A sub web site of http://www.rcflier.com
This web site is hosted by Bob Hudson.
The pages on this web site document MY procedure and assembly of my Carden Edge 540I am by no means a professional or "master" builder and these procedures may not be the best methods for you.
Carden provides a nice construction guideline and color photos as an aid to building their kits.
I have chosen to build things in a little bit different order than they lay out in their manual
Part 5 - The Foam Parts
After the fuse is framed up we can test the fit of the bottom foam pieces. These foam pieces can be sheeted (in your favorite method). I am not going to glue the rear main foam block in place until I install the servo wire tubes and hopefully locate the rudder pull – pull cables.
The main bottom foam and the quarter round foam being pre fitted before sheeting
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Next step is to start sheeting the foam pieces.
I am choosing to sheet the pieces for the fuse first since the fuse is is basically built and it would be nice to continue a bit more with the fuse to get it more completed and out of the way.
Since the fuse is still pinned to the board I will sheet the bottom pieces first so can trial fit them again, sheeted this time on the bottom of the fuse. I don't want to glue the bottom foam onto the fuse at this time because I want access to the inside rear of the fuse to install pull pull cable guides and servo wire tubes.
Carden provides top quality balsa sheets to do the sheeting with. They have pre-sorted and bundled the sheeting by density and in their manual show you what density of sheeting to use for the different foam parts. Follow their guide in this matter.
You will notice that Carden edge trues all the balsa sheeting for you at their facility. This is big help in sheeting as the process of edge truing balsa sheeting is a time consuming and tedious job.
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See the edge trued sheets pre-taped on one side |
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See The other side (to be the outside) taped full length |
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Having had good success with it in the past, and knowing the good case history now on Probond use by so many "Giant Scale" modellers, I will be using ProBond Poly Urethane adhesive for all the sheeted parts. |
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See the Probond bottle |
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See The ProBond with a spreader |
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With the Probond method we simply run masking tape the full length of the joint on the outside side of the sheeting. For wing skins, stabs and fin / rudder sheeting it usually isn't necessary to "pre-glue" joints. For contoured pieces where the skin bends around a part, such as a turtle deck, the rear belly pan (as on this plane) or the front quarter round pieces I will pre-glue the joints with Titebond (or similar carpenter glue) to ensure the joints don't "crack open" as the Probond cures. |
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See The 1/4 round skins ready to be glued to the 1/4 round foam |
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See The 1/4 rounds clamped in the shucks curing |
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While spreading the ProBond "crack" open the joint on the (inside or reverse side) joint to be sure you get adhesive in the joint. Spread the ProBond with a putty knife or spatula. Be sure to "squeegee" off as best you can so you don't leave an excess of adhesive on the balsa sheets. This adhesive works very well and soaks into the balsa quickly. While curing it actually works it's way into the foam beads and makes an exceptional bond. Line the inside of your foam "shucks" with waxed paper. Put the balsa skin into the "shuck" and in turn put the foam part back in the "shuck. Put another sheet of waxed paper on top of the foam piece and place the other foam "shuck" over that |
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See Put some weight on the top of everything and leave it overnight (or for at least 6 to 8 hours) to cure. |
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See After the "foam sandwich" has cured trim the excess skins from around the perimeter of the part |
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See The ends still need to be trimmed flush with the rear "belly pan" part |
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See Trial fitting the sheeted belly pan to the fuse |
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See The belly pan and fuse, front view, getting ready to drill the landing gear plate |
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Next is the Turtle deck (October 7th) Edge join the balsa sheets with masking tape to prepare the turtle deck skins. Once again I pre-glue the joints on "awkward" pieces like turtle decks where the skin has to form around tight bends. I use Titebond (or yellow carpenters glue) leave the joints to dry for a couple of hours. to be sure the glue is dry in the joints. After the glue has dried spread the ProBond on the skin and place the whole assembly back in the shucks to cure. |
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See The turtle deck in it's shuck with weights on it |
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See Turtle deck view two-front / side view |
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See Turtle deck view three-rear view |
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Next step I did was to glue on the belly pan and quarter round filler blocks on the bottom of the fuse. I followed Steve's advice by gluing down one side of the belly pan first. Then the other side afterwards. Since the belly pan (and the turtle deck will act the same way, so I'll follow the same procedure for it) tends to "spring out wider than the fuse a bit after it is sheeted one side is glued down first. I put beads of Probond along the bottom fuse longeron but left 4 strips about an inch long, one at the front, one at the rear and 2 spaced out along the length of the belly pan-glued". I put CA on these 1" strips in order for a "quick set" to hold the side down while the ProBond sets. |
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See The first side of the belly pan glued down and taped in place while the CA sets. |
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See Another view of the first side taped in place |
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Once the first side is glued down and the CA has set you can work on the second side The second side tends to "spring out" beyond the width of the fuse so you need some way of holding it in place. I don't have big clamps with a deep enough throat on them so I had to come up with some other way of holding the belly pan in flush with the fuse. You will probably use the same method when gluing on the turtle deck in the next step. I used some of the 3/8" square balsa sticks left over from the fuse construction and "tacked" them vertically onto the side of the fuse with a couple drops of CA. |
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See The balsa blocks glued in place. |
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See The belly pan is lifted about 3/8" so I can put the ProBond and CA beads in place |
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See The second side is taped down |
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See Another view of the second side taped in place |
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See The quarter round blocks (on top o the gear plate) are ready to glue in place. |
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See The gear plate screws epoxied in place for added security (suggested by Carden, good idea) |
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See Don't forget to "dimple" the quarter rounds where the landing gear plate screws are |
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See The 1/8" ply "cap" I'm going to put on the rear face of the belly pan |
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Behind the belly pan is a "filler' piece to blend in with the rear of the fuse. I am going to make this piece removable to provide access to the rear inside of the fuse. This will facilitate pulling and connecting the servo wires, the RX antennae, and the rudder pull-pull cables. I will put a couple of 1/4" dowels in the front of the filler block (one on each side left and right) which will lock into holes on the 1/8" rear ply face plate of the belly pan (similar to the canopy / hatch hold down dowels on the top of the fuse). The rear end of the filler block will be held down with one or two 4-40 socket head cap screws. Notice the red cardboard tube for the servo wires and the red tubes for the two antennae |
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See Rear view at end of the belly pan, looking down into the fuse (remember the fuse is upside down). |
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See The rear hatch is fabricated. It is foam
sheeted with 1/16" balsa. Capped from and rear.
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Notice the pointed dowels in the belly pan top "spot" the hatch for drilling it's hold down dowels |
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See The rear hatch is in place. Notice the 1/8" multi ply tail wheel plate. |
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See The rear hatch has a 3/8" dowel glued in place and drilled for 6-32 cap screw |
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See The belly pan and quarter rounds all finished and pre-sanded to blend in with the fuse nicely |
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See The other side of the fuse |
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See Rear view of the finished fuse. (this photo was taken before the rear of the hatch was capped) |
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See Top view of the fuse before the turtle deck goes on |
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See The turtle deck being fitted for gluing. |
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See The turtle deck is now glued on and has had a "rough" sanding |
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With the turtle now in place we can go ahead and build the front hatch / canopy assembly |
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