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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.


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