Military/Government Issued Slide Rules

Read Alex E.S. Green's own account in the Friends Journal Vol.23, No.3, Fall 2000 The 20th AF Slide Rules of WWII, August 1944 to September 1945

Read Alex E.S. Green's own account in the Friends Journal Vol.23, No.3, Fall 2000 The 20th AF Slide Rules of WWII, August 1944 to September 1945

Notes: The scales are obviously for artillery calculations. There are three slides for ranging the 75mm and 155mm Howitzer with various charges. There is a C and D scale which qualifies the rule as a slide rule. The rule is of the Mannheim type. The base of the rule is mahogany with a lighter wood used for the stators. The surface of the wood is painted and the scales are screened on.
Archive - Clark McCoy Collection

M114A1 155mm Artillery Crew Vietnam

Overview: To eliminate the difficulties in computing firing data that result from the need to interpolate, the graphical firing table was created. The GFT provides all the information needed to compute firing data in a slide rule form.

Parts: All GFTs are made in two parts.. The rule is a rectangular wooden base on which is printed one or more sets of scales. With a few exceptions, GFTs are printed on both sides. The second part of the GFT is the cursor. This is a transparent plastic square that slides on the rule. Engraved in the plastic of the cursor is a manufacturer's hairline used to determine values from the scales.
Types: The basic GFT format is the same for all weapons. These formats may be divided into three types: low-angle GFTs, high-angle GFTs, and shell illuminating GFTs.
Identification. All GFTs are labeled for identification. The first line of the label on low- and high-angle GFTs indicates the type weapon in bold type; that is, HOW 155mm. Immediately below the weapon type, in smaller print, is the identification of the TFT on which the GFT is based; for example, "155AM2." This is followed by the projectile type and nomenclature, such as "HEM107." The last line of identification of low-angle GFTs tells the charge for which the GFT may be used, such as "CHARGE 4." High-angle GFTs indicate the trajectory "HIGH ANGLE." Shell illuminating GFTs reverse the label with "PROJECTILE ILLUMINATING" on the top and the weapon type on the bottom.

To read more about a 155mm Field Artillery unit in Vietnam see The 1/92nd Field Artillery Association website.

155mm Ordanance

TM 6-240 Manual 3.35MB Pdf
Field Artillery Military Slide Rule

Go to the Aviation Related Slide Rules Gallery to see all other military and commercial air navigation computers.

V2 Rocket Ballistic Ranging Slide Rule

Note from ISRM curator, Mike Konshak, who is certified to build and fly high powered rockets: On the V-2 Rocket slide rule, all the scales are a variation of High vertical climb (maximum altitude), maximum range, burn closing speed. The V2 ballistic missile would shut off its motor at some point in its flight (burn closing speed) which was the maximum velocity at that point, which was determined by it s inertial guidance system. This would vary based on the desired range. At that point it went from the boost phase to the coast phase and begin slowing down due to parasitic drag and fell (still very fast) to its intended target. It was was not very accurate as it only went in the compass direction it was told to go. Full cutoff determined the range. This slide rule was not very different from other artillery calculators. The replica was made by the Curator from the image.

The Slide Rule at West Point by Fred Rickey (1998)

1905

"For the purpose of acquainting the cadets with the various mechanical devices used as aids in performing calculations they have received instruction in the use of the slide rule and of several calculating machines. The required use of the slide rule in the solution of the problems in connection with the daily lessons had given to a large part of the class a satisfactory facility in the use of this instrument. An arithmometer, one of the best of the calculating machines, has been purchased for the use of the department [of Ordnance and Gunnery]. This machine, together with other machines of like nature in the possession of the other academic departments, has been a subject of instruction." [Superintendent's Report, 1905, p. 41]

1906

After Echols was sent to Europe in 1905-06 he wrote a Report of Visits to Foreign Schools and Recommendations Resulting. The original of this is in the USMA Archives. Here is one comment:

"It seems advisable that time be found in the course in mathematics to resume the instruction in the theory and use of the slide-rule which was once taught in conjunction with the course in surveying and is now taken up in the course of Ordnance and Gunnery. It could be best added to the course in trigonometry of the 4th Class year, its use to continue throughout the next three years."

You will find my notes on the report of Echols at

http://www.dean.usma.edu/math/people/rickey/dms/DeptHeads/Echols-Europe.htm .

I don't know if the surveying course mentioned above was taught in mathematics or not; I will do some more checking and try to figure it out. But the way Echols expresses himself it seems that the slide-rule was taught at WP in 1906; it addition it appears that it goes back a few years. The quotation in the previous section  shows that it was indeed taught in Ordnance and Gunnery in 1905.

