Cozy
Chapter 18 - Canopy
Canopy Deck
Next came the bit I'd been looking forward to - carving the foam. But first you have to fit the foam.
With my lower F28, 2 inches was just enough depth so I put one piece flat all the way across the front
shaping it to fit up against the glass and under the lip. Shaping to fit that complex curve took a while. Shaping the next piece took even longer. I checked other web sites and yes, I was doing it right, you DO have to shape every piece of foam individually all the way to the turtleback. It took me most of a day to get all the pieces carved and microed down. Once this was done I put the canard back on and cut up some more urathane foam to make the canard cover. That evening, once the micro was cured, I began carving. This is my favorite part of building. After hacking with a hacksaw blade and sanding for an hour I started to see the shape. I wish I'd learned about Spline sanding (or Oreste's little sanding trick) before doing the shaping of the fuselage sides. It seems so easy now, but then, I've had a lot of practice.
I abandoned the BL0 template since my tape was deliberately lower and my F28 was 0.7 below where the BL0 expected it to be. The templates for FS 41, 50 and 60 were about an inch higher than my tape line, but I still used them to check the shape. I would have used the one for FS 70 as well, but I think the dogs have run off with it.
As I cut and trimmed the foam the dogs were having a field day, grabbing chunks of urathane and taking them to the back of the yard to chew. Ah well, it's way too late for training and it does saves me cleaning up.
Char came out for a "hands-on" experience and helped work on [and supervise] the carving on her side, and by late evening I had the shape pretty much done. I think I like it. The canopy cover flows nicely onto the nose and there is just enough curvature to make the top of the nose look good. The canard cover is pretty thin, [down to 1/16 inch at one point] but I think it'll work. I think I'll hard shell the canard cover - some of the urathane is too thin to sand and is coming off. My nose looks quite pointy, but that's what I wanted. I also have quite a bit more of the oval part of the canopy glass showing at the front which adds to the pointyness. This kinda goes with the lower rear windows and much reduced fairing. IMHO it makes the whole bird look more aerodynamic. At the end of the day my nose will be "my nose". If I like it, and Char likes it, then I'm happy.
Once I'd got the foam looking just right I glassed the canopy deck. I used Wayne's template method and followed his suggestion to keep the flox channel a little low. See - I do read other people's stuff! I must have been out of practice with big layups. I had expected to get this layup done in an hour, but it's more complex that I expected and it nearly "got away from me". The hair dryer came out, even though the temperature was well into the eighties. I used a lot of epoxy and rushed the edges a bit. Using 4 mil plastic saved me because I was able to squeege all the air and excess epoxy out of all the plys at once. Dinner was ready in between layups 2 and 3 and I was really hungry. I ate the whole meal in about 45 seconds. Char wanted to know if I'd like the Alka Seltzer with the meal, or later. In the end, after 4 hours, it was a good layup, but I did have some glass threads, stray flox and epoxy laying on the tape here and there. After it cured I peeled back a little of the tape to see if I would get a straight line. I'm going to have to work at it a bit, but it can be done.
Now to get my scissors back! I cut the turtleback off with a hacksaw blade and a dremel. I tried hard not to got more than 3/8 deep, but like many other builders, I still cut the drip rail in a few places. Isn't it wonderful what a strip of BID will fix! A little leverage under the TB, a hacksaw through a stray lump of flox, and up she came. I built the legs and lifted the canopy assembly onto the bench, then onto the floor since the bench was too high to work on it comfortably. It took a while to figure out what to do inside. After studying plans and other web sites I figured out that we want a nice curve from the 2 inch perimeter to 3/4 depth at the canopy glass. We trim the glass back to that height.
Out came the dremel again. This time I used the thicker abrasive cutting disk and the cut went very easily, perhaps better than the thin cut off disks I'd been using. I figured out where the hinge pads go. I have bad news and I have good news. The bad news is that I'm supposed to dig out the foam exactly where my 1/4 spar cap crosses the turtleback. The good news is that I can dig out foam from the other (glassed) side and reinforce it from the top. One of the canopy bolts will go through the spar cap, which will be much stronger than any flox / BID reinforcement pad. Carving the foam wasn't too bad, except that I'd used quite a lot of micro on the urathane pieces. I'd thought it wouldn't get in the way if I put it at the bottom. This was true when carving the top. Not true when carving the inside. Duh! It didn't cause much of a problem because most of the micro came out with the foam as I hacked out chunks with the hacksaw blade.
