The small, amateur sports plane J-2 “Polonez” was constructed by Jarosław Janowski.
It was a further development of the J-1 “Prząśniczka” aircraft. The J-2 aerodynamic model was tested at the Warsaw Polytechnic. Drawings of Polonez were helped by Janowski, Andrzej Wiśniewski from the Institute of Aviation.
Particular emphasis has been placed on the most-far-reaching simplicity of design and manufacturing technology. the plane can be built entirely using basic carpentry tools. Most of the steel elements and fittings were designed in such a way that they could be made using the locksmith method, without the necessity of using hard, difficult in amateur conditions, machining. Airplane plans have been published in Poland and abroad. About 200 copies of the documentation were sold. The execution of the Polonez required 800 hours of professional carpenter’s work.
Construction:
Single-seat, self-supporting, medium-wing wooden structure.
The bifurcated rectangular flap has a NACA 23015 profile over the entire span. The leading edge made of pine slat. The main box girder from pine strips is glued with 1.5 mm plywood. Between the lower and upper girders of the spar, in the place of the main fittings, fillers were filled with multilayer plywood. 5 mm thick pine strips are glued in places corresponding to the spacing of the ribs. Aileron girder in a C-section sash, made of pine slats with a 1 mm plywood strip glued on. Ribs made as a two-part truss made of 5 x 7 mm pine slats. On both sides along the upper and lower side members of the rib, stiffening walls of plywood 1 mm are glued. The trailing edge made of a pine slat with a triangular cross-section, is covered on both sides with 1 mm plywood overlapping the ribs. The part of the wing covered with 1.5 mm plywood, on the remaining plywood l mm, forms a caisson working on twisting. The caisson is covered with a glass-epoxy laminate. The rest of the wing is covered with cotton canvas. Ailerons are made from the cut off of the flow part of the wing’s ribs. The ailerail girder with a C-section made of pine slats has a glued plywood l mm wall. The trailing edge has the same construction as in the wing.
Hull – in the front part, accommodates the pilot’s cabin. The cabin cover is made as a frame made of lamellated pine slats, to which glass with organic glass is fastened with wood screws. Hull side made of two 20 x 20 mm pine slats. In the front part, laminated on both sides with 1.5 mm plywood and filled with styrofoam inside – sandwich structure. The back part is only on the outside covered with plywood. Between the sides of the hull – behind the pilot’s back are five frames made of plywood 10 mm. Between the first three frames, the main landing gear compartment was pasted. The frames: third, fourth and sloping, and the fifth closing form a spatial structure – box, covered behind the pilot’s cabin along the outer surfaces with 1.5 mm plywood. The bottom of the hull covered with 2 mm plywood, and the upper hull surface with 1.5 mm plywood. The cabin is covered.
An arrangement in the T. The vertical stabilizer with an oblique contour forms the whole with the hull and is covered with 1.5 mm plywood. The main girder and the closing beam of the vertical stabilizer are at the same time the frame of the hull in its final part. Vertical stabilizer beam with a C-section, made of 15 x 19 mm pine strips, has a 1.5 mm plywood strip glued on. The design of the girder is identical to that of the main girder and has fixed rudder suspension fittings. The rudder consists of a girder, four ribs and a trailing edge. A rudder girder with a C-section made of pine slats with a 1 mm plywood strip glued on. Ribs made of pine slats. The nose of the rudder, covered with 0.8 mm plywood, forms a caisson. The trailing edge made of pine slats is covered on both sides with a plywood belt overlapping the ribs. Height-plate height plate. Ribs made of pine slats with glued plywood strip 0.8 mm. Height girder, C-section made of pine slats, has 1.5 mm plywood walls. The leading and trailing edge made of pine slats. The space from the leading edge to the girder, covered with 1 mm plywood, forms a caisson. In addition, the caisson is covered with a glass-epoxy laminate. The rest of the rudder is covered with cotton air canvas.
Technical data J-2:
Span – 7.0 m,
length – 4.84 m,
height – 1.35 m,
bearing surface – 7.0 m2.
curb weight – 105 kg,
total weight – 235 kg.
speed max. 160 km / h,
cruise speed – 120 km / h,
stall speed – 60 km / h,
climb – 3.0 m / s,
flight time – 3 h.