Thermal Hunter (oz1830)


Thermal Hunter (oz1830) by Frank Zaic from Popular Science 1936 - plan thumbnail

About this Plan

Thermal Hunter. Free flight rubber model. August 1936 Popular Science.

Quote: "HERE is a model airplane that may break the existing world records for flight this summer. By utilizing the rising air currents, this so-called 'thermal hunter' quickly attains considerable height, and its gliding range is much longer than the average miniature craft.

With most of the present outdoor rec-ords well over the half-hour mark, model airplane builders are faced with the prob-lem of how to establish new records. The propeller run of an average model is be-tween one and two minutes, and the problem is how to get the needed extra thirty to forty minutes. The qualities needed are lightness, streamlining, a high climb, and a good glide. Lightness and strength is had by using sheet-balsa in the form of box construction. Streamlining is just a matter of having a good shape with round corners, sanding and polishing all moving elements, and lining up the thrust line with the wing and tail incidences. High climb depends on the amount of rubber used. The glide depends on the adjust-ments made on the model while testing.

Draw the fuselage outline and uprights on white paper, tacked to a soft board, and wax all points at which the cement is likely to touch it. Stick pins on this outline wherever the up-rights meet the longe-rons, and where the curves are severe. Hold the longerons in place against the pins with other pins. Fit the uprights with emphasis on the proper angle. Make two uprights at a time and set one aside for use on the opposite side. After one side is finished and recemented, the other side can be built right on top of it.

The two sides are assembled by cementing the center cross braces first. Line up the sides and hold them in position with square blocks. The remaining braces are cemented from the center out. The braces should be cut to size before assembling. Note the extra large braces at the front and at the rear-plug point. Also note the curve as well as the incidence of the stringers on which the stabilizer rests. Let the , fuselage stay in the jig until the cement is dry.

The landing gear is made of wire be-cause it cannot be broken. The tripod system is used so that no soldering is re-quired. Bend the wire to the shapes indicated. The axle portion is of X-form with the upper portion closed. The four struts are made from one piece of wire so shaped as to form two V's connected by a flat upper portion, which is fixed to the fuselage. Note how the connecting loops are made. Place the shaped wire in the fuselage without fixing it until the loops arc connected. After the loops are intertwined, the wire is bound and cemented to the cross braces and longerons..."

Supplementary file notes

Planfile includes article.


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Thermal Hunter (oz1830) by Frank Zaic from Popular Science 1936 - model pic


Thermal Hunter (oz1830) by Frank Zaic from Popular Science 1936 - pic 003.jpg
Thermal Hunter (oz1830) by Frank Zaic from Popular Science 1936 - pic 004.jpg

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User comments

Pics of his completed model are thanks to MarcoAGuillermo. He says: "I have made a Frank Zaic 'Thermal Hunter 1936' too, it flies very well in R/C version."
SteveWMD - 20/02/2013
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