Hardpoints
I decided to do the hardpoints before carving all the foam because the foam tapers to a point next to the hard point once you carve it. This worked out well. I did carve the foam down where the door handle goes. Wayne said the hard points were "interesting". I started mine at about 9pm. After a few layers were in the pads were starting to get a bit warm. I was definitely entering exotherm country here. I decided to wait a while before adding the next layer, but even after a half hour break I was hovering on the edge. I opened the hot box door and dumped some room temperature resin and hardener in the pump. That did it. No more problems with excess heat. It takes a while to build up two inches of BID and flox. The whole layup took me about 4 hours. After cure I used my belt sander to level the tops of the hard points where they'd strayed a bit at the edges.
Glassing the Inside
Other than the cowling, this will be my last large lay-up. After practicing on the outside [visible] layup, this one went quite well. I had no trouble getting the glass to sit around the corner onto the acrylic. I'd read that others have had fit problems or warping, so I decided to let the layup cure in place. I did the alignment pins early, used 4 mil plastic on the layup [as always] and, after it had cured for an hour, I placed the assembly on the fuselage and weighted it. While checking the alignment I noticed a bit (1/4 inch) of a bump on the port side near the instrument panel. Char held the canopy up while I climbed inside to check. The canopy cleared the instrument panel nicely, but it was touching the electrical conduit behind the panel. We whipped the canopy off again, attacked the channel with the band saw and put it back. Good clearance now, but still the bump. The outside surface had cured while the canopy deck had been resting on the electrical channel. I heated the outside skin with a hair dryer and used two drywall screws and large washers to screw the deck down.
How to get fiberglass off acrylic
I seem to spend a lot of time in this web page explaining how I screwed up, so this time I'm saying nothing. I will, however, offer a few tips which might help anyone who happens to need them. First, make a light cut along the line of the tape with a razor blade, taking care to scratch the surface of the epoxy, but not cut through it. Now remove the tape bending the epoxy at the cut line. Most of the stray epoxy will [I'm told] break cleanly at the edge of the tape. Where fibers have "crossed the line" a good way to get a nice clean line at the edge of your canopy [so I've heard] is to gently slide a blade into the join between glass and acrylic, such that the metal of the blade protects the acrylic. First bend the blade a little by hand until it matches or slightly exceeds the curvature of the canopy. This stops the corners of the blade scratching as you slide it into position. Now use a hacksaw blade held flat against the razor so that it cuts against the fiberglass edge. A slow sawing motion with the hacksaw will permit you to clean off any stray fibers and bits of epoxy without damaging the canopy. Move the razor along the edge, doing an inch at a time until you've been around the entire perimeter. Should you happen to get any drips of epoxy on the acrylic itself, don't worry - it is not the end of the world. [I understand that] Epoxy doesn't stick well to unprepared acrylic and can be removed in one piece by simply scratching it off with a fingernail.
Removable Fuselage Top
I considered glassing the front part of the deck in place to give better structure at the front. In the end I reasoned that plenty of Cozy's are flying just fine with a removable cover so I decided to make mine removable too. I made the wood doublers from some left over pine and floxed, then glassed them in place. Reading ahead in the plans and thinking about hinges I decided that now was a good time to "whip out" the hinge pins from the canopy hinges. I'd wondered why these hinges had been in place since chapter 8. If I'd had any sense I'd have fitted a nutplate under the seat back support [per 'Hicks'] and left the hinges in the drawer, but no - these hinges had been epoxied, microed, painted and used to support the fuselage while it was upside down. It took me close to two hours to "whip out" the hinge pins using a variety of tools including a hammer, a blow torch, a set of grips and many short lengths of hinge pin. When the doublers had cured I made the hinges for the IP cover and floxed them in held in place with clecos. Later, lying in bed, I suddenly had this vision of the clecos becoming a permanent part of the airplane. I jumped out of bed, drilled and pop-riveted per plans and removed the clecos.
