Mark 8 Fire Control Computer

The Mark 8 Fire Control Computer was developed by Bell Laboratories during World War II. It was initially requested by the USN Bureau of Ordnance as an alternative to the Ford Instruments Mark I Fire Control Computer, in case supplies of the Mk I were interrupted or were unable to be manufactured in the required numbers.^[1] The Mk 8 computer used all electric methods of computation, in contrast to the Mk 1, which performed most computations via mechanical devices. The Mk 8 was found to be more accurate than the Mk 1 and substantially faster in reaching a fire control solution,^[2] but by the time it was developed and tested in 1944, supplies of the Mk 1 were found to be sufficient in quantity. The USN extensively tested the Mk 8 and may have incorporated some of its technology into the post war Ford Instruments Mk1A computer. The Mk 8 technology was similar to that used in the M9 gun data computer used by the US Army for coast defence fire control and in the SCR-584 radar system computer.

Notes

^ Higgins 1982.
^ Higgins 1982, p. 232: "...The development model of the Mark 8 (Figures 9 and 10) was delivered to the Naval Research Laboratory Annex at North Beach, Maryland, on February 15, 1944, whereupon extensive comparison tests of it and the Mark 1 were made, using both the Mark 37 and the Bell Labs Mark 7 radar as tracking devices. These tests were primarily photo-data runs, with actual aircraft (usually executing ordered manoeuvres) as targets; firing tests were not practicable at North Beach. These tests indicated that the two machines were comparable in the accuracy of the gun orders delivered, except in regions where mathematical approximations inherent in the design of the Mark1 sometimes resulted in substantial errors. (The Mark 8 geometry was substantially free of such errors.) It was also found that the Mark 8 reached solution much faster than the Mark 1. Since one of the drawbacks observed in fleet experience with the Mark 1 was its sluggishness, it was decided to attempt to modify the Mark 1 in accordance with the principles of the Mark 8 to obtain a faster solution time..."

References

W.H.C. Higgins; B.D. Holbrook; J.W. Emling (July–September 1982). "Electrical Computers for Fire Control". Annals of the History of Computing. 4 (3). IEEE: 218–244. doi:10.1109/MAHC.1982.10026. S2CID 18464927.

[FOOTNOTEHiggins1982-1] Higgins 1982.

[FOOTNOTEHiggins1982232-2] Higgins 1982, p. 232: "...The development model of the Mark 8 (Figures 9 and 10) was delivered to the Naval Research Laboratory Annex at North Beach, Maryland, on February 15, 1944, whereupon extensive comparison tests of it and the Mark 1 were made, using both the Mark 37 and the Bell Labs Mark 7 radar as tracking devices. These tests were primarily photo-data runs, with actual aircraft (usually executing ordered manoeuvres) as targets; firing tests were not practicable at North Beach. These tests indicated that the two machines were comparable in the accuracy of the gun orders delivered, except in regions where mathematical approximations inherent in the design of the Mark1 sometimes resulted in substantial errors. (The Mark 8 geometry was substantially free of such errors.) It was also found that the Mark 8 reached solution much faster than the Mark 1. Since one of the drawbacks observed in fleet experience with the Mark 1 was its sluggishness, it was decided to attempt to modify the Mark 1 in accordance with the principles of the Mark 8 to obtain a faster solution time..."

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