# US 5,343,823 A · Large diameter low RPM propeller for torpedoes > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,343,823 A - Document ID: US5343823A - Status: Granted - Kind: A - Application number: 08/041,535 - Filed: 1993-04-01 - Granted: 1994-09-06 - Earliest claimed: 1992-01-10 - Assignees: Hughes Aircraft Company - Inventors: John G. Blaha - Web page: https://patentgrep.com/patent/US5343823A ## CPC - B63H 5/10: of coaxial type, e.g. of counter-rotative type - B63G 8/08: Propulsion ({schnorkels B63G8/36;} nuclear propulsion B63H21/18; submerged exhausting apparatus F01N13/12) - B63H 1/22: the blades being foldable - B63H: MARINE PROPULSION OR STEERING (propulsion of air-cushion vehicles B60V1/14; specially adapted for submarines, other than nuclear propulsion, B63G; specially adapted for torpedoes F42B19/00) - B63G: OFFENSIVE OR DEFENSIVE ARRANGEMENTS ON VESSELS; MINE-LAYING; MINE-SWEEPING; SUBMARINES; AIRCRAFT CARRIERS (means of attack or defence in general, e.g. turrets F41H) ## Abstract A propulsion system for a submerged vehicle which operates at a relatively low RPM includes a pair of coaxial drive shafts for producing counterrotating torques. A first propeller unit is attached for rotation with one of the drive shafts and a second propeller units is attached for rotation with the other drive shaft. Each propeller unit includes a plurality of arcuate propeller blades which are deployed upon rotation of their respective drive shaft. Specifically, this deployment is from a first configuration wherein the blades are disposed along the surface of the vehicle and into a second configuration wherein the blades are extended from the surface of the vehicle. ## Claims ### Claim 1 A low RPM underwater propulsion system for a submerged vehicle which comprises: a drive mechanism for producing counterrotating torques; a first propeller unit fixedly attached to said drive mechanism, said first propeller unit having a cylindrically shaped cross-section providing a curved outer surface and having a plurality of blades, each said blade being hingedly attached to said propeller unit, said outer surface of said first propeller unit having a plurality of arcuate slots for housing said plurality of blades in a first configuration, each of said blades being curved to conform to the outer surface of said first propeller unit to minimize the cross-section of the first propeller unit in said first configuration, said plurality of blades being deployed in a second configuration by centrifugal force upon activation of said drive mechanism for rotation of said first propeller unit in a first direction at a first RPM, said deployment of each of said blades on said first propeller unit occurring within a first plane perpendicular to a thrust axis of said propulsion system; and a second propeller unit fixedly attached to said drive mechanism, said second propeller unit having a cylindrically shaped cross-section providing a curved outer surface and having a plurality of blades, each said blade being hingedly attached to said second propeller unit, said outer surface of said second propeller unit having a plurality of arcuate slots for housing said plurality of blades in a first configuration, each of said blades being curved to conform to the outer surface of said second propeller unit to minimize the cross-section of the second propeller unit in said first configuration, said plurality of blades being developed in a second configuration by centrifugal force upon activation of said drive mechanism for rotation of said second propeller unit in a second direction at a second RPM, said deployment of each of said blades on said second propeller unit occurring within a second plane perpendicular to a thrust axis of said propulsion system. ### Claim 2 (depends on 1) A propulsion system as claimed in claim 1 wherein said RPM in said first direction is substantially equal to said RPM in said second direction. ### Claim 3 (depends on 1) A propulsion system as claimed in claim 1 wherein each said blade is arcuate. ### Claim 4 (depends on 3) A propulsion system as claimed in claim 3 wherein each said first and second propeller units further comprise a plurality of detents formed into said unit, and each said blade is positioned for engagement with one of said detents to hold said blade in its developed configuration. ### Claim 5 (depends on 4) A propulsion system as claimed in claim 4 wherein each said blade is hydrodynamically shaped to propel said torpedo upon rotation of said blade by its respective propeller unit. ### Claim 6 (depends on 5) A propulsion system as claimed in claim 5 wherein each said propeller unit has four said blades mounted thereon, and each said blade has a length which is approximately equal to an arc distance that is one quarter circumference of said outer surface of said respective propeller unit. ### Claim 7 A system for moving a substantially cylindrically shaped torpedo having a curved outer surface, comprising: a first cylindrically shaped propulsion mechanism having a curved outer surface; a second cylindrically shaped propulsion mechanism having a curved outer surface; drive means including a coaxial drive shaft for counterrotating said first propulsion mechanism and said second propulsion mechanism in first and second directions at respective first and second low RPM's that are substantially equal; a first plurality of arcuate blades hingedly attached to said first propulsion mechanism, each said blade being extendably deployed upon rotation of said first propulsion mechanism in said first direction from a first configuration wherein said blade is disposed substantially within said outer surface of said first propulsion mechanism and into a second configuration wherein said blade is deployed to extend beyond said outer surface, each of said blades being curved to conform with said first propulsion means outer surface when in said first configuration and being positioned to deploy by centrifugal force resulting from rotation of said first propulsion mechanism, said deployment of each of said blades on said first propulsion mechanism occurring within a first plane perpendicular to a thrust axis of said system; a second plurality of arcuate blades hingedly attached to said second propulsion mechanism, each said blade being extendably deployed upon rotation of said second propulsion mechanism in a second direction from a first configuration wherein said blade is disposed substantially within said outer surface and into a second configuration wherein said blade is deployed to extend beyond said outer surface, each of said blades being curved to conform with said second propulsion means outer surface when in said first configuration and being positioned to deploy by centrifugal force resulting from rotation of said second propulsion mechanism, said deployment of each of said blades on said second propulsion mechanism occurring within a second plane perpendicular to a thrust axis of said system; a plurality of detents formed in said first propulsion mechanism for holding said first plurality of blades in their deployed configuration; and a plurality of detents formed in said second propulsion mechanism for holding said second plurality of blades in their deployed configuration. ### Claim 8 (depends on 7) A system as recited in claim 7 wherein each said blade is hydrodynamically shaped to propel said torpedo upon rotation of said blade by its respective propulsion mechanism, and wherein each said propulsion mechanism has four said blades mounted thereon, and each said blade has a length which is approximately equal to an arc distance that is one quarter circumference of said outer surface of said respective propulsion mechanism.