Zlin Cmelak (oz5133)


Zlin Cmelak (oz5133) by Jaroslav Fara - plan thumbnail

About this Plan

Zlín Z 37 Cmelak. Free flightl scale model for 1cc engine. Wingspan 110 cm. Scale is 1/11.

Direct submission to Outerzone.

Update 11/1/2024: Added article, thanks to rocketpilot.

Quote (google-translated): "Cmelák. Free flight sports model for 1 cm3 engine. Construction by Jaroslav FARA, Dáblice.

The model is a semi-maquette of the new Czechoslovak Z 37 'Cmelák' agricultural aircraft in a scale of 1:11. Compared to the model, the wing struts and the area of the elevator are enlarged, it lacks some details, eg flaps and wings, landing gear struts, etc. It is foldable, the wing and the elevator are attached in the usual way to the hull with rubber through pins.

BUILDING: We build all the parts of the model on a rigid worktop directly on the plan, which is the most accurate.

The wing is made of three parts, which we build separately in the usual way on the plan. On the lower bar of the beam and the beam of the undercarriage (glued from the bars), we put the ribs of the middle part A, B, C (glue the pre-glued half-ribs O on four of them), we glue the top bar of the beam, the ground drain and the untreated lead bar here. After drying, cover the upper surfaces with balsa. After removing from the plates, we clean the parts P and R for fixing the undercarriage and finish the lower cover, process the leading part and drill 2.5 mm holes for the undercarriage and securing screws.

We build the outer parts of the wing in a similar way and connect them to the middle part with a web S, for which we carefully make a cutout in the extreme ribs C and D between the beam slats. We glue the ribs together over the entire surface (pay attention to their inclination during construction!).

The hull without stringer has a rigid balsa coating. On the worktop (we will make cutouts in it for partitions 2 and 3), we will assemble the upper part, to which we will "hand" the lower part. partitions, secure them and stick the top cover in. Gradually finish both long sides, the cabin and the rest of the cover (without the front round part).

After removing the fuselage from the plates, we insert the engine bed 13, the cabin floor, the upper cover between the partitions 2 - 3 and the plywood for the pins at the elevator. We will glue the lower parts of the partitions, the crossbar with the spur, the bottom cover, the reinforcement of the side panels 14 in the place of the wing and both side panels. We have to measure the exact shapes of the covering parts only during construction according to the hull frame!

The engine cover is fixed on the hull, only the part above the engine is removable. We glue the longitudinal ribs 15 to the engine bed and to them the front part 1, which we glue from plywood and the rest of the balsa. We glue in the lower rib 16 and the short longitudinal members 5 x 6 and 17. Wet the actual covering of the cover from the outside, bend it on the cylindrical object and glue and sand it only after it has dried. We will similarly make the cap directly on the body (be careful not to stick it to the body!). The engine cover blinds are finished and glued (only in a few places) only after the model has been flown.

We glue the tail surfaces with the profile of a straight plate as a frame, sand and round the edges. We glue the turn signal firmly to the riser. We cut a longitudinal hole for it in the top cover, so that the elevator can be used as a dethermalizer (with a silicone line, limiting its deflection). The chassis, which has both parts the same, is sensing. We slide it into the hole drilled diagonally in the slope of the leg in the groove of the beam in part P. We secure the chassis with an M3 x 12 screw with a larger washer, screwed into the hole in the plywood R. The spur is firmly glued in the hull.

Engine: The plan shows the Jena 1 cm3 detonation engine with which the model was tested. It is without an auxiliary release spring, but equipped with an exhaust extension (from the store), which is necessary for this model, so that the inside of the engine cover is not dirty. We fix the motor with the help of plates 18 with soldered M3 nuts, which we secure with nails after flying. We control the carburetor needle with an auxiliary tube, split at the end, which we pass through the hole of the cover during seriation and put on the needle.

We will glue the fuel tank from celluloid. 1 - 2 mm or we use a transparent plastic plug of 5:5 20 mm from Spofa drugs. We glue the tank to the right front part of the cover so that we can see the amount of fuel. We thread the supply hose to the carburetor with the slanted end through the hole to the bottom of the tank. The tank content of 2 - 3 cm3 pine is sufficient for normal sports flying.

The propeller on the prototype was wooden (from the pro-shop) measuring 180/110 mm. It can be similar - up to the size of 200/100 mm; plastic has the advantage of greater resistance. Basically, we fasten the propeller so that it remains in a horizontal position after the engine stops.

Coating, surface treatment: After sanding the entire model with fine sandpaper, cover it with medium-thick fiber paper (Modelspan, Mikelanta). We stick the paper on the entire surface of the hull with adhesive varnish, on the other parts with white paper glue, but only around the perimeter..."

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Zlin Cmelak (oz5133) by Jaroslav Fara - model pic

  • (oz5133)
    Zlin Cmelak
    by Jaroslav Fara
    from Modelar
    44in span
    Scale IC F/F LowWing
    clean :)
    all formers complete :)
    got article :)
  • Submitted: 12/12/2013
    Filesize: 503KB
    Format: • PDFbitmap
    Credit*: MartinDilly
    Downloads: 5539

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User comments

In 2013 I built this pretty little scale model and here are some images of it [model photo & more pics 003-005]. Best EASTER wishes!
OweCarlson_Sweden - 05/04/2018
I bring over some new images of my Cmelak Z-37 from 2013 [more pics 006-009]. Drawing was found in a German model magazine. Some data: span 38" (980mm), weight incl. 800mAh 2S 800g, BL 2820, ESC 18A. Very steady to fly and has excellent lowspeed capacity.
OweCarlson_Sweden - 13/04/2018
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