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).
Engine performance, supercharger details, and methods for controlling oil consumption and bore wear.
| Identifier | ExFiles\Box 116\1\ scan0007 | |
| Date | 10th November 1937 | |
| -3- although the general noise level was, of course, rather high. The engine at the time was running at 1,500 r.p.m. developing 127 B.M.E.P. and full consumption .338 pts/BHP/Hr, there was no smoke from the exhaust. By holding a piece of clean paper to the exhaust we saw that the paper remained perfectly clean until it was held so close to the exhaust that it was singed. They state that they can run at 140 B.M.E.P. without smoke from the exhaust. Supercharger. This, as stated previously, was exhaust driven, at 1500 engine rpm. the blower speed was 34,000-35,000 rpm, it was remarkably free from whine. The blower was water-cooled, but they had no thermometer giving the temperature of air from the blower, they were in fact just riggin up a thermo-couple to determine this, but had not finished the job when we left. From feeling the pipes we should say the temperature was in the region of 65°-70°C. We were introduced to the representative of the supercharger people but did not get his name, nor the name of the supercharger owing to the noise in the engine room, but gathered that he had met Wd.{Mr Wood/Mr Whitehead} in Switzerland, the blower being, we believe, a Swiss product manufactured in this country. The representative stated that they had supplied two blowers to us, and that he was expecting to visit these Works within the next week or so. Oil Consumption and Bore Wear. They use a bevelled scraper ring at the bottom of the skirt to control oil, their reason for this being that they can then control the oil consumption with worn bores. They say that they have found it impossible to control oil consumption with a scraper ring above the gudgeon pin centre, how much this is due to the ring arrangement, and how much is due to the extra oil supplied to cylinders since the adoption of lead bronze bearings, we could not find out. In their opinion, the best way to control bore wear and oil consumption is to have a metered oil supply to the piston skirt fed in through the side of engine similar to our old scheme for extra oil supply and the use of a ring at the bottom of the skirt, and shields to prevent oil from crankshaft getting into the bores. They are at present using a plain 5% nickel iron material for cylinder liners, but are experimenting with various materials such as nitrided liners and "Vaorit" liners. | ||