Crace's Change of Bearing Instrument: Difference between revisions
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==Sliderule== | ==Sliderule== | ||
The sliderule had two discs. | The sliderule had two discs:<ref>''Annual Report of the Torpedo School'', 1914, pp. 32-33. I am inferring that "S" given in the source document represents "Own Speed".</ref> | ||
* the inner one had '''''OwnSpeed * sin(Bearing)''''' | |||
* the outer one '''''(pi * Range) / (100 * TimeIntervalBetweenBearings)''''' | |||
The result would be the [[Torpedo Deflection]] to passed by [[Navyphone]] to the director position. | |||
==Experience== | ==Experience== | ||
Revision as of 16:19, 14 March 2011
Crace's Change of Bearing Instrument was a Torpedo Control instrument conceived by a Lt. Crace of Australia to determine the bearing rate of a target so that the deflection can be computed to set a Torpedo Director.[2]
Instrument
It used a special telescope atop a gyro compass receiver. The telescope had crosswires and a prism in it that permitted the operator to simultaneously observe the target beneath a 5 degree arc of the gyro compass card below. The operator worked a training gear to keep the crosshairs on target and call out the bearing to a second man. This second number was equipped with a circular slide rule and also received ranges by voicepipe.
Sliderule
The sliderule had two discs:[3]
- the inner one had OwnSpeed * sin(Bearing)
- the outer one (pi * Range) / (100 * TimeIntervalBetweenBearings)
The result would be the Torpedo Deflection to passed by Navyphone to the director position.
Experience
By late 1914, it was determined that sufficient practice gave good results, but the amount of calculation required seemed worrisome.[4]
See Also
Footnotes
Bibliography
