An Interview with Walter MacWilliams

 Developing the First “Working” Transistor Application


Oral History – Walter MacWilliams



The project involved the construction of a data handling system for simplifying the assignment of track-while-scan circuits to the search-radar blips, the assignment of gun directors to the tracks on the most-threatening incoming aircraft, and a data presentation display for dynamically displaying the tactical situation. How effective could the ATEWA be, with its automatic evaluation of rapidly-changing  attack and defense data, compared to the manual operation of the sophisticated attack and defense display?   A much-debated question was how effective an air defense could be provided by gunnery personnel, simply by making use of the sophisticated calculation of critical data on the attack and the capabilities and limitations of the defense data display. To answer this question, I proposed the construction of a Gunnery System Simulator, which would represent incoming air attacks, represent the defense assignments of gun directors to incoming aircraft and groups of defensive gun mounts, and compute the effects of the defensive gunfire, in real time, so that the defense personnel would be working under the same time constraints that would exist in an actual air attack.


Before discussing the Gunnery System Simulator, it’s appropriate to say a word about the course of the Mark 65 project following construction and use of the Simulator.







Oral History – Walter MacWilliams


Following the tests using the Gunnery System Simulator, the Mark 65 system was successfully designed and installed in the USS NORTHAMPTON for the control of  its six 5”/38 gun mounts.  The tests of the system included defense at sea, both manually-aided and fully automatic, against simulated air attacks by actual aircraft.  The means for handling the data and making defense decisions worked  well.

With the passage of time, surface-to-air Terrier missiles began to supercede the 5”/38 gun mounts, and the antiaircraft defensive armament became a mixture of gun mounts and surface-to-air missiles.  However, the track-while-scan and assignment-switching features continued to be used, with appropriate data displays.  These arrangements became known as Weapon Designation Equipments, and were used in around 100 combatant ships in the U.S. and about 20 Allied navies. 


One component of the Simulator was the Gun-to-p-computer switch, which represented the individual shots fired against the incoming aircraft, and allowed the computation of “p”, the probability that a particular projectile would destroy the aircraft against which it was directed. 




Go To MacWilliams Oral History, Pg 5


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