Yazar: Süleyman Atılgan

Karda Off Road teknikleri
Off road da Engel Nasıl Aşılmalı ?
Offroad ‘da Ağır Araç mı Hafif Araç mı ?
Denge off-road‘un neresindedir ve önemi nedir ?
Dik çıkış mı daha tehlikeli ? Dik iniş mi daha tehlikeli ?
Yol kenarı Devrilme Analizi
Derin Su Geçişi, Alınması Gereken Tedbirler ve Riskleri Nelerdir ?
Artikülasyon ‘un yol tutuşa etkisi nedir?
4×4 Off-Road Araçlar da Diferansiyelin Önemi Nedir ?
Off-Road Araçlar da “Orta Kilit” ve Önemi Nedir ?
Lastik Büyütme ve Offroad Sürüşüne Etkileri Nelerdir ?
Arazide Hangi Lastiği Tercih Etmeliyim ?
 

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Blog Türkiye

Snow driving and handling

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Off-road Basic Technical Information
Dear off-road and nature enthusiast friends, we are together with another sharing of our Off-road Basic Technical Information article series. The information I will provide; These are concentrated, technical-based, lived experiences, and some of the details that will find a name in the off-road literature for the first time. With the hope that it will benefit the readers.
Our topic today is “Driving on snow and handling ” :
I would recommend you to read it in your quiet time. It’s long and a little confusing. At least read the “ results and recommendations ” section.
There is nowhere else you can find such in-depth analysis. In general, the subject is whether we will inflate or deflate the tire, and there is a math in this business. An original work. Inside; there are the basic laws of physics, soil mechanics, strength and statics. Mathematics exists only to express this information.
The basic rule of road holding is not to slide. If the vehicle can hold the road, it will walk, if it cannot hold the road, it cannot walk or be controlled. Whether offroad or onroad, this is the most basic rule. There must be a force between the tire and the surface to avoid slipping. This force appears in three ways. Friction, shear strength, passive thrust.
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Friction :
Traction is the basic force that allows the vehicle to walk between the tire and the road. Traction is essentially a medical term and not a definition that has anything to do with offroad. However, since it is a term expressing handling and traction in the unwritten offroad literature, I use the same expression. Only the surface is the case of force arising from the surface. The upper limit of this force, that is, the highest value it can take, is the “friction force” between the surfaces. The frictional force is equal to the product of the normal force (perpendicular force) between the surfaces and the coefficient of friction between the surfaces. If the force transferred from the tire of the vehicle to the road exceeds the friction force, skidding starts. It occurs on the surface where the outer side of the tread of the tire contacts snow or ice. Since the coefficient of friction between two surfaces is equal to the product of the total vertical load, whether the surface is wide or narrow is unimportant in terms of friction force as long as the coefficient of friction remains constant. However, tire width can affect the friction coefficient depending on the snow condition. The surface pressure is high on the narrow surface, and the surface pressure is low on the wide surface. As the surface pressure increases, the snow becomes more crushed and icy, as the icing increases, the friction coefficient will decrease and the friction force will decrease accordingly. This means; When evaluated in terms of the friction force between the solid part of the tire and the surface, the contribution of road holding will decrease due to the decreasing friction coefficient as the tire gets narrower. This is the first case. However, since the total horizontal friction force is only the parameter of the total vertical load and the coefficient of friction between the two surfaces, if the friction coefficient does not change, the friction force does not change either. So wide or narrow tire may not make a difference. This is the second case. Which of these two opposite situations will occur will be determined by the snow quality. In other words , the snow quality will give the answer to the question of whether it is a narrow tire or a wide tire.
The tire material is the parameter of the coefficient of friction. Winter tires coded as M+S give a higher coefficient of friction in cold weather, while tires with normal rubber provide a lower coefficient of friction.
The quality of the abdomen is the most important parameter in terms of the coefficient of friction. It is higher in dry snow, lower in wet snow, and close to zero in ice.
The coefficient of friction between the tire and normal snow is considered to be ~0.20. So this means that if the other road holding parameters of the tire, such as shear strength and passive thrust, do not occur, when you release the vehicle from a slope of 20% or in other words arctan(0.20)=11.31°, if there is no pile etc. to prevent it from moving, it will move in the direction of the slope. can slide with its weight.
There are two types, kinetic and static. The coefficient of kinetic friction is lower. This means that if the skid starts, the handling of the vehicle will become even weaker .
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Shear Strength :
If the snow that enters between the tire treads and the crushed snow on the ground stick together and work as one piece, this compressed snow will provide as much grip as shear resistance (also known as shear or shear resistance). Here, whether the tire is wide or narrow is an important and contradictory parameter. The wider the tire presses on the ground, the higher the shear strength will be, as the amount of snow will be more intervening. This is the first case. Another factor that positively affects the shear strength is the compression of the abdomen. The greater the pressure on the snow, the more it will be compressed. This will only be possible if the tire is narrower. This is the second case. Which of these two situations will provide more positive handling will again be determined by the quality of the snow. In other words , the answer to the question of narrow tire or wide tire will once again be given by the characteristics of the snow.
The basis of the opinion recommending that tires be inflated rather than lowered in snow is actually a recommendation related to shear strength. When the air of the tires is deflated, an inward collapse occurs in the tread. This, in the form of snow tires, causes the gaps between the treads of the tires to narrow and less snow to get in between. Less snow means less shear strength and will automatically weaken the grip. MT or XT tires with coarse treads will not behave like narrow tread tires, as they are already designed to serve at low air pressures.
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Passive Propulsion:
In order for passive thrust to arise, the part entering the snow must be very low in proportion. Passive propulsion is almost nonexistent in soft snow. The snow should be crushed and hardened by the weight under the tire. May occur on medium hard ice and hard snow. It is difficult for the tires to interact to create passive resistance alone. Passive resistance is expected to occur in the use of studded tires and chains. The forces generated by passive resistance are much greater than the forces generated by friction and shear strength. That’s why studded tire or chain grip is generally better than any type of tire. An effect that can be considered as a passive effect can also be evaluated as the scratching effect of the scratches on the tire or the tread on the snow, which is hard enough to allow this behavior. This effect is more pronounced on snow tires or AT type tires rather than coarse tread tires. Therefore, it can be said that AT tires are more successful than MT tires under certain conditions. However , it is up to the wife to decide on this issue .
Definitions:
Friction coefficient :
The friction coefficient is the ratio of the force pressing against each other to the frictional force that occurs between them. It is a scalar (unitless) value. It has two different values as static and kinetic friction coefficient. Its values are determined by the inclined plane test.
Frictional force :
It is the force obtained by multiplying the normal (perpendicular) force on the contact surface between two objects by the coefficient of friction between the two objects. It is in the opposite direction of the motion in sliding objects, and in the same direction as the motion in rotating objects.
Passive propulsion:
It is the case of not applying any force while at rest, but countering it with a force when a force is applied to it. It can be evaluated within the framework of Newton’s 3rd law (action-reaction principle). To illustrate with a clearer example, consider a paw on ice. After the claw enters the ice, a state of equilibrium is established and there is no mutual force. If you claw on the claw, the place where the claw enters exerts a force on the claw as much as the force on the claw. As long as the material strength in the place where the claw enters is not exceeded, the cling will continue.
Shear strength :
The total resistance to the shear stress occurring in the plane parallel to the applied surface is called shear strength.
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Now let’s evaluate snow driving in the light of these basics.
The rule of driving on a slippery surface is very clear, neither the accelerator nor the brake should be pressed too hard. If it is downhill, the vehicle is left with the flow of the road in low gear. If it is uphill, it is tried to walk in high gear at low speed without skidding.
If your wheel is not turning at a speed appropriate for the speed of the vehicle, you will either spin or the vehicle will tend to slow down and come to a stop. However, if the ground is icy and the friction coefficient is too low, the vehicle will slide in both conditions. If the car slides downhill, gravity makes the rules.
If the tires are spinning at a speed higher than the speed of the vehicle, it will be positive spin, and if the tires are spinning at a speed less than the speed of the vehicle, it will be negative spin. If there is skid, there is no grip.
The most successful tire on snow is the winter tire , especially if you are driving on a paved track. The Extreme tire is the most successful tire when making the first trail. AT tires, like winter tires, provide good grip when driving on open tracks. While MT tires are successful in opening the first track, unfortunately, they exhibit extremely poor handling performance, especially when walking on an opened track. This is not a valid determination for all MT tires.
When we examine the tread patterns of large MT tires, you will see that the treads are also large and the outer surface of the tread is flat. The outer surfaces of these teeth are so wide that when driving on a trail opened in snow, a few of them can carry the vehicle on hardened and icy ground without sinking into the hardened snow. As a result, the vehicle behaves as if you were trying to drive on ice with a zucchini tire . After all, you go wherever gravity takes you.
Let’s talk a little bit about MT tires. Although MT is called “Mud Terrain”, “mud ground”, it is not very successful in mud. The track where the MT tire is successful is dry loose ground and rocky ground. If you watch BF Goodrich commercials, you will see MT tires on DAKAR-style tracks rather than mud or snow tracks. I will examine the subject of tire types later as a separate topic.
When you bring the same tire with 235 tread width side by side with a 35”x12.5” Bf Goodrich MT tire, you will immediately notice that the patterns of the 235 tread tire look like an AT tire next to the 35”x12.5” tyre. If we take into account that AT tires are more successful on the opened track, small size MT tires can also act like AT and be more successful. While a 35” MT mounted rubicon will struggle, a 235 base MT suzuki will be able to walk away.
When evaluated in terms of friction force depending on the snow quality, the narrowing of the tire will adversely affect the road holding.
When evaluated in terms of shear strength depending on the snow quality, narrow or wide tire can either increase or decrease road holding. Nothing definite can be said, the qualifications of the abdomen are decisive.
A studded tire nail or chain that penetrates hard snow or medium-hard ice by inserting a fingernail adds passive resistance to the tires as the tire tries to turn. This resistance provides grip to the vehicle. If the ice has become too hard due to extreme cold, the nail or chain cannot penetrate the ice, so it serves only with the grip provided by the friction between the two materials, not the claw effect. So in extremely cold and very hard ice, chain or studded tires are not very efficient either.
In narrow-toothed tires like snow tires, reducing the air of the tire and providing contact with a wider base will create a negative effect, not a positive one, for the reason we explained above. In MT and XT tires, on the other hand, providing a wider contact surface by deflating your tires may or may not have a positive effect depending on the snow conditions.
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Effects on the vehicle in snow driving:
If the snow is deep; The passive thrust created by the snow touching the chassis, axles, bumper, body, etc., the snow piling up in front of the tire and the slope are the major effects that prevent the vehicle from walking.
If there is a slope, the effect of the component of the weight parallel to the road. If there is a slope in the direction of movement, it has a positive effect, and in the opposite direction, it has a negative effect.
Other than that, even the wind is an effect, but it won’t be a big one.
If the snow is deep, the narrow tire will cause more sinking and more pile resistance against the vehicle.
Nails and chains are inefficient on soft snow, more efficient on medium-hard snow and normal-hard ice, and useless on very hard ice.
In the case of going uphill, a restraining force occurs due to the slope.
If we write the parameters collectively;
– tummy tuck
– snow depth (depending on vehicle height)
– the slope of the road. (This is just a topic on its own)
– the dough of the tire,
– tread pattern of the tire
– tread depth of the tire
– diameter and width of the tire
– the mechanical capability of the vehicle (presence of mid-rear-front lock)
– piloting
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Let’s examine the depth of the snow a little.
In deep snow, my observation is that solid axle vehicles with a differential watermelon in front are more successful. If you examine the trace it leaves behind, you will see the trace left by the differential in the middle of the trace swept by the axle sleeves. In other words, solid front axle vehicles have a tendency to sweep, not rise above the snow.
If IFS (independent front suspension) vehicles are equipped with a flat-plate skid plate to protect the front wheels and the engine, when you drive in deep snow, the snow will tend to rise over it rather than sweep it. In this case, the grip of the front tires weakens, and sometimes they can be completely cut off the ground. Especially if you come back on your track to get the snow and speed up and move on the clean snow, you can hang. This situation may give different results depending on the characteristics of the abdomen.
A straight road is the most ideal situation, but it is the least achievable situation in the field. If the surface is slippery, the vehicle will tend to slide in whichever direction the slope is greater. That’s why on snow trips, cars often slip and fall on the right or left bank.

