The Long EZ Build: Canopy interior layups

With the top longerons flush with the rollover structure... it was time to focus on the canopy's interior layups.

But first I had to figure out where the hinges will be installed (so I can work on the hardpoint layups inside the canopy). I made a template of an 8" long hinge.. I had to make sure the AN509-10R30 bolts that install the hinges onto the fuselage was not going to interfere with the hardware used to install the rollover structure.

I then marked the location of where the hinges are supposed to go according to the plans...

The plans do a good job at warning us that the hinges must be in a straight line... and that the hingepin (hingeline) must sit outside the fuelage contour to prevent binding when the canopy is open. I spent quite a bit playing around with the hinge locations. I noticed that the farther apart the hinges are, the more they will stick outside the contour (since the fuselage walls are curved).

If I locate the hinges where the plans say, the aft hinge would have to stick out about 0.36"...

But if I move the aft hinge 5" forward, I'm able to reduce this by more than half. Also, it makes it easier to install the hinge later since 100% of it would lay on the rollover structure, rather than just a portion of it. By doing this, I'm risking that the aft of the canopy might not be held down as securely, but I'm betting that the latch on the left side will balance that.

I moved the forward hinge 1" forward for similar reasons...

Happy with the compromise of the new hinge locations, I used tape to mark their location...

I placed the canopy onto the fuselage... and used tape to mark the hinge locations onto the canopy...

I also marked the location of the latches on the left side of the fuselage... this required a lot of thought since the rollover structure was in the way of the middle latch... and because I modified my canopy forward lip to be round, the corners get in the way of the forward latch. After coming up with their new locations so that nothing would interfere, I marked the canopy with tape.

I then took the canopy back to the sawhorses to mark all hardpoints onto the foam...

I then milled out all the foam to make the hardpoint pockets...

All that micro had to go!

So I used a dremel to sand it all out..

With all 8 pockets complete... it was time for the hardpoint layups. The plans say 15 plies per pocket, but I figured 20 since my canopy frame sits taller than per plans (so deeper pockets)...

I started by painting plain epoxy to all 8 pockets... then poured ~1/8" wet flox...

... then 1 ply BID at 45...

I went to the next pocket.. and repeated it. The idea was to go around the canopy, put a little flox... install one ply... and go to the next one. By going one ply at a time, I would minimize the risk of exotherming and allow enough time for the ply to release some heat....

I didn't need plain epoxy to wet out the plies. I simply dabbed it with a brush and the wet flox would be enough to wet the ply out. Also, notice how my BID plies get wider the higher up I go.. this was excellent planning and worked out great!

About halfway up, I noticed the pockets were getting really hot! So I stopped for 45 minutes... let them cool a bit... and continued...

Slowly but surely, all 8 pockets were flush with the foam surface! Some pockets required 21 plies... case and point, I had extra plies of BID ready just in case I needed more...

The next day, I sanded all pockets flush...

With the hardpoints complete, it was time to shape the interior foam to its final contour...

I had to shape it so that it would match the fuselage contour...

I also had to shape the aft end to match the fuselage aft end rain lip...

Rounded all edges...

It was time to fill all foam notches. Theses were there due to the standoffs that held the canopy in place while I installed the foam blocks all around the canopy before the outside canopy layups.

I simply put tape over them...

And poured liquid foam into them...

A few minutes later, they cured and were ready to be sanded flush...

A little more sanding here and there...

Making sure all edges were rounded and smoothed...

All pads were sanded dull for a nice glass-to-glass bond...

I decided to not worry about the aft end for now. I will do that one as a separate layup after cure so that I could make a nice flox corner on it to combine both layups...

Making a flox channel along the side rails.... making sure to remove all micro from the inside surface...

I also sanded the front lip 0.5" down to the glass... for a nice glass-to-glass bond with the interior layup...

More sanding... smoothing...

I also gave the plexiglass another scuff all around to make sure the layup will bond well...

With all the interior layup prep complete, I wanted to make sure all lip edges were good to go.. so I sat in the pilot seat, and had friends place the canopy onto the fuselage. Made my checks and was happy with the result. Luckily, I have good friends that were nice enough to let me out after the check!

With everything prepped... it was time for the canopy interior layup! Started out by painting plain epoxy on the sides of the flox channels and putting wet flox into the side rails. Then slurried all the foam...

Painted all hardpoints with plain epoxy...

I used flox for all voids between the plexiglass and foam... and painted plain epoxy all around the plexiglass lip...

I was so busy I didn't take any pics in between plies. I should note that I followed the plans layups schedule... but added a ply of UNI on the side rails. This was to try and strengthen the canopy frame since some builds complain about the canopy warping. I avoided using carbon fiber this time since this layup will come in contact with aluminum hinges.

I purposely left the aft ends long... they will be trimmed post cure...

I let the inboard skirt overhang onto the tape protecting the plexiglass...

After cure, I began to trim things up... started with the outboard edges...

Then sanded the edges flush. The flox corners came out great and I'm super confident the interior layup is well bonded with the outside layup...

Trimmed/sanded the canopy front lip...

Now to trim the inboard edge all around... used a dremel with a cutoff wheel on the slowest speed possible. It was nerve wrecking at first, since I did not want to eat into the plexiglass... but after a few passes, I got comfortable with it and went all around...