Attaching the canopy hinges
Plans don't seem to say anything about when to fix the fuselage top hinges to the canopy deck, so I decided to do it at the same time as the canopy hinges. [Later note - it was on the next page]. I prepared everything, then dropped the canopy in place. There is a bit of a gap between the longerons and the canopy, presumably caused by all the duct tape plans told me to put along the longerons. I guess this is to make room for the weather stripping. I can always close the gap where I need to by pressing the canopy down onto some plastic using BID covered flox to perfect the fit. In general, the canopy fits well. Reaching through the front I was able to drill and rivet the canopy to the IP cover hinges. Reaching with a stick through my floor landing light holes, I could push on the 4 inch hinges at the back to get good contact. If I'd read the plans I'd have bondoed blocks to hold the hinges, but "it'll be fine". I was wondering how I was going to reach those hinge pins to release the IP cover when I realized that the deck gets sawed off next, and the canopy will then lift up to provide access. This was another case of not reading ahead, but I don't think it will cause me a problem. [Wrong!]
I sawed the deck off and proudly lifted the canopy on its hinges. Nice. OK, now to see how easily the IP cover comes off. I "whipped out" the pin from the right side. Smooth. I tried to pull the pin from the left [Char's] side. No way. I tried pliers, grips and a hammer - nothing. All the pin would do was twist 1/4 turn, then spring back when let go. Out came the blow torch again. With Tommy pulling and me heating the hinge we tugged for 10 minutes, then gave up. Out came the drill and the chisel. I drilled out the rivets and chiseled the hinge off. This is good to do, once in a while - you learn a whole new level of respect for flox as a structural adhesive. Once we got the hinge in the vice it came loose fairly easily. Despite careful taping, some flox had got into a couple of the hinge sections. I cleaned up the hinge and mating surfaces, then prepared to install it again.
Next thing to consider is the gas spring. Using a stick to hold up the canopy just doesn't cut it. Now
I have to figure out how to fit a gas shock to the canopy - I don't have the bulkhead it is supposed to attach to.
Asked Wayne Hicks if he had any ideas, since he's going to have the same problem. He had.
Use a warner ball screw/jack and electrically raise and lower the canopy!!!!
Remote, keyless entry. Just pray your battery never goes dead.
Hmmm. If I wire the screw jack to a couple of screws on the outside, I could open the canopy with external power in case of failure. But, then - what if I want to get out in a hurry and the power is off. Hmmm. I think I'll stick to the gas spring.
My prop Factory
I've heard that some builders make their own props. My prop factory is a little different. We have two purebred golden retrievers. While I was building the canopy, the female, Bailey, decided that it was time to have her first litter. When the puppies were born, everyone was excited. Me too. I was quietly figuring that sale of the first eight would pay for a good three blade. After the first eight were born our faithful dog managed a deposit on a Garmin GPS before giving up at eleven. See Who me? cold and calculating? Nahhh!
Project Rating
I BID taped the edges of the canopy and fuselage top, and BID taped the turtleback to the spar. While I was finishing off the canopy, my daughter Vicky and her friend Brittany visited. The puppies were considered Cute, but my Cozy project got a "So Cool! rating.
Engine mount reinforcements
I made both reinforcements a couple of inches bigger than plans in all directions. This is because I may be using large rubber Barry mounts to secure the Mazda 13B. The outside layup was easy, but the one on the inside was a bit tricky. How do you get a piece of BID to lay flat in a 90 degree corner? One way would be to cut it, but I don't think this is the method intended in the plans. I found that the best way was to stick the edges of the BID across the gap, then gradually tap it into place with a brush keeping it flat on all surfaces as I go. The two inside 8 ply layups took me about 4 hours and three teeshirts. (it gets hot inside the TB).
Firewall
I floxed the side pieces and the 1/4 inch clark foam in place and supported it all with a 2 * 4. Later (after this picture) I added more foam on the spar at either side.
Instrument Panel Cover
I shaped some urathane foam making sure I had a flat area on top for a good visual reference. I carried the foam onto the front of the panel all the way to the sides and shaped a rounded piece to cover the top of the panel and give me a place to put some simple panel lighting. Once cured and trimmed I found that the side pieces fit nicely. They remain part of the cover and slip into place beautifully if I rotate the cover as I put it in. Eventually this whole piece will be covered with thin foam padding and leather.
