Elevator & Rudder Hinges page 2

The Horizontal Stabilizer spar (for the elevators) or Tail Post for the rudder) must be drilled and a reinforcement tube is welded in place for the bolt to go through.  This is similar as was done on the aileron support frame to bolt the aileron cable pulley to it.

First, a hole was drilled in the Horizontal Stabilizer, aft spar, to receive the tube.  The hole must be located properly, as per the plans, and must be perfectly perpendicular to the spar (straight up and down).  To do this, I first made sure the Horizontal Stab was laying on the table top flat and level.  Then using my drill with the built in bubble level, the hole was drilled through, keeping the bubble center to assure the drill was vertical. I started the hole with smaller bits and gradually increased the size of hole until it was the correct size as was needed for the tube.  Here it is ready to be welded:

The tube was left extra long for welding.  This prevents the edges of the tube from being melted away.

After welding was completed, the tube was cut off and filed down on both sides until it was exactly 1" wide:

Now with the stabilizer ready to receive the hinges, the forward holes in the strap hinges can be match drilled with the stabilizer spar.  The elevator spar centerline is exactly 1 1/8" from the horizontal stabilizer spar centerline.  The top hole in the strap hinge was measured and drilled first, then the hinge was placed onto the horizontal stabilizer and clamped flat to the table.  The drilled was then run through the hole/tube in the Horizontal Stab and through the bottom strap of the hinge.

After the final holes were drilled in the strap hinge, the front edge was rounded off as shown in the above picture.

There is a small "V" bracket, welded to the aft edge of the horizontal stabilizer, that supports the hinge straps.  This is shown on drawing #21 in the hinge detail area.

Here is a side view picture showing the strap hinge bolted to the horizontal stabilizer spar and "V" support piece:

You can also see the grease fitting in place.  

A little thinking ahead goes a long way here.  The grease fitting must end up on the bottom of the hinges when the Horizontal Stabilizers and Elevators are bolted in place on the fuselage.  Remember, the elevators are both made in the same jig but one is a right and one is a left. Therefore, one elevator should have these grease fittings pointing downward when in the jig and the other elevator should have the grease fittings pointed upward while in the jig.  

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