If it is uphill, it is not possible to proceed. The most dangerous, in my opinion, is the descent. On the descent, gravity takes control. If your tire does not hold the road, you will go uncontrollably wherever gravity takes you. If possible, enter this state at low speed. Do not apply the brakes, try to ensure that the vehicle moves on foot rather than sliding. The brake will cause you to lose control completely.
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Conclusion and Suggestions:
Don’t get into pointless negotiations about narrow tire – wide tire, increase tire pressure – decrease. If you catch a bird with your mouth, there will be no more than what the snow quality allows.
In the video, the situation may be a little clearer.
If the ice sheet has formed and the tires cannot hold the road, it will not be possible to advance by piloting. If the tread layer is thin and there is no deep snow, the studded Tire, if the snow is deep, there is no alternative other than chains. (I know snow pallets too. We are talking about normal road conditions)
The laws of physics always apply. Even tracked construction machines are stranded under very severe conditions.
There is no exact arithmetic equation for this job. The quality and depth of the abdomen is the most important. Sometimes you can go with normal tires on snow cover, sometimes you can’t go with winter tires, sometimes you can’t go with 4×4 and MT+chain.
The main factor that causes slip is the icing of the surface that the tire is in contact with.
This situation sometimes occurs when the vehicle is opening its own trail, sometimes 2. or 3. It can happen when the vehicle is passing. Sometimes it does not happen at all due to the nature of the abdomen.
I wear chains when I start to slide.
And no matter what tires you wear, enjoy the snow.
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Regards, Love
09/03/2020
Süleyman ATILGAN
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Contact: Facebook & Instagram


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Deep Water Crossing, Measures to be Taken and What Are Its Risks?

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Off-road Basic Technical Information
Dear off-road and nature enthusiast friends, we are together with another sharing of our Off-road Basic Technical Information article series. The information I will provide; These are concentrated, technical-based, lived experiences, and some of the details that will find a name in the off-road literature for the first time. With the hope that it will benefit the readers.
Today’s topic is “ Deep Water Crossing, Measures to be Taken and What Are Its Risks ?” :
Water crossing is an activity that offroad vehicle owners approach very eagerly. In fact, this enthusiasm sometimes even causes us to treat our off-road vehicles, which are land vehicles, as amphibious vehicles .
Guys, be very careful at the water crossings. Internet videos whet one’s appetite for water crossing. It’s okay if you know every aspect of what you’re doing. If you enter the water without knowing what you are doing, the situation can have very serious consequences.
I will talk about 5 basic problems in water passage.
1.) Engine water intake:
Although this situation is generally thought to be a problem if there is no snorkel in the vehicle, this is not the case. Do not be too comfortable just because there is a snorkel. My guess is that the failure of the engine due to water intake from offroad vehicles is much higher in vehicles with snorkels than in vehicles without snorkels. We can say that the reason for this is the confidence and imprudence given by the presence of the snorkel. Even though we have a snorkel, if we roughly list the possible problems we may experience;
– There is a risk despite the snorkel if it is not mounted by a competent person with the right equipment.
– If the new owner of a vehicle with a snorkel, which is only used as a visual accessory, is not aware of the situation, it means that there is no snorkel.
– Although it provides a healthy service at the beginning, it may have gotten water from the joints and gaskets over the years.
– During land use, snorkel holes or crevices may have been created but not noticed by events such as branch strikes.
– After many years under the sun, the plastic material of the snorkel may become brittle and lose strength due to the UV effect, and it may be broken or cracked without the need for an extra effect in offroad road conditions.
Some other risks related to water intake of the engine can be listed as follows.
– We have always expressed our concerns about the vehicle’s intake of water from the air intake. If the vehicle stalls, the engine will be able to take back water from the exhaust system.
– With the increasing velocity in the water, the height of the water will be higher than when it is stationary due to wave motion. In other words, when you say that water does not come to the air filter, unfortunately the water will come to the air filter due to the water rising with the wave movement.
You can see the rising water in the video.
– In addition, performance style open air filters that are not located in a closed enclosure may cause problems in this regard, even under lighter conditions. Air filters, which are in a closed enclosure and provide air suction by indirect means, are not affected by water splashes. However, the performance style of air filters without enclosure box, which is exposed, may be affected by the water splashed by the movement of the vehicle.
I won’t go into too much detail about the damage caused by the engine being flooded. I guess people who are experts on this subject will give information. Let me just say it would be very annoying. Let me even give an example, even outboard marine engines that fall into the sea become unusable if not handled properly. If even equipment designed for use at sea can be so negatively affected, we should definitely be more careful with the engines of land vehicles.
2.) Problems with electronic circuits, electrical installation and electrical equipment:
Especially in old generation vehicles, electronics is almost at zero level. Defender in the attached photos is a good example of this. 12 V DC will not cause much trouble in fresh water. But this is not the case for salt water. Salt water can cause problems even in older generation vehicles, as it not only corrodes the vehicle but also provides electricity transmission.
Avoid salt water if possible. Even 1 Mix.
In the new generation vehicles, if the electronic circuits are not specially insulated, it will definitely cause problems. The problem may not be limited to this. If water gets inside the vehicle, especially the amplifiers and compact subwoofers placed under the seats, and the speakers in the vehicle doors may be affected by water.
3.) Swimming problem:
It is the situation that is overlooked and creates the greatest danger in the water passage. If the crossing is in a pond, the problem is less, and if it is a stream crossing, the swimming problem can have fatal consequences. The vehicle may drift out of control or even turn upside down in the water. See. Picture 2. Convoy transit practices and the measures that can be taken are a separate issue on their own.
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Especially new generation vehicles with well-insulated door seals and vehicle bases will tend to float earlier. If the part of the vehicle that we call the cabin is ~ 1.70×3.25 m in size, it makes 1.7*3.25~5.5 m2. That is, if ~35 cm of the cabin remains in the water, the buoyancy force applied by the water is 5.5*0.35~2 tons, according to the Archimedes principle. If we add the volumes of other equipment such as the tire under water to this volume, we will see that the buoyancy force is actually more than we calculated above. In other words, a 2-ton vehicle floats with 35 cm of its cabin remaining in the water. A floating vehicle cannot hold onto the road either. Do not get it wrong, this height is not the height of the water, it is the height of the part of the cabin that is in the water. Cup High vehicles may not be able to swim even in 1 m water depth. In other words, if the trophy of the vehicle is 50 cm above the ground, it is expected to continue on its way without swimming to a depth of 50+35 ~ 85 cm. It is expected, but it is not always possible for him to continue on his way even if he does not swim. Even if the buoyant force does not reach the level to clear the vehicle from the ground, it may weaken the vehicle’s handling and prevent it from moving.
The basic rule of moving in deep water is to make the vehicle sink. See picture 1.
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For this, if possible, it is necessary to open the doors and allow water to enter the vehicle. If you do not get water into the vehicle, you will float. Of course, you have to be ready to face all the problems that will come with taking water by opening the doors in the vehicle in this way.
4.) Objects and formations that may pose a hazard under water:
Coarse stones or rocks that are not visible under water may not be noticed during the transition, so it may be possible to damage the vehicle. There may even be pits that will swallow the vehicle.
5.) Differential, gearbox and land gearbox water intake:
The oil chambers of all three equipment are atmospheric, that is, they do not have fully closed air-water-tight chambers.
Sometimes water may enter these equipments due to the hydrostatic pressure of the rising water, and sometimes due to the suction effect created by the volume drop caused by the sudden cooling of the heated equipment in the water.
All have ventilation holes. If the ventilation holes are not moved as high as possible in the hood with the extension hoses and the ends of the hoses are not equipped with special equipment to prevent the ingress of water, water may enter inside. ARB differential breather kit (ARB differential breather kit) is the right equipment to use for this purpose. See. Picture 3 .
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In the differential, the contact with the external environment is also tried to be limited through the axle seals. Felts, which normally would not allow water to pass through, may take in water as a result of suction resulting from sudden cooling and volume reduction if the ventilation pipes are clogged.
Sometimes klingrite cork gaskets may also be used on the covers. Since the bottom of the gasket of the cover is in contact with oil, even if it remains sealed, water may leak out because the top remains dry. Get through the water, but don’t age in the water.
Conclusion and Suggestions:
– Use your offroad vehicles with the awareness that they are not amphibious vehicles. Prefer to obtain water tools for use in water. See. Picture 4.
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– If you are not 100% sure about your snorkel, do not go into the water to a depth that will require snorkeling. Safari is a good option for your snorkeling vehicle. See. Picture 5 .

