Jean_LAMESCH_Sliderules_Collection_BOX

1791_DALTON_Aircraft_Navigational_Computer_Mark7

US DALTON Aircraft Navigational Computer Mark VII, from 1931 (or 1935?). Plastic corpus; two quasi rectangular sheets moveable around a common center, and one moveable disc also on each side. Standard "dead reckoning" aircraft computer in the US . More here , manual of the following model E-6B here . Bio of Philip Dalton here , and article on wind-Triangle navigation here .