Polar Star (oz15328)

About this Plan

Polar Star. Control line scale model.

Quote: "Lincoln Ellsworth's famous Northrop makes a perfect control model. Polar Star, by DA Newell.

THE Smithsonian Institution (Aircraft Building) is the final resting place of most record breaking or otherwise famous airplanes of the United States; Lindbergh's Spirit of St Louis and Wiley Posts' Winnie Mae are a few of the famous planes that share this honor.

Among the airplanes in this exhibit is a bright orange colored, sleek looking airplane equipped with skis. On the fuselage side can be seen the words 'Polar Star - Lincoln Ellsworth Transantarctic Flight' lettered in black.

It was in this Pratt & Whitney Wasp powered Northrup plane that the famous explorer Lincoln Ellsworth flew over the South Pole on November 23, 1935 from Dundee Island in the Wedell Sea to Little America, Bay of Whales. The plane was flown with wheels, skis and standard pontoons during its lifetime and the model can be so equipped.

Our model is built to the scale of 2/3 in on the model equals 1 ft on the full size plane. This size allows engines from .099 to .29 displacement to be used. We used radial mountings, and most engines today can be mounted in this manner. The wheels and skis are interchangeable within a few minutes. Notice the skis are made from sheet plastic and are bent to shape after heating in boiling water. These proved far superior to wood or metal skis.

The fuselage construction is a combination of carved and built-up construction. The bottom half is the main supporter of fuselage stresses. Begin by tracing the top view and carving to shape. Repeat for the side view. Now, fellowing the fuselage cross sections, carve the exterior of the bottom half to shape and sand smooth. Take care in carving the fillet. The body is now hollowed to the lines indicated.

Cut the tail from the specified stock and sand to a streamline shape. Use a Vecc, combination control horn and elevator joiner. Install this item now, and hinge the stabilizer and elevator using fabric hinges. Cement the stabilizer to the fuselage bottom. Install the bellcrank and connect the control rod. Cut out the bulkheads and cement in place. Add the upper portion of the carved nose and plank the fuselage top using slow drying cement. When dry sand smooth, Add the fin and rudder. Cement the 1/8 plywood bulkhead to the front of the body applying plenty of cement. The engine will be held in place on this with wood screws. This arrangement worked quite well for us.

The two wing spars are cut from plywood. Notice that the forward spar is the longer. Cement this to the roughly shaped leading edge pieces. While this is drying, cut the ribs and wing covering to shape. Cement the ribs to the bottom covering and then cement this to the leading edge and forward spar. Install the center section first, followed by the outer panels one at a time. Cement the rear spar in place.

Bend the landing gear and attach both pieces to the spars. These are sewed in place around the spars and plenty of cement should be applied. Bind the landing gear joints with thin wire (milk bottle top wire will do) and solder well. The trailing edge of the bottom covering must be bevelled and then the top covering can be added. This is butted against the leading edge and is worked back to the trailing edge. Be sure to apply cement to all the ribs. The soft balsa wing tips are now added and, when dry, the entire wing is sanded to shape.

The pants are made of two pieces of 1/2 in balsa cemented together lightly and cut to external shape. Pry apart and hollow as shown. Reassemble and cement in place onto the wing. When dry it can be cut in half horizontally as shown.

Cement the wing to the fuselage now and fillet well. The cowl is carved from hard balsa or turned from pine. Add the tail wheel and wire fork. Install a control line guide on the inboard wing.

Three coats of sanding sealer should be applied and sanded smooth. The entire plane is colored orange. We used Aero-Gloss fuel proof dope. After three coats we rubbed this down, with a good compound and added Simoniz: then the celluloid canopy and engine. Cement the cowl in place. Add all trimming with black Trim-Film.

The skis are sheet plastic, available at most hobby shops or war surplus stores. These are cut to shape with a coping saw and sanded smooth. They are bent by heating the front portion in boiling water until pliable. Attach the bottom fin strip first before bending. Bend both pieces together for a good fit. When the skis are mounted, the rubber bands should be under tension..."

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