– In some sources, the water height considered as a reference for safe passage is the vehicle tire height. Knowing that this is a general recommendation; It is useful to know that the water at a height of 60% of the air inlet of the air filter box from the ground in terms of taking water into the engine will be suitable for relatively safe passage of water at heights not exceeding 20 cm from the cabin floor of the vehicle, in terms of keeping the vehicle from floating and keeping it on the road. Before making the water crossing, be sure to have information about these dimensions of your vehicle. Do not enter water deeper than these limits without a snorkel.
– If the snorkel air inlet is at a height of 180 cm or even 200 cm, but the vehicle is floating at 40+35=75 cm, you may be attaching a snorkel to a vehicle that we do not want to get water into. Seeing the entire windshield in water while driving through water does not indicate that the water level is at the level of the vehicle’s roof. If the water is at the ceiling level, the vehicle will already float, where will you pass from? This is splashing water, the splashing water cannot easily enter through the air filter, which takes air indirectly under the hood.
– In order for a vehicle with a sufficiently high air filter air intake to be affected by water, where the vehicle can walk without floating, the water block rising in front of the vehicle must be at the air intake level for a long time. The conditions for this are also clear. This can happen at certain speed levels and if you are crossing a long track. If you do not have a snorkel, try to keep your speed at a level that does not raise the water as blocks in front of you, even if the water is not very high and the course allows passage at any speed. You can determine the right speed only by experience.
– If you are stranded during the water crossing, be sure to attach the strap-like equipment that needs to be attached to the vehicle in order for other vehicles to save you, before entering the water, and place them in a way to prevent entanglement. Take this precaution at both the front and back.
– In some sources, you may come across information that you cannot pass through water that you cannot pass on foot, either by car. This is a generally accepted rule, but contradictory information. How consistent is the decision of a 165 cm tall, 65 kg Jeep Wrangler Rubicon driver with 35″ tires and 4.5″ lift, and the decision of a 190 cm tall, 120 kg Lada Niva user with 27″ tires and no lift?
– When the possibility of swimming is clearly seen, especially at the crossing of the river, connect the vehicle entering the water with a long rope to other vehicles on land and start the transition accordingly.
– In order to control the tendency of the differential to absorb water from the axle seals, which will be created by the reduced interior volume due to sudden cooling, allow it to cool a little before entering the water.
– The ignition system of gasoline engines may be sensitive to water, if necessary, apply a water-repellent spray to sensitive areas before transition.
– In the research you will do on the internet, you will come across serious warnings about the radiator fan. There are warnings to remove the fan belt depending on the fan type. This is a topic that I can comment on, but that I have not experienced. The general concern is that the fan blades, which normally rotate freely in the air, can become deformed when they start to rotate in the water and can move back and forth, causing physical damage to the radiator.
It can be a problem, especially in older generation vehicles. However, I do not think that this will be a problem in more reasonable current model vehicles. Also, you can’t remove the belt or something in vehicles with electric motor fans, without belts, maybe the power plug can be removed.
– Check the crossing route visually as much as possible, if possible, also study on foot.
– Do not enter the water without cooling your discs right after a long downhill track with continuous braking. Sudden cooling may cause deformation of the discs.
– Activate all mechanical possibilities of the vehicle before the transition, do not try to do anything halfway. The generally accepted correct transition is to drive the vehicle through the water at low speed.
– After completing the water passage, or at least after your tour is completed, drain a piece of oil from the lower plug of your differential, if there is water coming out, change your differential oil immediately by cleaning it.
– Never stop the engine of your vehicle at the water crossing, if it does, start it immediately. There may be a backflow of water from the exhaust.
– Do not change gear while shifting in manual transmission vehicles.
– If your crane is not in ip68 standards, do not make long passages through water above the level where the crane is mounted.
– Do not enter deep water unless you have a vehicle that is free from electronic circuits and electronic devices.
– It may be better not to wear your seat belt, especially in deep river crossings.
– Do not go into deep water unless you have a vehicle where the engine failure caused by the water will not hurt you. Let me state my personal preference, in order not to gain unnecessary courage, I did not have a snorkel fitted to my vehicle, nor will I.
– If you do not have a vehicle that does not sink like a stone thrown into the water and takes water immediately, do not go into deep water.
– Never go into salt water. Do not go even 1 inch deep, let alone.
– Never fight in a stream. If you do not know the rules and methods or do not have enough experience, do not embark on the adventure alone, you must have someone with you who knows what to do.
– If you need to cross quickly to stay in the water, do not enter the water without a snorkel.
– Let’s try not to prefer open performance filters, which are not in a closed enclosure, on offroad vehicles. If we are going to use it absolutely, let’s be aware that these vehicles are not used on the street and let’s put the air filter in a case that physically protects it from splashing water or short-term rising water.
Shared in attachment;
Since the vehicle seen in Picture 1 is a vehicle that sinks into the water like a stone, it did not experience any problems such as swimming and not holding the road.
The object silhouetted under water in Picture 2 is a vehicle. The photo is from the archive of our dear friend Taner Eraslan. The last condition of the vehicle, which cannot be controlled due to its tendency to float at a stream crossing, is in the photo. Our friends were still in the vehicle when the photo was taken.
Picture 3 shows a ventilation kit with up to 4 connections.
Picture 4 is a good example of the right thing to do if we love water very much.
In Picture 5, we see a snorkel whose quality we can trust.
In the short pass in the photos below, the vehicle in front has a snorkel, and the shooting vehicle does not have a snorkel, but the air filter has only been able to tolerate the effect of the water rising as a wave.
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Regards, Love
09/03/2020
Süleyman ATILGAN
`
Contact: Facebook & Instagram

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Roadside Rollover Analysis

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Off-road Basic Technical Information
Dear off-road and nature enthusiast friends, we are together with another sharing of our Offroad Basic Technical Information article series. The information I will provide; These are concentrated, technical-based, lived experiences, and some of the details that will find a name in the off-road literature for the first time. With the hope that it will benefit the readers.
Our topic today is “Roadside Rollover Analysis ” :
Before this article, I recommend you to read our article on ” Off-road and balance “.
It is a situation that we may be exposed to especially in narrow forest roads, road crossings that narrow due to tiny landslides, sometimes due to snowdrifts accumulating on the side of the road, and sometimes on roads that are split due to precipitation. While we are not likely to experience this situation, we will seek the answer to the question of under what conditions and under what conditions can we suddenly lose control and the vehicle slides towards the slope. What are the risks, what are the points to be considered?
I’ll summarize first to remind you of the basic principle of balance. As indicated in Picture 1, if the projection of point “C” exceeds point “O”, tipping occurs. That point is where the vehicle is based. Sometimes it can be the outermost part of the tire, sometimes the axle sleeve, sometimes the chassis.
If there is no bump on the side of the road to prevent us from slipping or there is no tree to lean on, this situation poses a great danger.
Let me also verbally convey the situations that I want to express in pictures.
When the vehicle tends to slant down a steep slope, the axles, the lowest part of the bottom of the vehicle, will rest against the corner of the slope. But can this stamina hold the vehicle safely? The problem is at this point.
As can be seen from the drawings, if ;
If your tires are big and your vehicle is high, there is a high probability of overturning.
If your tires are small and your vehicle is low, your vehicle may not topple over, however, if the vehicle weight is high, it may continue to slide and come to a tipping position even though it has endured.
If your vehicle is narrow, even if your tires are small, your vehicle may overturn.
If the vertical line passing through the center of gravity of the vehicles exceeds the vertical line of the corner where the vehicle is leaning, the vehicle will overturn.
If the roll-over went from tilting to a somersault, the equipment we call a roll bar becomes vital. It is a mandatory equipment to have, especially in vehicles that participate in professional offroad events.
When we roughly scan the vehicles we use in the field, the vehicles that offer roll bar equipment as standard, the JEEP wrangler model produced by the JEEP group especially for use in the field will come to the fore. If we are to pronounce the more recent versions with their names; JEEP WRANGLER YJ, JEEP WRANGLER TJ, JEEP WRANGLER RUBICON JK, JEEP WRANGLER RUBICON JL are vehicles that have been and are being sold to the market with a roll bar as standard.
Conclusion:
Try not to put your vehicle in such a position. If the situation is unavoidable, also know this;
The bigger your tires are, the more likely you are to tip over.
The higher the vehicle is, the more likely you are to roll over,
The narrower the vehicle, the more likely you are to tip over.
The heavier the vehicle, the more likely you are to roll over.
Regards, Love
07/03/2020



 

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Is the steep ascent with the vehicle more dangerous or the steep descent more dangerous?

“Whether with your private or off-road vehicle, do you think the steep ascent is more dangerous, or is it more dangerous to go down a steep ramp ?”

: Before this article, I recommend you to read our article on “ Off-road and balance ”.

Who knows, knows. We bring up the issue again for those who do not know and are not sure. Otherwise, these issues were discussed 30 years ago.

What are the risks;

What are the Risks of Off Road Vehicles on Steep Ramps?

Straight somersault, backflip, side somersault .

Flat somersault:

This can happen if the descent is very steep, if the vehicle is short chassis, if you are descending with excessive braking. To get rid of it, you have to gasp and go. If the conditions are not suitable, your gassing may pose other risks. You may not be able to do this on a long steep ramp. On a short ramp descent, you can gas up and straighten yourself out.
My suggestion is not to make long steep descents with short chassis off road vehicles.

Backflip :


If the ascent is too steep, if the vehicle is strong enough, if the tires are holding enough road, the vehicle will tend to overturn. This situation occurs mostly in short chassis vehicles. In order to escape, it is necessary to put the reverse gear in a very short time and stabilize the vehicle again.
My suggestion is not to make very steep climbs with short chassis off road vehicles.

Side somersault:


It occurs when the control is more difficult and the direction of the vehicle cannot be controlled due to both piloting and ground conditions. We can evaluate it in 3 categories.

