Werrej
Movement on ice and snow has many features. This type of transport, like an aerosleigh, combines a lot of advantages. However, there are also disadvantages. You can make a snowmobile with your own hands, using the largest number of materials at hand, ready-made units. At the same time, they will be no worse than many industrial analogues.
When self-manufacturing from scratch of any equipment, you must first complete the design project. It, in turn, is divided into four stages
- Design of technical conditions, characteristics;
- Technical proposal, at the stage of which there is a general layout of the product;
- Draft design, where a drawing of the product and its parts with the necessary calculations is carried out;
- A working draft in which drawings of the product are made taking into account the current standards, already available assemblies, mechanisms, and the manufacturer’s capabilities.
Naturally, a do-it-yourselfer in a workshop will not complete all the drawings in detail, and education usually does not allow. However, you need to try to make at least some drawings and calculations, especially when it comes to complex off-road equipment, such as snowmobiles.
Prestazzjoni tas-sewqan
The first parameter that should be taken into account is the traveling mass of the sled, G. It consists of the weight of the sled itself, cargo and passengers, and fuel in tanks filled to capacity. This parameter is determined approximately, it is advisable to choose it at the initial stages with a small margin. In preliminary calculations, one should start from the fact that the weight of the sled is no more than 14 kilograms per one horsepower of the engine, then it can be determined more precisely.
If you want to make snowmobiles of a certain carrying capacity, then you can roughly take serial samples and see their traveling mass. Again, it is better to take it with a margin, especially at the initial design stage. It is always easier to recalculate for smaller loads than for larger ones.
Thrust-to-weight ratio
The second parameter is the thrust-to-weight ratio, the dynamic coefficient D. It is determined by the ratio of the traction ability to the marching mass, D=T/G. This coefficient should not be less than 0.25, it is desirable to take it around 0.3. The thrust-to-weight ratio will show how fast the snowmobile is able to move, accelerate, overcome climbs and other obstacles. Traction capacity and traveling weight are taken in kilograms.
In the previous formula, the thrust parameter T was used. It is determined based on the engine power and propeller parameters using several formulas. The simplest one is if the specific thrust of the propeller is known in kilograms per horsepower, T=0.8Np. Here N is the engine power, p is the specific propulsion power in kilograms per horsepower.
You can determine the pulling power by another formula that will work for most standard two- or three-bladed propellers, T=(33.25 0.7 N d)²/3. Here N is the rated power, d is the propeller diameter in meters, 0.7 is a coefficient that depends on the characteristics of the propeller. For ordinary screws it is 0.7, for others it may differ.
Karatteristiċi Oħra
Other characteristics such as range, speed, climbing and descent will be highly dependent on the selected engine, tank capacity and dynamic coefficient. It is worth paying attention to the area of u0.1bu0.2bthe skis so that their specific pressure on the snow is no more than XNUMX-XNUMX kg / sq. cm, and if they are designed to move on ice, make an amphibious snowmobile in case of ice cracks. Such a machine is also very useful for summer fishing when moving among thickets of water lilies, otherwise the propeller will wind them on itself and break. Similar snowmobiles are used by the Ministry of Emergency Situations to rescue people from the ice in the spring.
It is worth remembering that the manufacture of large snowmobiles for several people is possible only when a powerful engine is used. In itself, its use increases the cost of the structure many times over, and fuel consumption in such snowmobiles will be very large. This puts an end to homemade designs in terms of cost savings. For example, the consumption of gasoline by serial snowmobiles for 5-6 people is more than 20 liters per hour, and they move at a speed of up to 100 km / h on an icy surface, on snow – up to 60-70.
The mobility indicators of such snowmobiles will be comparable to the cross-country ability of a snowmobile of the same carrying capacity. However, they will have less climbability, worse handling, the inability to go at low speed through the trees and maneuverability will be inferior to the snowmobile. If you plan to move through the winter forest, then it is best to use a snowmobile.
Low-powered snowmobiles may well be made on their own. Many do-it-yourselfers make snowmobiles with a lifan engine, chainsaws that are designed for one and work successfully.
Snowmobile for fishing
Ideally, if they are:
- Have positive buoyancy
- Have a removable propulsion device with the ability to rearrange it on a boat in the summer
If the snowmobile can be used as a full-fledged boat, then there is no need to remove the engine for the summer period.
Basically, snowmobiles are made by fishing enthusiasts in the countryside, living next to large expanses of water. It is most rational to use them in spring time on clear ice, when the snow cover on it is minimal. There are very good arguments in favor of abandoning the classic ski design, and on the bottom to use the classic three-rib for gliders.
At the same time, the stiffening ribs are made reinforced so that they can perform the function of skates. When there is water on the ice, it will make it easier to move. At the same time, the snowmobiles will reach an almost full-fledged gliding mode, reducing the resistance of the environment. In summer, such a hull will be a full-fledged boat with high seaworthiness – overcoming small flooded spits and rapids on the river will not be such a problem for her as for an ordinary motor boat.
However, it is undesirable to use “Kazanka” or an old “Progress” for such things. The fact is that their bottom has insufficient strength. Yes, and depreciation will suffer. And from hard blows, the bottom will fall apart even more. The design of most modern snowmobiles and air boats for fishing involves the presence of a rigid bottom, which has an inflatable deck with a polyk. Thus, shock absorption occurs during movement. Other designs should be recognized as not very suitable.
