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).
The construction of a baffled tube oil cooler and analysis of engine heat to water.
| Identifier | ExFiles\Box 173\1\ img221 | |
| Date | 6th February 1934 | |
| The tubes are manufactured by taking a rectangular slab of solder, say 1" x .250", and drilling holes in it where found most efficacious. The solder slab is made the required tube length and then nickel-plated to any desired thickness. When the solder is melted out a baffled tube remains, much stronger than a drawn tube, and on account of the additional turbulence given by the baffles, twice as efficient per unit area. I have samples of this, it would appear to be ideal for our purpose. So far they are not in production with this:- 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 analysing 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 c.c. 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. | ||