VT Proximity Fuze Manufacturers of World War Two

This page added 5-6-2021.

An American Auto Industry in World War Two Special Edition

The VT proximity fuze program was one of three top secret programs the United States had during World War Two.  It was the only one that remained secret throughout the war and was never discovered by the enemy in action nor through spies. The Manhattan Project was penetrated by spies.  The American radar program was only secret in that it had the magnetron tube.  The Germans and  other combatants had radar.  The VT program was so secret that VT fuzes were taken to nearby airports in unmarked trucks to be flown to their final destination.  The aircraft flew directly to military bases, where the fuzes were then attached to shells.  If the fuzes were shipped by train in a boxcar, a U.S. Marine guard would be in the boxcar at all times until the load arrived at its final destination.

The VT fuze consisted of a small radio transmitter and receiver of several miniature electronic tubes, electronic components, and safety devices that were mounted in the nose of anti-aircraft shells.  When fired at an attacking aircraft, the VT shell would detect a change in the received frequency when near an enemy aircraft, and the VT fuze would detonate the shell.  This was far superior to the other method of pre-setting the time-to-detonation of a fuze of an anti-aircraft shell before the shell was loaded in the anti-aircraft gun.  This was problematic at its best in attempting to predict, in the heat of an aerial attack, how long it would take a shell to reach the area of fast moving enemy aircraft.

For the U.S. Navy, the VT fuze is considered to be one of the main reasons it was able to progress so quickly back across the Pacific during World War Two.  It was shown at Pearl Harbor and the sinking of HMS Repulse and HMS Prince of Wales three days later that aircraft were the biggest threat to the American fleet in the Pacific.  With the aid of the VT fuze built by Crosley, Eastman Kodak, McQuay-Norris, RCA, and Sylvania, it is estimated that the U.S. Navy's Pacific campaign advanced months faster than it would have without it.  Many lives were saved, and fewer ships were sunk than if the VT fuze had not been produced by these companies.

The U.S. and British Navies were the first users and the driving force behind the vast scientific, engineering, and manufacturing project.  When first used in combat, they were only used on ships, so any duds would fall into the ocean.  In doing so, duds could not be recovered by enemy troops, reverse engineered, and used against the Navy.  Later, they were used over land in defending Antwerp, Belgium from V-1 attacks.  Another version of the VT fuze was designed for artillery shells for air bursts against enemy ground forces.  This was first used very effectively during the Battle of the Bulge.

Engineering and development of the VT proximity fuzes was carried out at the Applied Physics Laboratories (APL) of John Hopkins University.

This cut-away diagram shows the major components of the VT fuze.

The VT fuze was made from components purchased from U.S. Navy authorized suppliers.  The original cost of a VT fuze in 1942 was $732.  By 1945 it had been reduced to $18.  This is $11,514 and $256 in 2020 dollars, respectively. 

This cut-away of a VT fuze is on display at the National Electronics Museum in Linthicum, MD.   Author's photo.

This cut-away shows how the VT fuze fit in a shell. 

There are several excellent websites that explain the technical issues and the end use of the proximity fuze during World War Two.  However, this is the only one that recognizes the many different companies that contributed to the making of the fuze that was so important to an expedited U.S. Navy's winning of the war in the central Pacific.  Most of the companies listed in the several tables on this page no longer exist.  Over eighty years after the U.S. Navy began working on the concept of a proximity fuze and over 75 years after the end of the war, time, technology advancement, and attrition have reduced the number of companies to just a handful that contributed to this important product.  For a person who grew up after World War Two, many of the names of the companies on this page are recognizable.  Someone considerably younger will have a difficult time recognizing any of the names on this page.

Final Assembly Plants:  Five different companies built the VT fuze.  Crosley was the first into production.  RCA had two plants dedicated to the production of the VT fuze.  The Sylvania plant in Ipswich, MA produced the most VT fuzes of the six locations.  Eastman-Kodak was the only company that continued to build the VT fuzes after World War Two.

Crosley Corporation was the first of the VT fuze producers to cease to exist.  On August 8, 1945, even while the war in the Pacific was still in progress, the owners sold the company to AVCO and Crosley became a division of AVCO.  By 1956 it was gone.  Eastman Kodak still exists, although it had to file for bankruptcy in 2012.  It is a former shadow of itself.  RCA only remains as a brand name, which is owned by a foreign company.  Sylvania is also now a brand name owned by a foreign company.  McQuay-Norris was an auto parts manufacturer that merged with Eaton Yale & Towne in 1969.

McQuay-Norris of St. Louis, MO has the distinction of being the only automobile industry company that contributed significantly to the VT fuze program.  St. Louis was also as far west as any of the suppliers were located.  Most were in NJ, NY, and PA.

Major Suppliers:  Over the course of the VT fuze program in World War Two, many companies from a variety of industries supplied components for the fuze.  Some were used in the initial phase or for a short period of time.  The companies listed in Table 2 below contributed large amounts of critical components for use in the VT fuze.  The complete list of suppliers in Table 10.  Early suppliers are listed in Table 9.

Jefferson Electric and the Hoover Company together supplied 100,000 mercury safety switches per day at peak production.  These were the most difficult of the products made for the fuze.  The Hoover Company is a classic example of a company that produced highly technical products during World War Two that were totally foreign to its normal non-war products.  For Hoover this was vacuum cleaners.  It was one of many American companies that ended up making products during World War Two that were totally different from their peacetime products.

RCA:  RCA had two plants committed to the production of the VT fuze during World War Two.  The Bloomington, IN plant made radios prior to World War Two.  Then it became RCA's main television assembly plant after the war.  The Bloomington plant received the Navy "E" Award after the end of hostilities in recognition of it producing its VT fuzes in a timely manner.  It could not receive the award during the war because of the top secret nature of the VT fuze.  

Photo courtesy of the Monroe County Historical Center added 8-23-2020.

The RCA plant in Bloomington, IN.

Sylvania:  Sylvania was a key company to the VT fuze program with twenty-three plants.  Fifteen were dedicated to the production of components and the final assembly of the VT fuze.  The company was supplying 400,000tubes per day at peak production.

The miniature tubes were held in place by wax, to protect them from the intense g-forces when being fired from an anti-aircraft gun.  The wax also held them in place from the large rotational g-forces of the shell.  Sylvania produced over 100 million tubes for the VT program. 

Below are three Sylvania post-war documents detailing the VT fuze and the miniature tubes.

Crosley Corporation:  For a more comprehensive look at the Crosley Corporation's participation in the VT fuze program and its other World War Two products, please visit my Crosley page listed at the top of this page.

The Mk 32 was the first VT fuze used in the Navy's 5"/38 dual purpose gun.  It was 12 inches long, 3.3 inches in diameter at its widest point, and weighed 6.81 lbs.  It would detonate within fifty feet of a target.  When tested at an over-water firing range, it would detonate 130 feet above the water.  Note the number of modifications the Mk 32 had over its lifetime and the change in the shape of the antenna cap.  It was a Crosley-built Mk 32 that shot down the drones in navy testing, and a Crosley Mk 32 was the first VT fuze to shoot down a Japanese aircraft in the Pacific.  Crosley built 1,368,785 Mk 32s. 

Eastman Kodak:  The company at the end of the war was producing 23,000 batteries per day along with doing final assembly.  After World War Two, Eastman Kodak continued to make the VT fuze.

McQuay-Norris:

Other suppliers: