WITH AEROBRIGADA – SPEED CORD

AEROBRIGADA - SPEED CORD Today we offer young modelers rather unusual development of high-speed cord models apropriada. Novelty design in unusual approach to design. Perhaps this is an approach based on the full (but competent at the same time, taking into account all the important factors) simplification, truly perfect. For good reason, among these designers, there is a widespread saying: “a Difficult decision can find any, and to solve the task a minimum number of simple parts and assemblies — only genius.”

First, we note that the majority of their latest development of sports training techniques in ship modeling class B1 based on technological solutions, housing and other key nodes, in fact, eventually approaching a school model for the outer contours to the championship standards. That is, the search was precisely technological properties. Perhaps this is correct, as the champion scheme brought to perfection, and basically you need to allow juniors to learn the ropes in practice it way features. As well as the reference designs are based on less accessible technologies and supermaterial, various technological simplification and the search in this direction is justified in terms of clubs training Junior athletes.
 
In addition to outward signs a champion of the scheme, “school” speed aerolizer always wore the signs of struggle for maximum weight saving. In this question lies the main difference, which allowed us to find sorpotel new design model. So, first stumbled on it.
First we ask the value of potential of speed Junior speed. For simplicity, we choose 180 km/h, which is achievable with forced compression KMD-2,5 with a well-chosen prop. And then, at least conceptually, try to find the difference between the models 500 and 1000 g. If you consider that the system of the suspension cord together with the bridle and carabiners because of their aerodynamic drag consumes up to B5% of engine power and the remaining 15% is spent approximately equally on aerodynamic and hydrodynamic resistance of the model itself, then… will be: both options are almost equivalent! More precisely: a heavier model will have resistance the entire complex, increased only 7%, and for rapidity yield lightweight superobese only 2%! Such conclusions are easy to make, if you are familiar with the law of the cubic dependence on a required power of speed.
 
THE MAIN CHARACTERISTICS OF THE MODEL
 
Fig. 1. Basic geometric parameters of the model aerolaser with internal combustion engine working volume of 2.5 cm3
 
Fig. 1. Basic geometric parameters of the model aerolaser with internal combustion engine working volume of 2.5 cm3.
 
R and p. 2. The main body of the model
 
R and S. 2. The main body of the model.
Material — select pine or aspen, a low specific weight and streng-<about the latest member of plywood (the base of the redan).

 
 
Fig. 3. Aft float
 
Fig. 3. Stern float.
Material — select pine or aspen.

 
R and p. 4. Stabilizer
 
R and S. 4. Stabilizer.
Material — a single layer of aviation waterproof 3mm plywood or plywood out of three layers of mm plywood (for the latter option, the dotted line shows the relief of the Central layer).

 
 
Fig. 5. The engine
 
Fig. 5. The engine:
1 — main body, 2 — glued metal tube to approach the adjustment screw compression ratio of the engine with the standard key is a 3 — strut pylon (cut integral with the contour of the fairing of the plant from parklea two layers of 1.5 mm plywood epoxy binder; 2 identical parts), Microdrive, 4 KMD-2,5 rotated 90° rear wall Zolotnik, 5 spinner (aluminum), 6 — insert fairing (Linden, it is needed to ensure a smooth transition from the rectangular cross-section main part of the fairing to the round in the area of Coca), 7 — upper fairing trim (plywood ! mm), 8 — the carburetor air intake (dugout detail from Linden or aspen), 9 — frame (plywood 3mm), !0 — fuel tank (soldering of tinplate with a thickness of 0.3 mm), 11 — boss (Linden or aspen). 12 — lower fairing trim (plywood 1 mm), !3 — beam engine mounts (hornbeam and beech).

 
Fig. 6. Fuel tank
 
Fig. 6. Fuel tank:
1 — housing (tinned plate 0.3 mm thick; preferably the walls to do with the border width !,5 mm to increase the reliability of soldering), 2 — drainage-filling tube (copper 0. 3X0. 5; if desired, it is also used for pressurization of the tank volume pressure taken from the crankcase), 3 — a feeding tube (copper 0 3X0,5).

 
 
Fig. 7. The terms of the balancing of the completely assembled and equipped model aerolaser on the bridle suspension
 
Fig. 7. The terms of the balancing of the completely assembled and equipped model aerolizer for bridle suspension.
 
 
Fig. 8. Getting the shoulders eyelet for hanging bridles of the usual big screw
 
Fig. 8. Receiving eyelet for hanging up the shoulder of the bridle out of the ordinary large screw.
 
