Model Editor and
Model Designer for
POPULAR AVIATION.

OUR model for this month is the latest Army attack ship. The Northrop with its distinctive markings and fine detail is an interesting and attractive decoration. Test flights also indicate that it is an excellent flyer. Do not attempt to build this model in too short a time for the beauty of the model depends on good workmanship and patience.

Fuselage and landing gears are new Army blue. Wings and tail surfaces are Army yellow. Details are silver, black and white.

It is necessary to place a sheet of ordinary wax paper over the plan to prevent cement from sticking to the plan. Now you are ready to build the fuselage, which is constructed one side at a time. The longerons, vertical and diagonal braces, etc., are held in place until securely cemented. This is done by inserting straight pins on either side of strips.

When fuselage sides are completed, they are pinned to top view of the plan in such a manner that the top longerons face down and the sides are at right angles with the table. The cross-members are now cemented in place, forming a rectangular fuselage.

Cut formers from 1/32-inch sheet balsa and cement in their respective positions as shown on plan. Balsa nose plate is built up from 1/8 sheet balsa.

The cylinders are carved and sanded from balsa blocks. When fourteen cylinders have been formed to represent fins, wind heavy thread around them. Make crankcase from two pieces of balsa. Rocker arm housings, push rods and other small details of the motor are also made of balsa.

This wing is made up of three separate panels. Cut all ribs from 1/16-inch balsa. Pin the spar in position on the plan. Now, cement ribs in their proper locations. The leading and trailing edges are cut and sanded to shape and cemented to the ribs. The panels carry movable ailerons which are a great help in controlling the flights. Make wing tips from 1/16-inch thick balsa. We highly approve of this type of wing tip because it is much easier to construct and is also neater in appearance.

These are built from 1/16-inch square and flat balsa and are constructed on the plan. Their construction is very simple and no trouble should occur here.

The construction of landing gears is clearly shown on the plan.

Apply tissue to the various framework members, using a light grade model airplane dope to fasten it to the outer edges. Stretch tissue as tightly as possible to remove all wrinkles. When edges have dried, apply coat of water to tissue. When all water has dried completely, tissue will become taut. May we suggest that you pin wings, elevator and such to flat surface to prevent warping.

After the wing panels have been cemented to fuselage, make fillets from paper and fill in open spaces between fuselage and wing panels at trailing edges. Other small details are clearly shown on the plan.

Two types of propellers are used on this model. One, which has a wide blade, is made of fiber. This type of blade causes the motor to turn at less r.p.m. and greater flights result. By twisting the blades the pitch can easily be adjusted. The balsa scale propeller is used for exhibition purposes only. Six strands of 1/8 flat rubber are sufficient to fly the model.

With the rubber motor and flying propeller in place, gently launch your model over tall grass. By this method you can see if your model is properly balanced. If model glides a short distance and nose rises abruptly, it will be necessary to add weight to the bottom of nose block. If model dives, add weight to tail. After the model is balanced to glide on an even angle, you are ready to test your model under power. In making test flight, the principal thing to avoid is possible damage. Gliding and flying it over tall weeds is the safest because the weeds or tall grass break the fall gently in case the model should stall or dive.

A few trial flights will acquaint you with the ship and all other .adjustments can be made through the adjustable control surfaces.