Budget snowmobiles: manufacturing process
The following describes conventional snowmobiles of classical ski construction with a frame. They can be used for fishing, hunting and trips for one person.
Frame
The manufacturing of the frame of the snowmobile should provide them with light weight. Usually the lower part of the frame is made in order to fit a seat there, a rectangular or trapezoidal shape. It is necessary to place it slightly ahead of the center, since another engine, tanks, propeller, luggage will be added, and it is desirable to place the center of gravity in the middle of the frame. This is followed by the manufacture of a frame for the engine, transmission and propeller. It is made triangular, the top will be the bearing on which the lead screw rotates.
The screw frame must be at least as strong as the bottom frame. It must withstand serious loads, because the force that sets the snowmobile in motion is applied to it.
This frame has wide gussets in the form of rods that are attached to the triangle posts and go forward. It is undesirable to occupy a seat in the back, as this will interfere with the rotation of the propeller.
The frame material is selected from thick reinforced polypropylene pipes. These pipes give satisfactory strength, but over time they can lose their shape under load. If possible, it is advisable to use aluminum pipes and connect them with spurs, tees. Aluminum joints for welding at home are a rather complicated thing, and even in the presence of argon welding it will lose in strength to the connection to squares.
Screw and motor
A fairly powerful Lifan 168f-2 four-stroke engine is used. Four-stroke engines start up a little worse in cold weather, but are much quieter. A plastic additional gas tank from a walk-behind tractor is used. By itself, the power-to-weight ratio is quite sufficient for a snowmobile with a total traveling weight of up to 500-600 kilograms.
The propeller is made independently, two-bladed, has a diameter of 1.5 meters, enlarged according to the drawings for aircraft models. Making a screw yourself is a rather complicated process and will require carpentry skills. In addition, you will need wood from maple, hornbeam, beech, ridged Karelian birch or other fairly durable wood, dry. If possible, it is better to purchase an aluminum screw with predetermined characteristics from the store.
From the engine to the screw, a reduction gear is used on belts with a ratio of 1: 3 from a woodworking machine, with a tension roller. With the choice of speed modes for snowmobiles, everything is rather sad, and it’s difficult to talk about a gearbox here due to the fact that the propeller itself will only work effectively at sufficiently high speeds, and reducing them does not increase traction, on the contrary.
Layout, skiing and handling
The seat is located immediately in front of the engine, under it is the trunk. An additional trunk is available near the footpegs. The engine is controlled by the gas and clutch pedals. You can take them from an old car and connect them to the engine with cables.
There are two additional handles on the front. They are connected by cables with the front pair of skis, which can turn left, right on a vertical thrust bearing, and also synchronously with the steering flags, which are located in pairs behind the left and right of the propeller. The left handle controls the left side, the right handle controls the right. They can be used independently, and when braking, it is enough to bring the skis and flags inward by pulling both handles towards you.
The snowmobile has four skis, two front and two rear. The front two skis are short, made of alloy steel. The back two are longer, made of plastic. The rear skis take part in driving the snowmobile. Skis are mounted on special triangular supports, have a swinging stroke and are sprung in the front.
Painting and lighting fixtures
The snowmobile must be painted in a bright color that will be noticeable from afar in the snow. It can be red, brown, blue, purple or any other similar color. Also be sure to paint the prop guard brightly, preferably a color that is different from the main body of the snowmobile. Usually orange is used for painting.
Of the lighting devices, it is imperative to put marker lights, as well as lights on the propeller – green to the left of it in the direction of travel, and red to the right. Headlights must have sufficient power. The fact is that daylight hours in winter are short, and moving only in daylight is usually not possible.
To save weight, the headlights and lights are powered by a battery that is charged separately from the snowmobile before riding, eliminating the need for a generator system.
Typically, the battery lasts for 3-4 hours of travel, which is enough to get home in the dark. If you want to protect yourself so that the headlights burn all night if you get lost, you can recommend installing lighting coils from an old motorcycle.
When to Use Airsleds
Of course, for the use of snowmobiles in extreme conditions to ensure the life of a village or an individual, no permit is required. In order to ride them on ice, where you can meet a fish protection inspector, to drive even on unpaved snowy roads, you will need to register them with the Technical Supervision authorities.
This is a rather complicated and lengthy procedure. You will need to obtain a safety certificate, design verification calculations. The cost of the procedure itself negates the process of making snowmobiles on their own in order to save money. You can’t do without registration, since the engine size for them is usually from 150 cubes. You can’t set a smaller one, it simply won’t pull the propeller. To operate a snowmobile, you will need to obtain a special driver’s license.
Therefore, in most cases, snowmobiles are not the best choice for an all-terrain vehicle, primarily due to bureaucratic reasons. The second reason is the increased fuel consumption, especially in deep snow and in soft snow during a thaw. Compared to a snowmobile with a caterpillar layout, snowmobiles consume 1.5-2 times more fuel for the same needs. The third is the inability to pass through the forest.
Therefore, snowmobiles, although they are a fairly simple and reliable mode of transport, are not always a good choice for those who want to have their own all-terrain vehicle-snowmobile, especially for a fisherman who would be more interested in fishing.