Thor (oz1656)

About this Plan

Thor. Free flight gas model. For Brown Jr power.

Originally published in MAN Feb 1939, this here is a low res copy of a redrawn version of the plan, that appeared in SAM Speaks May 2011 - which was in turn earlier sourced from the plans coop, it bears the ref #003058.

Note this is not a fullsize plan.

Update 11/03/2021: Added article, thanks to RFJ.

Quote: "BUILDING A SKY KING
How You Can Build a Consistent Contest Winner. A Gas Model With a Fast Climb and a Flat Glide

Thor - 'Ruler of the skies' - is a model which lives up to its name. Since last November 1937, it has won two trophies, five model motors, cash, an airplane ride, airplane wheels, and a book on model planes. Sounds like inventory, doesn't it ?

This model has a steep, spiral climb and a glide as flat as the proverbial pancake. It soars on the slightest thermal. This is not due to lightness in weight as is usually the case, but to efficient aerodynamic design. The thick high-lift section absorbs excess power, which results in a steep climb and slows down the glide. The comparatively small cross-section of streamlined contour cuts down induced drag to a minimum. Correct distribution of lateral area has made it absolutely spiral-dive proof.

This ship is also very rugged, having crashed into numerous obstacles including a car headlight, which resulted only in a broken prop. (Yes, it busted the bulb too.) Its highest official contest time is 12 :15 with actual motor run of only 21 seconds. (Trenton Eastern States Contest). But 'procrastination is the thief of time,' so let's get on with the actual construction.

Construction of Fuselage: There is nothing extraordinary in the construction of the fuselage. It follows common practice ; consisting of box framework, formers and stringers. The box framework of the fuselage is made of hard 3/16 square balsa strips. Apply two extra coats of cement at all the joints. the formers are made of medium 3/32 sheet balsa. Note that the notches for the stringers are cut only 3/16 deep. Notches are cut after formers are in place on the box framework.

Make the nose blocks out of medium balsa. Do not glue these permanently to the fuselage until the landing gear is in place, but merely cement them lightly for shaping. Care should be taken to shape the blocks so as to conform to the fuselage contours. The landing gear is glued and bound in place with heavy thread after the nose blocks have been shaped.

The motor mounts are made of 5/16 x 9/16 white wood. The nuts for the bolts that hold the motor are soldered to brass sheets which are in turn glued to the underside of the motor mounts. Care should be taken to solder the nuts in line with the holes in the motor mounts. Mount the aluminum drip-pan as shown in the plans before the motor mounts are permanently installed. Do not omit the drip-pan, for without it the structure will soon be oil-soaked and greatly reducing its strength.

The coil and the condenser are securely held in place by a balsa panel to which they are fastened. This panel is between bulkheads No.1 and No.2, where the coil and condenser can be seen through the windshield for ignition checkup. The battery box is very simple, being of the ordinary box-type with brass sheets for terminals. One end is hinged and rubber hands arce wrapped around the box to insure tight contact.

Timers with long arms are preferable as they can be installed inside the fuselage out of the slipstream to reduce drag. Dowels through the fuselage arc used to hold the wing rubber bands.

Wing Construction: A board or table whose surface is perfectly straight should be used in the construction of the wing to avoid warpage. The wing uses the Grant X airfoil which has been found to give excellent results. All ribs should be cut out of medium soft balsa. Care should be taken in notching ribs for the trailing edge to preserve the accuracy of the airfoil.

In assembling the wing, the ribs are lined up on the hollow main spar. Other sparts are installed, followed by the leading and trailing edges. Cap strips are added before the trailing edge is shaped. Wing tips are covered on top only with 1/16 sheet. Cut away the main spar only from bottom for tip ribs, as negative angle is thereby created in the wing tips increasing the stalling angle of the wing.

The center section should be constructed now. The center section braces are added and the wing panels are joined as shown in the plans. The center section is then covered top and bottom with 1/16 sheet..."

Supplementary file notes

Article.

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