Decided that I should update the website, not that I've made a lot of progress but it does keep me motivated to push on. The sides are finished and pulled off the jigs, which left some pretty nasty divots in the foam, some micro will fill these in before glassing. I did a trial fit of the bulkheads to the sides to ensure a nice fit. It took some trimming and adding foam to minimize the gaps. The areas where the bulkheads are bonded to the sides were sanded as well as the areas on the bulkheads to ensure a good bond. I also sanded the area for the fuel sight gauge and floxed the base for the gauge. I decided to hold off on installing the entire gauge because holes need to be drilled later (that allow fuel into the guage) which would cause trapped shavings in the site glass (plexiglass).
So it was time to set the sides up vertically which is what the temporary firewall is for. The temp. firewall has cutouts for the longerons to poke through which keeps the sides upright. From reading other builder's websites, several builders recommended stiffening the temporary firewall so that it doesn't flex when making measurements and verifying that everything is level and vertical. I also made it adjustable vertically so that it would be easier to set the upper longerons at the prescribed 23 inches above the table. Many of you may think this is overkill, but it's the little things like this that make things easier in the long run. Also, I don't have much time in the evening to work on the airplane, maybe an hour, so I try to do the little things that you might otherwise try to take shortcuts on and save the weekends for the major layups and construction.
Due to the limited space in my garage I'll be assembling the fuselage on top of my table, I know it's level and if it isn't I can easily adjust it. The plans have you do the assembly on the floor which makes it easier to reach over the sides to do the glassing. I'll make a long scafold to stand on which should help a bit. So here's the fuselage sides sitting on top of two 2X4s leveled with the upper longerons set at 23 inches above the table. The two sets of doubled 2X4s are set precisely 101.75 inches apart which insures that the fuselage length is correct which is important for center of gravity (c.g.) concerns. After measureing the lengths of the fuselage sides several times and leveling everthing it appeared that the fuselage was too long, while in Chapter 5 it seemed like they were barely long enough. Well after running the the doubled-up 2X4s on the table saw to get sharp and perpendicular corners my brother-in-law and I determined that the ends of the fuselage sides were not square. I did have a hard time trimming the ends in Chapter 5. So the top longeron was the correct lenght but the bottom was about a quarter inch too long. Drew a line with a carpenter square and trimmed it again with the Fein sander. Thanks Erik for all your help. F22, the front bulkhead is being held in place with nails tapped into the upper and lower longerons as is the temporary firewall in the rear.
I remembered that I still needed to make the center cutouts in the front seatback. I didn't have the guts to do it in Chapter 4 after spending so much time making it and it being the first real layup of the project. The cutouts were angled at 45 degrees to accommodate the reclining angle of the seat back. It wasn't very difficult once I thought about it a little, I used the Feign sander to make the straight/vertical cuts and a file to get the 45 degree angle.
Trial fit the seatback, instrument panel and F22 with the fuselage sides and they all fit really well. Of course spending the time earlier fitting up/trimming the bulkheads to the sides while the sides were still attached to the jig made all the difference. At first I was going to short cut that step but it is important in getting a good fit at this stage where fitting, trimming and rechecking would be much more difficult. I am really amazed how well it all fits together, it far surpasses anything I've attempted in the past. I think (know) this is attributable to how great the plans are and following them, thanks Nat.
Here you can see the fuselage clamp to squeeze the fuselage sides to the seatback. They're made using the scrap wood from the fuselage side jigs, that's why they're tapered so oddly. I only need to finger tighten the nuts on the threaded rod to eliminate any gaps between the sides and the seat back. I have another set of clamps to clamp the sides to the instrument panel but am short one length of threaded rod so they're not shown. Always need at least two or three trips to the hardware store to get everything I need. My Harley tries to sneak into every picture.
Sunday Feb 8, 2004
The weekend started off building some heavy duty picnic benches. They're built from 2X4s and a 2X10. The 2X10X10 was specified in the plans to use if you assemble the fuselage on the floor, when I bought it I didn't really know what it was used for but got it anyway just in case. Well I put it to good use, I cut it in half making each bench 5 feet long. The benches are 22 inches tall which gives us plenty of height to reach over the fuselage sides to flox in the bulkheads.
