2nd Try, Inner Flange
 

Since the first inner flange was unsatisfactory, I made another one. Here it is, still in the canopy as laminated. I?ve removed the peel ply but haven?t separated it yet. I hope it's not too thin....



I?ve also attached the elevator tips permanently, although they will need some filling and shaping when I get closer to the finish and am doing that sort of thing.

Dave

The inner flange has been removed, marked and trimmed is ready for prep for the bond.

In the meantime, I thought that you might be interested in the maintenance manual that I?ve been preparing. When I come across something that seems like it?s worth remembering for future maintenance, I?ve been jotting it down, along with photos. At first it was all in one manual but the organization got unwieldy, so I separated it into chapters. At the time, I was using the Mac software Pages. More recently I changed to the free open-source Office-like package, Libre Office, which I like a lot. Hence the ?.odt? suffix.



I finally got the inner flange glued to the canopy and outer flange. Here?s the stack curing. I clecoed it down to ensure that it doesn?t warp. I used 2216 for this bond because it sticks to the canopy.



Although the fairing is in place, that?s not part of this bond. That?ll come shortly. I knew I wouldn?t have time to manage that joint, too. It's there to give me something to cleco the flanges to.

Dave

Before I went to bed that night I glued the inner flange on, I pulled that green electrical tape off on the inside. It’s purpose was to keep the black sticky 2216 glue off of the canopy. The glue had flowed over the tape, not unexpectedly, and there were some glue tentacles that remained as I pulled that tape off. I tried to keep it off the canopy but was unsuccessful. It was still in a state where its adhesion was greater than its cohesion; I couldn’t pull it off the canopy where it had touched. I went to bed knowing that I’d have a real problem.

When I got the canopy back upside down the next morning and had a look inside, I thought that maybe I could grind the epoxy off. Yeah, that would work, sort of, leaving a lot of polishing ahead. But the glue hadn’t completely cured. I could sand or file it, no problem, but an Xacto chisel blade was able to remove it. In most case there was no residual mark. I was so lucky. Problem solved.

On the flanges, though, it wasn’t so easy. The canopy itself had been unprepared where I removed the excess glue from it. The canopy flange was fiberglass and had a roughened surface. The 2216 didn’t come off there. For those, I’ll have to grind them off.

3M’s 2216 epoxy really does a good job of sticking to things.

In case you’re wondering how the flanges and the canopy all go together, here’s a sketch that I made. The flanges are rounded at their apexes but that’s a bit hard to do with my drawing package. You’ll have to imagine that for yourself.



The canopy latch handle is located - hope it’s in a decent position. The aft canopy latch, at the aft most end of the canopy, is operated by this. The actuation rod is shown here with the latch handle. The bend closest to the latch is undergoing several tweaks and this is not the final version of that. The rest is, though.



It continues outside the cabin but inside the canopy. The red circle closest to the cockpit marks where a guide bushing will go, and the rod itself will engage a standard eye-bolt in the fuselage that pokes through the canopy fairing at the red ellipse.



Fortunately, I realized that I needed to set this up before the canopy is bonded on. There’s not room to access it later.

Dave

The forward-most guide flange was made in two passes plus trimming. I wrapped a foam block in packing tape and taped it to the fairing. Then I made a fillet of flox and laid up six layers of BID.



With the block removed and the flange and fairing sanded, I made a similar fillet and laid up four more layers of BID for the other side of the flange.



Finally, I trimmed it. I keep a set of washers of various sizes handy for use as templates for different sized curves and used one here.



The bushing needed to have an ID of 5/16” and that’s a size that Van’s doesn’t sell. But Grainger does, and the bushing is now in place. And yes, the flange clears the canopy.

Dave

Man, I spent so much time over-thinking my canopy, and I rebuilt what was left of an existing one! I started it at one house in Michigan and finished it in another house in Tennessee! My next airplane is going to be a pre-punched kit with good instructions. I want to do more and think less. The canopy turned out pretty nice, at least. Have fun! :D

Amen Katie!
Outstanding work David! What fun watching your work from afar.

Aft Canopy Latch, Check
 

Katie, you’re absolutely right about the thinking that’s going into this. At this point I’m beginning to look forward to other parts of the construction. Kentlik, thanks for the comment.

Things are slowing down right now in the shop, due to outside matters. I’ll make progress as I can. This shouldn’t last too long. I did find time to make some progress at the aft end where the actual connection is. Here it is unlatched:



And with the canopy latch engaged:



The actual bar that passes through or on the various pieces is not the final one, and I don’t have the right size screws yet. There’s a bit of work ahead here. The final bar will have its end tapered, too. But this part of the canopy latch works, and I was using the cockpit handle to operate it.

