IL-4 ELECTROThis unusual model was built by members of syt Berezniki, Perm region. Copy flies perfectly, performs such demonstrations as “flying under the 45° angle” and “pipeline.” Remote speed adjustment of electric motors allows the model to freely come to the “stopover” and after run on the ground again soar into the air so that sometimes it seems — before you the real Il-4. With the design of the copy you are acquainted the head of the aeromodelling circle N. YAKIMOV.

First of all, about why we stayed in the Il-4 (DB-3F) as the prototype for elektromodul. According to the regulations of the competitions, poster assessment and evaluation flight conducted by the rules of modeling. So that flight was not only entertaining, but also brought the young athlete satisfaction, you need to do any demonstrations. Ideally, there should be five. On single-engine models, the choice of shapes is limited; to compete in aerobatic qualities with machines equipped with internal combustion engines, “trains” it’s hard. Single-engine difficult to implement, say, a system of harvesting and release of the chassis, this dramatically weighted would and worse its flight properties. Multi-engine machine is much energooborudovanie, in addition, there is the opportunity to get in the competition with additional points.

It was agreed a copy will be twin-engined, prototype drawings we found in the journal “modelist-Konstruktor”. Beautiful external form, Il-4, a wing of large aspect ratio and area, developed the stabilizer can expect that the model will be good to stay in the air and will be easy to manage.
Now it was the selection of motors. As PA any other copies, power and weight of the power plant determine the mass, major dimensions and flight characteristics of the model. We stopped for widespread domestic DK-5-19. Of course, they had to cross and also improve the temperature resistance of the engine as a whole. This thermoplastic material collector and the lid replaced on the PCB, in the housing and in the cover slotted holes for the passage of cooling air. For flying models the last method of cooling is highly effective, especially given the small heat capacity of the light plant. And the dependence of the intensity of the blowing of the load is favourable: more power — more heating of the engine, but at the same time increasing the speed of the propeller, increasing the volume of cooling air passing through the casing of the motor.
Fig. 1. Cord model-a copy of the Il-4 with two electric motors and the simplified fuselage and the nacelles.
Fig. 1. Cord model-a copy of the Il-4 with two electric motors and the simplified fuselage and nacelles.
Standard motors I have another weakness — collector. Its base is made of thermoplastic which when heated softens, the result is the contact plate of the manifold are closed. Therefore, the basis we have also replaced textolite, copper plastuny secured it with heat-resistant glue BF-2.
Heating converted engines were significant, but quite acceptable — engines serve long and reliably.
Propellers we picked up during test flights of the model. To simplify this work has allowed the use of the hub-Coca, machined from magnesium alloy MA-1T. Wood (Linden) rotor blade, pinched between the cook and the support disc, can be expanded, thus changing the installation angle of attack.
Designing the airframe is a copy, we set ourselves two key objectives to reduce the mass of the model and the minimum consumption of scarce balsa. That happened, says take-off weight of microbombardment equal to 83 g. It is a span of 600 mm and given the mass of two electric motors!
To achieve this ease of the device failed due to the failure of the simulation of the hard plating stacked wing. Ribs carved from Linden veneer, and greatly facilitated, the longitudinal set of pine, balsa, only edges and endings.
Fig. 2. The design of the control knob.
Fig. 2. The design of the control knob.
To increase the number of copies per cell, the set of the fuselage covered with a thin (thickness 0.8—1 mm) balsa veneer. Unusual simulated glazing: frame with covers cut from plywood with a thickness of 1 mm and is tightened from the inside transparent Mylar film. Lantern arrow stamped from thin celluloid. The finished fuselage as the wing, fitted by a thin long fiber paper — “Japanese” — amalite.
Empennage design repeats the wing, only its elements are carved from balsa. Recommend that after assembling the tail not to wait until the fuselage is finished, and immediately Zapatista trim fin and stabilizer, obtenus them dyed long-staple “Japanese”. In this sequence of works is less than the likelihood of inaccuracies in vzaimoponimanii elements of the airframe, and therefore a better finish wing separately from the fuselage. The finish of a limit color of paper and her painting (the application of additional surface layers of opaque enamel significantly increased the mass of the model). Before final Assembly all parts must be completely finished, ready pas dig are issued only fairings.
The performance of the nacelle does not require special explanation, in design they are similar to the fuselage.
The control system includes a rocking chair made of insulating plastic rod, made from the stem of chiy, and the simplest actuator of the elevators of the usual type.
Landing gear carved bamboo, paper helped accurately reproduce all the thickening on the uprights and their braces. Thin celluloid went to the imitation shutters hatches chassis. Wheel of finely porous rubber is sandwiched between the halves of the hub (MA-1T).
Completely finished, assembled and finished copy is checked for the correct position of center of gravity set such small details as the instrument air intakes, antennas, flaps rudders, and simulate navigation lights and machine gun. In most cases, the best material for them is solid bamboo, its use will insure the finest elements from damage when the model runs.
Fig. 3. Design cord copies of Il-4 with engine-motor schema.
Fig. 3. Design cord copies of the Il-4 engine single-engine scheme.
It remains to make a control knob with a variable resistance to adjust the “gas” and Konami in assembling the power supply. The model flies well on two strands of wire marks PEL Ø 0.25 mm with a length of 4-5 m. as the current source used ten Nickel-cadmium batteries the SAG is 1.5. giving average PA handle about 12 V.
I want to mention another variant of the model, Il-4, also developed in our group, copies of the dugout with a boxy fuselage and a full simulation of the hard skin of the aircraft. This Model melkosortnogo cut from the packing foam. Surround the nose and nacelles extruded from thin sheet celluloid, the chassis has a valid depreciation stands, repeating the design of the prototype, and wheel-quilted welded from raw rubber. This model looks just like the real Il-4, but a few flies worse than the first. May be affected by the shortcomings of used engine brought heavy and thin (he is one, by two screw rotation is transmitted by belt from the drive counter of the tape recorder “Comet” so that the motor shaft is unloaded from the influence of the radial force), heavy and finish — it is made with white glue, followed by color. Take-off weight of 200 g. copy
And we talked about this model why. As it turned out, to the “trains” should be taken quite seriously. I hope that they will eventually get in line with the sports models. But the new vehicles for missions in the premises requires a new approach to the design of any element. And we are sure that in the end, using another, it may be a classic, twin-engine scheme of the plant and different methods of exterior foam, you will be able to “teach” a copy of Il-4, very close to reproducing the prototype to fly as well polyopia. And our experience will be useful for adherents of electrosetstroy.

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