Composite failsafe torque tube

Abstract

An air vehicle control surface includes an upper skin, a lower skin, a plurality of composite spars extending between the upper skin and the lower skin, and a failsafe torque tube. The failsafe torque tube includes an outer composite tube and an inner tube disposed within the outer composite tube and extending coaxially with the outer composite tube.

What is claimed is: 
     
         1 . An air vehicle control surface, comprising:
 an upper skin,   a lower skin,   a plurality of composite spars extending between the upper skin and the lower skin; and   a failsafe torque tube comprising:
 an outer composite tube; and 
 an inner tube disposed within the outer composite tube and extending coaxially with the outer composite tube. 
   
     
     
         2 . The air vehicle control surface of  claim 1 , wherein the inner tube comprises a metallic inner tube. 
     
     
         3 . The air vehicle control surface of  claim 1 , wherein the inner tube comprises a composite material. 
     
     
         4 . The air vehicle control surface of  claim 1 , wherein the failsafe torque tube is disposed between at least two of the plurality of composite spars. 
     
     
         5 . The air vehicle control surface of  claim 4 , wherein the at least two of the plurality of composite spars physically contact the outer composite tube. 
     
     
         6 . The air vehicle control surface of  claim 1 , wherein at least the outer composite tube comprises a plurality of cured composite plies wrapped around at least a portion of the inner tube. 
     
     
         7 . The air vehicle control surface of  claim 6 , wherein the plurality of composite spars are co-cured with the composite plies of the outer composite tube. 
     
     
         8 . The air vehicle control surface of  claim 1 , wherein the outer composite tube and at least one of the plurality of composite spars are cured together. 
     
     
         9 . The air vehicle control surface of  claim 1 , wherein the outer composite tube is non-rotatably disposed in the air vehicle control surface. 
     
     
         10 . A method for forming a composite air vehicle control surface, comprising:
 forming a composite failsafe torque tube between an upper skin and a lower skin of an uncured composite control surface structure in a outer mold line (OML) mold, wherein the composite failsafe torque tube comprises an uncured outer tube; and   co-curing the uncured outer tube and the uncured composite control surface structure.   
     
     
         11 . The method of  claim 10 , wherein forming the composite failsafe torque tube comprises positioning an inner tube in the OML mold, and forming uncured composite layers around the inner torque tube to form the uncured outer tube, the inner tube comprising a mold for forming the uncured outer tube. 
     
     
         12 . The method of  claim 10 , wherein the OML mold comprises an upper mold and a lower mold, and wherein the method further comprises:
 positioning a forward bag carrier on the lower mold;   positioning a mid bag carrier on the lower mold; and   positioning an aft bag carrier on the lower mold,   wherein the composite failsafe torque tube is positioned between the forward bag carrier and the aft bag carrier.   
     
     
         13 . The method of  claim 10 , wherein the composite failsafe torque tube further comprises an inner tube disposed between inner sidewall portions of the outer tube and comprises a length that extends coaxially with a length of the outer tube, wherein forming the composite failsafe torque tube comprises at least partially wrapping plies of a composite around the inner tube to form the uncured outer tube. 
     
     
         14 . The method of  claim 13 , wherein the inner tube comprises a metallic inner tube. 
     
     
         15 . The method of  claim 13 , further comprising placing an inner mold line (IML) bag into a hollow inner volume portion of the failsafe torque tube. 
     
     
         16 . The method of  claim 15 , wherein the IML bag is further positioned over a bag carrier. 
     
     
         17 . The method of  claim 10 , wherein the uncured composite control surface structure further comprises a plurality of spars extending between the upper skin and the lower skin 
     
     
         18 . The method of  claim 17 , wherein at least one of the plurality of spars and the outer tube are cured together to prevent the outer tube from moving. 
     
     
         19 . The method of  claim 17 , wherein curing the outer tube joins the outer tube to the control surface structure. 
     
     
         20 . A method for using a composite air vehicle control surface, comprising:
 forming a composite failsafe torque tube between an upper skin and a lower skin of an uncured composite control surface structure in a outer mold line (OML) mold, wherein the composite failsafe torque tube comprises:
 an uncured outer tube, 
 an inner tube disposed between inner sidewall portions of the outer tube and having a length that extends coaxially with a length of the outer tube, wherein the outer tube extends a length of the inner tube, and 
 wherein forming the composite failsafe torque tube comprises at least partially wrapping plies of a composite around the inner tube to form the uncured outer tube; 
   co-curing the uncured outer tube and the uncured composite control surface structure; and   connecting at least one end of the inner tube and at least one end of the outer tube to an actuator.