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).
Page discussing engine cooling challenges in large cars and the possibilities and limitations of cooling fans.
| Identifier | ExFiles\Box 178\1\ img033 | |
| Date | 15th February 1926 guessed | |
| - 17 - (e) Handicap of large car As we have previously shewn, a large engine gives less heat to the cooling water per B.HP. generated than a small engine of similar design. It may therefore be a source of surprise to the average person that large cars suffer from over-heating complaints while small cars are often immune. The answer to this problem is that the permissible frontal area of radiator on a car does not increase in the same pro-portion as the engine dimensions. To cite a concrete instance, the 10 HP. Fiat car has a displacement of 1460 c.c. and to ensure adequate cooling, the makers have provided it with a matrix face area of 302.7 sq.in. The Phantom engine displaces 7660 c.c.'s so that propor-tionately it should be provided with a face area 5 1/4 times that of the Fiat or 1760 sq.in. which is manifestly an absolute impossibility. Actually, the present radiator on the Phantom, which is about the largest practicable, has a face area of only 510 sq.in. while the Hispano has 554 sq.in. (4) POSSIBILITIES AND LIMITATIONS OF FANS. (a) Difficulties of fan drives. A fan is an invaluable asset to a cooling system at low speeds when the velocity of the car through the air is insuffi-cient to ensure an adequate flow of air through the radiator. The main difficulty with a fan is to provide an adequate drive. The reason for this is because the power required to drive a contd. | ||