Flight Recorder MS-61

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     MS-61 (In Russian МС-61)   The aircraft recorder is designed for recording speech from a receiver or laryngophones. The design is very old, but successful, and similar modernized tape recorders P-503B (П-503Б) still produce in Nizhny Novgorod.
     Using a wire as a magnetic carrier allows a long recording time of about 5.5 hours with a wire diameter of 0.05 mm. For more efficient use of this time there is an autorun mode by the presence of an input signal. The device is controlled from the console, which contains the necessary switches and a brightness control for the backlight. Dimensions without cushion support 160 x 132 x 160 mm., Weight 4 kg. Power 27 volts DC. The speed of the wire is variable, 145 - 195 mm / sec. There is also an auto-stop, the construction of which is described below, and a wire break detector. When the wire breaks, a backup recorder is included, for which there is an appropriate connector.
     The case of the recorder itself is very durable, cast of aluminum alloy, but it was also planned to install it in an armored casing. More detailed information about the parameters of the tape recorder can be found in the instructions that can be easily found on the Internet, for example here. This tape recorder naturally only records, and for playback is intended ground MN-61 (МН-61) recorder, analogue of which P-504N (П-504Н) is also produced so far.

Photos can be enlarged

My set of tape recorder with remote control has the same serial numbers. It was made in 1969. The dimensions of the control panel are 92 x 75 x 78 mm.

The power cord has wires marked with polarity. Through the round window in the cover, you can see the rotation of the supply coil

Between the heads is a wire break detector. The wire tension keeps the sensor lever in an upright position. When the wire breaks, the lever is released and the sensor switch is triggered.

The recording and erasing heads are mounted on a plate that moves up and down, laying the wire on the spool in even rows.

The photo below clearly shows the coil springs for fixing the coils

Hitchhiking works according to the old proven principle. A flat spring is attached to the coil drum, which is pressed with a wire. When the wire on the coil ends, the spring is released and touches the annular contact located under the coil, after which the auto-stop circuit turns off the engine. The photo above shows the ring contacts of the auto-stop. The photo below shows the design of coils with a spring.

Before releasing the recorder, I certainly photographed the factory seals

Inside, everything is done in the usual style for the Soviet defense industry, the printed circuit board is covered with a thick layer of lacquer, on all the details of the seal of military acceptance. Workmanship is good, such a design should normally tolerate vibration and overload.

Despite the seemingly archaic method of recording on wire, analogous wire recorders P-503B (П-503Б) still produce in Nizhny Novgorod. Photos from the manufacturer's website