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).
Test report on radiator and bonnet modifications, focusing on cooling efficiency and bonnet knocking.
| Identifier | WestWitteringFiles\W\May1931-August1931\ Scan096 | |
| Date | 5th August 1931 guessed | |
| -5- RADIATORS to LOP.E.81428. (2 RADIATORS) STAYBRITE FINISH. RADIATOR SHUTTERS AND CONTROLS to LOP.E.81007 - LeC.2799. (1) 1 Complete to the above LOP. using .268 Hexagon Matrix Tubes. (American) (2) 1 Complete to the above LOP. using .312 Hexagon Matrix Tubes. (American) (3) Anti-Splash Radiator Cap to LeC.2899. (4) Double Stay Tube fitted between Radiator and Dash to Hs.{Lord Ernest Hives - Chair}367. We brought out an extra radiator with smaller hexagon tubes to compare the cooling efficiencies of the radiators. We have carried out numerous tests and fully reported the results to Derby. We have run the majority of our mileage with the large tube radiator. The cooling efficiency of this radiator is a definite improvement over any other previous radiators we have tried in France. On well known stretches of roads with approximately the same air temperatures, we have not boiled with this radiator, whereas we previously boiled. The present radiator, however, does not cope with the water temperatures under certain conditions. During our tests on the Col-de-la{L. A. Archer}-Faucille, we overtook and could not pass a large charabanc proceeding up the hill. We had to drop into 3rd. gear and proceed at a speed of approx. 15 MPH. The water started to boil in a very few moments and continued to boil during the following of the vehicle. We have again experienced this feature when having to follow traffic, at a slow rate. We have found that with the small tube radiator, we get an advantage of 3° cooler. The bonnet shutters were open with the above conditions. BONNET to LOP.E.80836. E.81914 Bonnet Fastener Springs 100% Stronger than standard, fitted to off-side Catches of Bonnet. New Side Plates fitted with Shutters - 3 each side to N.S.3233. We have reported that we get an a fair amount of pressure under the bonnet. With the bonnet shutters open, and travelling at 60 MPH. the two sides of the bonnet are forced open at the bottom approx. .125". With the shutters closed the opening is increased to .375". In conjunction with our tests with torque reaction dampers and radiator mounting, the knocking of the bonnet was also gone into. We found that with the double stay tube fitted between the radiator and the dash, the stay had a period of its own, which caused a period of rapid oscillation of the radiator. This had a tendency to cause the bonnet to knock. We replaced the double stay by a standard stay, and | ||