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).
Letter detailing cooling issues with the Phantom III car, including hot air escape from the bonnet and a discussion on oil coolers.
| Identifier | ExFiles\Box 149a\3\ scan0170 | |
| Date | 16th June 1936 | |
| -3- Hs{Lord Ernest Hives - Chair}/Std.17/KW.16.6.36. Finally, the cooling of the Phantom III car while stationary is bad; i.e., after a fast run the car will boil if left idling for approximately five minutes, even with the air temperature as low as 10°C. We appreciate of course that this is mainly a question of size and speed of fan. As regards the escape of hot air from under the bonnet, the exits are (1) a gap approximately 3" wide extending the width of the radiator at the base of the radiator, (2) two gaps at the base of the dashboard, each approximately 60 sq.in. in area, discharging in front of and below the gearbox, (3) Louvres in the engine sideguards or undersheets; these give a total exit area of 28 sq.ins., (4) bonnet shutters or louvres - in the case of the shuttered bonnet these consist of three equally spaced doors along each bonnet side, giving total outlet area of 78 sq.ins. In the case of the louvred bonnet the bonnet sides are louvred for the whole of their length and give an outlet area of 287 sq.ins. Turning to the question of oil coolers, your latest type of cooler is certainly a tremendous advance on any other type, particularly as regards strength. We should very much like to receive a specimen of such a cooler from yourselves if that is possible. Judging by the dimensions given on your photograph we could easily fit an eight-plate cooler to our engine (attached is a drawing showing our present matrix size). We shall also be very grateful for information as to manufacture, structural details, etc., as promised in your last letter, especially with regard to the method of hydrogen brazing. There is one point which we should like you to clear up for us, and that is, the reason for the plate with holes of varying sizes which is fitted externally on to the Viscon element of the Buick cooler, so that the circulating water has to pass through it. This is presumably some form of distributor, but we are unable to see a reason for it. We apologise for troubling you with so many drawings, but we have endeavoured to include all necessary data for you to be able to form an opinion as to the reasons for our cooling difficulties. We should like to thank you for the help and information which you so willingly give us from time to time. Yours faithfully, FOR ROLLS-ROYCE LIMITED. | ||