Cleaning up the canopy edges
At one point, the plans say not to epoxy the canopy shut "or you'll be in big trouble". No, I didn't. Then. Since I'd already done the strakes now was the time for me to do the top strake fairings. See Chapter 24. Once the strake fairings were done, and recut along the longerons I found I had a lip of canopy deck sticking up above the longerons. I cut it off and saved the piece. Once I'd floxed all the edges and got the canopy deck flush with the longerons I put a strip of duct tape down, then a piece of flat TV antenna wire about 3/8 inch wide, then covered this with more duct tape.
I then piled flox on top, roughed up the contact area on the lid and closed the canopy, then floxed the strip of glass onto the upper lip. After cure and removal of the duct tape and wire, I had a perfect fit and a nice 3/8 * 1/8 groove in the flox on the upper join. I'd got some low temp P shaped soft rubber weather strip to put in the groove later. This will work to seal the canopy edges. I'm not sure yet how I'm going to seal the lips at front and back. My P weather strip is probably too thick. [Later note - the P strip was too thick for the sides too. I had to remove it and replace it with some thin draft excluder foam.]
I stored the canopy in the living room until I was ready to install the canopy latch mechanism.
Canopy Stop
After using Rick Maddy's Cozy handy little search engine to find the equivalent part numbers I ordered the plans gas spring PN 8195587 and bracket with studs PN 735-1592 from my local NAPA store. Fitting had to be a bit different since I don't have the bulkhead plans say to attach it to. I measured the travel of the gas spring and figured out that the best place for the brackets would be in the center of the seat and about 8 inches from the longerons on the passenger side. I dug out a 2 inch wide 1.5 inch deep hole at the center in the rear of the seatback right at the top of the seat brace and floxed in a 2 * 1.5 * 1/4 al hardpoint. I tapped the bracket in place so that it was between the al hardpoint and the top glass and the vertical flat of the bracket was up against the inside glass of the vertical seat brace support, then floxed and 2 BID taped the join. Next I dug out a similar hole in the horizontal turtleback support I'd made and floxed in another al hardpoint there. Again, I tapped the bracket in place above the al and BID taped. After it cured I clipped the gas spring in place and closed the canopy. Nice! When the canopy is closed, the spring has no moment on the canopy and doesn't lift it at all. Once I get it about one foot high, the spring takes over and very gently lifts it the rest of the way. When the lid is shut, the gas spring is hidden under my horizontal TB1 replacement bulkhead. Unfortunately there's no way to get the gas spring to go "over center" per plans. This means that, if you lift the canopy half way, then let go it can slam down hard. This has happened to me a couple of times already. I must remember to drill and tap those al hardpoints for screws and screw the latches in place. Right now the flox is holding, but I think I'll put screws in as well, per plans.
The only other problem I can see is that I've got the fit so good that there's no easy way to get you're fingers under the canopy to lift it. The new latch system from Jack Wilhelmson will solve this. If not I'll have to come up with a spring to lift the canopy the first inch or so once the latch is released. Later Note: Jack has since told me that the latch will pop the canopy up 1/2 inch to the safety.
Canopy Latch
Plans say that if everything fits, this should take 4 hrs. I had to "adjust" things quite a bit to get the canopy closing nice and tight. In the end I probably spent 8 hours on this job. When it came to fitting the extrusions to the canopy lid I used my own method. I held a screwdriver flat on top of the longerons and adjusted the tube lengths so that all three latches came down on the screwdriver at the same point. Next I tightened the screws on the latch with washers each side for spacing. Then, with the extrusions fixed in place and all at the same angle, I moved the latch to the closed position, put bondo on the edges and close the canopy on them all at once. The canopy was still maybe 3/16 open when it came down as far as it would go, so I dug out the flox pads a little to recess the extrusions. It seemed a pity to drill through my nicely finished, ready for paint canopy lid, but a little micro filled the holes easily.
Before drilling through the longerons I floxed my walnut burl trim pieces in place. These pieces, which match the dashboard, go along the sides of the longerons from the dashboard to the back of the cabin.
Safety Catch
I got to drill three more holes in my beautiful finished canopy deck. Plans say to use a CS13 steel spacer and 301 steel. I don't have these, and I'd got a suggestion to use "blue spring steel" for the catch. Hmmm. I searched around in hardware stores for "blue spring steel" but couldn't find any. Then it suddenly occurred to me where I could get some - I went down to Home Depot and bought a $3 putty knife. Perfect! I made the spring out of this, then looked for something to use as a spacer. Eventually, I found a small socket which was just the right size. I cut 0.15 inches off the end, so I now have a chrome plated spacer.