Well, after a little trimming of the front ends of the fuselage sides to make them square with the table and checking that everything was level and vertical it was time to dive in and do it. Of course to do it you have to take everything apart and spread out the sides at the front so that the seat back and instrument panel can be installed. My wife Lynn was instrumental in getting this done, she worked tirelessly for 4 hours straight. We used the plastic baggy icing method to spread the flox on the ends of the seatback, instrument panel and F22, and at the proper locations on the fuselage sides. This really worked great and created an even bead of flox where ever it was needed even on the vertical sides. We peel plyed all the joints to make the sanding easier.
Here are some more pictures.
Sunday April 25, 2004
As usual I've been negligent in updating the website, probably because there have been a lot of little things to do and nothing major to show. The little things were to go back and sand/grind all the floxed corners and then lay up two plies of BID. Even though we made nice rounded smooth fillets of flox in the corners it was still a chore to get the BID glass to lay down smoothly without bubbles, especially where there are compound curves. The best and in my opinion, only way to make the BID glass tapes (strips) is to cut the glass cloth (at 45 degrees) and then wet them out between two pieces of plastic. Cut the wetted cloth and plastic into the required strips. Peel off one layer of plastic, the remaining plastic holds the wetted glass in shape. Lay the glass strip (with one layer of plastic) in place and then peel off the remaining piece of plastic. Now you can stipple the cloth down to conform to the corners and curves and eliminate bubbles. After that apply one layer of peel ply. The peel ply is even harder to get to conform to compound curves and angles. Several darts need to be cut into the peel ply to make it lay down. It’s important to get the peel ply to lay down completely because the adhesion between the peel ply and glass can cause the glass to pull up from the surface. The grinding and sanding took a lot of time.
The top corner of F22 receives 7 plies of BID reinforcement which is where the canard will eventually be mounted.
The next step was to install the F28 bulkhead, this was straight forward other than the actual location of where it is to be installed. The plans say to install it 5.9 inches aft of the F22 bulkhead. But many builders have experienced not having enough room to install the canard with F28 that close to F22, they’ve had to cut out F28 and reposition it at 6.25 inches aft of F22. So I installed F28 at the 6.25 inch position. Later I’ve heard that the 5.9 inch position should be fine. Well, I’m not going to worry about it until I get to the point of installing the canard. We’ll see.
Next I installed the aft landing gear bulkhead (aft LGB). Needed to trim and file it for a proper fit and then floxed it in. Followed the plans suggestion to hot glue wood blocks covered in duct tape to the fuselage side walls to make sure the aft LGB is in the proper position and perfectly vertical. This created a bit of a problem since the flox squeezed out between the aft LGB and the wood blocks which put the LGB forward of where it needed to be. So I scraped the excess flox away and repositioned it. After the flox cured I found that the aft LGB was not quite vertical, off by about a half degree and skewed by a sixteenth of an inch. I queried the builders group and half the responses said it was close enough and continue on and the other half said to fix it. I decided to fix it since the forward LGB needs to be parallel and vertical relative to the aft LGB. So if one is out they’re both out. Also I thought it would be a good learning exercise for future fixes and repairs. My one concern was that the fit of the aft LGB would not be as tight as before, but according to the builders group the flox is much stronger than the foam/glass that makes up the ends of the bulkheads, so I shouldn’t worry. Using my trusty Fein sander I cut out the bulkhead very cleanly. A small portion of cutting had to be done with a hacksaw blade, about a half inch worth. After using the hacksaw I had even more respect for the Fein sander and flox. I modified my wood blocks to allow for flox being squeezed out.
Sunday Aug 1, 2004
I'll dispense with my usual excuses of not updating the website. The forward landing gear bulkhead was installed similar to the aft landing gear bulkhead the only additional challenge was that it needed to be precisely 8 inches forward of the aft landing gear bulkhead and also be parallel and vertical to it. The plans suggest making a bookend type fixture to insure the spacing and parallelism. So, I went about in my usual fashion of cutting up wood in various trapezoidal shapes until I ran out wood. So I finally broke down, purchased some straight pieces of wood and went over to my brother-in-law's, and Erik cut me 4 perfectly square 8 inch pieces of wood, then gluing them together to make a perfect 90 degree bookend.The corner of the bookend also functions as a guide to drill pilot holes in both bulkheads in a straight line. The holes will eventually be enlarged for bolts that will hold the arched landing gear spring.
