AT A GLANCE Type:
Construction:
Wing span: Wing area: Length: Weight:
Wing loading:
Engine required: Prop:
C/L Sport Scale
cardboard with some balsa and ply
513
60 inches 612 sq. in. ⁄4
inches 78 ounces 18.4 oz./sq.ft.
.40–.50 two-stroke 9–6
TheMew Gullis a distinctive looking design with its slab sided fuselage and low profile cockpit located aft of the wing (above). Scoring and folding methods make it an easy airplane to model using cardboard, while still giving good scale appearance, with a wingspan of 60 inches and a length of 51³⁄₄ inches. Even with its large size, the cost is minimized by using corrugated cardboard as the primary building material. The bottom of the airfoil is flat with a curved upper surface. The wing and stabilizer tips are painted black (below). The wing tips are built up from ½-inch lightweight balsa sheet hollowed out for additional weight saving.
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-
Construction tips Before you 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 straight edge 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
FLYING MODELS
posed edges of the model are covered with strips of gummed paper tape. Obtain a one- inch wide roll from a stationary 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 direction of the corru- gations when cutting out the cardboard parts. Score and fold cardboard parts as in- dicated on the plans. Empennage: The fin, rudder, stabilizer
and elevators are each made from two pieces of ¹⁄₈-inch cardboard laminated together cross- grain to give ¼-inch thick surfaces. Add a ¹⁄₈ × ¼-inch balsa strip to the fin leading edge and round off. Add ¹⁄₈×¼-inch balsa strips to the stabilizer leading and trailing edges and the elevator leading edge and round off. Join the two elevator segments together with a ¼- inch dowel. Seal all raw edges with gummed paper tape. Hinge the elevators to the stabi- lizer with flex hinges at four places.
Wing: Make the left and right wing spar
sections from ¼-inch balsa capped with ¹⁄₄ square spruce strips. Join the spar segments together with ¹⁄₈-inch ply joiners, front and back, making sure to maintain the correct dihedral. Glue the ¹⁄₈-inch ply gear mount into the bottom of the right wing panel. Glue the wing spar into the right wing panel. The wing ribs 1 through 7 are then added,
with the ribs at the ply spar joiners being shortened by ¹⁄₈ inch to account for the join- er thickness. Add cardboard doublers (four pieces) over each ply gear mount. Glue a one-ounce weight to the right wing tip. The top wing panel on the plan is slightly over- size, so fold the top wing panel over and trim it to fit the bottom wing panel. Apply glue to the top of the wing spar, the top of the ribs and the trailing edge of the wing and fold the center top wing surface down and pin se- curely in place until dry. Build the left wing panel in a similar fash-
ion. Add the balsa tips to the wing and sand to shape. Make a line guide from ¹⁄₈-inch ply. Cut a slot in the left wing balsa tip and glue the line guide in place. Cover the trailing edge and all seams with gummed paper tape.
53
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 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76