I did not make the door as shown in the plans. Once its ready I'll be installing Jack Wilhemson's "mother of all canopy latch systems" which will open the lid from across the ramp with a remote key.
The MOA Canopy Latch
Jack Wilhelmson let me test the very first prototype of his MOA (Mother Of All) canopy latches. It arrived attached to a wooden mock-up of the fuselage side. The basic idea is a custom built electric actuator which fits under the longeron just aft of the instrument panel on the port side. The actuator moves a push pull shaft which operates the plans latch system and connects to the same bolt as the forward C3. Th entire system weighs 20 oz. The forward catch/handle (C1-L) is replaced by a shorter C2-L and C9 is discarded. Limit switches mounted on an aluminum plate run against the forward C2-L to control the motor. Switching is by a small switch and or a remote key ring type switching device of your choice. Manual operation is achieved via a geared shaft at 90 degrees to the actuator. The shaft fits up against the fuselage skin and can be operated from the outside by an allen key. It takes about 4 or 5 complete 360 degree turns of the allen key to retract the latch. The hole in the fuselage is about 1/4 inch and could be filled with silicone to be removed only in the event of battery failure. Manual operation from the inside is achieved by turning a knurled knob (four or five revolutions). Manual operation is relatively slow and the electrical failure mode is locked gears and hence a locked canopy. The failure mode in case of stripped gears (see below) is a totally locked canopy since there is no way to retract the actuator. For this reason, Jack suggests a quick release pin on the bolt that attaches the unit to the pushrod. This pin would be removable from inside, or outside in case of emergency.
The MOA worked great in the mock-up, so I drilled the required holes to mount it under the longerons and hooked it up to the plans latch system. The shaft which permits manual operation from outside was about 1/4 to 5/16 too long on the prototype. I wanted it to be flush with the inside skin, not sticking out as Jack had planned. Because of this I ended up with the MOA mounted about 1/4 inch too far inboard, but I used a longer bolt to hook the actuator to the latch pushrod and everything worked fine. I hooked up my battery charger and, after a few adjustments I had the MOA opening and closing the latches like a banshee.
The next step was to try it with the canopy. Jack's instructions say to fuse it at 5 amp, but I figured the battery charger would do just fine. I closed the canopy onto the latches and operated the MOA. It grabbed the canopy and pulled it down tight. Unfortunately I hadn't adjusted the limit switch correctly and the motor was still turning when the canopy wouldn't come down any more. This is where the 5 amp fuse would have been handy. The motor struggled onward for a second, then spun freely. Oops. That doesn't sound right. It wouldn't retract. Next day I sent an embarrassed email to Jack to let him know I'd stripped the (plastic) gear on the motor. "No problem", says Jack , "I was planning to use a metal gear in the production model anyway." He was kind enough not to berate me for failing to fuse the power. I agreed, sheepishly, to return the MOA for repairs.
I had originally thought that a trunk latch from a Lincoln Town car would be perfect (you know the type - you close the trunk part way and the latch grabs it and closes it the rest of the way automatically). These things have both manual and electronic release. In a conversation with Jack we agreed that, while this would be a nice solution, the weight and cost of three of these would be too much. For the time being, I'm sticking with the plans latch and no way to open it from the outside.
The SOA Canopy Latch
I must have spend over 3 1/2 years deciding on the best way to handle opening the canopy. In the end, by default, I just did what the plans said and built the 'Son of all' canopy latches.
Here's are a few of my abortive thoughts about canopy latching....
I think I wish I'd done the front opening canopy. At that stage of the game I was too nervous to change anything so I went ahead per plans. Looking back, I should have got the front opening plans from Uli Wolter or Jeff Russell and given this method serious consideration.
