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 principles, types, and benefits of engine air cleaners, including fitting instructions for a specific model.
| Identifier | ExFiles\Box 135\4\ scan0092 | |
| Date | 8th February 1926 guessed | |
| It is quite apparent that the most desirable Air Cleaner for your car is one having a high, over-all efficiency, viz.: one having a high cleaning efficiency at all engine speeds; one which preserves the full power of the engine; and one which does not affect the lubricating oil detrimentally; and in addition, one which requires a minimum of attention. Now for some of the technique of the various types of cleaners, in a brief way. Outside of the air washers, which employ water for removing the dust, practically all readily available Air Cleaners on the market are of two types, either the filter or whirler principles being used. The whirler type is the development of the old time “sawdust-and-shavings cyclones,” which sets up a whirl in the air column, and removes the dust particles by keeping them on the outside of the column—by batting or fanning them out, as it were, rather than throwing them out, as would be the case with a truly centrifugal action. The principle of the whirler is one of circumferential velocity, and as velocity is always accompanied by resistance, or stated in another way, as resistance is always a function of velocity, and one varies with the other, it is quite evident that the higher the velocity, the greater the resistance will be. The resistance, however, does not vary directly as the velocity, but as the square of the velocity so that if you have a velocity resistance of six-tenths of an ounce, when the air is traveling four thousand feet per minute, and you increase the velocity to five thousand feet per minute, the resistance will be 5000² divided by 4000² times .60 or .94 ounces. And if you further increase the velocity to six thousand feet per minute—which represents the maximum speed of the air passing into the average carburetor at maximum engine speed—the resistance is as 6000² is to 4000² times .60 ounces, or 1.35 ounces. This, however, is only a part of the resistance which the engine must work against, but it is an essential part, which the carburetor manufacturer has considered in proportioning his fuel passages. [Image of an engine] FORD Price with fittings in U. S. east of Rocky Mountains $6.50 DIRECTIONS Just before attaching cleaner, dip in waste crank case oil. Unscrew, and screen part can be removed from base for this purpose. After draining a minute, attach, and leave alone for about 10,000 miles. It is easily cleaned, by simply repeating the process. It inhales enough oil from underneath the hood to keep wires in condition to attract dust. In the morning, a back-fire or two, will usually blow off all surface dirt. It is the only cleaner that will prevent back-fires from setting fire to your car, as it is built on much the same principle as the Davy miner's lamp. “The Crimp Does It.” 1—No perceptible air resistance. 2—Practically 100% efficient. 3—The most compact and lightest. 4—Can never cause owner trouble. [Image of an air filter] 5—Has no moving parts. 6—No change of carburetor adjustment. 7—Prevents flame from back-fire. 8—Easiest to get at and clean. 9---Muffles carburetor noises. | ||