By the Numbers…

This page has been compiled from various primary sources for the Dayton story. Each fact is sourced, and many of the sources are reproduced on this site.

New, 7 Feb 2017: Corrected and additional Information! see the table below

The Electrical Research Laboratory at the National Cash Register Company began with a staff of 2 people, Joseph R. Desch and Louis DeRosa, in 1938. After a successful model of a tube-based counting bank, the ERL was awarded several contracts:

-for research and development of electronic counting devices to measure velocity of shells at the Army’s Aberdeen Proving Ground;

-to operate radio-controlled land mines for the Army Signal Corps;

-to count radioactive emissions with megacycle speed for the University of Chicago.

-The bombe program was carried on under Contract NXs 7892 dated 1 July 1942


On Sept 3, 1942, Cmdr. Joseph Wenger, of the Naval Communications Intelligence section Op-20-G submitted a request to the Director of Naval Communications requesting authority to begin the Bombe program.

This was approved on 4 Sept 1942. The U. S. Naval Computing Machine Laboratory was established by letter from the Vice Chief of Naval Operation for “the purpose of assisting the contract (NCR) in the production of these Bombes and in the training and maintenance and operation personnel.” (Wenger, Engstrom, Meader, Bombe History)

Meader later wrote “The entire bombe technique was developed there including components which heretofore did not exist.” (Meader, Meader, Postwar Report ).

“The design of the Bombe eventually required material and components from some 12,000 different suppliers. Certain components had to be designed and developed, and production equipment obtained and put in operation. Among these were the 4 section diode, the 204 miniature gas tube, and a commutator capable of taking 104 inserts and designed to rotate at 1850 R.P.M. while in contact with 104 carbon brushes. (Meader, Meader, Postwar Report)

The first production models of the machine were operated at Dayton until September 1943 when the facility at 3801 Nebraska Avenue, Washington, was ready for occupancy. The machines were shipped from Dayton to the Laboratory starting in September at the rate of four (4) a week. (Wenger, Meader, Engstrom, Bombe History)

Civilian personnel in the Electrical Research Department of the NCR Co. had to be increased from 17 in August 1942 to 800 in May 1943, a period of 8 months. (Meader, Meader, Postwar Report)

“The peak personnel load at the U.S. Naval Computing Machine Laboratory, Dayton, Ohio, occurred during the summer and fall of 1943 when a maximum of 425 naval personnel and 782 civilians was reached. The naval personnel at Dayton has been fairly constant since the middle of 1944. There were 93 on the rolls in January 1945 and 91 in June 1945….The civilian personnel has tapered off considerably as evidence by the following figures:” (Engstrom memo)

1 August 1944 400
1 January 1945 238
15 March 1945 182
1 June 1945 114


NCR Co. designed, developed, fabricated, and put into operation the following equipments. (Meader, Meader, Postwar Report)

Contract, date Machine name # manufactured language used for and additional info
7892, July 1942-Dec. 1943 Experimental Bombes 2 to analyze Enigma communications
Regular bombes 96 to analyze Enigma communications
Double Bombes 2 handles Enigma double encipherment
M-9 35 test bombe hits
49702, Dec. 1943-July 1945 Copperheads I 5 Scanners Japanese JN-25, tape scanner
6 Punches
Vipers 10 Japanese 157 cipher
Mike 1 takes data from 2 teletype machines simultaneously
Pythons 6 Japanese: Naval Attache code
Rattler 3 Japanese: 157 cipher
Gypsy-Topas 2
Duenna 5 Enigma: added pluggable reflector
Statistical Bombe 1 Research on equipment which would not need a crib
Double Bombe 1 Enigma: handles double encipherment
Asp 1
Sliding Grenade 2 cuts Grenade running time by a factor of 26
M-9 60 hand machine to test Bombe results
for the M-9 506 extra wheels
M-8 8 carries out decipherment from punched tape
Parallel Grenade 1 runs 4 standard Grenades simulaneously
Mamba 1 Japanese: device to aid in recovery of additive ciphers
Wave filters 30
Boa 60 Enigma:pluggable reflector used in M-9
Special Boas for Duenna 10 Enigma
Satyr 1
Pluggable Reflectors 495 Enigma: Bombes equipped to handle rapid reflector changes
Standard Grenades 4 Enigma: Bombe attachment
Drag Grenade 1 Enigma: applies a short crib to 13 positions simultaneously
Coast Guard Grenade 1 solves double encipherment problems
Cilli Grenade 1 simultaneously runs several wheel orders
Inverted Bombes 8 converts Bombe wiring for days when wheel order and rings are known but not stecker
Bombes modifiedfor double input 25 modification on 25 Bombes to run certain weaker cribs
Special Cryptographic model for DNC 25 “special cryptographic project assigned by the Director of Naval Communications”
Squelcher Circuit special selective circuit
9581, July 1945-Aug 1946 Special Counter Printer Punches 6
Full Selector 1
Amber Projects 2
Morse Printers 10
9582, June 1946-Dec 1946 Recorders 15
Amplifiers 10
Morse Printers 10
53322 Bombes 25
25120 Counter Printer Units 3
Relay Control Units 3
GRAND TOTAL 1003


The magnitude of the above equipments is a matter of record and need not be amplified here, other than to give one example. One Duenna contained 2,000 relays and 3,000 tubes. In the overall performance at Dayton, over 200,000 items were shipped to Washington from Dayton. Some 56 carloads weighing 17 tons each were sent. (Meader, Postwar Report)

Regarding the work on a Japanese strip cipher: “A project was initiated on 16 December 1944 to build a machine which would accomplish the complicated process of decipherment directly from a keyboard to a page copy. This equipment involves over 1,000 relays, 50,000 soldered connections, stepping switches, controls, etc. Less than 30 days elapsed between the original inception of the project and the completion of the equipment which is now in operation in our Pacific section. Original rough designs were prepared by our research group. The equipment was designed, fabricated, wired, and assembled by naval personnel attached to the U.S. Naval Computing Machine Laboratory, Dayton, Ohio.”(Commendation, Joseph Wenger, 15 Jan 1945)

Research and development work continued in Dayton until 15 August 1946. The work moved then to Engineering Research Associates, a quasi-governmental organization founded by Naval Officers Engstrom, Meader and Norris. It was located in Minneapolis/St. Paul. Bill Norris of ERA later morphed this company into Control Data Corporation which was an industry leader in computing for many years and is an essential member of the “family tree” of computer development.