American cinematographer. (1944)

Top left, Fig. 3. Top right, Fig. 4. a premium and handling is difficult the package sizes are very useful. In spite of these reductions in weight and size, the sound quality obtainable with the equipment very closely approxi¬ mates the general average of commercial sound recording. Picture quality and re¬ sults are entirely dependent upon the camera and its operation, as the only purpose which the recording equipment serves in this connection is to provide a means of driving the camera in synchro¬ nism with the recorder. In this respect the drive is identical with that provided for studio location purposes. Recorder Unit The recorder unit is the heart of the equipment. It contains the entire record¬ ing channel except for microphones, head phones and battery. The film compartment in the front houses the film movement and the gal¬ vanometer and also serves as a film magazine during operation. A rear com¬ partment readily accessible by opening the rear cover, houses the driving motor, amplifier and all of the miscellaneous equipment required to complete the re¬ cording channel. Control panels are lo¬ cated in the top of the box with all of the voice controls, such as the mixer, volume indicator, meter switches, etc. at the operator’s left, and a power panel controlling the motor systems at the right. The case is constructed in such a manner as to make all of the various ele¬ ments quickly and easily accessible while at the same time being of sufficiently sturdy construction to withstand the kind of treatment which it is apt to get under field conditions. Figures 3 and 4 show two views of the recorder unit. Figure 5 shows the control panels in the top of the recorder unit box. When not in use these control panels are cov¬ ered by doors which swing out of the way to make the control panels avail¬ able for operation. Film Drive The film drive employes a single sprocket which acts as a combined pull¬ down and hold-back sprocket and a re¬ cording drum, which is controlled by a flywheel system of the rotary stabilizer type. The take-up clutch is mounted on the sprocket shaft and has provision for adjustment from the film compartment. The clutch drives the take-up spindle through a silent chain. All of the various rollers associated with the film drive are mounted on a re¬ movable plate. To use either 35mm or 16mm film the proper plate is installed and the corresponding sprocket is placed on the sprocket shaft. Film Handling The conventional external magazine is eliminated in this design and a form of daylight loading technique has been adopted. Film as received from the sup¬ plier is loaded in the dark room onto a reel which is composed of two flanges screwed on either end of a hub. A cover is then placed over the loaded reel with three or four feet of threading leader brought out through a slot in the cover. In this condition the reel of film may be exposed indefinitely to daylight. To load a reel of film into the recorder, a film reel with its cover in position is placed on the feed spindle and all of the thread¬ ing operations are carried on with the reel cover in position. When the thread¬ ing is complete the reel cover is removed and the film compartment door is closed. Unloading is done in the reverse fashion, that is, the film compartment door is opened and a reel cover placed in posi¬ tion on the take-up reel. A loading bag is supplied which covers the entire re¬ corder during the reel cover removal to prevent light striking the film. It was the original intention that gray anti-halation film stock should be used. In this case the use of the loading bag was unnecessary except under extreme light conditions. However clear base film is now a standard in the Services so that the use of the loading bag is specified for all loading and unloading operations. The film reel parts, loaded reels, film covers, film supply and loading bag are carried in the film unit, Figure 2. The use of this form of film reel and the Fig. 6 elimination of the conventional magazine makes quite a saving in weight and size of equipment and offers no more diffi¬ culty in operation than in the use of 16mm. or Eyemo camera equipment. Motor Drive System Both recorder and camera driving mo¬ tors are a special design of the cQnven- tional DC interlock type, operating from 24 volt direct current derived from the storage battery unit, with a three phase, 24 cycle, 110 volt interlock supply derived from auxiliary windings in each motor. The four pole recorder motor, which is an integral part of the recorder unit, oper¬ ates at 1440 RPM. The two pole camera motor operates at 2880 RPM. Field rheostats controlling the speeds of the (Continued on Page 243) American Cinematographer • July, 1944 225