Purpose built mechanical calculation machine for determining the drift of aircraft when operating in crosswind conditions. This device has an eyepiece and a prismatic periscope for viewing a distant feature being tracked. This device has calibrated rotary scales for height, speed (in KNOTS and MPH), and an adjustment to preset the 'crab angle' of the aircaft for cross wind compensation. The device can be opened for cleaning or maintenance purposes. Refer to the following extracts for information about bomb drift: "Crosswinds brought into the bombing problem a new factor, "drift" In order to fly a given ground track in a crosswind, an aircraft had to "crab" into the wind; the angle formed between the aircraft's true heading and its ground track was called the "drift angle" In a crosswind, the bomb would impact directly behind the aircraft and along its longitudinal axis at the moment of release. But this meant that the bomb would strike the ground at some point downwind of the aircraft's ground track. Thus, in order to score a hit, the bomber had to fly a ground track that ran upwind of the target." "Air resistance acting on a bomb after release caused it to lag behind the drop point and hit somewhere behind the bomber. The distance from a point beneath the aircraft at the instant of bomb impact to the point of bomb impact was called "trail." Trail increased as the bomber's airspeed increased or as its altitude increased. Furthermore, since different bombs encountered different resistance in the air, trail was also a factor of bomb shape."A. M. Drift Recorder MKII REF. No 6B/190 No 2668/41 X/ 3606 3E4H28

NIDS-1-39

The site of Rorke's Drift is probably most renowned for the defence by a British Force of less than 200 soldiers who held out a against 2000 Zulus in 1879. The story of the epic battle is portrayed in the film ZULU starring Michael Caine and Stanley Baker. Brass British Army Button found at the Site of Rorke's Drift Natal South Africa with 4 recent photos and research. Made in Birmingham on the reverse.

Data card giving the required elevation for the weapon over various ranges from 0 to 7515 yards. It also gives drift, probable error and time of flightFT106-B-2106 mm rcl, firing tables

Coloured Geological Map of Ballarat, edged with masking tape. The map show alluvial silt, gold drift, geological orders, volcanic, and gold workings. Scale is 8 chains to an inch. WGS 84 Centroid: 37 degrees 33 feet 33 inches south 143 degrees 52 feet 02 inches east W.E. extent: 5km NS extent: 3 kmballarat, ballaarat, geology, goldfield, phillips, j. phillips, mining, alfred selwyn, ferguson and mitchell

non-fictionAttempt to provide overview of aerial navigation in simple terms, circa 1940bearings & courses, effect of wind, velocities, dead reckoning, course & distance calculator, drift, direction finding wireless, cross bearings