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Elevator Control Rods

This weekend I took the time to build the control rods for the elevators.  This is a task I did before when I did the ailerons, but it had been awhile.

No pictures for cutting and priming the tubes.  You can use your imagination.  The real issue is you have to drive X number of rivets around a circumference of a rod.  You start with a strip of paper that is the exact circumference of the rod.  Then you divide that value by the number of rivets.  So you have 8 rivets that need to fit a 6.5″ circumference, then you make a tic mark every 13/16″.   You then wrap the paper around the rod, and transfer the tic marks to the metal.  Drill.  Rivet.

Drilling can be done several ways.  I chose to use the drill press for more accurate holes.

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My drill press is plenty able to handle this with my pipe guide.

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I used my pneumatic puller to set the pulled rivets.

The one on the left is the rod from the control stick to the bell crank.  The one of the right is from the bell crank to the elevator.

Now I’m ready for the step after drilling all the holes in the HS.

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I Need Some Time to Ponder the Rear Spar

I have no idea why.  It is pretty easy.  Make a measurement, drill some holes and you’re done.  Its the measurement…it always comes down to the measurement.  The problem is the instructions.  They tell you to measure the height of the tooling holes in the inner rib of the HS from the deck.  This is really hard.  The holes are recessed into the HS so it is incredibly difficult to get a accurate measurement.  I tried multiple ways, and was just not happy with the consistency.  Shopping for something else at Lowes I determined that a 3/16″ rod would solve the problem.

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So there you go.  This will produce an accurate measurement.  I don’t need the actual value, I need to make sure the number is consistent on one side and the other.

Ok…the numbers are off.  I thought about just lifting one side, but that didn’t feel right.  It turned out I had some washers missing from the forward spar.  Once that was corrected the value was spot on.

There is one more important measurement here.  Looking at the rear spar, above, you have to get a measurement of 3/16″ from the bottom of the spar to the deck.  So I begin the search for something that is 3/16″ that I can slide under there to get the right measurement.  If you notice there are rivet heads under the spar, which means you have to find something that will fit in between the rivets.  About an hour of messing around with various methods and failing it suddenly dawned on me that the 3/16″ rod that I bought is, ironically, 3/16″.  Duh.

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Viola!  A precise 3/16″ gap.  The gap is required to get a 0° incidence from the HS.  Getting pretty close to time to drill.

Getting the Tail On

Its time to put some more wings on.  This time I am going to work on the horizontal stabilizer.  The date was in early January.  First thing is to get the HS situated on the tail in the correct orientation.  This took two of us as I had to wiggle it this way and that to get it just right.  Eventually I arrived at a position I like so I clamped it in place.  From there we measured to several locations around the fuselage to make sure everything was true.  I am happy that them measurements are within a 1/16″ so I called it good.

The first holes you have to drill are in the forward spar.  I deviated from the plans because I was super paranoid about the location of the hole I was going to put in the longeron.  So I drilled that hole first using a #30 after measuring a bunch of time to makes sure that I was getting it right.  I then had my daughter climb into the tail and drill up through the longeron and forward HS spar.  First with a #30 then with the final bit 3/16″ (I think).

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20170102_175258img_20170128_145813The two outer holes are a bit further aft then I wanted, but they are still legit.  The two inner ones are perfect.

Once everything was bolted on the measurements were still perfect.  Now the rear spar.