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).
Technical memo discussing engine cooling systems, including oil coolers, heat transfer, water flow, and fans.
| Identifier | ExFiles\Box 173\1\ img228 | |
| Date | 19th January 1934 guessed | |
| I am forwarding you the latest Harrison large size oil cooler as I expect it is more up to date than what we have. They are emphatic that the oil cooler must stand 150 lbs. to the square inch and at normal working temperature have a back pressure of 5 lbs. per square inch. ENGINE HEAT TO WATER: I am relieved to find that on analyzing the results of all the cars they have tested at Lockport, the small cyl. does not appear to impart appreciably more B. Th.U's per cc. to the cooling water at any given R.P.M. than the large cyl., i.e., the increased heat to cooling water with 12 cyls. at any road speed need only be expected to be proportional to the reduction in gear ratio with 12 cyls., compared with 6 cyls. of the same total displacement. This can be checked by taking a heat balance of the Bentley engine because as far as I can remember, and from theoretical reasoning, it is not to be expected. Harrisons deprecate carrying too much exhaust valve port in the cylinder head as this increases heat to water. Veight Ford exceptionally bad. They are in favour of series water flow i.e., because it increases velocity and reduces the possibility of any one cylinder being short circuited due to corrosion deposit. Advantage, front cylinder in still air should run 5°F.{Mr Friese} hotter than the rear cylinder, because under road conditions air on the block cools it 5°F.{Mr Friese} more than the rear cylinder. FANS: General speed of fans on high speed engines are about 3/4 engine speed. Never 1 - 1 to avoid resonance. No patent on staggered blades. Cadillacs have developed a fan with blades which flatten out at high speeds with rubber attachments to the hub - shall learn about this at Detroit. | ||