Chapter 20
Winglets:  Featuring split rudder and blended winglets.
  Winglet Foam
         Antennae Installed  
                  Hotwired foam ready for antennae and glassing.
   Antennae installed as per plans.  I change this later to forward facing antennae it should get better distance forward to the control tower or traffic.
  Winglets of Gold          Clipped Winglets.
Winglets are glassed, peel plied and mylar wrapped.  The only benefit of the outside layer of plastic is that it is easier to see if there are bubbles and they can be worked out.  I also considered  painting the plane gold.  I've seen a very nice golden Berkuit.
    Both winglets are clipped together to be filed and sanded to a perfect matching set.  I don't think this is in the plans but I think it's a great idea.
  Split Rudder Cutout.
         Split Rudder 2
 Split Rudder has been cut out.  I first cut the fiberglass surface with a dremel diamond wheel then hotwired the  foam.  I want it to fit into the stabilizer like a glove.
               Glassing the split rudder and forming for a uniform fit.
  Modified Cozy Girls Hidden Belhorns.
         Bellhorn, hinge, split rudder
  I use the CG Belhorns.  (CG = Cozy Girls, not Center of Gravity)  Nice work!           Split rudder showing hinge, bellhorn, and bottom swing area.
  Lathe Spring Cap
   spring tension assembly
     I turned a plywood spring retainer cap for the rudder tensioner on a small lathe.                          
        Rudder tension spring assemblys await installation into winglet.
  Tension Spring Mounted
         Foam Extension
    Rudder tension spring is floxed into port hole.  The stick and elastic are holding the spring clip errect while it cures.  The spring hook is shown on the end of the rudder near the hinge.  It is floxed in under the fiberglass skin.
Wings shown with foam extensions, for installation of my blended winglet modification.  I had already made the curved cut as per plans before I decided to go with the blended winglet.
  Winglet Platform
   Supported Winglet
Winglet platforms installed.  They were hotwire cut from plans winglet templates.  This put the winglets out 3 1/2" and up 3".           
     Winglet supports in place.  My mounting measurements were derived from the plans measurements and checked with intersecting circles on my CAD system for the correct change of winglet location. 
  Hidden Belhorn rigging.
   Hidden Bellhorn channel
I glassed the inside of the winglet first because I wanted to get rid of the supports and get my bellhorn rigging done.  This inside square corner is built up as per plans.                       
 Hidden Bellhorn channel is formed with a cutout in the foam fairing.  Under this foam is a triangle shape which has been glassed and coated with 2 BID and 5 layers of UNI.  Some of the different lengths can be seen here where it has been sanded.  
  Blended Winglet Structure-
         Winglet and Hidden Bellhorn
   Partial view of winglet buildup structure.  Triangular frame 3 BID inside and out.  All corners shown in blue are flox buildups.  7 layers of plans layup schedule on inside small triangle, outside small triangle, outside 45 degree length, and then curved foam buildups.  A layer of UNI was added overall to the full length of the winglet and onto the wing about 18".  There is also a Box spar shown below.  My radius is 4 1/2 inches inside and 7.5" outside.
                      Inboard blended winglet and hidden bellhorn.  This will be filled better and painted during the finishing process.  The control cable is accessable with removal of the split rudder.  The mechanism can be inspected when the split rudder is in the full out position.
  Winglet box spar
   UNI cord is applied.
Here the wing is upside down and the winglet is hanging down.  The wing spar has been hollowed to 3"depth and a 7" long slot cut into the winglet to create a box spar.  The inside corners have been routed for flox buildup before fiberglass layup.  The cables are for antenna and marker/strobe lights.  Later I  wished I had formed some kind of conduit.  We learn.
Uni-directional cord fiberglass has been laid-up inside of the box spar and the side walls have 3 layers of bid added inside and out.
  Spar pour foam added.
         UNI cord applied to outside of spar box.
Pour foam has been has been added.  I believe pour foam is more consitent when the area poured has been pre-heated with a hot air gun. 
 I have skipped showing one step on glassing in all of the triangle shapes but it has been done prior to this photo.  Here it has been squared off and micro added prior glassing the plans schedule of layups.  Blue cardboard is there to temporarily protect belhorn control cable.
  Ouside is pour foamed to shape.
         Outside kevlar added to resist bad landing abrasions
               More pour foam is added to work in the final shape.  Kevlar has been added on the outside to resist bad landing abrasions, a risk which should be reduced by a wider stance retractable landing gear.

  Blended Winglet 2
         Blended winglet 1
                        Blended winglet shown prior final finishing.

 A view of the blended winglet looking at the leading edge.
  Fairing radius sanding blocks.          My support Team  
  My fairing radius sanding blocks were hotwire cut to masonite forms and lined with heavy cardboard and 220 grit sandpaper. 
                         A good looking part of my support team.

What I learned:
Modifications take longer.  They are fun, and make the work enjoyable when they work out but they take extra time.  And yes, I've said that before.

These mods are somewhat controversial.  There are those that claim that blended winglets on a Cozy don't add that much speed and could cause less stability at low speed.  I will be adding vortex generators which will allow lower speed landings and takeoff.  Also I plan on putting a fence on the outboard end of my ailerons as well as addiing an additional vortilon.  There are some Long Eze drivers that have gone to blended winglets or at least have cut off the lower winglet and claim no noticable difference in low speed performance.

Both Todd Parker and JD were influencial in a consulting effort for my split rudders.  JD recommended it and Todd Parker carefully explained the virtues of it to me.  Todd Parker has been very helpful.  He's our EAA Chapter president and my build advisor.

I liked the way a blended winglet looks.  Michael Skorija encouraged me and gave me some direction on how to do the blended winglet.  Also I got some useful input from Marc Zeitlin's Oshkosh presentation on blended winglets.   I also got some strutural advice from John Lewis, Todd Parker, and Tom Holt from our local EAA Chapter.

Disclaimer:  These pictures in no way represent instructions on how to do this.  This is how I did it and I choose to be responsible for my own work.  Please be responsible for your own work.