CZ10715U1 - Model aircraft jet engine - Google Patents

Description

Technique Area

The technical solution relates to the construction of a model aircraft jet engine, which is used in aircraft modeling to drive aircraft models, especially run-off gliders and semi-scale aircraft.

Background Art

Known aviation jet bikes are usually designed with a metal combustion chamber, preferably duralumin, into which a gasket, a tablet propellant, a spiral twist, a further gasket and a nozzle bottom are inserted. Everything is pulled back with a spring steel yoke. The assembled motor is inserted into the holder on the model.

The advantage of this construction, namely that the motor can be used repeatedly, is compensated for by the disadvantage of complicated handling before each use.

The heat of the propellant is burned into the combustion chamber wall and the nozzle, which is red-hot and can cause burns. In case of premature landing of the model there is also a risk of ignition of dry grass, grain etc.

A further disadvantage of the described construction of low pressure metal combustion chamber engines is the large ballast weight of the chamber and the holder that is mounted on the aircraft. This worsens the flight performance of the models.

The essence of the technical solution

The aforementioned drawbacks are largely eliminated by the model aircraft jet engine for propulsion of aircraft models according to the invention, which consists in that the engine consists of a combustion chamber consisting of a layer of laminated paper, a lid and a nozzle bottom, preferably of pressed kaolin; a propellant and before use from a fuse inserted into the nozzle of the jet bottom.

The propellant comprises 45 to 60 wt. % of an oxidant, preferably ammonium perchlorate, of 20 to 40 wt. % of fuel, preferably zinc, iron, copper, nickel, or mixtures thereof, of 5 to 15 wt. binders of the class of natural or synthetic adhesives, preferably epoxy resin, polymethyl methacrylate, polyvinyl acetate, rosin, and / or varnish, 1 to 10 wt. a flame retardant, preferably dicyandiamide, dodecylamine, dimethyldodecylamine and / or oxamide, 1 to

2 wt. excipients such as silica, magnesium oxide and / or zinc stearate.

The fuse contains 40 to 60 wt. % ammonium perchlorate, 20 to 40 wt. % nitrocellulose, 10 to 20 wt. % nitroglycerin, 5 to 15 wt. powder alloys of iron and silicon or iron, silicon and chromium.

Although the modeling motor according to this technical solution is designed for single use against its predecessors, the material solution enables to keep the purchase costs low. The big advantage over the previous version is the simple handling, when the motor is already assembled from the factory and ready for immediate use.

The use of paper on the combustion chamber allows for the composition of a propellant with a flame retardant and excess metal fuel. Thus, a reducing environment is created in the combustion chamber to prevent the incineration of the paper combustion chamber. The paper chamber of the chamber, wound from multiple layers of paper, is slowly carbonized by the heat generated, and the fumes carry the excess heat through the engine nozzle. The surface of the combustion chamber is relatively cool and cannot cause behind

- 1 CZ 10715 Fire in normal conditions. Another advantage over the prior art is the much smaller flame emanating from the nozzle, which again contributes to greater safety.

The low-pressure paper combustion chamber model jet engine is easier to attach to the model fuselage than its metal counterpart, because the holder can be an ordinary paper cavity of negligible weight into which the engine simply slides.

The fuse used has an advantage in comparison with other types in a very small flame from which small sparks emerge. In contrast, conventional fuses burn with a large flame, leaving large pieces of fire that can burn the user or ignite the model aircraft.

List of drawings in the drawing

The technical solution is explained in more detail by means of a drawing in which the model aircraft jet engine is shown in section.

Examples of technical solutions

The model aircraft jet engine consists of a combustion chamber consisting of a sheet 1 of laminated paper closed at one end by a lid 2 and at the other end by a nozzle bottom 3.

Inside the combustion chamber, a propellant 4 is placed and the engine is provided with firing pin 5 just before use.

In the exemplary embodiment, the propellant 4 comprises 50 wt. % ammonium perchlorate, 30 wt. % zinc powder, 10 wt. % polymethymethylate as a binder, 9 wt. % dicyandiamide as a flame retardant and 1 wt. silica.

The fuse 5 comprises, in an exemplary embodiment, 50 wt. % ammonium perchlorate, 30 wt. % nitrocellulose, 10 wt. % nitroglycerin and 10 wt. iron and silicon powder alloys.

In use, the model aircraft jet engine of the present invention is mounted on an aircraft model, the fuse 5 being inserted into the nozzle opening of the nozzle bottom 3 and ignited. The driving element 4 is ignited from the fuse 5 and the escaping combustion products, cured by the nozzle of the nozzle bottom 3, serve as a drive for the model flight.

Claims (3)

PROTECTION REQUIREMENTS A model aircraft jet engine for propelling aircraft models, characterized in that it consists of a combustion chamber formed by a cavity (1) of laminated paper, a lid (2) and a jet bottom (3), preferably of pressed kaolin, further comprising: propellant (4) and before the actual 30 using a fuse (5) inserted into the nozzle of the nozzle bottom (3). A model aircraft jet engine according to claim 1, characterized in that the propellant (4) comprises 45 to 60 wt. % oxidizing agent, preferably ammonium perchlorate, 20 to 40 wt. % of fuel, preferably zinc, iron, copper, nickel or mixtures thereof, 5 to 15 wt. binders from the class of natural or synthetic adhesives, preferably epoxy % Of a resin, polymethyl methacrylate, polyvinyl acetate, rosin, and / or varnish, 1 to 10 wt. % flame retardant, preferably dicyandiamide, dodecylamine, dimethyldodecylamine and / or oxamide, 1 to 2 wt. adjuvants such as silica, magnesium oxide and / or zinc stearate. -2EN 10715 Ul A model aircraft jet engine according to claim 1, characterized in that the fuse (5) comprises 40 to 60 wt. % ammonium perchlorate, 20 to 40 wt. % nitrocellulose, 10 to 20 wt. % nitroglycerin, 5 to 15 wt. powdered iron-silicon alloys or iron-silicon-chromium alloys.