1914

The Slide Rule: A Manual of Instruction prepared under the direction of Gilbert A[lbin] Youngberg (1875-1962, USMA 1900, C#3947, Instructor USMA 1910-1914) by Roger G[ordan] Alexander (1883-1961, USMA 1907, C#4532, Instructor PME USMA 1912-16; First Dean of the Academic Board), was published at West Point in 1914. One copy is in the USMA library:  Textbooks-SPEC: QA73. A4

1919

"Difficulty was experienced in securing slide rules for the use in the department [of Natural and Experimental Philosophy] although they were ordered as early as practicable. These are now part of the regular equipment for the cadet in the department of philosophy and their appropriate use is obligatory in this department. [Superintendent's Report, 1919, p. 25]

1929

In 1929 the slide rule became a formal part of the mathematics program and served as the midshipmen's primary calculator until 1976. [From:"A Brief History of the Department of Mathematics" by Professor T. J. Benac] https://www.usna.edu/MathDept/_files/documents/mathdept_history.pdf]  http://www.pballew.net/mathbooks.html

1930

Notes on the Slide Rule: Notes on Precision of Measurements, Computations, and Graphical Methods. 1930. Copy in USMA Special Collections:  QA73 .N68 1930.  There were also editions of this in 1933 and 1935. [Mentioned in 1933 below.]

1933

"56. The course in natural and experimental philosophy extends throughout the second-class year. The  slide rule, precision of measurements, computations, and graphical methods, general astronomy, surveying, and a portion of technical mechanics (statics) are taught in the order mentioned during the second term." Then more details on each of these first term courses follows: "The Slide rule - Three periods only, based on Notes on the Slide Rule [see 1930 above] prepared in the department. This shout course is intended as a refresher course following theoretical instruction given in another department [which department ??] during the third class year. Following these three days' [sic] instruction on the practical use of the slide rule and after about two weeks' [sic] use in the section room, appropriate use of the slide rule for computations in the department is obligatory." [Information for Appointment, 1933, p. 19]

1934

In the Information Relative to the Appointment and Admission of Cadets for 1934 under the Department of Natural and Experimental Philosophy one finds "The slide rule . ─ At the beginning of Academic work on September 1 and for about two weeks thereafter, a portion of each period of instruction is devoted to the use of the slide rule, and thereafter proper use of the slide rule for computations in the department is obligatory."

1943

The 1943 Superintendents Report, p. 3, indicates that "Instruction in the slide-rule will be taken over from the Department of Physics."

1945

The slide rule is not mentioned in the 1945 Information Pamphlet.

1946

The 1946 Catalog, p. 44 (image 52), indicates that the slide rule is taught in the Mathematics Department for 9 periods of 80 minutes duration, i.e., for 12 hours. No detail is given about what is taught.

1947

Class of 1947 at MIT used slide rules.

http://brownalumnimagazine.com/printerfriendly.cfm?ID=1166

1961

In a memo headed "Report of Activities, Training Aids Committee" dated 19 June 1961 there is a note of contact with K & E "regarding plastic slide rule for use with the vu-graph." There is a handwritten note that these should be in use by late fall. According to another memo (9 February 1961) Mr. Thomas "arrived with a pilot model of a plastic slide rule for demonstration and comment" on 25 January 1961. Seven suggestions are made for improving the device. There is a list of training aids. It includes 23 string models and one Mechanical Integrator and 36 Spherical Blackboards, 27 "Slide Rule and Stands (8ft)" for use in Fourth Class slide rule instruction. [Mathematics Department Diary, 1960-1961, tab 13]. One plastic slide rule for use with the overhead survives (but is it the same one mentioned above?); apparently these had a tendency to soften and twist if left on the overhead too long and were then unusable.

The 1961 Howitzer, the cadet yearbook, has a photo of a cadet who has been stabbed in the back by his slide rule.

1979

This was the first class to be issued calculators.

References:

'Catalog' is the short title used here for United States Military Academy, West Point, NY, Catalog of Information.  This began publication in 1946 and supersedes the Information for Appointment.

'Information for Appointment'  is the short title used here for Information Relative to the Appointment and Admission of Cadets to the United States Military Academy, West Point, NY.  This was published annually by the Government Printing Office. The year is specified in the citations above. This was published until 1944. In 1945 the title was Information Pamphlet. Then it is succeeded by the Catalog.