Weight Rule Model (oz8856)

About this Plan

Weight Rule Contest Model. Rubber power competition model. 138 sq in area, weight 4.2 oz.

Quote: "Redrawn by Loren Williams, Mar 1980"

Quote: "A Weight Rule Contest Model. Here Is A Reliable Contest Model of Three Ounces Per One Hundred Square Inches of Wing Area That Is Easy to Build. By Earl Stahl.

A GOOD contest model need not only be capable of making long flights, but it should be stable, durable and sufficiently powerful for various conditions encountered in contests. In order to accomplish this the model must be stable, durable and sufficiently powerful to carry it to high altitudes.

Simplicity and flying ability are the key notes of this plane. Its construction is entirely conventional, and it is easy to adjust and fly. Its stability and power permit it to be flown in any weather.

The plans and instructions presented here are for building a plane to the new NAA weight rule of three ounces per 100 square inches of wing area, but if a model of the old weight rule is desired it can be had by simply making the entire structure slightly lighter, reducing the power, and using a slightly larger propeller. This plane is an adaptation of just such a model.

Before starting construction it is advisable to make a full size plan. Since the drawing is one-fourth actual size, a full size construction can be made by enlarging four times with the aid of dividers. The fuselage top has three degrees of built-in incidence where the wing sets on, and zero degrees where the stabilizer is attached, so great care should be exercised to make this correct.

Fuselage: The whole fuselage is constructed of hard balsa. The two sides are constructed one over another in order that they be exactly alike. Join the sides together with 1/8 square spacers and glue on the front formers. Bend the wire landing gear fitting, and secure it to the fuselage with thread at the position indicated. Cut the removable tail piece from the fuselage, and glue several laminations of 1/16 sheet into place to provide an anchor for the rear hook which is made from .040 or larger diameter wire. This hook incidentally should be protected by rubber tubing to prevent cutting the rubber motor, and it should have a hook on its end which will make it possible to lock it.

Finally glue a piece of 1/8 sheet balsa to the front of the tail piece so it will fit snug to the rear of the fuselage, and keep the tail from turning when the motor is wound. The shaded parts of the fuselage, both front and rear, are filled with 1/16 sheet balsa for additional strength, and to provide a place to hold when the motor is being wound.

Wings and Empennage: The wing and tail surface construction is very similar except that the wing is built and covered in three separate pieces. Nineteen wing ribs are cut from 1/16 sheet balsa, and the medium hard spars attached. The tip ribs are trimmed to shape and size, and the tip outlines are cut from 1/8 sheet. The whole leading edge on the top is covered with 1/32 balsa as shown on the plans.

The tail surfaces are constructed in a like manner except that they haven't any sheet balsa covering. Note that the tips of the stabilizer are 1/16 square bamboo. Be careful to have the rudder constructed so the flat side of the airfoil will be on the right of the model when the rudder is mounted..."

Scan from DBHL, cleanup by theshadow.

ref DBHL-6248.

Direct submission to Outerzone.

Supplementary file notes

Article pages. Includes original layout drawing as printed 1938.

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