Yak-3 (oz5145)

About this Plan

Yak 3. Rubber scale fighter model. Scale is 1/20.

Note this Yak-3 plan appeared along with Spitfire XIV (oz5142) both in the same article. The text covers both models, together.

Quote (google translated): "Yak 3, Spitfire MkXIV. Models of fighters with rubber drive (M 1:20). Designed and written by Lubomir Koutny.

Small rubber models have become a popular category. After all, this is also evidenced by the interest in the plans released so far, so we do not hesitate to present another pair to interested parties. This time they are typical representatives of fighters from the second half of World War II, ie aircraft that still had enough 'wings' and a relatively large propeller to be able to fly even as models. However, on the other hand, the low-wing layout and rather narrow wingtips offer enough opportunities to use ingenuity to make the model obey.

These differences from normal modeling practice required a more extensive description of construction, control and flying, which in its main features applies not only to the Yak-3 model and, with the exception of the coloring, to the Spitfire Mk XIV, but to similar models in general.

The tradition and successes of the Brno 'hatchery' of small rubber models are a guarantee that there is no need to doubt the models or the experience.

BUILDING is described in the sequence of the recommended most suitable procedure, therefore the individual parts are discussed seemingly randomly.

The hull is assembled from four main (axial) stringers embedded in the notches in the bulkheads. We cut the upper and lower longitudinal members to the shape according to the plan using a curve directly from a 3 mm thick board of light, strong balsa. From the same board are also the side longitudinals, which we hang straight and put them into the appropriate shape directly on the partitions; their cross-section is 3 x 3 in the front, 3 x 5 on partition No. 4 and 3 x 2 mm at the turn signal.

We carefully redraw the partitions on a thin white Modelspan, roughly cut them out and paint them onto the balsa board with a thin adhesive varnish (we choose the lightest possible balsa, rigid against bending - with a radial cut, with a thickness of 1 to 1.5 mm). We will then precisely cut out the partitions from the board that has been reinforced against splitting in this way.

From strong and light balsa 1.5 to 2 mm thick, we cut a strip 420 long and 35 mm wide, smoothly grind it along the length from 1.5 mm thick at the front to 1 mm at the back, and cut it into 1.5 mm wide strips . What remains is to cut partition No. 1 from balsa with a thickness of 5 mm.

We will start assembling the hull by placing all the bulkheads on the lower axle stringer, then the two halves of the upper axle stringer into them, and the two side axle stringers into the partitions No. 1 and No. 2. After checking the verticality, we seal everything with adhesive varnish and let it dry for about an hour. We then tie the side axis stringers at the back and gradually from the front carefully insert them into all the partitions. We check the verticality again and glue. After proper drying, we glue the auxiliary longitudinal members..."

Direct submission to Outerzone.

Update 23/6/2024: Added article, thanks to Monty.

Supplementary file notes

Article.

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