What are the Risks of somersaults on steep descents and ascents with an Off Road Vehicle? Important Considerations for 4×4 Vehicles on Steep Ramps

Stupid sideflip:
If you try to maneuver to stop and turn on a steep slope, you may somersault if the slope is dangerous. The only way to avoid this situation is to be smart while driving off-road.

Conclusion and recommendations:
The steep ascent is definitely more dangerous. The danger is that if the ascent is not achievable, lowering the vehicle back down the ramp is difficult and more uncontrollable.
If possible, complete the steep ascent in one go.
On the descent, try to lower the vehicle by walking without slipping. If the vehicle is walking, it can be controlled by the steering wheel. If possible, start at low revs and in a low gear, try to control with engine compression instead of braking, in this case be aware that you may need to step on the gas a little. The brake can cause the tires to lock and slip and lose control.

Side somersault on exit:
If the vehicle stays on the ramp due to inability to hold the road, piling up, excitement, etc., and if it cannot maintain its position when stopped and slides uncontrollably, a side roll may occur. When the vehicle is sliding backwards uncontrollably, the vehicle should be tried to go downhill by walking rather than sliding, and the steering wheel should be used carefully to ensure this. The difficulty is that if you do not know the direction of the steering wheel at the moment of falling into this position, it may be too late until you find the right direction when you back the car. Until you understand the situation, you can reach the point of no return. In addition, this process, which must be done with sudden decisions and correctly, is easier when going forward, but not so easy when going backwards.


My suggestion is not to make long steep descents with short chassis vehicles. Backflip :
If the ascent is too steep, if the vehicle is strong enough, if the tires are holding enough road, the vehicle will tend to overturn. This situation occurs mostly in short chassis vehicles. In order to escape, it is necessary to put the reverse gear in a very short time and stabilize the vehicle again.
My suggestion is not to make very steep ascents with short chassis vehicles. Side somersault:
It occurs when the control is more difficult and the direction of the vehicle cannot be controlled due to both piloting and ground conditions. We can evaluate it in 3 categories.

Don’t drive loose.
Make sure to set your eyes on a route for gassing, just in case you need it on the descents.
Especially on the steep Ascent, do not try to take precautions halfway. Activate all mechanical possibilities of the vehicle before the start of the ascent. Don’t try to do anything halfway that will help you keep the exit uninterrupted, just start over.
Never perform a turning maneuver on a ramp.
Do not make very steep ascents or descents with short chassis vehicles. Regards, Love

Side somersault on descent:
If the tires do not hold the road and the tire rotation speed cannot adapt to the vehicle speed due to braking or engine braking, the vehicle may roll over because you cannot control it. To avoid this situation, it is necessary to accelerate the vehicle to steerable speed with the steering wheel. That is, up to the speed at which the vehicle can go without slipping on the tires. You have to control it by driving the vehicle. Otherwise, your job is up to Allah. I would like to touch on the subject of skating a little here. The rule of thumb is, if there is skid, there is no grip. Skating occurs in two different ways as positive and negative skid. There is a synchronization between the rotation speed of the tires and the walking speed of the vehicle. If you step on the gas suddenly on loose ground, this balance is disturbed and the vehicle will spin positively. If you reduce the tire rotation speed with both engine braking and normal braking on a slippery surface while the vehicle is traveling at a relatively high speed, this synchronization will be broken again and negative skid will be experienced. It is common when descending at low rpm and low gear, on loose or slippery steep surfaces.

05/03/2020 Süleyman Atılgan Contact: Facebook & Instagram

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Where is the balance off-road? Off-Road Vehicles What is balance and its importance?

Our topic today is “Where is the balance in off-road and what is its importance in off-road vehicles? ” : Our topic today is not about an off road equipment, vehicle equipment or mechanism, but a concept. “Balance” .

With its definition within the framework of basic physics rules, ” an object is considered to be in equilibrium if it is stationary or moving at a constant speed “.

So, where is the balance in off-road driving and what is its importance?

If you don’t see off-road as a hobby consisting of driving off road on a dirt road, the balance is everywhere and in every moment of off-road . 4×4 vehicle tilting, off road vehicle overturning , pickup truck overturning etc., which occur in the videos you watch or in situations you actually witness, are all events that occur because the balance conditions cannot be met . Therefore, it is useful to observe the balance conditions while doing off-road . Balance conditions in Off Road are obvious in static and dynamic situations, but they are slightly different from each other.

How to Maintain Balance in an Off Road Vehicle in a Static Condition? ;

Connect the contact points of the all-terrain vehicle, if 4 tires are on the ground it is a quadrilateral, if 3 tires are on the ground it is a triangle. See. Picture 1 If the projection of the vehicle’s center of gravity goes outside this triangle or quadrilateral, the vehicle will overturn. See. Picture 2

The rollover conditions of 4×4 vehicles can be perceived as very difficult when the static situation is evaluated alone. However, static conditions are only available when the vehicle is stationary. Due to the fact that the vehicle is in constant motion ; Dynamic effects can also be called effects that cause variable loss of balance under different conditions due to the effects of momentum, centrifugal force, suspension system and rotational effects from the engine to the wheels, and sometimes the braking effect , etc. Since these effects are all mass-related effects , we can think of them as acting from the center of gravity of the vehicle. To summarize in a simple way; With a raised vehicle and a vehicle with items in the roof basket , there is no need for off-road, if we enter the corners quickly, we can overturn our vehicle, or with the same vehicle, our vehicle can overturn on a ramp where a normal vehicle can easily travel in a horizontal position . If we can’t adjust the speed of the vehicle correctly in a bumpy ride where we can walk safely at low speeds, we may jump and overturn with the effect of the off road suspension system . On a very steep descent, if we do not adjust the speed of the vehicle correctly and we apply the brakes more than necessary, the vehicle may roll over . This trend will be more on short chassis vehicles . On a very steep ascent, if we press the gas of the vehicle more than necessary, the turning effect from the axles can cause the nose of the vehicle to lift and backflip . This trend will again be more in short chassis vehicles. If we cannot predict the balance conditions of the vehicles we winch or try to save with the stap under the forces we will apply, we may cause the vehicle to overturn .

Conclusion : Let’s not forget the fact that vehicles used for off-road are higher than normal vehicles, and this causes balance loss more easily. Best regards, 05/03/2020 Süleyman Atılgan Contact: Facebook & Instagram

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What is the Differential for 4×4 Off-Road Vehicles? What is the Great Importance of Differential?

Off-road and differential : Differential is one of the most important elements of offroad. The answer to why a vehicle we think is a 4×4 is actually a 4×1 is hidden here. Everyone who goes to the field should have this basic knowledge and interpret what he can or cannot do with the land car under what conditions. None of the sentences are quotes. Some of the information is original and only reasoning that belongs to this article. So it’s not anywhere else. Our aim is to explain the differential with a philosophical approach. The difference between differentials with different mechanics or their own details is not very important to us. The important thing is the purpose of use and the service they provide.

What is a differential? How does the differential work?

What is a differential and why is a differential needed? It is the general name of the mechanism that provides power transfer to the tires by tolerating the lap difference between the wheels during differential driving . The differential does not make the wheels turn at different or the same speed, it just allows it. When a vehicle is cornering, all 4 wheels go on different tracks. Because each track has a different radius, all wheels rotate at different linear speeds. We can see this in the first picture. If there is no internal mechanism to tolerate this situation, the wheels will try to tolerate the lap difference with short skids. These skids force the vehicle’s drivetrain unnecessarily and cause the tires to wear more than normal. If the driveline is not strong enough, it can also cause axle cuts or similar breaks.

What is the main working principle of the differential?

How does the differential work? Before reading my answer to the question, I will recommend you to watch these two videos.

As explained in the videos and understood from the second picture, the joint called the U-joint (universal joint) at the end of the shaft connects the shaft to the bevel shaft and drives it. As a result, in the differential the chainring starts to rotate . In the differential housing, 4 pieces of axle gears, 2 each 2 in opposite directions, and known as idler gear-cross gear-spider gears etc. There are gears . In the differential, the housing is fixedly attached to the mirror. When driven from the shaft, the bevel rotates, the beveled chuck rotates, the chamfer rotates the housing, the idler gears actuate the axle gears by pushing, not by turning . Pay attention here . By pushing, not turning. This activates both axles. In other words, the rotational movement transferred from the gearbox to the differential and from there to the axles is not a uniform gear movement as it is known. If for some reason the axles feel the need to make different turns, then the idler gears respond to this need for different turns by not only pushing but also turning. This is the main operating principle of the most well-known differential type. It is not important to us what the details of the differential types with different mechanics are. The important thing is that they all provide the same service. Here’s the answer to why we couldn’t keep moving forward when the vehicle fell diagonally. Motor power is like electric current, where the resistance is less, it escapes to that side. So if a wheel loses traction, it absorbs all the power of the engine and continues to idle. In the meantime, the vehicle struggles and stalls because there is no power going to the wheel that is on the ground, which can provide traction. Although this situation usually occurs in the position we call diagonal, there may also be situations where two wheels on the same side have simultaneous gripping problems.

What are the differential types?

When you do research on the subject on the internet, you will see the following differential types in both domestic and foreign sources.

1-) Open Differential Type (Open Differential)

2-) Locked Differential

3-) Viscous Limited Slip Differential Type (Viscous Limited Slip Differential)

4-) Mechanical or Electrically Controlled Limited Slip Differential Type (Mechanical Clutch-Type LSD, also eLSD)

5-) Torsen & Helical Differential

6-) Torque Vectoring Differential

BLA bla. There are conceptual contradictions in these classifications. Therefore, I will touch on the subject with a different approach without depending on these classifications. As I said, we will have a philosophical approach in this article. Above I explained what a differential is and what we need in off road vehicles. That’s why we’re just going to call the differential differential throughout this article, taking into account the basic function of the off-road differential , regardless of the differences in its working principle.

What is a locked differential?