The forward landing gear bulkhead is actually two pieces, upper and lower halves, these parts were all built back in Chapter 4. The lower half was installed previously, the upper piece is attached with flox and 2 plies of BID along the seam of the upper and lower half (both sides) and angled to follow the built up portion of the fuselage sides. Again, I used some wood blocks covered in duct tape hot glued to the fuselage sides to hold the upper half at the correct angle. The hot glue isn't a very strong bond so you can easily remove the wood blocks later, you might have to sand some of the residual glue off, but it sure works great for positioning parts while curing. Also several plies of UNI are applied along the sides.
Applying some additional plies of glass to the bottom side of the Fwd LGB was next which required removing the temporary firewall and turning the entire fuselage upside down. Unfortunately my camera batteries died before I could download the pictures to the computer, so here are some shots of the reinforcement to the Fwd LGB and installation of the lower portion of the real firewall. Although I've been using the technique of wetting out the glass between two pieces of plastic all along I've found that it is beneficial to leave the top piece of plastic in place while you lay the glass down on the part. This allows you to really press and squeegee out any air bubbles without distorting the weave of the glass cloth. If you're laying up on a flat part it really works great, on curved parts the plastic won't conform to the curves but you can still use the plastic to squeeze out the air bubbles and then remove the plastic and then lightly squeegee any remaining bubbles, following-up with peel ply.
Installing the lower firewall was essentially the same as the landing gear bulkheads, just making sure everything is vertical, perpendicular to the center line and parallel to the landing gear bulkheads. The more parts you add, the more checks you have to make. The challenge here was that the upper and lower longerons pass through the firewall, so trying to make the cutouts in the correct locations was difficult especially since the lower longerons (shown on top in the pictures since the fuselage is upside down) are angled downward. The pass through for the electrical channel is also cutout. Anyway, after a lot of measuring and double checking I made the cutouts and realized that the cutout for the upper longeron needed to be slightly larger than the actual size to allow for the angle of the lower longeron. Any gaps were filled with flox. I got lucky with the location of the electrical channel, it just missed the 4 screws embedded in the firewall for the rudder pulley mounts. When making the electrical channels in the fuselage sides in chapter 5 the plans are not specific where the channel exit needs to be and many builders have had a problem with the exit interfering with the pulley mount screws. The large rectangular cutout in the center of the fuselage is for a NACA air scoop that provides the engine with intake and cooling air. You can see that all the landing gear bulkheads have this cutout but are progressively smaller the further forward they are, thereby creating a "V" shaped scoop on the belly of the fuselage.
Since I'm now out of parts to stick on to the fuselage I've got to make some more. There are two actually, the Hot Air Duct and the Seat Back Brace before I finally make the fuselage floor. Unfortunately the pictures showing the build-up of these parts were lost due to the dead camera batteries so I only have shots of the completed parts. It's a shame, because these were a bit labor intensiveto make. Many of the other Cozy websites will have shots of what's involved though. To start off, I made a common mistake, which is not making right and left sides for the seatback brace. In the beginning of the plans it shows the optimal layout of the parts on the sheets of foam and it appears that the sides of the brace can be made by bisecting a rectangle along the diagonal, don't do it. Because the base and the vertical legs of the triangle are different lengths you need to lay them out on the foam separately and then make sure you glass the correct inside surface of each side, if that makes any sense. If you do make two right or left sides, don't worry there is enough foam to cut out another side. Just include another sheet of foam in your next order, because you will need more of that foam later.