Next I considered a trunk latch approach. My problem was not holding the canopy shut while flying - the plans latch system is designed and proven for this job. I just didn't like the little door or the everyday (or emergency) access method to the aircraft from outside. Hmmm. I could keep the plans latch, but leave it unlatched when exiting the airplane. (Later note: wrong - you have to close the latch to close the canopy). The trunk latch would only need to hold the canopy shut when the airplane is parked - so I'd only need one. It could have an emergency release on the outside, which I would disable when parking. In an airborne emergency I'd release the plans latch when cutting the master just prior to touchdown. It would be cool to have a remote canopy opener, but then I'd need a mechanical backup entry method. I'd hate to be locked out of my own plane at some distant airport.
Much later, in March 2003, I still hadn't done anything more about canopy latching. The engine was on, most of the upholstery was in, the plane was painted and trimmed, but still I had no way to get in and out of the sucker. Time to make a decision. I'd agonized long enough and at this stage of the game I wanted to get on with the final issues and get this damn plane in the air. When in doubt - follow the plans. After all the ideas and schemes for canopy opening it was pure relief to just go back to the plans and do what they said. I measured out where the plans said the door should go, got out a hacksaw blade and cut. In no time I had a nice big hole in the side of the fuselage. I made the lips around the edge, but used mixing sticks under the tape to give a little room for weather stripping. Rather than bondo my finished and polished surfaces I used duct tape and mixing sticks to hold everything in place while the door lip cured. The inside catch was made from a small piece of AL angle. At this point, I had an idea for the emergency access method. I may even implement it when I get a "round toit". Here's my new plan, in case I forget:
I'll use the door locking and latching system per plans. Once access has been gained to the parked airplane I'll leave the key in the unlocked position and use an additional latch to open the door from either inside or outside. On the inside will be a rectangular piece of aluminum with length just less than the diagonal of the door and width of about 1/2 inch. This latch will rotate on a pin through the center of the door. Latched position will be vertical. Unlatched diagonal. On the outside of the door will be a D handle which sits in a matching recess in the door face when latched. To unlatch from the outside this D handle is pulled and turned.
Back to the work at hand. Determined to change something, I didn't like the plans approach of attaching the aluminum catch to the panel. Instead I used a piece of bent stainless spring steel (cut from a sheetrock putty knife) riveted along with the door hinge. I also attached circular crimp connections to the door side of the hinge and the latch handle so I can detect whether the door is closed AND the canopy is correctly latched. The canopy latching and opening mechanism is a little cumbersome, but it's done and the method is proven. The only change I made is the spring steel catch attached to the hinge instead of the panel. I floxed and glassed over the attachment rivets so I don't see how this can come loose. I actually like the look of the door in the side of the plane. Once I'm flying I'll decide if I want to change the door locking mechanism, but for now ..it's done and I can move on.
A new paint scheme?
As expected, I damaged my finished paint surface while building the door and installing the hinges. When it came time to repaint I decided on matt black. The Columbia tragedy was on my mind and I thought it would be nice to paint the plane like the shuttle. It made sense too. What's the point of an emergency door that no-one can find? Beside - I was out of white paint. I painted the door black and planned to surround the door with black and yellow stripes. I'd use the same scheme on other important external items, like the static vent. Getting carried away a bit, I also thought I'd paint the lower quarter of the nose and the lower wing and strake leading edges black to add to the overall "shuttle look".
Perhaps I was going a bit overboard here. Hmmm. I asked Char to take a look at the door, and described my plans for yellow/ black stripes and matt black leading edges. She shook her head. I explained why it made sense to paint the emergency door so people could find it in case of an accident. She shook her head again, more firmly this time. "It looks ugly. Paint it white. Let's just avoid accidents so no-one will need to find it." she said. SO much for my logic.
Charmaine is HOA (Head of Aesthetics) in our house, and all logical reasoning is superceded by aesthetics. I'm not sure why that is, but it's definately the case. I rubbed off the black paint and painted the door white. Damn. My plans for a "shuttle look" are out the window, and I'm going to have to order more white paint. At this point I hate Polyfiber Top Gloss so much that I'm considering using an automotive aerosol spray.
Cleaning up the Acrylic
My acrylic canopy suffered a few minor scuffs and scratches during the long period of canopy deck construction. I'd slipped with the sanding block a couple of times and there was a bit of overspray on a few of the edges. I'd read about some products which would allow me to "restore" my brand new arcylic. Eventually I ordered a KR-70 kit from Micro-Surface in Iowa. The stuff worked great. I used it lots of times during the building.
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