Gull (oz16932)

About this Plan

Gull (Bird Wing). Free flight sport model. Wingspan 43-1/8 in.

Note the Gull was first published in Air Trails, Dec 1936. This here is a later redrawn plan, from MB 5/86.

Direct submission to Outerzone.

Note the main article here is the short MB 1986 text. See supplement for the 1936 Air Trails article, thanks to Pit.

Quote: "Bird Wing. The Gull. There's a challenge to your model-building skill, and worthwhile performance reward in this graceful and efficient wing shape.

WHAT is the most efficient wing shape? Is it a taper wing, gull wing, straight wing, long, narrow wing, or short. stubby wing? Each modeler has a. wing type he thinks is most efficient, and each is convinced his choice is the best. It takes only the slightest suggestion to start a group of builders arguing about wing shapes.

This month we present our favorite candidate for the honor of the most efficient wing shape. It's a gull-shaped wing of aspect ratio 10 - a value which falls between the extremely low value of 6 advocated by some and the higher values of 12 to 14 supported by others.

We picked a gull wing because it has certain advantages over the other types of wings. A wing which is tapered at the tips and at the center shows better efficiency than a straight wing which has uniform chord length throughout. A straight wing shows considerable drag and also a loss in lift both at the tips and at the center, where the wing joins the fuselage. The loss of lift at the tips results from the circulation of the air around the wing, which causes the air to spill out from the end. This breakdown in the air stream causes turbulence and a resulting increase in drag and decrease in lift.

Where the wing joins the fuselage there is likewise a letdown in the wing's efficiency. This results from interference between the air flowing past the fuselage and that moving over the wing. The result is that the section of the wing adjoining the fuselage shows marked increase in drag and decrease in lift.

There are two mettaxls of improving the efficiency of this section. One is to fillet the wing where it joins the fuselage. These fillets make the transformation between the wing and the fuselage gradual and smooth out the airflow, thus reducing drag. But a more effective way of reducing the interference is to taper the wing where it joins the fuselage. Drag and lift both show desirable changes following a reduction in wing chord at the wing-fuselage junction.

In contrast to the desirable aerodynamic characteristics, the gull-shaped wing is undesirable from a construction viewpoint. The taper at the center makes it difficult to build in sufficient strength. If the wing is externally braced with struts, the problem is simplified, but in a cantilever wing it is a difficult problem. Likewise the shape of a gull wing doesn't lend itself to easy construction, the curved portions proving difficult. Fortunately these two construction problems are not as difficult in models as in real-plane construction. so let's try the Gull.

Our model proved to be a good flier. It was not meant to be a contest ship, but one which can be flown repeatedly with little effort and trouble. Construction is fairly conventional and the instructions will emphasize the unusual steps in the procedure.

FUSELAGE: Making a full-size drawing of the side is the first step. Draw the datum line and lay off 2-1/2 inch spaces along it. From the drawing find the depth of the fuselage at the various positions. The dimensions given are measured from the datum line to the outside edge.

The two fuselage halves can be assembled without the help of a full-size drawing. Cut the cross braces to the length given in the top-view plan and cement them in position. Pin the fuselage together while the cement is drying. Check to see that each half is bent equally. The upright pieces should be at right angles with the cross braces. Check this with a square or a triangle, for proper construction will insure an efficient, rugged job. The rear tip is cut from a balsa block and cemented to the ends of the longerons. This block is tapered to a point to round out the fuselage shape..."

Update 11/8/2026: Replaced this plan with a clearer copy, thanks to GeorgeGilbert.

Update 11/8/2026: Added complete article (AT 1936), thanks to Pit. Note this includes drawings as originally printed.

Supplementary file notes

Article.
Article (AT 1936)
Previous scan version.

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