Remember, what this thing does is prevent the aft end of the canopy from lifting up. Imagine the fuselage trying to sink below the fairing in the photo and it's a bit easier to grasp.

Dave

Canopy Fairing Has Its Hinge
 

Life has caught up with me again. Here and there, I worked a few moments at a time. Sometimes I was delayed for parts, but most of the time it just happened.

Well, enough whining. Here’s what’s been done.

I disassembled and then reassembled the latch mechanism, after lightening it up a bit. Flight hardware this time, etc.

Shifting back to the fairing, I applied micro to the top inside of the fairing, the places that would be at least awkward to get to, and perhaps impossible, once the canopy is on. Here’s a pic of the aft most two sections with the micro on. I might have been a skosh lavish with the stuff.



After sanding, well, after considerable sanding, I gave it a shower. Feel free to look away if you’re a sensitive person - here it is in the shower, posing. It’s not the least bit shy.



Since it was both simultaneously too warm and not humid enough to spray the Ekopoxy primer that I’m using for the interior, I needed something else to do. What I did was drill and cleco the canopy hinge to the longeron and to the fairing. With it all clecoed together, I could do something so basic and so important it could have been a milestone all by itself: I opened the canopy fairing. And hey, guess what? There’s no way to hold it open yet. Plus it’s about as floppy as a newspaper in a spring breeze. While I know that the canopy itself will stiffen the assembly, what I need to do is build a frame. The basis for it is in place, a stiffener just above the hinge.

Here, the fairing is resting on the roll bar, not a permanent rest for it. You can just barely see the stiffener inside the fairing near the hinge.



There are some considerations for the hinge worth noting.

1. There needs to be a way to remove the canopy and fairing and frame from the fuselage. Somehow, that hinge pin has to be able to be removed. What I plan to do is at the aft end, bend the pin inboard, then down, and finally aft, where it should rest in a tooling hole in the seat bulkhead. That’ll secure it when I don’t want it removed. When I do, I’ll pull it around and slide it out of the hinge aft-ward.

2. The hinge needs to be slightly outboard of the longeron or the fairing/frame will bump into the side of the fuselage. I did not allow for this when I made the fairing, but it’s sure as heck included now. It would have been easier to do it earlier, and the manual even mentions this, too.

3. There needs to be some sort of weather protection at the hinge, lest the cockpit flood. That’s TBD but shouldn’t be too hard.

Not precisely part of the hinge, but there also needs to be something to hold the canopy open, as I hinted above. Ideally, it should be incorporated into the part of the frame that I still need to build at the seat bulkhead. Some people attach it to the roll bar but I failed to provide provisions for that when I built it, and am reluctant to retrofit that now. Have ideas but haven’t settled an an approach yet. But I have ruled out a cord/cable/rope/chain/etc. in favor of something which will provide a positive stop. Right now I’m thinking of either a folding strap latch like some people have used or an air spring. Or something else, and yes, I have something in mind that might work, but probably won’t.

I should probably mention that after consulting with Van’s Support, I’m using LP4 rivets for the hinge to longeron joint roughly per the RV-4 Preview Plans. For the hinge to fairing/frame, I’m using AN426AD3 rivets and am gluing the hinge to the fairing/frame. The rivets here are per Drawing 33.



These photos are hosted elsewhere. Now here they are again in VAF hosting, as an alternate.

Dave

Dave,

On my RV-3B the canopy hinge had two pins that inserted from the center of the hinge outboard, each. So the bent end of each pin met in the middle. I think one of the hinge bulbs was removed where they came together. So instead of one long hinge pin accessible from the outside the two shorter ones were accessed from the inside and there was less alignment and friction problems than on long pin. And no hole or other access feature was needed on the outside to accommodate pin insertion/extraction.

This is the same concept used on many of the seat back hinges where there are two pins on the seat back hinge, each pushed from the center outboard for half the hinge line as it would be impossible to insert one pin without there being a hole in the exterior skin to compensate for the straight length of one hinge pin inserted from the side.

Also, my canopy hold open device was an over-center link that folded from the center up. When in the pilot's seat I could release it with my elbow. It did a good job of holding the canopy. It was attached to the seat back bulkhead rather than the roll bar.






Jim

Thanks, Jim, I appreciate the pics.

Having just put the pin in today, fighting it the whole length, I might go for the split pin arrangement. Have to say the whole length one was a pain. Confirms my plan not to use piano hinges for the cowl.

The hold-open arrangement you use is one of the three most likely options I'm considering. The other two are a different sort of folding strut or an air spring.

Dave