Journal of the Society of Motion Picture Engineers (1930-1949)

I Fig. 10. Eastman Camera and CFR L-head engine fitted with quartz window. sec and flywheel rim velocities of about 47 ft/sec the numbers and degree division marks were sufficiently clear that readings to the nearest one-half crankshaft degrees could be made on each picture. An example of the results obtained by using the fluorescent frame, the Linagraph Pan film and the short focal-length lens is shown in Fig. 9. When the opportunity presented itself in 1951 a newer engine more nearly like the modern automobile engine was equipped with a quartz head (Fig. 10). The work on autoignition was transferred to this engine with three alterations in the photographic procedure. First, since the head of the engine was unobstructed, photoflood lamps could be used at shallow angles of incidence to illuminate the quartz frame. Second, the flywheel division marks were made narrower and longer allowing the crankshaft angular position for each frame to be determined within 0.1°. The third change in photographic procedure was brought about by the desire to obtain both motion pictures of the combustion process and, simultaneously, oscilloscope pictures of the pressure records of the combustion processes. A Fairchild oscilloscope camera was used to take the oscilloscope pictures and, in order to relate the pressure records to the corresponding engine combustion process, both a small incandescent lamp in the oscilloscope camera and a 40-w incandescent lamp in the field of view of the highspeed camera were flashed simultaneously. By having one explosion related, the remainder of the two films F. W. Bowditch: Research Photography 483