Chapter 18

Canopy
 
 
  Canopy Turtleback Jig
         Canopy Turtleback Jig 2
 
     Canopy/turtleback jig.  I tacked masonite to round out the curves.  I then stapled the foam in place.  After fiberglassing the staples easily pulled out of the foam when lifting it out of the jig. 
 Another view of the canopy/turtleback female mold form jig.  This went together fast.


 
  Canopy turtleback formed
         Canopy turtleback cut line
 
 Inside of foam is formed and glassed.  Staple holes will be microed and then the outside surface will be glassed.  Nice smooth form.
   Laser formed cut line for canopy and turtleback seperation. 

 
  Canopy window clecos
         Canopy Cleco pads
 
   Clecos are used to hold the window in place while it gets floxed.  The windows are coated with 3 coats of spraylat protectant so I don't scratch it.
    Pieces of circuit board material with foam pads are held in place by the clecos to secure the window while the flox cures.

 
  Canopy Lip Clamps
         Canopy base platform.
 
          A Canopy Lip is being clamped to form seal and drip rail.        Platform to support plexiglass and foam while forming forward canopy.

 
  Canopy continuous form.
   Canopy window glassed
 
        Foam is formed around canopy glass.  Ready to fiberglass.
                        
 Nose top section and canopy were fiberglassed at the same time to keep lines uniform.
 






  Canopy luggage rack
         Canopy cable and hard points.
 
 "Luggage Rack" is built to allow removal so work can be performed on the inside of the canopy. Hard Point cutouts are made as per Uli Wolter's plans for forward hinged canopy.  Slot shown for cable routing.
  

   Canopy dome light routing.
          Canopy hinge test piece.
 
         Canopy Dome/Map light wiring is run inside of canopy foam.     A canopy test piece was made to simplify experimentation with hinge fit.  Hardpoints shown.  Hard points here are found to be too far out.
  
 
  Canopy various hinges tried.
   Canopy wood hinge test.
 
I made several "J" and "P" hinge test pieces to finally get the hinge that worked best for me.  I used  phenolic, plywood, and hardwood pieces (whatever I had) until I got the shape I wanted.  I went with the "P" hinge
on the bottom right.
                        
 This worked best for me.  The hinges will not penetrate the instrument panel cover, keeping instuments dry, and the canopy does not rub anywhere while opening.  The hinge is a straight piece that will be floxed into the canopy.  Wooden test hinges are shown.

 
    Canopy hinge pre-flox
   Canopy hinge stands ready
 
Anodyzed blue aluminum hinge and bracket shown prior to installation.  Grooves are cut to "lock" the aluminum hinge bar into the flox.  It gets mounted to F-28 and the hinge bar is floxed into the leading edge of the canopy lip.                          
The canopy has been strengthened with Carbon Fiber.  I added 3 layers per side locally over the hinge area and 2 extending partially up the side of the canopy on both top and bottom.  The hinges are mounted and the nutplate shown.   F-28 has been strengthened and has a drip rail.  All is ready for insertion into forward lip of the canopy.  1/8" Nutplates also add strength and support.   
 

 
  Canopy lift
   Canopy Hinge and Nutplate
 
I used this hoist system so I could work on the canopy by myself.  It was great for testing.
                        
                 Hinges work well.  Next I need to add gas struts.
 
 


What I learned:

   
Stapling the white foam into the canopy/turtleback female mold beats using tape.  Tape just wasn't holding well for me.  The staples hold the foam to form the shape.  The staples will pull right out of the back side of the foam after the inside has been fiberglassed.

   Todd at Todd's Canopies was helpful in making the larger (what he calls "Texas Cozy") size canopy for me.  It arrived  by truck in short order and it was packaged well.  I had plenty of plastic material to work with.  Thanks so much Todd!

   Some other builder told me in advance to make the nose and canopy deck in one continuous shape and the lines would work out better.  I did this and I'm glad I did.  It worked out well.

   I followed Uli Wolter's plans while making the forward opening canopy.  There are things I would do different.  You learn after you've made it that the canopy and hinge system will work better with the hinges closer to center of the fuselage.  Also I like these helpful hints from the Cozy girls: 

"The key to "C" or "J" hinges is, room permitting, to have the hinge point as close to the upper surface as possible and further away from the opening edge. The object is to have a greater vertical component than forward component to the travel. I suggest doing a paper layout and trying whatever you come up with."

   I first drew the parts on my CAD system then I made hinge parts out of plywood to test the hinge shapes. 

   My hard points were not in the best position for good hinge action.  They work better further in from the sides.  As it turned out I didn't need the hard points.  I used 3 layers of carbon fiber and one normal UNI on the front of the canopy inside and out, (the UNI is sacrificial for sanding and shaping without sanding into the Carbon Fiber)  then floxed the 3/4" by 1/2" thick and 7" long hinge arms into a slot cut through the end of the canopy.  The strength of it is good.  It is stable.  If you don't like the J-hinge arrangement this works fine.  If you follow Uli Wolter's plans take some time to consider your hinge and hardpoint placement.  My hinges are 18" apart.  9" each from centerline.

    The forward opening canopy can add a margin of safety to your airplane.  Crashes have occured with side opening canopies that lift open in flight.   I believe this is a worthwhile modification.  It takes a little longer but it's worth it.

   I still have to add the gas struts and the canopy lock system.  That will be shown here when completed.