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 comparing the cooling performance of American Harrison Film and Marston Mark III radiator matrices against the standard hexagon matrix.
| Identifier | ExFiles\Box 149a\2\ scan0023 | |
| Date | 29th June 1932 | |
| XC4516. Copy for Brooklands File. X788. Brooklands 29.6.32. The results we have obtained so far show a very big and surprising advantage by using the American Harrison Film radiator matrix; the Marston Mark III matrix is considerably better than our standard but nowhere near as good as the American. We have been running all out with a top water temp: of only 55ºC in spite of a high air temperature of 23ºC. (Lap Speed 74-75 M.P.H.) 19.G.IV. runs very well and consistently; H-14(Lodge) plugs, fitted, are very good, no preignition or other trouble, in spite of the 5.9:1 compression ratio. The fan is of no advantage for cooling all out and even at 60 M.P.H. it only reduced the temp: one degree; we can lap at 1 to 1.25 M.P.H. faster with the fan built off, we have checked this over several times. We had fan belt trouble at first due to the pulleys being over .250" out of alignment, and even after lining them up we are in trouble at top speed; we ought to do some test bed test on power absorbtion at the equivalent engine speed of 75 M.P.H. A summary of results so fae is as follows. (1) All out Conditions full bonnet ventilation. Marston Mark III is 7ºC cooler than R.R. hexagon matrix. Harrison Film matrix is 21.8ºC cooler than R.R. hexagon matrix. (2) 60 M.P.H. No bonnet ventilation. Marston Mark III is 7.5ºC cooler then R.R. hexagon matrix. Harrison Film matrix is 14.75ºC cooler than R.R. hexagon matrix. | ||