Cozy Construction Chapters.
Chapter 18 Canopy and Turtleback
Started 03/07/2009 finished 08/08/2010 Hours worked this chapter :166
Purchased Tinted Canopy from Todd's Canopies window too. Living in Houston I felt I needed to cut down on the sun as much as possible.
04/01/08 - Purchased Turtleback from Feather Lite. Working on wings right now.
Test fit Feather Lite purchased turtleback.
This is a change from the plans, I liked Brian DeFord design and going to follow his lead. Thanks Brian. You can just see the hard point where the lift strut will attach used to hold the canopy open, it will be hidden when closed.
Windows and drip rail installation, if I had to do it over again I'd remove all the inside glass making it recessed all the way around each window. The sticks are there to hold the windows tight and are covered in packing tape for easy removal later.
The fit on the outside work out just fine and I hope with the finish work still to come on the inside I will work out a solution for the uneven look on the inside. As you can see the drip rail is in the wrong location. One thing about fiberglass you can remove it and go again.
Working on the turtleback inside, the drip rail that was installed before the windows where installed, afterward I found that my measurements where off and that the rail was 1 1/2" to far back on the sides but okay in the top center. I thought about the problem and figured that I had not take into account the thickness of the 1 x 4 I used as a straightedge. So I cut out the drip rail and relocated it forward so that it bisects the distance between the two windows on both sides. All is good to go forward, that god that you can do this, you can't tell it was ever moved.
Everything has been trued up and ready for flox. It works out well that I've got two digital levels. The red center line is matched with the center line of the main spar.
Mounting the main spar in side view, you can see the flox.
In this picture you can see the foam I removed to get down to the wood longerons. The next step is flox and bid glassing all around inside and out. Use wax paper to wet out the glass, the odd angles and up side down work is made much easer this way.
Did things a little different than called for, I floxed and bid taped the upper firewall in place on the inside and outside on top of the main spar, then floxed the turtleback to the fuselage and firewall. Why I did this, with the turtleback out of the way I could work on the complicated bid-flox lay-ups on the main spar /firewall it is a inside and outside lay-up, you'll have to see the plans instructions, it came out good and square.
Here you can see the turtleback with bid tap and peel ply, the 5 lb sand bag is there to push down and align the firewall top with the turtleback top.
Turtleback and firewall bid tap, flox, and foam build up. The red color is because I am using fast cure
Here you can see the turtleback bid tape on top of the spar and the glassing about the engine hard points, the red color epoxy is caused by it being fast cure type. I've found the small lay-ups don't take long there for the fast cure is one way of getting several steps done in one day or weekend, where the slow cure may not let you get to the second step in the same area.
Turtleback in floxed in place with the firewall, then comes flox and bid tap all around.
In this shot you can see the canopy roll bar and on the sides there is extra turtleback glass hanging over the edge of the fuselage, this will be trimmed off later.
Time to set the canopy to the turtle back. The canopy comes over sized from Todd's Canopies you can see the tape line where the foam desk will be and the black marker cut line below that.
Here you can see the cutting of the canopy so the angle is set correctly using the temples, it is resting on tape and a pencil to create the correct spacing.
In the picture you see the cutting wheel I used to trim the canopy, take your time.
Canopy trim with tape set at deck build line. Sand the edge getting ready for glassing.
On to setting up the decking for the canopy, which will hold the block of foam the makes up the forward part around the canopy. I use hot glue to hold supporting blocks in place, you can see once on the back of the seat, I've found it easer to clean up using a razor knife and a sharp chisel, some just pops off.
My daughter Sarah helps me when home from college.
I used two 5 lbs sand bags to help the canopy and turtleback to line up.
Bid glassed and floxed the canopy onto the turtleback, the plane and the temp wood desk is covered with cut up garbage bags. It's cheep and works good.
Things line up so well that I didn't need a big head liner. Depending on how the finishing goes I may extend with paint.
Here you can see the nice smooth transition between the canopy and turtleback.
In these next few shots you can see the blocks of foam that makes up the deck. I've spent several days fitting the blocks and now they are macro in place. I used the macro very sparingly I thought. It turned out that I had in some spots over did it. That did slow down the shaping process for each line of macro I had to use my dermal tool to grind down the macro lines between the blocks, but I got there.
The sand bags was most likely over kill but I have to make sure everything is just right. I do enjoy working with the foam, creating all the shapes from block of foam still amazes me. Fun stuff.
I took my time with the shaping of the foam, you can just see that the hinges are not visible and the indent for the cut line just in front of the canopy. I made a paper template for each side of the deck out of sheets of paper taped together. Then I laid them down on top of the glass at the cutting table marking the edge with "L" and "R" for each side.
