Mr. Smoothie
A length of 1
⁄4
-inch aluminum tube (above left) is used to align all the nose
block pieces. Here, the removable front nose block is about to be glued to the male nose plug. The faint, un-charred lines from the laser cutting make proper alignment a snap. The spinner backing plate (F1) (above right) has been carefully sanded, fitted and glued inside the spinner’s rear edge. The spinner
was then dry fitted to the 1 -inch aluminum tube, and the nose block sanded to ⁄4
shape around it. The finished fuselage assembly with spinner (below left), ready for the wing slot cut-out to be done. The wing slot has been cut (below right). The fuselage assembly is very fragile at this point so handle the fuselage carefully!
center, then lift one wing half away from the plan; block up the tip of the other to the di- hedral angle suggested on the plan. Now use a right angle at the centerline to mark where to cut the top spars to length. Repeat for the other wing half, then dry fit the two halves together to make sure the joints of all the spars, leading and trailing edges are tight at the centerline—but don’t glue them just yet. Before gluing the centerline joints, I like
to sand the wing panels. Sanding them sep- arately before gluing them together makes it easier to profile the leading and trailing edges. You can use the burn marks from laser cutting to your advantage here. Take a length of clear packing tape and apply it across the tops of the wing ribs, with the
long edge of the tape right up against the front of the trailing edge. Set the wing pan- el down on a dead flat surface—I use a piece of 1⁄4 × 8.5 × 22-inch glass with two pieces of 220-grit sandpaper glued to it. Using a long, flat sanding block and some 220-grit sandpaper, begin to sand the taper into the top of the trailing edge. The packing tape will help to protect the tops of the ribs from the sanding block until you get the TE sand- ed flush to the ribs. At the point that you begin to see the tape
sand through and the laser burn disappears at the joint of the ribs and the TE, you’re done. Do the same thing for the LE. Once you are satisfied with the profile, remove all the tape and use the sanding block to touch up the ribs and remove the laser burn.
The two wing panels can be glued togeth-
er now, the center rib fit and glued, and any gussets added. Although not shown on the plan, I also glued some 1⁄32-inch balsa web- bing between the main wing spars, three bays out from the centerline. Once every- thing has dried, use a long, wide sanding block or the glass plate/sandpaper to lightly sand the bottom of the wings, just enough to remove the laser burn and smooth all the rib/TE/LE joints. With all of the main assemblies built, give everything a careful sanding with 220- or 360-grit sandpaper in preparation for cover- ing. If you like to “scallop” your fuselage for- mers between the stringers, now is the time, but first—read the paragraph about cover- ing the fuselage. Once finish sanding is com-
The right wing panel has been blocked to the proper dihedral (above left), and a right angle square is being used to mark the upper spars for trimming. The procedure will be repeated for the left wing panel. Both wing panels (above
54
right) have had the leading and trailing edges sanded to profile at this point. Fitted in place and blocked for dihedral, the spars, leading, and trailing edges are glued together. Finally, the center rib will be fitted and glued.
SEPTEMBER 2012
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68