Leading edges of empennage and elevator hinge line (above left) are capped with 1⁄8 x ¼-inch balsa strips and rounded off with sandpaper. The elevator is joined to the stab with flex nylon hinges at four places. The wing (above right) has a two-piece spar comprised of a ¼-inch light balsa web capped top and bottom with ¼-inch square spruce strips, making for a lightweight and strong
finished spar. Note the cardboard ribs, leading edge folds, 1⁄8-ply spar joiners at the dihedral break and ply gear mount inserts. Four cardboard doubler pieces (below left) are glued over the ply gear mount inserts for extra strength. The wing tip (below right) is carved balsa with a 1⁄8-inch ply line guide inserted. Note gummed paper tape along the joint.
Construction tips Before we begin, take a look at these spe-
cial tips for working with cardboard. Glue: Water base glue, such as white glue
or Titebond, is recommended. Contact ce- ment is not recommended since parts cannot be shifted when gluing surfaces. Folding: The scoring of the fold lines is
done with a screening tool available at any hardware store. It consists of a handle with a 11⁄2-inch radius wheel at one end, which is run along a metal straightedge on the fold line.
Finishing: Cardboard gives a solid sur-
face with no open areas to cover and is non- porous. The easiest finishing method is to give two coats of clear dope, sanding lightly between coats with #400 sandpaper, fol- lowed by two coats of color dope. However, a wide variety of finishing materials may be used on the cardboard. Coverings, such as Solarfilm, MonoKote and vinyl paper can be used. With any of these, it is recommended that the surface not be doped, which will re- sult in a better bond. Paper tape: All seams, joints and ex-
posed edges of the model are covered with strips of gummed paper tape. Obtain a one-
inch wide roll from a stationery store. Sim- ply cut a thin strip to length, dip it in water and smooth it over the seam. Construction: Be sure to note the direc-
tion of the corrugations when cutting out the cardboard parts. Score and fold cardboard parts as indicated on the plans. Empennage: The fin, rudder, stabilizer
and elevators are each made from two pieces of 1⁄8-inch cardboard laminated together crossgrain to give ¼-inch thick surfaces. Add a 1⁄8×¼-inch balsa strip to the fin lead- ing edge and round off. Add 1⁄8×¼-inch bal- sa strips to the stabilizer leading and trail-
Flat fuselage sides are lined with balsa strips recessed 1⁄8 inch and have cardboard supports (above left) for the bellcrank and the fuel tank ply mounts. Note cutouts for flying wires and elevator pushrod. The ply firewall (above right)
FLYING MODELS
has blind nuts for the KM40 engine mount and cowl attach. The bellcrank and fuel tank are attached to 1⁄8-inch ply supports. The fuel tank is held in place with rubber bands.
45
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