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).
Improvements to radiators and bonnets, including square tubes, overflow valves, and bonnet vents.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan022 | |
| Date | 14th October 1930 | |
| HS.{Lord Ernest Hives - Chair} ) FROM R.{Sir Henry Royce} BY.{R.W. Bailey - Chief Engineer} ) [Struck through] Copy to SG.{Arthur F. Sidgreaves - MD} Copy to WOR.{Arthur Wormald - General Works Manager} [Struck through] E, Da{Bernard Day - Chassis Design}, Er [Handwritten and struck through] RADIATORS & BONNETS. SQUARE TUBES, OVERFLOW VALVE, & BONNET VENT. X7250 X5250 X7260 X5260 X1085 X766 SQUARE TUBES. HS{Lord Ernest Hives - Chair}' message says that the above are some degrees better than standard, but not as good as Derby expected. When I suggested this scheme I feared it would be less good than standard small round tubes, but I afterwards hoped they would be better. We cannot expect much more than reported but we may also benefit with this in other ways. (1) It will shew up better comparatively when we get air away better from under the bonnet. (2) Being less resistance to the water flow the temperature can be higher before cavitation on the suction side of the pump takes place (very important.) (3) The whole engine house will be cooler. (4) It carries less water which is better for weight, and expansion of the water, which causes loss. (5) Strong construction, and cheaper to handle in building up. (6) Better for cleaning, and repairs. Years ago we had more indirect cooling, and also crinkled tube radiators, but they were not strong, or easily repaired, and the heat under the bonnet was greater, resulting in the whole car being hotter. OVERFLOW VALVE. We have also the more important improvement in the overflow being covered by the valve, which will make a very definite difference in the water lost, and is the best of the recent improvements. BONNET VENT. I am again inclined to return to bonnet shutters as an alternative to horizontal louvres, which latter are the only ones I can tolerate. We should however improve our shutters, which are about 25 yrs. old, by using more in number and easily opened from the outside. There is no need for controls to the dash. They could be specially opened in hot weather, and always closed in cool weather (i.e. generally closed.) R.{Sir Henry Royce} | ||