:: Airplane Modeling - Constructing a glider in fibre glass.


by: Edson Nóbrega

Choice of the model .

        The gliders constitute one of the most fascinating machines controlled by a radio-control. The elegant evolutions of a glider, without a doubt, leave us "opened mouth", still more if the model will be conceived by we ourselves.

        I always observed with attention all the categories of gliders, much even so, I never have practised some of them. When I took knowledge of the gliders of F3J class, I could not resist the allure of these models, although not to be a competitor of the category.

        After all what it has of so fascinating in everything this? Well, for me, it does not have prettier print of the one than a model flying in a thermal a two hundred meters of the soil. It will have who finds this boring…

The model that I decided to construct, is from F3J class. The gliders of category F3J approximately possess a spread of the 3 3,5 meters. The fuselage measures 1,5 meter of size generally, having in its posterior part a conventional tail in form of cross (drag rudder and of depth) or a tail in "V", where only two surfaces of control play the role of profundor and helm.

The all up weight of a glider F3J at the moment of the take-off is of about 2,3 the 2,5 kg. This not only understands the weight of the proper model, as all the equipment of the radio reception it has also controlled (receiving, battery and servants), beyond the weight placed in the airplane inside of tubes, located below of the Center of Gravity (CG) for the regulation of (CG), measured that provides stability to the flight of the glider, besides becoming the model fastest, if adding weight the set.

        Initiating the Mold's Manufacture

Models of class F3J, in its great majority are molded, or either, the fuselage are made in molds and plated in Kevlar, fibre glass or Carbono. In fact, our model is made in fibre glass.

All the materials for construction of the model can be found in store that sells fibre glass and similar.

The first step is to manufacture the mold from a called model "Plug". Plug can be made in wood, isopor® or even though of a fuselage that we desire to copy. Initially we must prepare the Plug applying some layers (minimum five) of wax of carnaúba so that the surface is total polishing and cover with a fine wax layer. We do not have to use silica base wax. After the wax have evaporated all the solvents, it is time to apply the PVA base unmold. To fix the mold junction is accurately in the central string of the fuselage, it is necessary that let us make a wooden frame with the silhouette of plug.

As the manufacture process demands some knowledge in resins and fibre glass, the interested parties in model manufacturing will be able to find some difficulty, however, there is nothing to worried about. Everything is available in the Internet, diverse sites on the subject, as these.


Mold Preparation

Now we go to detail the process, using as model a simple piece of wheel. The process of preparation and lamination is the same used for any part, that we desire to make in fiber.

We must leave only the half of plug visible, and the other part is in low of the used platform dividing the plug in two parts. This end to use one compensated of 4mm, in the case of a fuselage, must use one of at the very least 10mm. The compensated one must have the same silhouette of plug, as well as, must leave a small space between plug and the edges of the compensated one. This space must be filled with mass. I always use mass race (those used masses for walls) is simple and easy to apply. Plug of being waxed before this process.

The part that we use as plug, must have the definitive central string before cutting the platform. As the polaina of wheel is very small, I decided to divide in the cross wind axe, but in the majority of the times we use as reference the longitudinal axle of the molded part. It is the case of a fuselage.



For this, you only need to create, exploring the features offered for the most diverse manufacturers of inks and plastic models, never forgetting that this is just your hobby! Enjoy it! .