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).
Overheating troubles in Australia, comparing single and two-branch exhaust systems on the 40/50 engine.
| Identifier | ExFiles\Box 38\4\ Scan080 | |
| Date | 9th April 1925 | |
| R.R. 493A (50m) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. Expl. No. Y3436 REF: Ha/Rn{Mr Robinson}/L.C9.4.25. To EY. from Ha/Rn.{Mr Robinson} c. to EP.{G. Eric Platford - Chief Quality Engineer} c. to Sg.{Arthur F. Sidgreaves - MD} c. to EJ. OVERHEATING TROUBLES IN AUSTRALIA. Y3436 X766 Bench tests have shown that the single branch exhaust system makes no appreciable difference to the heat imparted to the cooling water by the 40/50 engine. We have recently carried out tests to determine whether any over-heating was likely to occur on the road due to this substitution of a single branch manifold for the original two-branch system. The tests were conducted in exactly the same manner as those reported on in Ha/Rn{Mr Robinson}/LG25.11.24. Method B. This test has now been used on a number of occasions, and familiarity with the means employed has enabled the present results to be obtained with a high degree of accuracy. The thermometers used are special instruments made for us by Negretti & Zambra and are carefully calibrated before each series of tests. The speedometers are also calibrated. We have found that there is a slight variation in different cars of the same type, and to avoid this masking small differences, the same car was employed throughout these tests. The car was first fitted up with a single branch system, then with a double-branch system, tests at 30 m.p.h. and 40 m.p.h. being carried out. We were able to detect absolutely no disadvantage from fitting the single branch exhaust manifold. contd :- | ||