, the critical air temperature figures are best used to estimate relative cooling. On the attached sheet are shown critical air temperature figures for the Ph.II car previously obtained at Brooklands. From comparison of these it is seen that the Ph.III cooling is not greatly inferior to the Ph.II cooling, especially if a louvred bonnet is utilised. We think that this type of bonnet should be standardised, especially as the automatic tappet gear makes complete enclosure of the engine less necessary. | ||