Empennage Installation Continued (4/25/14)

1.7 Hours –

The first thing I wanted to do was to get the elevator pushrods reconnected to the bellcrank in the fuselage.  I struggled reaching these parts the other day, but then I realized that the forward top skin still hadn’t been riveted to the fuselage and could be removed to ease access.  Once I took a few clecoes out, and could duck under the side of the skin, getting the bolts through the rod ends and bellcrank was a piece of cake.

After the pushrods were installed on the bellcrank, I reattached the aft pushrod to the elevators.  With everything connected, I placed the bellcrank in the neutral position and then checked to see if the elevators were also neutral (in-trail).  The elevators were slightly up, which meant the pushrod needed to be shortened.  I removed the pushrod from the bellcrank, gave the rod end a couple twists and then reconnected everything.  With this slight adjustment, the elevators and bellcrank were both perfectly neutralized.  I then double checked that more than half of the threads on the rod ends were engaged (well over half on the aft rod end, and almost all on the forward), torqued the jam nuts on the pushrod and marked them with some torque seal.  The pushrod should not need to be adjusted anymore (hopefully).

Both elevator pushrods are now attached to the bellcrank inside the fuselage. The length of the aft pushrod has been set, but the forward pushrod still need to be attached to the controls.

Next, I bolted and riveted the up elevator stop to the fuselage, and then riveted the F-781 plate to the forward spar of the vertical stabilizer.  Fortunately, all of these rivets could be reached with my pneumatic squeezer.  Once the elevator stop was in place, I checked to make sure it was the first thing the elevator horns hit.  While the elevator horns hit both the up and down stops before contacting anything else, I still need to check the amount of elevator deflection and possible shorten the stops if the deflection isn’t adequate.

Finally, I re-installed the vertical stabilizer.  Right now, the vertical stabilizer attaches with 6 bolts.  Two bolts are through the aft spar and the up elevator stop, and four bolts are through the front spars of both the horizontal and vertical stabilizers.  Now, all that is left for the vertical stabilizer installation is to drill the lower portion of the rear spar to the aft bulkhead of the fuselage and the tail wheel mount.

The F-781 plate was riveted to the forward spar of the vertical stabilizer. Then, the stabilizer was mounted on the fuselage.

The up elevator stop was riveted and bolted to the fuselage and vertical stabilizer. There is a washer on the between the stop and the vertical stabilizer on the left side to help with the offset of the stabilizer. I do need a longer bolt on that side though.

Everything except the rudder!

Looking more and more like an airplane!

Vertical Stabilizer Installation Started (4/20/14)

4.0 Hours –

The goal for the day was to have the vertical stabilizer drilled to the fuselage.  I came close to completing this, but I was sidetracked with other tasks that I thought would make installation of the vertical stabilizer easier.

First, I double checked the verticalness? verticality? of the vertical stabilizer.  To do this, I measure from the upper most rudder hinge on the aft side of the vertical stabilizer to equivalent rivets on each side of the horizontal stabilizer.  Since the distances were the same, the vertical stabilizer should be vertical.

Next, the F-712D up elevator stop is clamped to the vertical stabilizer’s aft spar and the aft deck of the fuselage, and drilled to the vertical stabilizer.  I wasn’t happy with the F-712D stop that I made the other day, so I decided to make a new one.  This time, I fabricated the part using a combination of measurements taken from my fuselage/vertical stabilizer and the plans.  By doing this, my new F-712D was slightly larger, but it gave me more edge distance to play with.  I figured I could cut the part down a bit after all the holes were drilled.

Once the vertical stabilizer is positioned, it can be drilled to the F-712D up elevator stop.

Last, the F-712D up elevator stop is drilled to the longerons.

Once the new F-712D was made and drilled to the vertical stabilizer and longerons, it was time to position the leading edge of the vertical stabilizer.  To do this, the F-781 plate is clamped to the forward spars of both the horizontal and vertical stabilizers.  Once clamped, the rudder hinge line on the aft spar of the vertical stabilizer is checked with a straight edge to ensure it is straight.  There are multiple ways to fix the vertical stabilizer if the hinge row is not straight, but I didn’t have to worry about this as mine checked out OK with the forward spar of the vertical stabilizer clamped directly to the aft side of the F-781 plate.

Next, the leading edge of the vertical stabilizer needs to be offset from the centerline of the fuselage a 1/4 inch to the left.  The point of this is to counteract the left turning tendencies of the airplane.  I only had to make a slight adjustment to get the 1/4″ offset, and then I rechecked the rudder hinge line once more to ensure it was still straight.  With everything checking out, I match-drilled the F-781 plate to both the horizontal and vertical stabilizers.  I was able to easily drill all but the uppermost row of rivet holes on the F-781 with the vertical stabilizer on the fuselage.  To get the upper row, I had to take the vertical stabilizer off and use an angle drill.

The leading edge of the vertical stabilizer is offset 1/4″ to the left of center in order to help counteract the planes left turning tendencies.

After the leading and trailing edges are positioned, the vertical stabilizer’s forward spar is drilled to the horizontal stabilizer and the F-781 plate.

