THE FUSELAGE FLIGHT CONTROLS

 

 

The flight control system installation in the fuselage was started with the assembly of the center section.  I made a decision at that time to put the cross-tube in place during the assembly of the center section.  The plans called out to modify two of the center section ribs by cutting a section out and replacing it with a section that is re-movable.  I figured that if I bolted the cross tube in place and left it there that this modification would be un-necessary. See the two photos immediately below.

 

Control cross-tube assembly in place The plans called out mod to two of these ribs

The flight controls did not get further attention for over a year while I completed most of the fuselage structure construction.    In November of 2004, I finally got back to the flight controls.

Tubing that will make up the elevator control Cut lines on the tubing

In the picture above left I have the two sections of tubing that will ultimately make up the elevator control system in the fuselage.  The smaller tube is for the forward section and the larger tube is for the aft section.  In the photo at right, I have marked each tube to be cut to its proper length. 

Layout of the rod end fitting attach holes Another view of the layout

In these two photos, I have tape on the ends of the tube with marks where the holes will be drilled for the rod end fittings.  Instead of me describing how I did laid these holes out here, go to the Left Wing Aileron and Control section.  I used the same procedure for the lay-out of these holes.

A picture of surface corrosion in initial stages Control tubes ptimed

 

In the picture at the left above, you can see one of my fears coming to light that caused me to prime nearly every part of this airplane.  What you see are little "freckles" of surface corrosion starting on the larger of the two tubes.  At this stage the only damage is to the anodized coating on the tubes.  Above right you see my solution: etch, alodine and prime.

 

Painted push/pull tubes Primer inside the end of the tubing

Above left is a photo of the two push/pull tubes after I painted them with "Whisper Gray" Awl-grip.  This color is very close to the same color as the powder coated gray that comes on all of the steel parts in the kit.  Above right I am putting primer in the end of one of the tubes with a cotton swab in preparation for the installation of the rod end fitting.

End of the tube primed Rod end fitting primed

 

No matter which side of "The Great Primer Debate" that you were on, I believe this step is a good idea.  I put primer on the inside of the tube and more primer on the outside of the rod end fitting.  The rod end fitting is made of steel on the smaller tube and even though it is cad-plated I wanted an extra barrier against dissimilar metals corrosion.

 

Drilling rivet holes Installing CR3243-4-3 blind rivets

In the left photo above, I am transferring the rivet holes that I previously drilled into the forward (smaller) push/pull tube to the rod end fitting.  In the photo above right I am installing a CR3243-4-3 "Aircraft Quality" blind fastener into the tube/rod end assembly.  I think that the next great debate should be about the use of aircraft quality blind rivets versus the hardware store "pop" rivets supplied with this kit. 

Rod end fittings installed on each tube Preliminary step to adjust lenght

 

The picture above left shows the two elevator push/pull tubes with the fittings installed.  At right is a picture of the first step towards adjusting the tubes to the proper length.  I put a strip of masking tape on the work bench with a line on it.  I put another strip of tape with a line on it on the table with the distance between the two lines the distance that is prescribed in the plans from hole to hole. 

 

One end of tube with bolt in middle of the line The other end of tube with bolt in middle of line

I then put a bolt in each rod end to use as an indicator.  I adjusted the rod ends until each bolt was in the middle of each line.  This gives me the dimension that the drawing calls out.  I also spaced each rod end so that the number of exposed threads was approximately the same on each end.  I tightened the jam-nuts up and this push/pull tube is ready for installation.  More than likely, more adjustments will be made when I do the final rigging but I do not like leaving bolts or nuts loose.

Installing the forward tube I had to remove the rod end

 

It was now time to install the forward push/pull tube.  I must have missed a step in the plans because putting this thing in place was like trying to figure out a Chinese nail puzzle.  The first thing that I had to do was to remove some material in the bulkhead hole at F-706 (above left).    Then in order to get the tube through the F-705 bulkhead I had to remove one of the rod-ends (above right).  To save my adjustment I put a piece of "anti-rotation" masking tape on the jam nut.  In that way, when I put the rod-end back on, I could easily put it right back where it was.

