THE LEFT ELEVATOR

 

July 10, 2002, I started on the LH elevator.  I inventoried all of the parts and studied the plans carefully.  I still made two errors that required repairs though.  I probably was in too much of a hurry.  One mistake was on the trim tab and the other was on the elevator skin.

 

LH elevator skin and stiffeners Stiffeners after trimming

 

Just like the rudder the elevator stiffeners have to be trimmed out of the “L” angles shown in LH photo above.  They are partially cut so the process is not difficult.  RH photo shows completed stiffeners ready for fit check.

 

Stiffener fit check. Status of LH elevator as of 7-14-02.

 

Two days after trimming, I fit checked the stiffeners to each skin and also checked the spar for hole alignment as well (LH photo above).  I then moved on to the trim tab (Not shown here.  See Elevator Trim Tab section).   After the trim tab was done it was on to the rest of the LH elevator. 

 

Another mistake, another repair!!!! Filler riveted in place (poor photo, sorry)

 

Because of business I did not get back to the elevator until September.  I laid out the pieces to get the elevator project started again (Notice the completed trim tab in with the rest of the pieces in the photo taken on 7-14-02).    I got in a hurry because of the lost calendar time.  I put another dimple hole beside the rivet hole near the trailing edge with the "C" frame dimpling tool.  It is on top and will show.  Also, I cracked the skin at the accidentally added hole.  My mistake was trying to use the long reach dimpling tool too close to the trailing edge.  I should have been using the pop rivet dimple tool at this point but I tried to save a little time and it cost me.  I had three options to contemplate before continuing; 1) Ignore the problem; 2) Replace the elevator skin or; 3) Repair the existing skin.  Making a repair made the most sense.  I decided to do a flush repair.  I removed the damage with a unibit.  The hole ended up at 3/8”.  I made a doubler to put on the inside of the skin between the skin and the stiffener.  The photo above left shows the doubler after I picked up three existing holes and added six more.  I then made a small filler (above right, sorry about the blurred picture) to rivet into the 3/8” hole.  The photo below shows a view of the doubler from the inside after it was riveted in place.

 

 
Repair doubler riveted in place  

 

Even though I made this foolish mistake, the bright side is that the repair was easy enough to make.  I am sure that this is not the last of the mistakes on this project.  I hope that they are all repairable.

 

Elevator parts primed. Stiffeners installed on lower skin

 

That is enough about the errors, back to the elevator assembly project.  The upper left photograph shows the elevator parts in the paint booth after they were etched, alodined and primed.  The upper right picture shows the elevator after the stiffeners were attached to the lower skin.  You can just make out the back riveting bucking bar sticking out from beneath the skin towards the left.  The doubler for the trim tab control access panel is also attached at this point.  I enjoy this back riveting process used to install these stiffeners.  The rivets come out uniform and the thin skin does not get warped as it would with normal riveting procedures.

 
 
All stiffeners installed Trailing edge formed ready for final assembly

 

The left photo above shows the elevator skin with all of the stiffeners attached.  The right photo shows the elevator after the trailing edge was formed.  The trim tab spar has been installed and the trim tab is in place to help keep the sub-assembly straight for final assembly.  The front spar is attached with clecos.  The end ribs will get a fit check at this point to make sure that there are no problems on final assembly.  It was time to put this away for another 2 weeks.  Business is calling again.

 

Fit checking spar LH elevator clamped for riveting

 

September 14th, 2002.  Today is the day for the final riveting of the left elevator.  The spar, outboard end rib, inboard end rib and the control horn are all attached with clecos.  The assembly is clamped to the work bench to keep it straight and in addition four buckets of clecos are put on the trailing edge to keep the elevator from warping.  The rivets in the upper skin are installed with a pneumatic squeeze for the most part, however, some are installed with a manual squeeze and some are shot with a rivet gun and bucking bar.  The outboard end rib gets a balance weight attached.  I had to be careful with the weight.  It needs to be installed before all of the rivets are in but its mass can distort the elevator if not enough rivets are installed. 

 

Riveting completed Warp and twist check

 

After the rivets were all installed, and the balance weight was in, I laid the elevator on the table to see if it had warped.  It checked out OK.   On this positive note, I decided to call it a day.  Tomorrow I will form the leading edge.

 

Ready for leading edge forming The first section is formed

 

Sunday, September 15, 2002, it is time to form the leading edge on the left elevator.  As I stated while I was doing this to the rudder, I would try forming one section at a time (above right).  This worked much better.  Again I dimpled the holes and used CR3214-4-2 rivets.  I also used a broom handle instead of a pipe.  This made it easier to roll and hold the elevator at the same time.

 

The last L.E. section partially riveted The completed LH elevator

 

These last two photos show the leading edge being finished (LH) and the completed elevator (RH).  I wasn't sure when I would get back to this project as we have leased an FBO in Gallatin, Tennessee and My wife and I have been spending a lot of time trying to get it up and running.  Almost my entire workshop has been moved to there.   I intend to set up and resume this project as soon as I can.