Build Log RV-10 #1

Blog for a Vans RV-10 Airplane Build

Rudder Trim

Started on August 11, 2009 - Build Time 29 hours

After looking for as many different ideas on  adding rudder trim.  I  have chosen to use the method that both Robin  Marks and Geoff Combs  have used.

I am thinking of making just a few changes to there  method and will try  to give as best description of this as I go.

My first step is to mark out on the rudder where everything will go.  I  tried to get pretty close to the middle of two skin stiffeners.  I  picked the ones that the middle hinge cutout is. 

The tab is  7" wide and 3 3/4" deep at and 2 3/8".  The difference is to  make the  front side of the tab perpendicular to the leading edge of the  rudder. I  then marked out the access plate, locating it       3 1/8"  from the  leading edge of the tab.

The next step was to drill a starting hole for the access plate.  I  then  clecoed and then match drilled all the outside holes with a #30  bit. I  probably should have used a #40 but used the #30 by mistake.  To  match  up all the rivets so they look the same, I will just use the  1097AD4-3  (also known as Oops Rivets).  I then clecoed the access cover  to the  skin and marked where I need to cut out.

The cut out was made with a dremel and cutoff wheel.  To make the cut  straight, I laid a straight edge to where the cut needed to be and ran  the dremel with a sanding wheel along it.  The cut came out nice and  straight.  I also made the elongated hole for the push rod also with a  dremel tool.

Everything was then deburred, dimpled then alodine  and Akzo primer  applied.

Tonight I started with cutting trim tab out of the rudder.  I used  once  again a dremel with cut off wheel then finished the trim work with  a  file and a sand drum on the dremel.  This was a bit nerve racking to  do,  but it worked out just about perfect.

I then made a  U-shaped rib to fit between the 2 skin stiffeners that  will give the  skin some more strength.  Also, the hinge for the trim tab  will be also  be riveted to it.

I then used a rivet spacing fan to mark out  the holes on the trim tab  and the hinge.  Then did the same for the  holes that protrude through  the skin, the new u-brace, and the hinge  attached to the rudder.

After getting this area for the hing  cut out, It came to me that I  should have flipped the hinge over so  that it did not protrude out.  It  is only a very little bit and do not  think it will make any performance  issues so I just left it the way it  was.

Then clecoed everything together to check the fit and  looked pretty good  except for some minor trimming.  Like a bit of skin  removal for the  hing pivot area.  Once that was done, I deburred all  the edges and holes  and dimpled.

I then moved on to the access  plate, I dimpled all the holes and riveted  on the nut plates  (k1000-06) and then riveted the access plate frame to  the rudder skin.   Since the nut plates use #6 screws, I had do  re-dimple the access  cover and plate with a number 6 dimple die.

Today I Finished cleaning up all the holes.  Had to dimple the holes  for  the piano hinge and the holes in trim tab.  Removed the brace that  runs  vertically placed by the trim tab slot that the skin and hinge  attache  to so it could be deburred and trimmed just a bit.

Then it was time to manufacture a control horn.  Just took an extra  piece of aluminum and cut to the shape I was looking for.  Then put in a  bend 1" down so that it could be attached to the trim tab with a  couple  of rivets.  If you look at the horn, you will notice that I had  to cut a  bit of it out to allow for travel on the forward side.

Once this was done, I riveted the brace in place.  Since it would be  impossible to try to run solid rivets into the trim tab, I ended up  using stainless steel cs-4 pull rivets.  I though about putting nut  plates in the hinge so it could be screwed on but the holes on  the ends  of  the hinge would not allow it.

My next step was to try and finish of the  slot where the push rod goes through the skin.  I used a fairing  purchased from Aircraft Spruce.  I put it in from the inside and then  finished forming the outside with Super Fill.  This worked out pretty  good.  Kind of nervous about how much travel I will get with such a  small hole so may have to bore out a bit.

I also used Super  Fill to go around the control horn on the trim tab to  fill in all the  gaps and cover the rivets.  This needs a bit more  sanding but turned  out better than I expected.  In addition to this, I  filled inside of  the trim tab also with Super Fill to make it stiffer.

Following  are some pictures with this all done with the servo and  control rod  just in place for pictures.  I am waiting for some Click  Bond studs to  mount the servo.

Finally received the Click Bond studs and got  them installed.  The servo  is now temporarily installed and mounted  with push rod.

I am having some issues with the push rod  hitting the rudder outer skin  when pushed and the flare when it is  pulled.  Trying to get some ideas  on how to get more travel.  Right not  there is about 1/2 an inch but the  servo has 7/8" of travel.  Otherwise, it is finished and I am pretty  satisfied with how everything  turned out.

Click on Images to view full gallery.