During the latter half of the war period, Elizabethport Works has concentrated its major effort on another gun fire control instrument, the Computer used in the fire control system of the B-29 Super-Fortress Bomber. The Army Air Forces deliberately designed this big bomber for long missions beyond the flight range of fighter escort and provided it with every possible facility for its own defense. Among other innovations, the bomber is provided with a system of electrically powered gun turrets which are operated by a sighting system in order to concentrate a broadside fire on enemy planes approaching from any angle. One of the vital elements of this sighting system is the mechanical-electrical computer whose function it is to make instant corrections for the speed of the bomber, the speed and direction of the attacking plane, altitude, temperature, windage, gravity, and the ballistics of the gun projectile. In addition, it makes correction for parallax, i.e., the distance between the sighting station and the remotely located guns. Elizabethport's accomplishment in the production of this Computer has been one of the outstanding contributions of the Singer Company to the country's war effort, one which gives every employee a sense of satisfaction as he reads reports of effective B-29 raids over Japan.

Image of B-29 Super-Fortress Bomber courtesy of The Great Planes - A Source About WWII Aviation.

Period of Preparation
The negotiations which led to the assignment of this project to Elizabethport Works started on Thanksgiving Day 1942. The Boeing Works were already busy on the production of the B-29 Bomber and the first planes were scheduled to be ready in less than one year. General Electric Company, who had designed the sighting system, subcontracted with others to produce the several instruments and units making up the system and General Electric undertook to assemble and wire up the systems for installation in the planes. Elizabethport Works, operating as a subcontractor for the General Electric Company, has tooled up and produced the major portion of all the Computers required for the B-29 project and has also produced quantities of subassemblies and parts required by the General Electric Company and others for their part in the program.

As in the case of the Director M5, Elizabethport was required to take the initial steps on the Computer project before design drawings and specifications were available. Profiting by experience gained in the Director work, Elizabethport engineers were able to accomplish much, deciding on production methods, ordering materials, designing tools and fixtures, and producing special handling equipment while awaiting final design of the instrument. As approved drawings became available, the design and production of the necessary tools and fixtures, gauges, etc. proceeded until all parts were in production and the final assembly was under way. During this period, approximately 8000 tools and fixtures, over 200 gauges, and about 100 patterns were produced for Computer work within the Elizabethport plant. Permissions were obtained for the use of the D.P.C. machine tools previously procured for the manufacture of Director parts and this held to a minimum the number of new machine tools purchased for the Computer work. Even so, it was necessary to produce and install 650 machines of various sorts.

Image courtesy of the Franklin D. Roosevelt Library Digital Archives.

Plans were made for the final assembly of the Computer in Department 110 and nearly 200,000 square feet of floor space, much of it formerly used for Director assembly, were eventually devoted to this work. The final inspection and test specifications required considerable special equipment, notably, cold test rooms to produce temperatures ranging from 70 degrees below zero to 140 degrees above, infra-red defrosting racks, a massive vibration machine, as well as other Singer designed mechanical and electrical test equipment.

Major changes previously made in the Foundry to permit the production of large quantities of aluminum and bronze castings for the Director work proved useful in the production of Computer castings, although, generally speaking, Air Corps specifications proved to be much more rigid than the specifications governing Director Castings. It was, therefore, necessary to install x-ray equipment, tensile testing machinery, and the electrical Magnaflux which reveals hidden flaws in bars or shafts. One of the most interesting processes used on certain Computer castings consists in the freezing of the part to a temperature of 120 degrees below zero, thereby increasing hardness and giving longer life. Other parts are exposed to high frequency induction heating which brings the cold metal to white heat in a few seconds. Equipment necessary for these and other special processes was purchased and set up in the Foundry.

Initial production of Computers became available in September 1943, less than ten months after the original commitments to undertake the work had been made.

Period of Production
Generally speaking, the production of the Computer was achieved in much the same was as was the production of the Director. Most of the individual parts were produced throughout the factory in the various departments either on Singer owned machine tools with special fittings or on Government owned D.P.C. machines. The specifications for the Computer and its parts were more rigid than those covering the Director and in most cases the tolerances and fits were closer. New manufacturing techniques were developed in many cases, viz., the winding of precision potentiometers, the production of precision aluminum gear assemblies with close tolerances on concentricity and squareness of hub bores, selective assembly of the tiny but precise gear differentials, the lapping-in of lead screws, bevel gears, and various other parts for free operation without play or backlash, and the manufacture of various special wiring harnesses and other electrical assemblies.

Starting in September 1943, weekly production stepped up gradually, reaching a rate of approximately 250 complete Computers per week at the end of 1944, and over 500 per week in July 1945, at which time a total of 20,794 complete Computes had been shipped out of the factory. About one-third of these Computers have been Double Computers, incorporating two computer mechanisms. In the Spring of 1945 the Double Computer was discontinued but the cancellation of this quantity was partly compensated for by some increase in the requirements of the Single Computer.

As in the case of the Director, special packing methods have been employed to protect the delicate Computer during shipment, especially for overseas movement. Cartons are triple sealed against moisture and enclose a moisture absorbing agent.