A locked differential is a differential whose turn difference tolerance capability between the right and left axle is reduced or completely eliminated , depending on the method used to lock it. In fact, the differential types given above are somewhat of a variation on these key method differences. That’s why I’m going to call the lock a lock. After all , when you say locked differential, you understand, as I said above, “differential with reduced or completely eliminated lap difference tolerance between right and left axles” . The master thesis is derived from the lock types and working principles. That’s why I won’t go into too much detail and I will examine it in 4 main categories. Behaviors in these categories can be achieved with different methods and mechanical structures. This detail is not very important to us. The service we receive and the result are important to us.

Differential Systems Providing Full Locking in the Vehicle

These differential systems provide a complete locking in the vehicle mechanically and transfer half of the power from the pinion gear to the right axle and half to the left axle. The lock that interests us more is the mechanical lock . What is a mechanical lock? The basic principle of the mechanical lock in the vehicle is to prevent the axle gears from turning in different turns . This is easily achieved by preventing free rotation of the idler gears. In other words, whatever your left axis turns, your right axis will turn the same. That’s why we never activate such locks on non-slippery surfaces in order not to force the vehicle mechanics unnecessarily in corners that need a lap difference.

Differential Systems Providing Partial Locking in the Vehicle i

The most widely known is the LSD differential. (Limited Slip Differential). These 4×4 differential systems serve similarly to full locking differentials, but they can never transmit power equally to the right and left axles. Or, in the differential systems of some vehicles, the wheel must be on the ground in order for the locking mechanism to function. Therefore, they are more inefficient than fully locked differential systems . In fact, due to the mechanical wear experienced over time, its presence or absence is incomprehensible in old cars.

Differential Systems That Can Transfer Different Power To Right And Left Axles

VLSD (Viscous Limited Slip Differential) , e-LSD is one of this group of differentials. These systems have different power transfer capabilities between the right and left axles depending on the need. In some systems, the system does not activate until the difference in lap between the axles occurs. There are heating problems in conditions where they are switched on and off very often. In addition, mechanisms have a lifespan, too frequent switching on and off shortens this life.

Differential Systems utilizing the Vehicle Brake Mechanism

What is EDL? (electronic diffrential lock) EDL-based traction support systems. We can include all electronic traction control systems in this group. Each brand gives a different name to EDL-based systems, but the basic working principle is this. Off-road vehicles with EDL roof traction support system have sensors that count laps on the axle. These are ABS sensors. Although their main task is to serve in the ABS braking system, it is the basic data provider of many systems such as EDL, ASR, ESP etc. The vehicle detects the lap difference on the right and left axles through ABS sensors. If the difference is outside the prescribed tolerances, it automatically brakes the wheel with the excess lap. Therefore, the engine power does not flow senselessly to the idle wheel, but to the traction wheel, and the vehicle can continue walking.. Although this system seems successful , it is not efficient under heavy usage conditions . It’s like pressing the accelerator while pressing the brake at the same time. It may cause problems such as abrasion, heating, scratching etc. on discs and pads. Let alone the new generation, the land is located in almost all of the passenger cars with different names.

If we look at the lock situation collectively; If you do not have a middle lock and differential locks in your off-road vehicle: Your vehicle is 4×1 . If one wheel of your 4×4 off road vehicle loses traction, that wheel will absorb all the power of the engine and you will not be able to drive your vehicle .

If you have a Middle Lock but no differential locks : Your vehicle is 4×2. If the front two wheels or the rear two wheels are holding the road, you can continue driving. If one of the front and rear wheels (no matter left or right) loses traction at the same time, you will not be able to continue driving. If there is a middle lock and a rear lock: Your vehicle is 4×3. As long as the two rear wheels and a front wheel do not lose traction at the same time, you can continue your ride. If the rear two wheels lose traction, all power flows to the front shaft. If a front wheel also loses traction, this time all power goes to the one wheel that loses traction at the front. This is a difficult situation to deal with. If there is a middle lock and front-rear lock: Your vehicle is a 4×4. Unless all four wheels lose traction, you’re not stuck on the road.

Off road differential options depending on your preference that you need to apply in order to modify the 4×4 off road vehicle, which has the ability to go anywhere in difficult terrain conditions.

Conclusion and Suggestions: There are many criteria for the selection of the off-road car. In my opinion, the most decisive of these criteria is personal taste. Therefore, there is no arithmetic such as 2*2=4 for this job. My advice, do not buy a vehicle that does not have a middle lock. If possible, get at least a vehicle that originally had a rear lock, or one that could be rear-locked without much expense. If you don’t have one, put the rear lock at the beginning of the modifications you intend to make to the vehicle you bought. Regards, Love.

02.03.2020 Süleyman Atılgan Contact: Facebook & Instagram

You can view other articles professionally prepared by Süleyman Atılgan, which include off-road basic techniques and off-road driving advice, below.

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What Should We Consider When Choosing an Off-Road Vehicle?

Our first topic is; I will go to the land, should I be careful when choosing a 4×4 vehicle ?

In my opinion, the major factor for off road vehicle selection is personal taste. The landlord is in love with his 4×4 vehicle . If the lander’s eyes weren’t blinded by this love, there wouldn’t be such a variety of off-road vehicles . Everyone would say “this is the right thing to do” and only one off- road vehicle was agreed upon and only that car was used.

Now let’s come to the factors that affect a successful off-road driving. Each of these factors are issues that need to be examined on their own. As a matter of fact, I will talk about all of them in detail in the ongoing process. Here, I will only mention it as the main topic and give some personal preferences and general opinions.

– 4×4 Traction system :

The vehicle must be a 4×4 . Sometimes there is a desire to go out into the field with 4×2 double cabins. While 4×2 double cabins that are sufficiently high from the ground can serve on dirt road driving, one should not expect more.

Another question is 4×4 or AWD?

Rather than the technical differences between them, I will address the philosophical difference between the two in a longer article. Although land users generally tend to use 4×4 vehicles, I have actually witnessed in the trips I participated in that AWD vehicles are more successful than many 4x4s within the vehicle’s physical capacities. However, if we are going to do off-road, our preference should be 4×4.

– Land Transmission (transfer case)

All-terrain vehicle, in addition to being a 4×4, must be able to serve with a land transmission locked ( middle lock ). If there is no middle lock, it means that you start the land match with a 2-0 defeat. Although it is very rare, some vehicles may not have a middle lock.

What should we pay attention to in the Selection of Off-Road Transmission?

There must be a low rpm option, which we know as Low . In most cross-country transmissions, the center lock cannot be activated in 4H (high speed 4WD) mode. In order to activate the middle lock, you need to switch to 4L (low speed 4WD) mode. No matter how much you press the gas in 4L, there may be more difficult passes or unsuccessful rides on some tracks, since the vehicle is not as agile as in 4H. Unfortunately, very few vehicles offer the middle lock option on the 4H.

I repeat, when choosing off-road vehicles , do not think about vehicles that do not have a middle lock.

Off-Road Araçlar da “Orta Kilit” ve Önemi Nedir ?

– Differential locks :
I can’t say for sure that there are differential locks. Because there are not many vehicle options with both front and rear locks. If we say this is it, we will limit the options for 4×4 vehicle selection . However, if possible, at least try to choose a vehicle that offers the rear lock as standard. Or try to choose a tool that can be done later without the cost and hassle of locking.

4×4 Off-Road Araçlar da Diferansiyel ne işe yarar ? Diferansiyelin Büyük Önemi Nedir ?

– Off-Road Tire Selection for 4×4 Off-Road Vehicles
HT-AT-MT-XT comes to mind when it comes to off road tires . The aspect I will mention is the size of the off-road tires rather than the pattern. The bigger the tire of your off-road vehicle, the greater your ability to overcome obstacles with your off-road vehicle. In addition , the only reasonable way to increase the ground clearance of the off road differential watermelon in solid axle off-road vehicles is to use large MT or Extreme off road tires . Using portal axle , which is another method, is a very expensive solution. Try not to prefer off-road vehicles that do not allow you to expand the tire at a reasonable level due to both mechanical constraints and physical constraints in the area where the tire is located. In order for an off road tire to be enlarged, it is not enough just to physically fit inside the fender. All elements in the powertrain of the vehicle must be strong enough to withstand the increased effects due to the growing tire. Frequent axle cuts of 4×4 vehicles with large off-road tires are caused by ignoring this and growing tires.

Lastik Büyütme ve Offroad Sürüşüne Etkileri Nelerdir ?

– Height :
All-terrain vehicle. The cup should be as high off the ground as possible. Do not prefer 4×4 vehicles that are too close to the ground than the original. Because off-road vehicles do not have an unlimited ability to rise.

– Angles :
The higher the approach – departure – snow angle, the better the off-road performance in different conditions. If the nose of the vehicle is too long, the approach angle will be low. We can give Toyota Hilux as an example. This is the reason why some off-road vehicles leave a front bumper on off-road trips. Examine the vehicle’s front bumper structure well. No plastic hanging down. On 4×4 vehicles with a very long stern, the departure angle is very low. Almost all double cabin pickup trucks have this problem. That’s why strict landlord double-cab owners cut and shorten the body of the vehicle. Abdominal angle is related to both cup height and wheelbase. Short chassis vehicles are very advantageous in this respect.

– Axle and suspension system :
Off-road vehicles usually have solid axles, but some also have IFS (independent front suspension). Almost all double cabins are IFS. There are situations where both are advantageous and disadvantageous depending on the obstacle position. In general, solid axle is more preferred in the field due to both higher elevation possibilities and greater articulation capability . By the way, all trophy trucks are independent suspension. However, there is a gap between them and the 4×4 off-road vehicles that are the subject of our discussion.

One of the issues discussed in the suspension system is spring or spring systems? Choosing an off road vehicle sometimes does not allow you to make a choice in this regard. For example, if you are going to choose a double cabin vehicle, you will probably have very few options other than scissors. But the general trend is spring + shock absorber systems rather than scissors off road vehicles. I will also touch on shock absorber systems, which are the basic instruments of articulation, in a long article with numerical examples.

– Articulation ability :
The basic requirement for driving off-road is that the tires are in contact with the road. If the articulation ability is low, the vehicle will fall diagonally very easily, and if there is no mechanical lock or electronic supporting systems that will prevent the idle wheels from absorbing the power of the engine, you will not be able to move forward. Naturally, this capability is greater in large vehicles.

What is the effect of articulation on handling? What is useful articulation?

Artikülasyon ‘un yol tutuşa etkisi nedir? Faydalı artikülasyon nedir ?

