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).
Tests of Spectre engine water flows with modified crankcase passages and different water pumps.
| Identifier | ExFiles\Box 4\1\ 01-page333 | |
| Date | 25th April 1935 | |
| To E.{Mr Elliott - Chief Engineer} c. to Mor. c. to Hy.{Tom Haldenby - Plant Engineer} x 30D HM{Capt. W. Hallam - Head Repairs}/Swdl.{Len H. Swindell}2/KW.25.4.35. SpectreCodename for Phantom III Water Flows. Tests have been carried out with the modified crankcase water passages to Lec.4074 both with the original small pump and the larger pump to Lec.4162. In conjunction with the results obtained on the original system we are enabled to define the actual improvement due to the modification of the passages and the difference between the two pumps. Comparative flows, together with the temperature rise across the engine are shewn on SP.{Mr Spinney}16, these curves being taken with a tank in place of the normal radiator, a 1 1/2" diameter inlet pipe to the pump, the thermostat diaphragms removed and the inlet temperature kept constant at 70°C. As a guide to what are satisfactory figures obtained on a "proved" system, the results of the tests on the Phantom unit are quoted as follows; at full throttle, running at 500 r.p.m. a 13°C. temperature rise across the engine, down to a constant figure of 9°C. - 10°C. at the high speeds. The increased freedom through the water passages by the modification Lec.4074 has resulted in a considerable increase in the flow at all speeds with a consequent lower temperature rise across the engine. At 500 r.p.m. the temperature rise is reduced from 42°C. to 18°C. by the increased flow from 21 lbs/min. to 47 lbs/min. and at 4000 r.p.m. from 13.5°C. to 10.5°C. and 325 lbs/min. to 425 lbs/min. The temperature at the rear end of the cylinder head running at full throttle is an average of 9°C. - 10°C. higher than at the front outlet. Rather than correct this by blanking at the front end, which builds up back pressure in the system, it would be better to increase the outlets from the rear end of the head, together with less restricted top rails, the restrictions in the latter being the support bosses which surround the fixing studs. By removing the oil cooler matrix the increased flow is such that with the small pump an almost ideal temperature rise of 14°C. is obtained at 500 r.p.m. and 10°C. at 4000 r.p.m. | ||