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).
Article from 'The Autocar' magazine detailing vehicle testing equipment and procedures for vibrations, cold/hot conditions, and performance.
| Identifier | ExFiles\Box 160\3\ scan0237 | |
| Date | 3rd February 1939 | |
| February 3rd, 1939. The Autocar 183 connection with transmission tests is to ascertain quite how much of this intensive maltreatment should be withstood, since, in the normal life of a car, full torque on first gear is seldom employed for long. This ratio can only be determined by running in conjunction innumerable endurance tests on the road. I enquired as to the relationship disclosed between the b.h.p. of the engine and the b.h.p. delivered at the wheels. The reply was that a good car delivered rather over 80 per cent. of the engine b.h.p. to the road, counting all losses, including tyres. Further, I gathered that very wide differences are exhibited between cars of all makes. Some years ago a case was recorded of a foreign car which delivered only a shade over 50 per cent. of its engine power to the road wheels. This was traced to the fact that its particular form of worm final drive did not lend itself happily to such extremes of testing, although it performed reasonably under less arduous road test conditions. Despite our grumbles at the weather we do not know what it is to be really hot or really cold in this country, but Rolls-Royce cars have to perform faultlessly in any and every climate. Hence the experimental department has a large cold chamber, which can also be used as a hot spot. This room, with its foot-thick insulated walls and doors, is big enough to take any two of the largest passenger cars produced to-day. The temperature can be reduced to rather lower than 20 degrees below zero, a process which takes the greater part of 24 hours if cars are inside, because the cars themselves have to grow cold. Observers who go “Third Degree” into the cold chamber through a “sealing” chamber, have to wear arctic clothing whilst carrying out their work. In addition to ensuring that cars will start under conditions of low temperature, the cold chamber is invaluable for testing piston “scuffing” and crankcase oil dilution from wet residual petrol, which are by-products of cold starts. Conversely, by circulating hot instead of cold air, conditions may be raised in the chamber suitable for the causing of vapour locks in fuel pipe lines or fuel pumps, such as may occur in hot climates. Lastly, as the chamber is so heavily insulated, it is also used for silence tests. With the apparatus known as the “joggler” many readers will already be familiar, because many wise garage proprietors have it installed. It consists of four troughs into which the wheels of the car are placed. Each trough is carried on a battery of half-elliptic springs, between which is mounted a bob-weight driven by a jointed shaft from an electric motor. When the motor is started the rotating bob weights causes an oscillation of the troughs. The frequency of this oscillator can be varied from 100 to 700 per minute. Primarily this rig is employed for the purpose of inciting frame and road-spring resonance, with the object of investigating chassis vibrations and steering phenomena, but it can also be used for chasing bodywork squeaks and rattles. The joggler, when in full frenzy, looks as if it were able to shake the teeth off the gear wheels! (To be continued next week.) [Image Caption] Investigating chassis vibrations and steering phenomena. “The ‘joggler,’ when in full frenzy, looks as if it were able to shake the teeth off the gearwheels.” BEHIND THE SCENES Rolls-Royce and Bentley Testing Equipment [Image Caption] (Above) A specially made chronograph for obtaining accurate data of car acceleration and deceleration. [Image Caption] (Right) Brake - lining analyser, for determining the coefficient of friction. C 3 | ||