– Wheelbase :
When choosing a 4×4 vehicle, you should pay attention to the wheelbase. Being a long or short chassis has its own advantages and disadvantages. However, I do not like short chassis off-road vehicles because I keep general driving safety above all else. Short chassis vehicles are more risky on steep descents and ascents. On the other hand, long chassis is disadvantageous, while short chassis vehicles are very advantageous.

– Track width :
The greater the distance between two tires on the same axle, the greater the safety of the vehicle on side slopes. So be a little more cautious on very narrow 4×4 vehicles.

– Luggage Capacity :
The landlord has a lot of stuff. In addition to the fixed belongings of the car, there will be a lot of additional items that you take with you for the trip. Short chassis off-road vehicles are very disadvantageous in this regard. Double cabins are very advantageous. However, they pay the price of this advantage with a bad distance angle.

– Engine – power – torque :
A powerful engine is generally better. However, if you take the vehicle at low speed, the power of the engine should not be of great importance. Do not prefer if the off-road vehicle is piling up even though it is low-circuit. The answer to the question of high horsepower or high torque can be found in hundreds of places on the web. Let me give you the brief information, high horsepower is required for a high top speed and agile 4×4, high torque is required for high traction power. If you don’t drive in Rally format off-road, you should prefer torque rather than horsepower.

– Gearbox :
It is between manual and automatic options. Automatic transmission is one step ahead in terms of driving comfort and ease. But he also has problems. If it is used for a long time in very harsh conditions, the transmission oil will overheat and you need to rest the vehicle. You can also strip the pads in manual gear. In some conditions, manual transmission can provide more controlled driving. My personal preference is for 4×4 off-road vehicles with automatic transmission.

– Fuel consumption :
Needless to say, it’s okay to have a scarce one. However, it will not be possible to burn even a low-burning 4×4, especially in the field, and the power we desire must have a price.

– Fuel type :
My personal preference is for diesel, though not for much thoughtful reason. Diesel is less dangerous as it is not very flammable. If gasoline is left in the open, even its vapor can cause a fire. Apart from that, water passage is easier in diesel. Gasoline off-road vehicles are more agile. In general, let’s not forget that 4×4 vehicles that give higher horsepower are gasoline, while vehicles that give higher torque are diesel.

– Supply of spare parts :
Get spare parts cheap if possible. However, 4×4 selection should not be made just because the spare part is cheap.
The price is meaningless if the spare part is cheap or expensive, not available. Choose an off-road vehicle with spare parts available. Think about it, you are waiting for the part to come from abroad for 3 months. It also turns out to be incompatible, you wait another 3 months. The vehicle spends half the year lying down.

– Master who understands :
If your vehicle is a vehicle whose mechanics or electronics are very unknown, it shouldn’t be a problem until a problem arises. But when you start having problems and can’t find a solution to them, you curse the car and life. Try to choose off-road vehicles with enough knowledge and experience of our masters.

– Cost and age :
You will have to choose one of the old – cheap – many failures or new – expensive – less failure options. This is a generalization of course. Even if it is very old, a well-maintained off-road vehicle will not upset you. Before buying a 4×4 vehicle, make sure to take advantage of the appraisal service of someone who understands the language of that vehicle.

– Experience :
Respect the opinions of friends who have been channeled into a single off-road vehicle, but also take into account the opinions of our friends who have experienced 4×4 vehicle diversity.

All of these main topics are topics that can be written on their own for very long articles. In the coming days, I will continue to share detailed posts on both these issues and many other topics.

Regards, Love.

02.03.2020 Süleyman Atılgan Contact: Facebook & Instagram

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What is the “Middle Lock” and Its Importance in Off-Road Vehicles?

Our topic today is “Off Road Intermediate Lock”

From the comments made to my article in which I examined the relationship between off-road and differential , I realized that there is a conceptual confusion about the differential middle lock . I will try to make this matter as clear as possible.

4×4 systems are not systems that send equal power to all tires simultaneously . Motor power is like electric current. That is, there is a tendency to flow in the direction of the least resistance. The part that produces the power is the engine (engine) , the part that transfers it is the transmission , the part that distributes it in the 1st stage is the off road transmission case (transfer case), the off road accessory that distributes it in the 2nd stage is the differentials .

Let us note that there is an order based on producing – transferring – distributing . Off-road transmission and differentials are the most important elements in the vehicle’s walking or staying power.

If there is no limiting factor for the division of power at these power distribution points, it will determine how much of the power goes to which side and how much resistance is on which side. Then let’s first determine what is the element that creates the resistance, which will also answer the question of what is off-road . The main factor that creates resistance is the tire’s road holding ability. If the tire can hold the road firmly, it will show high resistance. If the tire cannot hold the road, it will show low resistance or even no resistance. That differential will also absorb all the power coming on the land gearbox to which it is connected with the shaft. This means that in a vehicle that is running without any lock activated, the loss of traction of even one wheel will make it impossible for the vehicle to move. This is a 4×1 situation and all the power can be transferred to only one wheel, and the vehicle cannot walk because that wheel cannot hold the road. In order to eliminate this situation, mechanisms that limit the division of power at the power distribution points (terrain transmission and differentials), which we call “locks”, have been developed. in the power distribution stage, that is, in the field gearbox “middle lock” refers to the one in the second power distribution stage, i.e. the differential “differential lock” When the middle lock is engaged, 50% of the engine power will be transferred to the front and 50% to the rear automatically. In this case, if the front two wheels or the rear two wheels can provide traction, the vehicle will be able to continue walking. In other words, we can roughly call this situation a 4×2 situation. However, if each of the front and rear wheels lose traction, this time the front wheel that loses 50% of all the power that comes to the front, the rear wheel that loses all of the 50% of the power that comes to the rear will absorb 100% of the engine power. it will still flow to the wheels that have lost traction. This is what we usually refer to as crossover. It rarely occurs on tires on the same side. When this situation occurs, the rear lock will be activated. When the rear lock is engaged, each of the rear wheels will equally share 25% of the engine power. And if the traction provided by the wheel is sufficient to drive the vehicle, the vehicle will walk. We can roughly call this situation the 4×3 situation. The next stage is when the front lock is also activated and the vehicle is a real 4×4. Since all locks are engaged, 25% of the engine power will be transferred to all wheels simultaneously. And if even one wheel is in a position to hold the road, the vehicle will be able to walk. We call this situation roughly being a real 4×4. The center lock function can be performed using different methods from brand to brand or model to model. Detailed information is available for different applications on the internet. Again, I will make my own classification independent of the literature.

1-) Power distribution systems with a differential mechanism in the middle: In these systems, power is distributed to the front shaft and rear shaft with a structure similar to the classical differential we know. In the open position, power is transferred to the front and rear shafts, while differential rotation of the shafts is not limited. When locked, this power distribution takes place with a fixed shaft rotation to the front and back. As far as I know, there is this type of transmission in Defender. See. picture 1

2-) The systems that transmit constant power to the land transmission: In these systems, the land transmission is in itself; 2H: High speed two wheel drive4H: High speed four wheel drive unlocked4HLc : High speed four wheel locked 4LLc : Low speed four wheel locked mode. Not all of these modes are available on all terrain transmissions. Since they are systems that provide a fully mechanical power distribution and transmission, both equal power and equal turns are provided to the front and rear shaft in 4HLc and 4LLc modes. This is one of the main differences between AWD and 4×4 vehicles. Philosophically, I will talk about the difference between AWD and 4×4 in a future article. See. Picture 2,3

Picture 2
Picture 3

3-) Cross-country transmission systems with variable power transmission: These systems are systems that can do more than just uniform power transmission with open or locked logic. They are systems that can decide how much power will be transferred to which shaft by processing the information (ABS, speed, steering angle, traction force, lateral acceleration rate, etc.) It can even transfer almost all of the power coming from the engine to a single tire, with systems that provide similar service in differentials. These systems are generally seen with different names in AWD vehicles rather than the real 4×4’s we are used to seeing in the field. See. Picture 4.5

  • Picture 4
  • Picture 5

All of the 2H, 4H, 4HLc, 4LLc traction modes that I mentioned above are not available in all terrain transmissions. For example, Jeep Cherokee KJ has all 2H, 4H, 4HLc, 4LLc modes. (This vehicle can be used 4×2 on asphalt, 4×4 can be used both on asphalt and off-road Jeep Grand Cherokee WJ has only 4H, 4LLc modes. 4LLc modes are available. is that it causes it to spin in different rounds. This is not the case. In normal road conditions, although a cross country transmission transmits 60% power to the rear shaft and 40% to the front shaft, the shafts will rotate in the same revolution. The ratio of the transmitted power and the amount of rotation of the shaft are different concepts . When the middle lock is on, the cause of the squeezing when cornering the vehicle is not the power transferred to the front and the rear at a different rate, but the inability to meet the different lap tendencies of the tires due to the lock. This may lead to premature wear and even breakage. Therefore, the basic rule is ; middle lock should only be activated in off-road conditions and on slippery surfaces.One of the factors that may affect the vehicle selection decision is the situation in which the middle lock of the off-road vehicles can be activated. For example, if the middle lock can only be activated when the middle lock is activated at low level, inadequacies may occur in certain conditions on the field. The most important parameter of a successful off-road driving is not only the middle lock and differential locks. Driving techniques depending on the track conditions are also important. For example, on tracks where the ground is very slippery with a short transition, if the slippery area is not entered quickly enough, the vehicle may remain despite all the locks. A vehicle without any locks can come and go at the appropriate speed. Or, if we put the vehicle on Low to activate the middle lock on a track where we can walk and pass by pressing the gas, no matter how much we press the gas, the tires will not be able to reach the speed to get us out of where we are. Conclusion : A vehicle that can be activated with the middle lock function in 4HLc, ie high speed 4×4, will be more desirable in the field.

Best Regards, 03/03/2020 Süleyman AtılganContact: Facebook & Instagram

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Offroad da Pilotaj ve önemi nedir, nasıl geliştirilir ?

Offroad anlatımları referans video 007 - Pilotaj

Bu günkü konumuz “Offroad ‘da Pilotaj”:

Geçersin iyi pilotaj, kalırsın kötü pilotaj.  Peki bir yafta olmanın ötesinde nedir bu pilotaj?