The fuel selector valve (selects fuel from the right or left tank) is mounted on the seatback brace. So a mounting bracket is made from small plate of aluminum about 3/16" thick. There's a full-size template in the plans which I traced and then stuck to the aluminum plate using adhesive spray which made cutting out the pattern and drilling the holes easy. Many builders have had trouble bending the 90 degree legs on the ends but I seemed to luck out there. Nut plates are riveted to the braket using very small 100 degree countersunk rivets. You need to use a 100 degree counter sink on the rivet holes otherwise the rivets won't seat properly. You don't normally find A 100 degree countersink in your typical hardware store, I was able to borrow one from a friend. Also the holes for the rivets need to be drilled with a #40 drill bit which is also not found in the hardware store. Wicks and Aircraft Spruce have all these tools and they're not expensive, I've since ordered a microstop (which lets you set the depth of the countersink very precisely) and several 100 degree countersinks with various pilot sizes and several numbered drill bits. I alodined the fuel valve bracket, safety belt mount tube and brake pivot tube (which gives aluminum a gold color) to prevent corrosion and provide better adhesion for the epoxy.
To provide some solid structure to mount the fuel valve bracket and the speed brake pivot the forward portion of the seat back brace has a triangular piece of birch plywood imbedded in it. The bracket and brake pivot are floxed to the plywood. Spacers provide additional strength to the seatback brace and form the map pocket. An another aluminum tube is embedded in the heat duct with flox which provides an anchor point for the seat belts. To make sure it doesn't pull out it gets 7 plies of UNI on top plus 2 plies of BID over the entire duct. Later, an additional 7 plies of glass tie it into the floor.
So, once you've glassed the outside of the heat duct and seatback brace, it's time to join the two parts together by glassing the seatback brace on top of the heat duct. Because my heat duct had a bit of a twist to it I decided to join them while temporarily fitted in the fuselage. This way I could ensure that the seat back would be vertical relative to the fuselage. The plans have you join them on your bench ensuring that both parts are vertical to your bench top, which wouldn't be possible with my heat duct. When in the fuselage, the heat duct needs to be aligned with the bottom longerons and the bottom of the instrument panel. I had to do some careful trimming of the seatback brace to fit in the angle created by the heat duct and seatback. This was a result of the seatback bottom not being flush with the bottom longerons, there's about a 1/4 inch gap. When joining the fuselage sides with the seatback and bulkheads I thought this little gap might be a good thing, it would prevent any bulges in the floor if the bottom of the seatback wasn't perfectly straight, and since I had everything set and floxed in place I didn't want to reposition it. I"ll compensate for the gap with foam when fabricating the floor. I made some cardboard templates of the seatback brace to see where and how much trimming needed to be done. The patience in taking this extra step paid off because my original geometric calculations would have had me trim much more than I needed to and the seatback brace would not have extended all the way to the top of the seatback. So after achieving a good fit, the seatback brace and heat duct were glassed together. After cure I mounted the fuel valve again to the seatback brace to check that it would be removeable once the whole assembly is permanently glassed into the fuselage. To get the clearance necessary to make the fuel valve removeable required filing a round hole in the existing slot in the center of the seatback.
Sunday Aug 8, 2004
Well, now there are no excuses left but to glass the entire seatback brace/heat duct assembly into the fuselage. So this involved floxing all the mating surfaces (seatback brace with seatback and heat duct with instrument panel), creating flox fillets in the corners and applying 2 plies of BID tape. All the while keeping everything horizontal, vertical and on the centerline. Didn't seem like a huge task but it took 5 hours nonstop to complete. I was feeling a bit under the gun since my parents and my brother's family were coming over for dinner and to celebrate my birthday and this was taking a lot longer than the three hours I thought it would. I needed to show some progress since their last visit though. Anyway, I got it done in time and now that I reflect on my 43 years of life, harsh, cold reality is setting in. I've been working on this plane for two years and I still don't have anything that looks like an airplane. At the pace I'm going I won't be done before I'm 50. I'm going to pick up the pace on this and work on the plane everyday. You hear from the builders that do finsih their airplane, that you've got to do something on your airplane everyday, no matter how small the task. So I'm commiting myself to work 2 hours a day during the week and as much as I can on the weekends. I really enjoy building but I want to be flying before old age health issues start cropping up. I mean, once you're 50, you can get hit by anything that will keep you grounded. OK, enough of my life is coming to an end routine, here are some pictures of the installation. Looks pretty much like the temporary installation when glassing the heat duct and seatback brace together. Oh, Lynn did give me an outrageous digital camera for my birthday a Canon Powershot S1 IS, 3.2 megapixel with 10X optical zoom. I'll probably continue to use my Photo Phaser for pictures taken during the actual layup and use the Canon for shots after cure and clean-up so that the camera stays clean. But with the zoom of the Canon I can really get some nice closeup shots like the fuel valve access hole in the pictures above. The pictures below were also taken with the Canon. On shots like these there's not a noticeable difference since I need to downsize all the pictures anyway to limit the website memory useage.
