FYI -- Dead Reckoning Computers installed in B-25.

[Waldo.Pepper]

Here are some details of dead reckoning computers that were installed in some B-25's. By some I mean perhaps as few as one per formation. Crew training on the equipment varied. Some crew members who were expected to operate it had only the vaguest of ideas of how yo use the 'box"

Anyway here is some info for any fellow nuts like me.

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Dead-reckoning computers, or odographs, have been developed. The control box of one such computer is shown in Fig. 7-2.

This device, developed in the Division 17 program of the NDRC, receives information from a true-airspeed meter and a repeater compass. These data are resolved into cartesian velocity components along the north-south and east-west directions, and these velocity values are integrated to provide continuous readings of air position with reference to any chosen point of departure.

A mechanism is also provided to indicate ground position by taking account of the effect of wind. The direction and speed of the wind (as determined from double drift readings, meteorological information, comparison of earlier wind settings with the actual course made good, radar fixes, or otherwise) can be set into the device by means of knobs shown

in Fig. 7-2. Wind velocity is resolved into components along the north-south and east-west directions, integrated, and the result added to the air position to give the ground position with respect to the point of departure.

Air position and actual ground position both appear on the counter dials shown at the lower left. The output signals of the unit can also be used to actuate a plotting arm which moves over a map table not shown in Fig. 7-2. With this addition, the device draws on a map the actual ground track made good by the aircraft carrying the instrument. Various map scales can be selected for the plotting table by means of a knob on the control box. The control box can also be provided with a gear train that actuates a mechanism showing latitude and longitude directly, in addition to showing the departure from the last fix. In a carefully made installation, fchc cumulative error of this instrument amounts to only 1/2 per cent of the total distance travelled from the point of departure.

[Klinger]

Ok, so it gives the operator something similar to the 'minimap path' that we can bring up in game.

Amazingly sophistiated bit of kit, as its presumably electro-mechanical. Looks like hard work to use.

Glad we've got that minimap