Cantilevered Hinges (part 2)

By: Tom Noser

The leading edge is made by cutting a 1/8" saw kerf in the back of the leading edge block and then tapering the block as required. Two sheeting kerfs are then cut into the edges. Cut transverse slots for the ribs and round the block to a half round shape. The hinge beams can now be located and the slots cut to allow free movement through about 30 degrees. Glue the hinge beams into the leading edge and put the top sheathing and all the ribs in place. You are going to need a solid block between two of the ribs to accommodate the operator shown in Figure 3.

To make accurate "Z" bends I drilled a 3/32" dia hole 1/8" below the top in one inside face of my vice. Bend a 1/8" leg on the end of a 1/16" or 2-56 rod using the vice and a hammer. Put the leg in the hole in the jaw face of the vice and close down on the rod. Hammer a bend in the direction opposite the first leg and remove the rod from the vice. I think you will like the result.

Figure 3 is definitely for serious builders. It will deliver all the torque your servo puts out without friction losses or slop. When used in conjunction with the hinge shown in Figure 2, the control surface is easily removed for painting or maintenance and, best of all, you’ve gotten rid of the turbulence and unsightliness of the outside operators.
The zero gap surface still needs a cloth seal between the surface and the rear spar as is done on prototype aircraft to eliminate airflow between the top and bottom of the wing, but I think that balancing the surface about the hinge line will eliminate flutter problems.

Figure 4 illustrates the aileron and elevator hinge for a Cessna 310. The 20% hinge line gets the aileron balanced with a minimum of additional weight in the leading edge.
Note that the operator in Figure 3 is not pinned to the aileron. It is free to slide in the telescoping tubing. Also, the 2-56 screw is tapped through the block and the 1/8" square tube.
The bracket in Fig. 1 can be replaced by a piece of 1/16" plywood, which is glued to an aileron rib. The hardwood block is slotted with a 1/8" saw kerf 1/8" deep and glued to a plywood plate.

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