Sunday Aug 22, 2004
Now it's time to make the floor of the fuselage, the construction is similar to building the fuselage sides but just a lot more to do. There are more spacers to make, have to deal with cutting out the speed brake and a much larger area to glass. On the bright side the fixture is much simpler, just a wood frame of 1X2s that I 5 minute expoxied together. I put a little flox in with the 5 minute epoxy and that helps fill gaps and keeps it from running where you don't want it. But before making the frame you need to trace the outline of the fuselage onto the foam and cut the foam to size and 5 minute epoxy the foam panels together just like the fuselage sides.
Once the floor panels are joined the foam floor is layed on top of the fuselage and the wood frame is built on top of that to get the correct curvature of the fuselage bottom (unfortunately I didn't take any pictures of this step). The plans have you use dabs of 5 minute epoxy to attach the floor to the frame. I decided to try alternative methods because of the huge divots I got on the sides of the fuselage using the plans method. Another builder used carpet tape which is tape that is sticky on both sides, it's about two inches wide and still very thin. This is the greatest stuff and I wished I'd used it on the fuselage sides. As you can see the fuselage isn't on top of the work table anymore. Well, there was still one small opening in the garage rafters among the two kayaks, three bicycles and wood storage already hanging from the rafters. I just hope the roof doesn't implode.
The speed brake is cut out of the floor panel. The speed brake is deployed from the belly of the fuselage while on approach to landing to help slow the plane down. Because of the efficient aerodynamics of the airplane slowing down can be difficult. The cutout is at a 45 degree angle. The plans say to use a light weight jigsaw to cut out the speed brake. My jigsaw isn't really lightweight but I practiced cutting foam with it but had trouble making nice rounded corners (1 inch radius). It's also difficult to see the line with the jigsaw angled at 45 degrees. I decided to make a fixture to hold my dremel tool at a 45 degree angle and use it to make the cut (my brother-in-law, Erik, helped me, he instinctively comes over whenever I need an, idea, a second set of hands, tools or something made very accurately). I wanted to make the cut as thin as possible so I used a small drill bit. I did some practice cuts using this setup and it worked better for the rounded corners. Initially it seemed like the drill bit was not cutting the foam and then it would just take off. What I realized was that the drill bit started cutting after it heated up a bit. Another aspect to this method is that you need to keep the base perpendicular to the cut line in order to get a true 45 degree angle. In retrospect I think I would use the jigsaw for the straight cuts and the dremel setup for the corners. The cutout turned out fairly good. In building this airplane most tasks are simple and straight forward, perhaps a bit labor intensive, but for some (as with cutting out the speed brake) there is definitely a learning curve and you do your best to get it right, and then it is what it is. You can always do it over but then your build time increases significantly. Erik and I celebrate the completion of each step with a few beers, everything looks better that way.
Now the fun part, making all those nasty spacers, similar to what was done for the fuselage sides. At least the beveled angle is 30 degrees everywhere, unlike the sides that had different angles in some locations. I had seen on John Slade's and Norm Muzzy's websites that they had setup their bandsaws to cut the foam to a 30 degree angle. For myself and the other trigonometrically challanged builders out there, here's a picture of the angles involved and why you need to setup the bandsaw this way. My first thought was, well I'll just setup the bandsaw table to 30 degrees and cut away. Well when you do this you end up with a 60 degree angle because the 30 degrees that you set the table to is 30 degrees from horizontal not relative to the blade. So you can see to get the foam cut at 30 degrees you need to clamp a block of wood as close as possible to the blade and run your foam piece vertically along the block of wood. Make sure your wood block is clamped parallel to the blade and table. Once you have it setup there's no special skill to cut the foam, just keep your fingers out of the blade. One thing to remember though is that you can't cut all the pieces this way because of the beveled corners, where two pieces meet. Depending on how you layed out your spacer foam, the larger lateral pieces will need to be done by hand while most of the long 2 inch spacer strips can be beveled on the bandsaw.
