Polikarpov I-16 Rata (oz13707)

About this Plan

Polikarpov I-16 type 24. Radio control scale model Russian fighter. Wingspan 2030 mm.

Quote (google-translated from the German): "The Polikarpov I-16 was built in almost twenty different versions. The first prototypes of this single-seater fighter were flown in at the end of 1933. The machine was so maneuverable that it could almost turn on the wing tip. The I-16 got its nickname 'Rata' during the Spanish Civil War, and it became known under this name. Over time, more and more powerful engines were installed in the various I-16 types Equipped with a 480 hp engine in 1933, the last version of the I-16 had a 920 hp engine. The last machines of this type were flown in Russia as late as 1943.

The model: When re-creating this extraordinary aircraft, we primarily wanted to transfer the beefy appearance and the agile flight characteristics of the original to the model. An overview sketch from the Aeromodeller Plan Service was available as the construction documentation for building the model. The sketch shows types I-16/6 and I-16/24. For the replica, we chose the Type 24 because it has an open canopy that is easier to replicate.

The scale of the model was determined by the chosen powerplant, a 32 cc Quadra petrol engine. The engine should be completely enclosed. This resulted in a cowling diameter of more than 30 cm with a fuselage length of 136 cm and a wingspan of 203 cm.

The model fully corresponds to the original in all dimensions (scale); however, no consideration was given to the material (Styrofoam surface!) during construction. The Rata is therefore to be regarded as a pure semiscale model.

Construction: Since this is (definitely) not a model for beginners, we don't want to give a detailed construction description, but only describe the most sensible construction sequence and point out some special features.

The Rata is made of a mixed balsa wood and polystyrene construction, with the wings and the front fuselage made of polystyrene, the tail unit and the rear fuselage made of light balsa.

In the rear third of the model you have to be stingy with every gram of weight, since the Rata has a very short front lever. The construction therefore begins with the elevator and rudder. The covered tailplane (damping surface and rudder!) should not weigh more than 100 g: our model weighed 70 g!

Similar to the elevator, the rudder is also constructed in a conventional ribbed design. However, while the tailplane is covered before installation in the fuselage, this is done with the sidetail only after gluing to the fuselage. If the tail units have been built to your satisfaction, you can start cutting the Styrofoam parts. (The technology and the required equipment will not be discussed in more detail in this context.)

Two ring frames made of plywood are required to cut the front fuselage section. These frames are attached to a cut styrofoam block. First, the outer contour around the frames is cut out (see sketch 1). Here it is very helpful to draw markings on the frames in order to guarantee a symmetrical cut out of the fuselage.

In order to be able to hollow out the polystyrene cylinder produced in this way, the cutting wire is threaded through a pre-drilled hole in the middle of the cylinder. (The hole can easily be drilled with a heated brass tube.) The finished styrofoam part should have a wall thickness of approx. 2-3 cm.

The rear part of the fuselage is built up with frames. These frames and the front part of the fuselage are connected with balsa strips and set up standing in a corresponding jig (see illustration). The fuselage is planked in strips of 1.5 mm balsa wood, which is pre-fitted and butted onto the balsa strips. The cutouts for the wing and tailplane are only made after the planking. Similar to the front part of the fuselage, the wing is cut over two auxiliary ribs made of Styrofoam and planked with 1.5 mm balsa wood.

The ailerons are only cut out of the surface after planking. Epoxy resin is best used as an adhesive for covering the styrofoam core. In order to achieve a stable and sharp trailing edge, glass mat strips made of 80 g material should be placed between the wood and the Styrofoam. Before the wing is adapted to the fuselage, the two lower parts of the wing transitions are cut out of 1 mm plywood. Then the wing cutout is marked on the fuselage sides and the lower fuselage section is removed with a fine jigsaw (see sketch 2). It will later be glued back to the adjusted wing. Adjusting the wing requires a bit of finesse, but it's easier than it reads as the fuselage material is very easy to work with.

The angle of attack of the wing to the fuselage axis should be 0.7° to 1° (7-10 mm). During fitting, this angle should be checked from time to time. The fully fitted surface is then screwed to the fuselage. The lower parts of the wing transitions are placed as an intermediate layer between the fuselage and the wing and glued to the fuselage in this position (see sketch 3). This achieves an optimal adjustment between the fuselage and the surface, and even small inaccuracies can be compensated for..."

Direct submission to Outerzone.

Supplementary file notes

Article, in German.

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