This Cold War Damage Prediction calculator [version 2] was commissioned by the Defense Nuclear Agency and designed by Horizons Technology Inc. of San Diego in 1986. The 8″ diameter rule is made of plastic and was produced by Perrygraf. It consists of seven desks, a base disk and three tabbed disks [for HOB, VN adjustment and yield] on either side.
See an earlier post for the 1982 version of this rule. The 1982 version of the rule colour coded the sides for P and Q type targets. This rule prints the target type on the rule. The rule has the same purpose as the Damage Probability Computer produced by RAND [see this post] but is far more sophisticated.
For more posts about Cold War calculators click on the Cold War Calculators category on the right.
The rule uses the vulnerability number system to calculate the probability of destroying a target given variables such as warhead yield, CEP [circular error of probability, accuracy of delivery vehicle], HOB [height of burst], WR [weapons radius] and the target’s vulnerability number [e.g. 18P5].
Like the earlier version of this rule it can be used for area as well as point targets and offset can be incorporated into calculations. Solutions are expressed in feet but a means of adjusting from feet to meters is provided.
A thirteen page users guide, written by Leland Welsh, was issued with the rule. The guide does not define what is meant by WR [weapons radius]. It is not clear if it refers to fireball radius, air blast radius or thermal radiation radius. It may simply be a term for an intermediate calculation.