 

Front end of push/pull tube Aft end of push/pull tube

Above is a photo of the push/pull tube with the forward rod-end re-installed.  The rod end is attached to the control cross tube.  the jam nut is tightened again and the attach bolt and nut are tight.  I have a maintenance practice that I preach about constantly.  Do not leave bolts or nuts loose.  Tighten them up every time you install them.  It takes mere seconds to loosen them back up if adjustments need to be made.  In this way you never have to worry about a loose bolt falling out of a critical flight control.  Now to get off of the soap box and on with the project.

Drilling co-pilot control "stick" Both control "sticks" installed

 

Above left is a photo of the co-pilot control column or "stick" as it is being drilled for a bolt to hold it to control mechanism.  I put a bolt in it (and tightened it up) but I may switch to a pit-pin later.  At right is a picture of both of the sticks installed. 

 

Aft push/pull tube adjustment Tape with line on it

The next step was to adjust the aft push/pull tube to its initial length.  The procedure was the same as the forward tube except the work bench was not long enough so I had to use the floor.  After the tube was adjusted I tightened the jam nuts and put it away.  It will not be installed until the tail feathers (empennage) are put on.

Rudder cross-tube bushing block Can't get straight shot to drill

 

The next thing that I tackled flight control wise was the rudder pedal assembly.  First, I drilled the plastic bushing blocks on the mini-mill (above left).  I then attached them to the rudder pedal cross tubes and clamped the assembly to the middle longeron for drilling.  I could not get a straight shot with a drill motor to drill the holes.  The drill motor would not get past the upper longeron and even if it did, the chuck would hit the skin.  This was a perplexing problem.  Maybe I should have drilled these holes sooner, like before the skin was riveted on.  There had to be a solution.

 

Flexible drill extension Works like a charm

 

Who had the solution?  You guessed it, Lowe's.  They sell a flexible drill extension (above left).  With this extension and a 3/16" hex based drill bit, I snaked right past the upper longeron and drilled the attach holes for the rudder bushing blocks (above right).

 

Two sets of holes Rudder pedal assembly installed (temporarily

The plans tell you that you can drill several sets of holes so that the rudder pedals can be put in different positions.  I decided that two positions should be enough so I drilled two sets of holes (above left).  The lines on the masking tape are for the forward hole in each set.  The sets are 2" apart.  Above right you can see that the rudder pedals are happily attached to each middle longeron via the plastic bushing blocks, however there is one more bushing block to install.

Center brace modification Center bushing block

 

There is a center bushing block on the rudder pedal cross bar and a brace that holds it.  The brace is basically a formed angle with one leg much wider then the other at one end, tapered to approximately the same width at the other.  The first step in the installation of this part is to modify the narrower leg (above left) so that the brace can fit between the vertical angle on the firewall and the recess in the firewall which is a stainless steel box that I have already installed.  Next is to drill the 3/16" holes in the center bushing block and very carefully cut it in half so that it can be placed on the cross tube assembly (above right).

 

Center brace gets attached to this angle No way rivets will fit in this narrow gap

The center bushing block gets attached to the F-6118 Rudder Pedal Brace (above left).  This brace gets riveted to the F-601-L vertical angle.   There is no way that the rivets will fit between the angle and the firewall recess (above right).  I made the decision when I built up the firewall to attach the recess at that time.  Did I shoot myself in the foot?  Stay tuned.  Every deviation from the plans could create a new problem but every new problem may have a solution.

Brace to be installed between angle and recess A shim will need to be installed as well.

The first step in the solution was to see if this brace could be installed on the inboard side of the angle, between the angle and the recess (above left).  Yes it could but the gap was too great.  A shim would be required.  After some trial and error type measuring, I determined that the shim would need to be .063 thick in this case (above right).

For the rest of the narrative, please press "The Fuselage Flight Controls Page 2" link below.