Sözlük anlamı ile bu soruya cevap verecek olur isek ; “bir hava taşıtını yönetme işi” olarak cevap verebiliriz.

Gördüğünüz gibi bizimle ilgili bir şey değilmiş aslında. Ancak biz yine sözlük anlamına hapsolmayıp, kendi hayatımızın içindeki anlamını irdeleyeceğiz.

Offroad ‘da pilotaj ; “bir arazi aracını sevk ve idare etmek” anlamında kullanılmaktadır.

Esasen offroad ‘da başarılı sürüşün şartları bellidir. Lastikler çekiş sağlayabiliyorsa yürürsün sağlayamıyorsa yürüyemezsin. Peki bu kadar basit ve tekdüze mi  her şey ?

Tabi ki bu kadar tekdüze ve basit değil.

Aracın fiziksel özellikleri (Yerden yükseklik, lastik ebat desen genişliği/darlığı, dingil mesafesi, iz genişliği, artikülasyon kabiliyeti),  aracın mekanik özellikleri (çekiş sistemi, orta kilit mevcudiyeti, diferansiyel kilitlerinin mevcudiyeti, motor gücü, güç akış hattında yer alan parçaların mukavemeti) başarılı sürüşün majör etkenleridir.

Off-road Temel Teknik Bilgiler

Sevgili off-road ve doğa tutkunu arkadaşlar, Off-road Temel Teknik Bilgiler yazı dizimizin bir paylaşımı ile daha birlikteyiz. Vereceğim bilgiler; konsantre, teknik temele dayalı, yaşanmış tecrübeleri içeren ve bazıları off-road literatüründe ilk kez isim bulacak detayları içeren paylaşımlardır. Okuyuculara fayda sağlaması dileği ile.

Başarılı  pilotaj ; araca mekanik anlamda zarar vermeden, sürüş güvenliğini zafiyete uğratmadan,  aracın hangi mekanik imkanları devrede iken sürüş yapılması gerektiğine, lastiklerin hangi izden geçeceğine ve geçişin ne hızda olacağına doğru karar verebilme kabiliyetidir .

Bazen gaza basarsınız geçersiniz, bazen ayağınızı gazdan biraz çekmek geçmenize imkan verir. Bazen lastiği öyle bir ize basarsınız ki, düz yolda gider gibi araç kabininde hiçbir şey hissetmeden gidersiniz, bazen takla atacağım sanırsınız.

Pilotaj ; insanda bir kabiliyet olarak var olabileceği gibi, bilgi öğrenerek ve idman yaparak geliştirilebilecek bir yetidir aynı zamanda.

Somut örnekler ile durumu izah edecek olur isek; bir parkur hayal edin, biraz uzun olsun. Parkurun belli bir bölgesinde araç yol tutuşunun mümkün olmadığını düşünelim. Araç yol tutmuyor ise, o bölgeye girildiğinde, eğer yokuş aşağı değil ise, yani yerçekimi bizden yana değil ise, araç hız kaybetmeye başlayacak ve bir yerde mahsur kalacaktır. Sayısal örnek verecek olur isek; 10 km/h hızla girdiğim parkurda, parkurun geçiş güçlüğü olan bir bölgesinde, lastiklerim yol tutuş kabiliyetini kaybetmiş ve o bölgeyi geçemeden hızım 0 km/h ‘e düşer ise parkurda mahsur kalırım. Şimdi aynı parkurda, sürüş güvenliğimi tehlikeye atmadan, parkurun geçişe müsaade etmediği bölgesine 10 km/h yerine 20 km/h hızla girersem, biraz hız kaybetsem de normal yürüyüp geçip gidebilirim.

İşte başarılı pilotaj; parkurun bu bölgesinde sürüş güvenliğini de dikkate alarak, hızımın ne olması gerektiğine doğru karar verebilme kabiliyetidir.

Linkte bu durumun bir örneğini izleyebilirsiniz.

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Yıllardır parkur idmanı yaparım, aynı parkurlardan tekrar tekrar farklı sürüş parametreleri ile geçerim, ne yapınca ne oluyor ya da olmuyor deneyerek gözlemlerim.

Bir parkur anımı anlatmak isterim. Derin bir yarık ve dik bir iniş kombinasyonu, lastiği doğru izden yürütmenin çok önemli olduğu bir iniş ve aynı yerden çıkış. İnişte sadece lastiği nereye basacağınıza dikkat ederken, çıkarken durum daha karmaşık oluyor. İlk zamanlarda risk almama adına, aracın bütün mekanik imkânlarını devreye alarak çıkışlarımı gerçekleştirdim. Sonra önce ön kilidi devreden çıkartarak denemeler yaptım, sonra arka kilidi de devreden çıkartarak denemelerim oldu. Sonra 4H orta kilitli olarak rampa ortasında dur kalk denemelerim oldu ve sorunsuz çıkabildim. Bir gün farkında olmadan, 4H ‘da olduğumu sanarak, 2H ‘da biraz hızlıca yürüyüp çıktım.  Sonra 2H ‘da daha düşük hızlarda başarısız teşebbüslerim oldu.

Bu parkuru da linkte görebilirsiniz.

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Bu denemelerden çıkan sonuç şu idi; birçok parkurun geçişi zor noktalarında ihtiyaç duyulan momentumu sağlamış olarak parkura girerseniz, sürüşünüzü başarılı bir şekilde sürdürmeniz mümkün olabilmektedir. Momentum, P=MxV (kütle *hız) denkleminde aynı araç için yorum yaptığımızı düşünür isek, kütle sabit olacağı için, momentum hızın doğrusal parametresi olacaktır. Yani hız ile bire bir değişecektir.

Zorlu noktalara ne kadar hızlı girerseniz, oradan takılmadan geçmeniz o kadar kolay ve mümkün olacaktır. Ancak burada dikkate alınması gereken diğer hususlar; güvenlik ve kırılma sınırları içinde kalmayı sağlayabilmek olmalıdır. Aracın devrilmesine veya mekanik bir kırılma yaşamasına neden olacak hızlara da çıkılmamalıdır.

Linkte verilen videoda yanlış momentum ile ve doğru momentum ile girilmiş bir parkurdan geçiş görünmektedir.

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Aynı parkurda biraz daha olgunlaştıktan sonra yapılan geçiş de aşağıdaki linkten izlenebilir.

Bu  videolar aynı zamanda offroad ‘da idman gerekliliğinin izahıdır.

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Tüm bu parametreleri doğru olarak değerlendirip uygulayabilmeye iyi pilotaj, tam tersine de kötü pilotaj denebilir. İyi pilotaj da kötü pilotaj da sürekliliği olan kavramlar değildir. Yani bir parkurda iyi bir performans sergiliyor olmanız her parkurda, hatta aynı parkurda bile kayıtsız şartsız iyi performans sergileyeceğiniz anlamına gelmez. Kötü performans için de durum aynıdır.

Sonuç ve Öneriler :

– İstisnai durumlar hariç, genel olarak “(Ağırlık) / (lastik taban alanı)” değerleri birbirine yakın olan hafif ve ağır iki aracı mukayese ettiğimizde, momentum açısından ağırlığı fazla olan, yani buna bağlı olarak kütlesi de fazla olan aracın aynı hızda, momentumu daha yüksek olduğu için, daha doğru pilotaj ile daha başarılı sürüşler yapması beklenebilir. Yani daha anlaşılır bir dil ile, ağır araç ve iyi pilotaj ile daha başarılı sürüşler yapmanız beklenebilir.

– Araçların farklı mekanik özellikleri, bazen sürüş kolaylığı sağlarken bazen de başımıza dert olabilir. Bazı araçlar ön kilit devredeyken direksiyonu biraz kırıp gaza bastın mı aks kesebilir. Ya da aksı güçlendirilmiş ise bu sefer diferansiyelinin içinde bir maraza çıkabilir. Bu problem akışı, motor güç akışının aksi istikamette, aks-diferansiyel-şaft-arazi şanzımanı- şanzıman-motor hareketli parçalarına kadar gidebilir. Beynelmilel arazi aracı olarak bilinen ve yaygın olarak kullanılan araçlarda dahi bu problemler yaşanabilmektedir. Aracımızı kullanırken momentumu korumak için gereğinden fazla gaza basar isek, aracımızı kırabiliriz. Aracımızın mekanik dayanıklılık sınırlarını bilerek kullanmamız hem güvenliğimiz hem cebimiz hem de yaptığımız işten keyif almamız için son derece önemlidir.

İyi pilotajın her şeyden önce aracını kırmamak olduğunu gözden kaçırmayalım.

– Motor gücü aracın son hızını ilgilendiren bir parametre olsa da, güce paralel artan tork, arazideki temel ihtiyacımızdır. Bir geçişin gerçekleşmesine ramak kala, araç low ‘da olmasına rağmen motor yığılabilir. Bu durumda pilotaj falan çöp olur. Hâlbuki arazi yeterliliği olduğu kabul edilen hiçbir aracın özellikle de düşük devire alındığında gaz yememe yığılma gibi bir probleminin olmaması gerekir. Buradan çıkan sonuç, arazi yeterliliği olduğu kabul edilen bazı aracın aslında öyle olmadığıdır. Arazi aracımızı seçerken motor güç yeterliliği konusunda dikkatli olalım, bizi zor durumda bırakacak bakımsız araçlardan uzak duralım, sahip olduğumuz araçlara da iyi bakalım.

– Her spor idman gerektirir, bunu offroad için de mutlaka değişmez temel kural olarak uygulayalım ve, aynı parkurlarda da olsa fırsat buldukça idman amaçlı sürüşler yapmaya gayret edelim.

Saygılar Sevgiler

13/05/2020

Süleyman ATILGAN

İletişim: Facebook & Instagram

Süleyman Atılgan tarafından profesyonel olarak hazırlanmış off road temel teknik ve off road sürüş tavsiyelerini içeren diğer makalelerini aşağıda görüntüleyebilirsiniz.

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Tavan yükleri ve güvenli sürüş açısından araca etkileri nelerdir ?

Bu günkü konumuz “Tavan yükleri ve güvenli sürüş açısından araca etkileri nelerdir ?”:

Başka hiçbir yerde bulamayacağınız derecede ince bir analiz.