Once the F-781 was drilled, I completed all the hole and edge finishing on both it and the F-712D up elevator stop.  I also scuffed, cleaned and primed both of these parts.

The primed F-781 plate and F-712D up elevator stop.

Finally, I decided that I would work on the elevator pushrods so that I could lock in the pushrod lengths and then remove the elevators.  With the elevators off I figured I would have much more room to work on the other tail parts (the elevator horns extend below the aft deck and take up a lot of access room).  Since I was going to work on the pushrods, I figured I would get both the forward and aft push rods set at the same time.  Getting the forward pushrod, which connects the control sticks to the elevator bellcrank, was a lot more work than I thought it would be because a whole lot of stuff had to be removed from the cabin/baggage area in order to get enough access to slide the pushrod into position.   By the time I had the forward pushrod in position, I had enough and decided to call it a day.

More Empennage Installation (4/19/14)

3.5 Hours –

Today, I continued working on the empennage installation.  However, before I could do any more work on the plane, I had to gather all the parts.  For the empennage, this meant climbing into the attic.  Normally, this is an easy task, but with a garage full of large airplane parts, lowering the attic ladder isn’t always possible without significant rearrangement.  Fortunately, I was able to push the tail of the fuselage far enough over for the ladder to come down.  Then, it was just a matter of handing the tail pieces down to my wife one at a time.  Surprisingly, these parts, which have been in the attic for years, had very little dust built-up on them, and absolutely no corrosion that I could see.

The first task was to install the elevators on the horizontal stabilizer and drill the elevator horns for the push rod bolt.  To do this, the horizontal stabilizer was placed upside down on my workbench.  The elevators were then installed with assembly pins and clamped in the “in-trail” position.  The elevator horns are not a matched set, so there is a little variance between parts.  Most builders do not have horns that are perfectly aligned.  Although my horns were close, the right horn is about 1/4″ aft of the left horn.  Once the aft horn is identified, it is drilled in the appropriate location with a #30 pilot hole.  Then, I made a spacer/drill guide for between the horns using a block of wood.  This spacer has a #30 hole drilled through it using the drill press to ensure that the hole is perpendicular to the block.  The spacer is then inserted between the horns and used to guide the drill for cutting the hole in the opposite elevator horn.  Once both horns have a pilot hole, the holes are enlarged for an AN3 bolt.

On the workbench, the elevators are temporarily installed on the horizontal stabilizer and clamped in the “in-trail” position.

The elevator horns aren’t a matched set, so one is usually aft of the other, and this must be accounted for when drilling the hole where the push-rod will attach. My right elevator horn is slightly aft (left in this picture since the whole assembly is upside down).

A wood block is used to make sure that the holes in the elevator horns are perfectly aligned. The wood block has a #30 hole through it that was made with the drill press to ensure straightness.

The aft (right) horn is drilled to #30 first. Then the block is used to align the drill for forward (left) horn. Once the pilot holes are drilled, the block is removed and the holes are enlarged for an AN3 bolt.

Next, the elevators were removed from the horizontal stabilizer so  I could move the parts to the fuselage.  Once the horizontal stabilizer was on the fuselage, the elevators were reattached, and I was able to bolt the push rod to both elevators.  With the push rod attached, I checked to make sure the elevators were aligned with each other and moved freely in both directions.  With the lightest touch, I could easily move the elevators, and there was no binding of any kind.  Needless to say, I had to play with elevators for a few minutes!

Once the elevator horns were drilled, the whole assembly was installed on the fuselage and the elevators were connect to the pushrod. Here they are, moving together, in the up position.

And, of course, here they are in the down position. Ignore my finger…without holding them, they want to go back to neutral or up.

Once I finished playing with the elevators, I moved on to the vertical stabilizer.  The first thing is to cut 5/8″ from the bottom of the forward spar of the vertical stabilizer.  I’m not sure why Van’s doesn’t have you do this before assembling the vertical stabilizer since it would be easier at that time, but it was still relatively easy to do this using my Dremel and cut-off disc.  Next, I clamped the F-781 attach plate to the forward spar of the horizontal stabilizer and then clamped the vertical stabilizer to the fuselage.  At this point, the vertical stabilizer has to be positioned so that it is exactly vertical and the leading edge is 1/4″ left of center (to offset left turning tendency).  I took some measurements and re-positioned the vertical stabilizer to where I think the fit is correct, but I want to take a break and re-measure before doing any actual drilling.  I’ll return to this tomorrow.

The vertical stabilizer is clamped to the horizontal stabilizer’s forward spar and to the rear bulkhead of the fuselage.

A closer view of how the vertical stabilizer is clamped to the horizontal stabilizer’s forward spar.

In the meantime, I started fabricating the F-712D up elevator stop.  This part is fashioned from some stock angle, and I managed to get the rough cuts done, but it still needs a lot of finishing work.  However, since this is the first part to get drilled to the vertical stabilizer, it will be at the top of my priority list.

The F-712D up elevator stop is the first part that gets attached to the vertical stabilizer. Here is the rough cut part…it still needs a lot of touching up before it will be ready to be installed.

Finally, one to show the FAA as proof that I’m the builder.