Redundant Aircraft Propulsion System Using Co-rotating Propellers Joined By Tip Connectors

Abstract

Multiple propeller blades may be joined by tip connectors to form a closed propeller apparatus. The tip connectors may create continuous structure between adjacent tips of a first propeller and a second propeller. Use of the tip connectors may reduce vortices created near the tips of the propeller blades, which cause drag and slow the rotation of the propeller blades. The tip connectors may also reduce noise caused by rotation of propeller blades. Further, the tip connectors reduce or eliminate deflection of the propeller blades by creating a support structure to counteract forces that would otherwise cause deflection of the propeller blades, thereby improving propeller blade loading. In some embodiments, the tip connectors may be formed of a malleable material and/or include one or more joints that enable at least one of the propellers to modify a pitch of blades of the propeller.

What is claimed is: 
     
         1 . An apparatus comprising:
 a frame;   a drive shaft;   a propeller coupled to the drive shaft, a first portion of the drive shaft located proximate to a first side of the propeller;   a first motor coupled to the first portion of drive shaft;   a second motor coupled to the first portion of the drive shaft, wherein power input from at least one of the first motor or the second motor causes rotation of the drive shaft and the propeller, and wherein at least one of the first motor or the second motor is coupled to the frame;   a first clutch bearing coupled to the first motor, wherein the first clutch bearing enables the rotation of the drive shaft upon a first failure of the first motor while the second motor is in operation; and   a second clutch bearing coupled to the second motor, wherein the second clutch bearing enables the rotation of the drive shaft upon a second failure of the second motor while the first motor is in operation.   
     
     
         2 . The apparatus as recited in  claim 1 , further comprising a first cogwheel coupled to at least one of the first motor or the second motor and a second cogwheel coupled to the drive shaft, and wherein the first cogwheel engages the second cogwheel to enable at least one of the first motor or the second motor to drive the rotation of the drive shaft. 
     
     
         3 . The apparatus as recited in  claim 1 , wherein the first motor is configured to operate at a first power setting, the first power setting including the first motor operating at a first number of revolutions per minute (RPM), and wherein the first motor is further configured to operate at a second power setting upon the second failure of the second motor, the second power setting including the first motor operating at a second number of RPM that is greater than the first number of RPM. 
     
     
         4 . The apparatus as recited in  claim 1 , further comprising a coupling support device that secures a first position of the first motor relative to at least one of a second position of the second motor or a third position of the drive shaft. 
     
     
         5 . An apparatus comprising:
 a drive shaft;   a propeller coupled to the drive shaft;   a first motor coupled to at least one of the drive shaft or a second motor; and   the second motor coupled to at least one of the drive shaft or the first motor, wherein power output from at least one of the first motor or the second motor causes rotation of the drive shaft and the propeller.   
     
     
         6 . The apparatus as recited in  claim 5 , wherein the propeller includes a first side, the drive shaft includes a first portion of the drive shaft extending from the first side, and wherein the first motor and the second motor are coupled to the first portion of the drive shaft. 
     
     
         7 . The apparatus as recited in  claim 6 , further comprising a coupling support device that secures a first position of the first motor relative to at least one of a second position of the second motor or a third position of the drive shaft. 
     
     
         8 . The apparatus as recited in  claim 5 , further comprising a frame that is coupled to at least one of the first motor or the second motor. 
     
     
         9 . The apparatus as recited in  claim 5 , further comprising a first cogwheel coupled to at least one of the first motor or the second motor and a second cogwheel coupled to the drive shaft, and wherein the first cogwheel engages the second cogwheel to enable at least one of the first motor or the second motor to drive the rotation of the drive shaft. 
     
     
         10 . The apparatus as recited in  claim 9 , wherein the second cogwheel is coupled to a frame via a clutch bearing, the first cogwheel including a first number of cogs and the second cogwheel including a second number of cogs that is different than the first number of cogs. 
     
     
         11 . The apparatus as recited in  claim 5 , wherein the first motor is coupled to a first clutch bearing, the second motor is coupled to a second clutch bearing, the first clutch bearing enables the rotation of the drive shaft upon a first failure of the first motor and the second clutching bearing enables the rotation of drive shaft upon a second failure of the second motor. 
     
     
         12 . The apparatus as recited in  claim 11 , wherein the first motor is configured to operate at a first power setting, the first power setting including the first motor operating at a first number of revolutions per minute (RPM), and wherein the first motor is further configured to operate at a second power setting upon the second failure of the second motor, the second power setting including the first motor operating at a second number of RPM that is greater than the first number of RPM. 
     
     
         13 . The apparatus as recited in  claim 11 , wherein at least one of the first failure of the first motor or the second failure of the second motor includes at least one of overheating, freezing, locking, jamming, or a failure to rotate. 
     
     
         14 . The apparatus as recited in  claim 5 , wherein the propeller is a first propeller, and further comprising:
 a second propeller coupled to the drive shaft;   a first connector to couple a first portion of the first propeller to a first portion of the second propeller; and   a second connector to couple a second portion of the first propeller to a second portion of the second propeller.   
     
     
         15 . The apparatus as recited in  claim 14 , wherein the first connector and the second connector create a continuous structure joining the first propeller and the second propeller, and wherein at least one of the first connector or the second connector includes at least one of a malleable portion or a joint. 
     
     
         16 . An unmanned aerial vehicle (UAV) comprising:
 a frame;   a power source coupled to the frame; and   a propulsion unit, wherein the propulsion unit includes:
 a drive shaft; 
 a propeller coupled to the drive shaft; and 
 a first motor coupled to at least one of the drive shaft or a second motor, wherein the second motor is coupled to at least one of the drive shaft or the first motor, and wherein power output from at least one of the first motor or the second motor causes rotation of the drive shaft and the propeller. 
   
     
     
         17 . The UAV as recited in  claim 16 , wherein the propulsion unit further includes:
 a first cogwheel coupled to at least one of the first motor or the second motor; and   a second cogwheel coupled to the drive shaft, wherein the first cogwheel engages the second cogwheel to enable at least one of the first motor or the second motor to drive the rotation of the drive shaft.   
     
     
         18 . The UAV as recited in  claim 16 , wherein the first motor is coupled to a first clutch bearing, the second motor is coupled to a second clutch bearing, and the first clutch bearing enables the rotation of the drive shaft upon a first failure of the first motor and the second clutching bearing enables the rotation of drive shaft upon a second failure of the second motor. 
     
     
         19 . The UAV as recited in  claim 16 , wherein the propeller includes a first side, the drive shaft includes a first portion of the drive shaft extending from the first side, and the first motor and the second motor are coupled to the first portion of the drive shaft. 
     
     
         20 . The UAV as recited in  claim 16 , wherein the propeller is a first propeller, and the propulsion unit further includes:
 a second propeller coupled to the drive shaft;   a first connector that couples a first portion of the first propeller to a first portion of the second propeller; and   a second connector that couples a second portion of the first propeller to a second portion of the second propeller.