Historical Photo of the Month - September 2005

Towing Channel Test
Photograph Number M-2970

In 1943, the staff of GALCIT Project #1, forerunner to JPL, wrote a proposal for the US Army Air Force Materiel Command Armament Laboratory. It recommended building a facility for testing scale models of the AAF's underwater rocket-propelled projectile, known as the hydrobomb. A contract was awarded to "the Project" and a hydrodynamic tank, or channel, was built - 500 feet long, 12 feet wide, and 16 feet deep. A rocket-driven towing carriage straddled the channel, with rubber coated steel wheels riding on steel rails at the edges of the channel. A model of the hydrobomb was suspended in the water, under the towing carriage. Part way down the channel there was an observation/instrument room, under the level of the water.

Three liquid fueled rocket motors put the carriage in motion, and the center motor continued burning to propel it down the length of the channel, as shown in the photo above. An electric motor with towing cable was originally planned, but because of wartime shortages, an alternate method of propulsion had to be found. A previous Historical Photo of the Month, http://beacon.jpl.nasa.gov/Histphotos/hpom/327-96d.html , showed the towing carriage at one end of the channel, raised into its service position.

The hydrobomb contract was closed in 1947, when the Navy took over responsibility for all torpedo-like weapons. The channel was drained and a floor and roof were added. It was used as a test facility for various large scale projectile experiments, and later for document storage and a classified document vault. It was demolished in 1973.

For information about the channel, or about the history of JPL, contact the JPL Archives.

Past Photos of the Month
Thumbnail pages 1996-2002 | 2003+

Past Photos of the Month Subject Index