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).
Technical paper discussing the history and limitations of stroboscopes and introducing the 'Stroborama'.
| Identifier | ExFiles\Box 155\3\ scan0134 | |
| Date | 1st March 1937 guessed | |
| FOREWORD. Capacity for perfecting or improving mechanisms depends largely on adequate equipment being available to the research engineer. Mechanisms, apparently perfect in design and construction while at rest, often develop faulty operation when set in motion, so it becomes very important to learn how the elements of the mechanism are performing, in order to discover the cause of the trouble and correct the specifications. STROBOSCOPES OF THE PAST. A method of research has been known and used for over thirty years, employing instruments called "Stroboscopes". These instruments are adapted for the observations of mechanisms while they are in motion, making them appear stationary or moving at a very slow rate of speed. This is obtained by a vibrating or revolving shutter, or by a flashing light. The instrument is synchronised so as to give a very short glimpse of the mechanism under observation, each time the moving part comes to the same position in its cycle. If the number of glimpses per second are sufficiently frequent, the successive images merge into an uninterrupted view of the moving part under observation. This is due to the phenomenon called "persistency of vision". The eye retains for a very short time, the impression of the image that has been presented. Stroboscopes of the shutter type are not practical, except for a few specific cases, where clear vision is not necessary. Observation is possible only by one observer, and from only one position. In ordinary Neon Tube stroboscopes, light flashes are produced by the discharge of an electric spark through the tube. The mechanism very much resembles the ignition circuit of an automobile engine. A contact breaker produces passages and interruptions of a low-tension current in the primary winding of a coil, creating in the secondary winding an intermittent high-tension current, which is led to the electrodes of the Neon Tube. Since the light producing current must pass through the points of the contact-breaker, the amount of current must, of necessity, be kept very small, therefore the illuminating power is very limited. This makes it necessary for the experimenter to work in a darkened room, and, furthermore, the field of illumination is so restricted that it prevents observation of mechanisms of substantial sizes in their entirety. Finally, working near high-speed machinery in a darkened room is not only dangerous, but it has a detracting effect on the efficiency and the acuteness of perception of the experimenter. NECESSITY OF STRONG, EVEN ILLUMINATION: Good efficient work can be accomplished only under normal conditions, the prime requisite of which is an abundant light, evenly diffused. Daylight is our normal working condition, and if artificial lighting is necessary, powerful electric lights are installed with light diffusing globes in order that workers may have a clear view of their tasks. A draftsman would not be expected to work under the light of a pocket flashlight: the drawing office is provided with either plenty of daylight or with strong electric lamps with their light well diffused to minimise shadows on the drawing board. This illustration is mentioned, since convenient and accurate stroboscopic observations likewise require a powerful well diffused illumination, and the effects produced by all other stroboscopes as compared with those of the "STROBORAMA" may only be likened to a pocket flashlight as compared with daylight. THE STROBORAMA OF THE PRESENT AND FUTURE In common with other stroboscopes, the "STROBORAMA" uses flashes of light through a Neon Tube, - but here all similarity between it and other stroboscopes definitely ends. The Neon Lamp of the Stroborama produces an illumination of 1000 candle power. The lamp and its reflector are purposely constructed to diffuse the light evenly over a very large area. Not only does this prevent excessive shadows and approaches normal daylight conditions, but large mechanisms, such as an entire engine, or an entire car, may be studied conveniently in any of their parts. In fact, the light is so powerful that it overcomes the Page 1. | ||