As you can see the results are nice clean, sharp corners, especially at the base where you want a smooth transition for the glass to lay into. Well I guess it's time for another beer.
Sunday Sep. 20, 2004
With the spacers cut and microed to the foam floor and the whole assembly fit checked to the fuselage, it's time to do the glassing. I'd seen that other builders had made a special tool to hold the end of the fiberglass as it comes off the roll, to keep it from distorting. This is especially helpful when doing large layups because the fiberglass tends to distort when holding it with two hands, it sags in the middle and you don't tend to pull on each corner evenly with your partner holding the other end. Erik and I devised our own tool that worked very well. It's basically a 42 inch length of 2x2 with a slightly oversized quarter inch wide slot, 1/2 inch deep (using a stacked datto) that traps the fiberglass with a flat piece of 1/4x1 inch aluminum stock. The aluminum captures the cloth in the slot and holds it evenly when orienting the cloth on the part. With the glass and aluminium pressed into the wood slot it's a lightly snug fit, so when releasing the glass out of the slot it gets a bit distorted, but that gets trimmed off anyway. The smoother you make the slot the better, I put a couple of coats of shellac on it.
Before laying the glass on the foam I made some thick micro to make smooth fillets as needed and let that set up for about half an hour so that when applying the micro slurry to the entire foam surface it would not dilute the thick micro fillets. I let the micro slurry also set up for about half an hour and had lunch since the actual glassing would take awhile, (about 5 hours). The glassing went fairly easily, the only difficult part was when laying the glass down on the foam it would create a flat roof over the depression created by the spacers, you really need to make sure that there is enough cloth to press into the corners. I needed to lift up the cloth to create some excess and push it into the corners otherwise you'll end up with bubbles because there won't be enough cloth laying down in the square depressions created by the spacers. Once the cloth is wetted out it doesn't want to move much without distorting. The plans have you glass the floor, flox and tape it to the fuselage all in one session. I'm going the route like many before me and breaking this down into three separate steps, 1. glass the floor and peel ply where the joints to the fuselage will be, 2. flox the floor to the fuselage and 3. tape all the joints.
Lynn does all the work and I do the celebrating.
As you can see I drew lines on the foam 45 degrees to the center line to ensure correct orientation of the fiberglass, 1 ply in each direction. The area behind the front seat back brace, where the back seat passengers will be stepping gets a third ply which I oriented 90 degrees to the centerline.
Sunday Oct. 10, 2004
With the floor glassed the next step is to bond it to the fuselage. Before doing that I sanded all the mating areas to ensure good bonding, this took quite some time especially in areas where I didn't have the forsight to apply peel ply. Lynn and I used the lunch baggy/cake icing method to squeeze a bead of flox on all the mating surfaces. One useful hint here is to reinforce the corner of the baggy with duct tape or you'll surely experience a blow-out.
It took some weight to get good flox squeeze out. Remembering to draw and redraw ceterlines on parts is important, lining up the floor with the fuselage was a little difficult because I drew the centerline on the peel ply once the peel ply is peeled off no more center line. Fortuately I could still see a faint line on the foam under the glass which was enough to get it positioned and could verify with a tape measure that it was indeed on the centerline. Once the floor was weighted down we got underneath and scraped off all the squeezed out flox to make sanding the joints easier for subsequent taping. It's amazing how much concentrated weight the foam can hold without denting it. You can also see that there are no divots in the bottom foam as there were on the sides. This is due to using carpet tape to hold the foam to the wood frame as opposed to 5-minute epoxy, carpet tape is great stuff.
For the next step of sanding and taping the joints I really needed to have the capability to rotate the fuselage. This will also be necessary when glassing the sides. So, I made a fuselage rotisserie. Basically some wood clamps on the front and rear bulkheads with some plywood spacers to provide centering and additional support. I needed to have mine set on top of my work table due to limited garage space, which made clearing the table, lights and garage roof a challenge.
Here is a better view of the fusealge on the rotisserie.
Return Home Chapter 5 Fuselage Sides