The rudder cables need to pass through the fuselage skin on each side of the tailcone. Yet the builder's manual gives us no help in determining where to cut the slot, how big it should be, shape, etc. A large portion of the time that I spent determining how to install the control cables, was dedicated to figuring out exactly where I should cut this slot. I DID NOT want to cut in the wrong location!

So I taped two large pieces of kraft paper to the hangar walls. On one I drew a full size line diagram of the fuselage top view, showing the exact bulkhead locations from Bulkhead A to the rudder control arm. On the other I drew a full size line diagram of the fuselage side view, showing the exact bulkhead locations from bulkhead A to the rudder control arm. These were not extensive drawings, just single line drawings to show the exact width/height.

This is going to be difficult to explain from here on, but I'll give it a shot. Before I could figure out where the rudder cable should exit the tailcone I had to figure out how the cables would run along the inside of the fuselage. I gave a lot of thought to this because the builder's manual tells us only to keep the cable as straight as possible. AC 43.13-B2 tells us that when using cable guides/fairleads the direction of the cable should not be changed more than 3 degrees.

I seriously considered installing rudder cable pulleys at bulkhead A and Bulkhead E as some builders have done. There are several photos of this type installation in the picture archives on the builder's mail list. While I think this is probably the best way to run the cables, in the end I decided that many more builders have used the cable guides/fairleads successfully, and pulleys would just complicate the building process. I've had enough complications during the building of this airplane and didn't want any more. So I just decided to use the cable guides in the best fashion I could.

The other issue here is how high/low on the fuselage inner wall do I mount the cable guides? If I mount them lower than the top rivet line of the inner corner wraps, then the cable is being mounted further inboard due to the radius of the corner wraps. This means that when the cable turns outward from bulkhead D, the angle outward will be greater.

I played with the positioning of the string on the drawings to try to determine where they should run along the inner fuselage and how the angles would be as the cable exited to the rudder horn. I found that the instructions to keep the cable run as straight as possible was much easier said than done.

As I stated earlier, if you mount the rudder cable guides low, in the curve of the corner wraps, that increased the outward angle the cable has to make to exit the fuselage. The higher the rudder cable guides are mounted in the fuselage, the greater the downward angle the rudder cable has to make in the tailcone as it exits to the rudder horn.

I decided that the only logical compromise was to mount the rudder cable guides along the top of the inner corner wraps from the carrythrough bulkhead to bulkhead D. In my opinion this was the point that would minimize both angles the rudder cable would have to make (downward and outward) as it continued aft of bulkhead D to the rudder horn.

Back to my drawings. If my full size drawings are correctly sized, I could (theoretically) obtain measurements from the drawings of the point where the cable (string) would pass through the fuselage skin. On the drawings, I marked the point where the string intersected the line of the fuselage skin, then I measured up from the bottom skin and aft from the bulkhead E. I transferred these measurement from the drawings to the aircraft tailcone. What I found was that because I was taking measurments from one dimensional drawings and transferring those measurements to a three dimensional object, the point I was measuring for was actually a 'point in space' outside the fuselage. I determined this was due to the combination of the curvature and taper of the tailcone.

So, to try to explain a little more, the fuselage exit point I was measuring for on the drawings actually turned out to be a 'point in space' just outside the curvature of the outside bottom corner wrap. At first this kind of threw me, but I surmised that even though this was a 'point in space', it was still on the path the actual rudder cable would take. I figured out that I would have to attach my cable (string) to the rudder horn, pass the string through this 'point in space' that I had measured to and, keeping the string taught, find where it intersected the fuselage skin and that is where the exit hole would be located.

I don't think I can adequately describe how I measured this 'point is space' without totally confusing anyone reading this. Suffice it to say that, from the full size drawings I measured from known points, ie; the plane of the outside skins, the bulkhead line, etc. So, from the drawings determine the distance aft of bulkhead E (or forward of the solid bulkhead). Transfer that measurement to the fuselage and mark it. Then go back to the drawing and determine how far above the plane of the bottom skin the point will be. Using a four foot straight edge placed vertically against the outside skin at the mark made previously, and a straight edge against the bottom horizontal skin, measure up from the intersection of the two straight edges the appropriate distance. This should be your 'point in space'. Make a note of how far below the horizontal rivet line the measurement is so that you don't have to use two straight edges to find it again. All you will need to do then is place the vertical straight edge against the skin at the aft mark and measure down from the rivet line.

OK, with the vertical straight edge in place against the skin at my mark, and my cable (string) attached at the rudder horn, using my one free hand I run the string taught along the fuselage. Extend the string forward with the thumb pressing it against the skin. Keep adjusting it (your thumb) high or low, forward or aft until the string just touches the vertical straight edge at the known distance below the horizontal rivet line. Where your thumb is at this point is where you will cut the slot for the rudder cable to pass through the fuselage.

With the string on the drawings running straight from bulkhead D to the rudder control horn, the string indicates it will pass through bulkhead E. The downward angle of the cable from Bulkhead D also exceeds three degrees. If I move the string to pass along the inner flange of bulkhead E, the outward angle of the string to the rudder horn exceeds 3 degrees.

I elected to have the rudder cable pass through bulkhead E. By doing this I could set a cable guide in bulkhead E at a position that was slightly higher, and slightly inboard, than a straight line, thereby easing BOTH angle changes between bulkhead D and the rudder horn. So I had to move my strings around on the drawings until I had the angles OK. I transferred these measurements to the drawing that I had made of the bulkhead radius so I could figure out where on bulkhead E I would need to drill a hole for the cable to pass through. I then had to recompute the point on the fuselage where I would have to cut the slot for the cable to pass through.

Once I believed this would all be OK, I thought about it more, measured everything else again at least a dozen times, decided it was as good as it was going to get, and drilled a #30 hole in one side of the tailcone. Then I drilled a #30 hole in one side of bulkhead E. I ran my rudder cable (string) the full length, tying it off to the rudder pedal, through the cable guides, through the hole in the bulkhead E, through the hole in the tailcone, and tied it off to the rudder horn. I checked the routing to see how I might need to adjust the hole in the bulkhead E or the tailcone. Then I gradually opened up the slot in the tailcone until I was satisfied with it. And I drilled the hole in the bulkhead E to 1/2 inch diameter to accept my custom made fairlead. But getting back to the tailcone slot, one idea that I saw and liked on Steve Sloan's and Chuck Bailey's Rebels was a cable guide installed in the tailcone slot for the rudder cable. I tried a stock cable guide as came with the kit but didn't like it because it created a sharp bend in the cable. To be usable, I felt it would have to be altered. So I fabricated my own from some delrin stock I had. I also fabricated a fairlead for the bulkhead E from the same material. See the attached photographs.

He did not like the angle of the rudder cable from the rudder pedal to the first cable guide at the carrythrough bulkhead. He suggested a small pulley here. He even offered to fabricate the pulleys on his lathe. So I made up some brackets out of some hefty .063 6061-T6 and used the pulleys he turned from aluminum stock.

I really like how they turned out. Initially I thought they would be obtrusive, but they really aren't in my opinion. At least no more obtrusive than the control column torque tube mounted in the middle of the cabin floor or the mixer arm assembly on the pilot's side; or the unshielded control cables running through the cabin.

My EAA Technical Counselor also did not like the angle of the rudder cables past the bulkhead A location and suggested pulleys here also. I fabricated brackets of .032 6061-T6 and used the same type pulley that Murphy Aircraft had provided for the elevator cable/bulkhead D station.