North American Apache (oz541)

About this Plan

North American Apache. Rubber scale model WWII fighter, by Earl Stahl.

Quote: "Here's a really new idea, a semiscale army fighter flying model with contest ability. Does 1:30 in calm air. Apache, by Earl Stahl.

ACCENTING superior flight performance and simplicity of construction, while still retaining the realistic appearance of the real fighter, we offer this month a semi-scale model of the North American Apache.

Currently in production at the Inglewood, California factory of North American Aviation, the Apache (XP-51) for the US Army Air Corps and its counterpart, the Mustang, for the Royal Air Force, should prove to be among the outstanding fighting planes of the world. Little information has been released about the ship but it is known to be powered by all Allison engine of 960 horsepower, and to have a performance-improving wing of advanced design. Bristling with eight machine guns and boasting a 412 mile-per-hour speed, it would indeed be all awesome foe.

In the model Apache are crystallized the desired characteristics for maximum flight performance and ruggedness of structure. A glance at the photos will verify the model's realism, and while it is very nearly scale, we have in a few instances readjusted the design to obtain greater stability and efficiency. Correctly proportioned tail surfaces and ample dihedral plus efficient setting of the wing and stabilizer produce a model of extreme stability. A powerful motor of considerable length spins the long, effective propeller, making possible flights of good distance and duration.

Very little adjustment was required to obtain top-notch flights from our model. With the rubber strands tightly wound, it leaps skyward like an interceptor. This ship, like most low-wings, goes from the power flight to the glide without a tendency to dip or stall. Because of the flat glide and fine stability, we feel that out-of-sight flights are possible under favorable conditions.

Construction of the Apache is very simple, yet rugged. Before starting to build, study the plans and instructions thoroughly. Select all materials with care and cement the various joints firmly.

CONSTRUCTION: The bulkhead and keel method of construction is used for the fuselage. To obtain the correct shape of the keels, trace the top, bottom and side outlines on 1/16 sheet balsa; each keel may be cut in several sections and then spliced to take advantage of the grain. Full-scale bulkheads are shown, and they, too, are cut from hard 1/16 sheet; two of each are required. Cut only the notches shown, positions of others are marked but they are not cut until later. To assemble the parts, first pin the top and bottom keel pieces to place over the side view, then cement half of the bulkheads to their respective positions - they should be exactly perpendicular to the keels. Attach a side keel, and when this structure is dry remove front the plans and add the remaining bulkheads and keel. Check and recheck for correct alignment.

Stringers are 3/32 square medium strips, or if the builder prefers, he may use 1/16 x 1/8 strips set on end. Attach the stringers nearest the center keel first, cutting the notches with a pointed razor blade as required. Always attach stringers to corresponding positions of each side to prevent pulling the structure out of line.

Members F-1 and F-2 at the wing position are cut from 3/32 sheet. When attached, they should fit exactly to the wing's upper surface. Small blocks of hard 3/32 balsa are attached between the stringers in the rear, as shown, to hold the bamboo pin.

The, sturdy nose provides a place to hold the model while it is being wound. First make the nose block from two pieces of 1/4 sheet cemented cross-grain. Remove the center of the block to receive the nose plug and then roughly cut to shape before cementing to bulkhead 1. The section from 1 to 2 is filled in with soft 3/32 sheet; accurately cut the individual pieces to fit neatly within each space. Once the cement has hardened, the entire nose is cut and sanded to a smooth, accurate shape.

Bamboo splints of about 1/16 diameter are cemented across the fuselage at the position shown so rubber bands can be wrapped about the ends and under the wing to hold it in place..."

Supplementary file notes

Article, thanks to GTHunter.

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