R and p. 9. The simplest valve for selecting the pressure from the crankcase
R and p. 9. The simplest valve for selecting the pressure from the crankcase:
1 – the valve body (steel rod diameter 3 threaded screw or MZ MZ with a smooth plot, drilled along a drill diameter of 0.8 and !,5 mm), 2 — steel ball valve 0 to 1.2 mm (when assembling the valve to utformat saddle by the same ball, causing him a blow with a light hammer via a terminal adapter), 3 — nut of the MOH (for sealing draped on the body of the nut carefully soldered), 4 stopper bead (1 tube 0. 5X0. 3 with a scalloped cutout at inner side; pressed in the valve body), 5 — a collar choke parts (wire ring 0 0.3— 0.4 mm; soldering on the valve body).

 
Why do we set a value of specific speed? The fact that it mind, we can all “harmful” amendments to kilo models further reduce to two times1 It at 180 km/h with a standard cord system and the height of the suspension cords of the Central riser, equal to 500 mm due to the centrifugal force occurs, the vertical component of the tension, the unloading action of the weight of aerolizer exactly half.
 
What other questions remain? Probably, the stability of motion on the surface of the waters. But, first, this is strictly a question of another kind, not directly related to the mass of the model; and secondly, our experience suggests that if the original technique was designed intelligently, in real conditions, the weight has no effect (especially the experiments have been conducted with good aerolister, which was loaded to twice the mass).
If we assume that the fundamental issues we have decided, then proceed directly to the design of the new model. The only thing that I would like to note: for such a high-speed important to be able to distinguish a fir wood from a pine or even a lime tree from ASP as well as confident enough to navigate in terms of the densities of these materials.
 
So: the main detail — the case of aerolister. He’s represented… one beam of light spruce or aspen! I guess some would call this decision exaggerated, especially if you get acquainted with the following parts. But… read again all that is written above, and try to take a similar approach. Then you will be able to absolutely other eyes to watch and evaluate the work of other designers.
 
The total volume of timber of the main body is equal to 900 cm3, when the real density of light spruce or aspen 0.3 g/cm3 will give a weight, equal to 270 g. For a pair of floats, these values are respectively 260 cm3 and 78 g. Add weight to the summary: the engine with a propeller and spinner — 200 g, telefonerna stabilizer (neoplachennom version) — 55 g, pylon fairing with the power plant and fuel tank — about 100 g and epoxy resin for the Assembly of coatings for exterior— 97g (a lot!). Total is exactly 800 grams! Is the total displacement of body parts 1170 g.
 
We would like to note: if you are lucky enough to find a light durable wood required density, the thickness of the blanks for the hull and floats to reduce in half (30 mm case and 17 mm for floats). The total displacement will be equal to 780 g, but the mass of aerolizer reduced. New weight summary would look like this: case—180 g, floats — 52, engine — 200 lightweight reduced stabilizer of three layers mm plywood — 34, pylon fairing and the tank 100 g and leitlinie materials — 54 g. the Finished model will weigh Assembly 620 g.
 
Wood density-0.5 g/CM1 is estimated without any knowledge of its properties as “severe”; therefore, for completeness we present only the weight of the model in shown in the drawings, when the density of the blanks for the hull and floats 0.4 g/cm”, it is equal to 916 g (with integral stabilizer and a large ink consumption). As you can see, even with fairly heavy material airboat with that said is within the rules.
 
After meeting with a record simple model you might seem somewhat over-engineered pole-alterately part. Perhaps you are lucky enough to design and more simple. The only thing I would recommend— do not use even a little bit serious Junior models the simplest plate-pole split at the crankcase. She bears the signs of “children’s” equipment not originally designed for the achievement of sports results. In addition, nasekomojadny motor with tank, it turns out, has the wind resistance equal to the resistance of the rest of the model aerolizer.
 
On the proposed high-speed used motor KMD-2,5 rotated 90′ Zolotnik with the rear wall of the housing and chrome-plated piston. About the benefits of the turn of the wall, we learned in one of the model aircraft publications in the “M-K”. Indeed, improved engine over speed with light propellers: he has no signs of overload, more power and a few quieter exhaust sound. Nutrition carb — under pressure taken from the crankcase through a valve which is screwed the upper left mounting screw of the wall (the position of the cylinder in this orientation is vertically upwards). Through the slot of the screw in the crankcase overlevelse inclined hole 0 1.5 mm with access to podporchennuyu area.
 
V. VICTORY, head of the society

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