The plastic that covers the fuselage are garbage bags cut apart.
Cut free and on the bench, I use hot glue to hold the support frame in place, it's only temporary and the hot glue pops off clean too.
Cut alone the drilled line, it was a slow process but worked out well.
Now that I can get back inside the canopy I completed the engine mounting hard points and the 8 layers of bid that run up the side of the canopy.
The aluminum has one rounded corner to fit better into the corner of the spar and firewall, the other two side are beveled at a 45deg angle to make the glass transitions smooth.
Moved the canopy to saw horses to make it easer to dig out and fill with flox the cut edge.
The plans calls for 3/4 thickness foam contour so I put tape on a stick pin and used it as a depth gage. Worked out nice the foam is soft enough so I could make depth makes in the foam and sand down to them.
Contouring the inside, adding the hard points for the front canopy that stays over the IP. On each side you can see the areas where all the foam has been removed, they will be filled with layers of flox and glass.
The hard points are filled with flox and glass layers, the aluminum hard point are flat and level with the foam. I used the same idea on the inside as I did on the outside, paper templates used to cut the glass to the correct shape.
Cutting the foam for the drip rail for the canopy area over the IP.
I used 5 min epoxy to hold down the foam. I've cut through most of the canopy deck with a few small spots to hold it in place.
Now I made flox corners and added two bid layers. You can just see the darker edges of the flox corners. Make sure you open up the cut line enough for the layers of glass on both sides.
Here's the other half of the cut line on the front part of the canopy, this is why you need to make sure you open up the cut line to make room for the glass.
I will knife trim and sand to it's final shape in a few days after green cure is about done.
Working on the drip rail on the back end. Here you can see the temporary foam block I use to turn the corner so that what water does make it into the the rail will be sent back out.
Here you can see the inside of the rail before knife trim.
Now that I've got all the rail work done it's time to put the bolts in the hinges.
The nuts are recessed by using a forstner bit that follows the a dowel that I put in the bolt whole. This makes the counter bore center over the bolt whole. Once I was happy with how everything lined up and the canopy operations I floxed them in place.
In this close-up you can see the change from plans, I followed Brian DeFord design change. I like the roll bar it protect incase of a roll over and gives a more open interior. My head resets will be attached to the cross bar.
point for the gas strut bracket made with aluminum plate, two nut plates all
imbedded into the set back with 3 bid layers. The two white spots you can
see are silicone caulk that keeps the epoxy out of the nut plates.
After cure I used my forstner bit to cut the glass out and then just picked
the silicone plug out clean.
The one by three is holding the canopy up until the hard point cures, you can also see the IP cover is curing too. The foam was hot glued in place and packing tape put over the form and onto the front deck of the canopy.
The gas strut in place testing how will it works. You can see that the bracket is 2" high, I did that so when the canopy is closed the angle of the strut goes past level and start pushing down on the canopy to help keep it closed. During my testing I found that the aluminum bracket was to light weight, so I've order 6061-T6 this can stand up to the torque when the strut hits the hard stop or wind gives it a push.
Here's the trimmed IP cover still need to add the hold down clips and remove the remaining foam off the IP.
After cutting the naca-scoop shape from the plans and removing the inside glass and foam. I sanded a transition from the outside to the inside and glassed it. The red color epoxy is the fast cure type. It will cure complete in about 2 hours. The color fades after cure. The stir stick is there to hold the outside glass out of the way.
In the picture you can see the inside with the flox and glass transition in red.
I created foam forms covering them with packing tape to create the parts for each sides vent duct work.
In this picture I've floxed the outside skin into the naca duct work that is floxed from the inside. The screw was cover with a light film of petroleum jelly to keep it from bonding with the flox epoxy mix. It is removed once the flox is cured and sanded smooth.
No cleco needed here just a screw and block of scrap wood to hold it all together till cured. You can also see the color change as the epoxy cures, the older part next to the IP is about a week old, the naca shaped part is one day old.
I liked the drawer pull that I saw at Home Depot
I didn't like the little door in the airplane used to open the canopy. Here you can see the inside latch location opening.
The latch is installed and floxed in place, I used a push/pull cable to control canopy three latches.
You can see that I will lose a little map pocket space as a trade off.
The flush mount nature of the handle and the lock access made the change from plans a key point for me.
The latch handle in the open position, it works smooth and clean.
Bench mount break I used to create the safety catch latch.
Made out of stainless spring steel
Here you can see canopy in the closed position.
The canopy in the open position
Still have finish work to complete, not sure what the interior will be covered with, thinking cloth like head liner, Something soft and sound proofing.
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