It seems that it does not intersect the path of the guys involved in designing the different kinds of models. And competitions are organized separately, and laboratories of its own, Avia – and ship-, auto – and aerospace modelers. But it is necessary to have someone appear more interesting novelty to emerge of a technical idea and it becomes the property of all. It happened with the advent of glass, of which the first avtomodelisty, and then the young shipbuilders began to mold the body and the body is Now this methodology successfully applied by the designers of aircraft models. Here’s how to do it modelers from the city of Erfurt.
Recently, German modelers successfully used in the manufacture of models of epoxy and polyester resin. Corps made for “epoxy”, light-weight and are durable. Vileika them on the CD reduces the time-consuming in comparison with the manufacture of bead housings. The experience of the Erfurt modelers, can be demonstrated on the example of the RC glider L. the Scar, which is one of the first in the GDR made fiberglass hull for flying models with radio control. Its weight with a wingspan of about 3 m 1400— 1700 (photo 1). This is, so to speak, multipurpose model.
Depending on the shapes and installation of bearing areas, it is able to fly like hovering or tethered glider, glider for aerobatics or motor. While the body remains virtually unchanged.
First, the “zero cycle” — the preparatory work. Made from soft grained block (basswood or poplar) to make a disc. In size it needs to meet the future product and to have the connector along the longitudinal axis (Fig. 1). Both halves of the seal pins. Surface thoroughly with sand paper and Polish.
Photo 1. The model glider for aerobatics
Fig. 1. Blank in the context of:
1 — connector pins 2 — part model.
The next stage is making the mould. Spread on the table, a thin plastic film. Put her plane down half blanks. Enclose it in a frame with a clearance of 4 — 5 cm (photo 2), cover with a thin layer of wax or paraffin. What to do about the form itself? Plaster is cheaper and it is faster but it does not give a good surface and goes down after receiving multiple (usually five) packages. Therefore, for a large “circulation” is better to use “epoxy”. You can use polyester resin, but they are during the solidification of a “sit down”.
So working with epoxy. First sing to apply a broad brush and immediately apply fiberglass sing (weight 160 g/m2). Make sure the cloth makes good contact with the disc at all corners and transition areas where there are radius corners, carefully remove any air bubbles. Let dry first sing and solidify, leaving the form on the day in a warm (20-25°) well-ventilated room. Then repeat twice without interruption of the operation. And after curing, place two more layers of thicker fiberglass (weight 250 g/m2). Following this, wash the form with resin so that the outer sing had a minimum thickness of 10-15 mm. (to reduce the flow of resin to the minimum, as filler to use dry sand or finely crushed gravel.)
Now carefully flip half of the mold together with the disc and film. Pins fasten the frame molding for the top half, as shown in figure 2.
Fig. 2. Form in the context of:
1 — connecting pin 2 — frame, 3 — form from fiberglass impregnated with resin.
Photo 2. Form.
The second half of the form is made the same way as the first. Traces of air bubbles zashpaklyuyte droplets of resin, and then treat cycles and fine-grained sandpaper.
Start manufacturing of the housing. First of all, both halves of the form on the inside cover with a layer of wax and Polish. Then cut the fiberglass so that it is everywhere beyond the edge of shape about 1 cm Try to use the lightest cloth and resin waste keep it short. Our experience shows that several layers of thin glass will give the body greater strength and elasticity than a heavier fabric with the same thickness. One of the authors, L. Scar, applied three layers of fabric weighing 160 g/m2. For pouring is equally suitable epoxy and polyester resin. The first is cheaper and better processed, the second at the same weight give higher strength. A significant advantage of synthetic resins is that they can introduce dyes: the body acquires the desired color, eliminating the need for varnishing.
In the manufacture of the body work is being done on the same technology as when making the mould. Feature only in the fact that areas exposed to particular stresses (cab fenders, fittings for wiring), it is necessary to strengthen additional layers of fiberglass or resin. After curing, all excess is carefully cut and carefully remove both halves. Then gently connect them with insulating tape (Fig. 3). The seam is well over a resin with a long, slightly curved brush. Wire hook retract into the housing (see Fig. 3) a strip of glass, of a width of 2-3 cm, impregnated with resin, and preformula her brush.
Fig. 3. Form factor:
1 — brush for greasing resin, 2 — extension rod, 3 — wire, 4 — electrical tape 5 — the voice of fiberglass impregnated with resin
The shape and weight distribution have correctly calculated the housing are such that after installation of the apparatus there is no need to put the nose of the lead weight for the additional alignment of the model. It is tough enough, but the front part should be strengthened frame, to which is attached a cab, and the two spacers located at the level of the steel pins Ø 4 mm, for fastening halves of the wing. The two halves are placed on these pins.
The hood of the cab otstupite of Plexiglas and secure with the help of a thorn and clothing button.
When working with polyester and epoxy resin is required to follow some safety rules. Keep the resin from falling on unprotected areas of the body. To do this, before work grease hands with vaseline, after a wipe with a swab dipped in gasoline, acetone or ether. Then wash your hands well in soapy water.
If You live in Volgograd and are thinking about buying a car, I suggest You look at a Kia Rio.
G. MILES, L. SCAR, Erfurt
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