This director (possibly referred to by the Japanese as Model 97) is a plan prediction type of computer. It is probably used with the Japanese Model 88 (1928) 75 mm antiaircraft gun.
Standard ballistics are obtained from cams; approximations and spot corrections take care of wind effects, muzzle velocity, and air density variations. The director is provided with telescopes, and with electric data receivers for azimuth and angular height, and for altitude or horizontal range.
The director imposes significant limits on altitude and horizontal component rates. The maximum altitude rate is +/- 179 miles per hour. The maximum horizontal component rates are 335 miles per hour. It is not known whether it is Japanese practice to orientate their directors with respect to true North; but if that is the case, targets flying in the cardinal directions with ground speeds in excess of 335 miles per hour would be beyond the capability of this director. Such ground speeds, when aided by wind, may be feasible. It should be noted that the director is capable of handling greater speeds if the target does not fly parallel to one of the principal coordinate axes.
Optical tracking is provided on the director proper. An electrical data transmission system provides for the use of an external tracker such as a radar unit.
SPECIFICATIONS
| Time of flight | 30 secs. max. | |
| Present altitude | 0 to 7,655 yds. | |
| Future altitude | -820 to 8,475 yds. | |
| Present horizontal range | 0 to 10,936 yds. | |
| Future horizontal range | 0 to 10,936 yds. | |
| N-S and E-W rates | +/- 164 yds./sec. | |
| Altitude rate | +/- 87 yds./sec. | |
| Lateral deection | +/- 800 mils. | |
| Horizontal range prediction | +/- 4,101 yds. | |
| Altitude prediction | +/- 820 yds. |
Japanese: p. 175 (March 1, 1945)