Zlin 226T Trener (oz8841)

About this Plan

Zlin 226. Radio control scale model.

Quote: Zlin Z-226T Trener. Pavel Bosak's design for .40 two strokes, suits four to five function radio control.

Without a doubt, Czechoslovakia's most popular aircraft is the Zlin Series 26, so called because each version bears the number 26. Following the three digit number is a letter indicating the version: A - aerobatic, T - training and B - 'pickaback' (sic.)

This plan shows the Zlin-226T as a semi-scale model and it is possible to adapt the design to other variants. For instance the Z-126 has a slightly shorter front fuselage while the Z-326 has a retractable undercarriage and a slightly different canopy shape. The aerobatic versions (226A, 326A and 526A) had a single seater cockpit. Various minor differences can also be found but are not really relevant to a semi-scale model, which is why the model is relatively un-detailed.

It was designed for .40 engines as I find this an economical engine to use and the finished model is smaller and easier to transport. Building it is easy for anybody who has built an R/C model before.

Construction: The wings are built first because they are needed for fuselage assembly. All the 1/8 in balsa wing ribs are formed by the sandwich method; sandwiching 14 balsa blanks between ply root and tip templates and sanding the whole block so that it tapered evenly from root to tip. The slot for the spar can be cut at the same time and then the sandwich can be released. Make one set of ribs at a time, left wing then right wing. Ribs K1, K2 and K3 are strengthened by doublers of 1 mm plywood and the notches for the undercarriage blocks are cut in. A 5mm (3/16 in) balsa spar web is prepared and all the ribs glued to this and the 3 x 7 mm (1/8 x 1/4 in) spruce spars. These basic frames, left and right, are built separately and then joined by the 1 mm. ply parts K18, which are formed around the necessary angle. (Adding the upper trailing edge sheeting at this stage can make align-ing the wing panels a little easier.) The centre section is completed with the dowel braces K17 and MB and the dowel K21.

At this stage the 5 mm (3/16 in) balsa leading edge is added (K20 on the plan) and then the 1/8 upper sheeting. The 1/8 balsa parts K22 are then fitted between ribs K1 to K7 and when dry sanded to profile as shown on section AA. Now the beech undercarriage blocks are epoxied into place. The plan shows the 226 layout, the 326 and 526 versions have the leg extending from below rib K3.

The aileron linkage is fitted next, the linkage can be made from commercial items or, as in my model, from 1.5 mm aluminium sheet. Fix the undercarriage legs, then the lower 1/8 balsa sheeting can be added. Sand back the overlapping edges of the 1/2 in sheeting and then add the leading edge and tips so that the whole wing can be sanded to shape.

Now for the flaps and ailerons. The flaps are carved from slabs of hard balsa, cut first to outline and then to section, finishing by cutting the recesses for the hinges. The rods for the flap operation run in paper bearings, these being epoxied to the wing..."

Zlinn 226, RC Model World, March 1988.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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