Araca etki eden kuvvetler temel olarak statik ve dinamik kuvvetler olarak ikiye ayrılabilir. Statik şartlar sadece araç durmuş vaziyette iken tek başına mevcuttur. Gerek aracın sürekli hareket halinde olmasından kaynaklanan; momentum, merkez kaç kuvveti gerekse süspansiyon sisteminden kaynaklanan etkiler ve motordan tekerleklere intikal eden döndürme etkileri nedeniyle, bazen de fren etkisi vs ile farklı şartlarda değişken denge kaybı yaratan etkilere de dinamik etkiler diyebiliriz. Dinamik etkilerin hepsi kütle ilintili etkiler olduğu için, hepsini aracın kombine ağırlık merkezinden etkiyor olarak düşünebiliriz.

Kombine ağırlık merkezi: Aracın kendi ağırlığı dışında içindeki sabit olan olmayan tüm ilave ekipman, eşya ve insan yükleri dikkate alınarak hesap edilmiş ağırlık merkezidir.

Sevgili off-road ve doğa tutkunu arkadaşlar, Off-road Temel Teknik Bilgiler yazı dizimizin bir paylaşımı ile daha birlikteyiz. Vereceğim bilgiler; konsantre, teknik temele dayalı, yaşanmış tecrübeleri içeren ve bazıları off-road literatüründe ilk kez isim bulacak detayları içeren paylaşımlardır. Okuyuculara fayda sağlaması dileği ile.

Araca yerleştirilen herhangi bir ilave yük, eğer aracın boş halinde hesap edilen ağırlık merkezinin üzerinde bir lokasyona yerleştirilir ise, aracın kombine ağırlık merkezini yukarı doğru kaydırır. Tam tersi, aracın boş ağırlık merkezinin altında bir seviyeye yerleştirilen ilave yük ise, aracın kombine ağırlık merkezini aşağı doğru kaydırır.

Denge-devrilme ‘nin temel kuralı, ağırlık merkezi yükseldikçe devrilmenin kolaylaşacağı, ağırlık merkezi alçaldıkça devrilmenin zorlaşacağıdır.

Konunun daha iyi anlaşılabilmesi için Denge offroad ‘un neresindedir ve önemi nedir yazımızı okumanızda fayda olacaktır.

Denge off-road‘un neresindedir ? Off- Road Araçlar Denge ve önemi nedir ?

Şimdi gelelim analizimize örnek olacak araç özeline.

Aracımızın lastik dışından lastik dışına 190 cm genişlikte olduğunu,

Araç yüksekliğinin yaklaşık 190 cm olduğunu,

Araç ağırlığımızın ~2000 kg olduğunu,

Araca koyulan ilave tavan test yükünün yerden 200 cm yükseklikte yerleştirildiğini,

Araca koyulan ilave tampon seviyesi yükün yerden 70 cm yükseklikte yerleştirildiğini,

Aracın kendi boş ağırlık merkezinin yerden yaklaşık 95 cm yükseklikte olduğunu kabul ettik.

Tavan yüklerini ; tavan çadırı, tavan sepeti, tavana entegre gölgelik, port bagaj vs oluşturabilir.

Tampon seviyesi yükleri ise ; demir tampon, vinç, tampon içi su deposu vs oluşturabilir.

Analizimizde temel olarak, araç üzerindeki ilave 100 kg ‘lık bir ağırlığın, tampon veya tavan pozisyonunda,  statik ve dinamik olarak araca müspet ve menfi etkilerini inceleyeceğiz.

Müspet etki : Dengede kalmaya yardımcı olan etki

Menfi etki : Aracın dengesini kaybetmesine sebep olan etki

Yani araca ilave olarak yükleyeceğimiz 100 kg ağırlığın, tampon seviyesinde olması ile tavan sepeti seviyesinde olması arasında ne gibi farklılıklar olacaktır ?

Bu cevaplara göre de aracımıza tavan sepeti, tavan çadırı, tavan gölgeliği, port bagaj gibi ekipmanları koyduğumuzda sürüş alışkanlıklarımızı nasıl regüle etmemiz gerektiğini tartışacağız.

Hesap kolaylığı olması için bazı ölçüler daha anlaşılır yakın sayılara yuvarlanmıştır.

Dinamik etkilerin yönü, etkiye sebep olan faktöre bağlı olarak değişebilecektir. Hesap kolaylığı açısından ve etkinin moment kolunun en yüksek değerde olduğunu düşündüğümüz yön örnek çalışmamızda esas alınmıştır.

Ayrıca bu bir değerlendirme analizi olduğu için aşağıdaki açıklamalar doğrultusunda da kabuller yapılmıştır.

F kuvveti, 100 kg ağırlığını oluşturan kütlenin fonksiyonu olmak kaydıyla; momentumun, eylemsizlik momentinin, merkezkaç kuvvetinin, fren etkisinin, süspansiyon sisteminin vs ‘nin fonksiyonu olarak araca etkiyecektir. 100 kg ağırlık için, kütle sabit olsa da, neyin etkisinde ortaya çıktığına bağlı olarak tavan sepeti hizasında veya tampon hizasında, araca farklı kuvvet değerleri ile etkileyebilecektir. Bu yüzden F1 ve  F2 olarak adlandırılmışlardır.

30 m yarıçaplı bir viraja 60 km/h (16.667 m/s) bir hızla girecek olur isek;

100 kg ağırlığında bir cismin maruz kalacağı merkez kaç kuvveti;

(100 kg) / (9.81 m/s2) * (16.667 m/s)2 / (30 m) = 94.39 kg olacaktır. Örnek hesabımızda, bunu yaklaşık 100 kg kabul edip, pozisyon farklılığının yaratacağı durumu göz ardı ederek F1=F2=100 kg kabul edebiliriz.

Notasyonumuz;  aracı dengede tutmaya çalışan tüm etkiler için  “+”, aracı devirmeye çalışan tüm için etkiler “-“ dir.

Örnek aracımız durağan ve düz vaziyette iken, hem kendi ağırlığı hem de ilave yükleri aracı dengede tutmaya çalıştığı için “+” olacaktır.

Araç düz pozisyonda ve hareket halinde iken araç ağırlığı ve ilave yükler “+” etki yaratırken, örneğin merkezkaç kuvvetinden kaynaklanan kuvvet “-“ etki yaratacaktır.

Aracın maruz kaldığı “-“ dinamik etki, aracı dengede tutmaya çalışan “+” etkiyi aşar ise araç devrilecektir.

Arazi şartlarında, aracın düz vaziyette olmadığını ve yana doğru yatık vaziyette olduğunu düşünecek olur isek, “-“ etkilerin çok daha küçük değerlerinde bu devrilme gerçekleşebilecektir.

Şimdi sayısal örneğimizi, aracın “dokunsan devrilecek” dediğimiz pozisyonda yani, aracın ağırlık merkezinin aracın devrilme noktası olan lastiğin en dış noktası ile aynı düşey hizaya gelecek kadar yatık olduğu durum için yapalım. Değerlendirme sadece ilave yük için yapılacaktır.

Bu durumda aracın ağırlığının devrilme noktasından geçen düşey eksene mesafesi 0 ‘dır. Yani araç boş ağırlığının, devrilme veya dengede tutma açısından etki eden momentinin kuvvet kolu 0 cm ‘dir. Doğal olarak M (moment) = G (ağırlık) x L (kuvvet kolu) formülünde L= 0 ise M = 0 olacaktır. Araç ağırlığının etkisinin 0 olduğu bu pozisyonda aracın tavan ve tampon seviyesine yerleştirilen ilave yükün etkisi ise şu şekilde ortaya çıkmaktadır;

Sadece statik etkiler için :

Tavan seviyesi yükleri için ,

M(-) = 100 kg x (-0.75 m) = -75 kg-m aracı devirecek şekilde

Tampon seviyesi yükleri için,

M(+) = 100 kg x 0.15 m =15 kg-m aracı dengede tutacak şekilde

Tampon seviyesi ve tavan seviyesi ilave 100 kg yük eş zamanlı araç üzerinde bulunuyor ise,

-75 + 15 = -60 kg-m devirme momenti fazlası ile araç devrilecektir.

Sadece tavan seviyesi ilave 100 kg yük araç üzerinde bulunuyor ise, -75 kg-m devirme momenti fazlası ile araç devrilecektir.

 Statik ve dinamik etkiler için :

Tavan seviyesi yükleri için ,

(Yukarıda izah edildiği gibi, F1=F2=100 kg kabul edildi)

M(-) = 100 kg x (-0.75 m) + 100 kg x (-2.10 m) = – 285 kg-m aracı devirecek şekilde

Tampon seviyesi yükleri için,

M(-) = 100 kg x 0.15 m  + 100 kg x (-1.15 m) = – 100 kg-m aracı devirecek şekilde

Tampon seviyesi ve tavan seviyesi ilave 100 kg yük eş zamanlı araç üzerinde bulunuyor ise,

(-285) + (-100) = -385 kg-m devirme momenti fazlası ile araç devrilecektir.

Sadece tavan seviyesi ilave 100 kg yük araç üzerinde bulunuyor ise, -285 kg-m devirme momenti fazlası ile araç devrilecektir.

Sayısal örnekten de anlaşılacağı gibi, tavan seviyesinde olan ilave yükler, araç özellikle yan yatmış pozisyonda ise hem statik durumda hem dinamik etkiler altında aracın daha erken devrilmesine sebep olacaktır.

Tampon seviyesinde bulunan ilave yükler ise, statik durumda aracın dengede kalmasına müspet etki yaratırken, dinamik etkileşim bu seviyedeki yükler için dahi, aracın devrilmesine sebep olabilecektir.

Sonuç ve Öneriler :

Hemen hemen hiçbirimiz, arazide kullandığımız araçları orijinal hali ile kullanmıyoruz. Arazi araçlarında en temel modifikasyonlar araç yükseltme ve lastik büyütmektir. Bu modifikasyonlar zaten aracın boş halinin ağırlık merkezini yukarı kaydırarak denge açısından olumsuz bir durumu beraberinde getirmektedir. Bunlara ilave olarak tavan seviyesinde koyacağımız her ilave yük aracın, özellikle yan durumda daha erken devrilmesine neden olacaktır.

Arazici aracını sever ve ona olabildiğince ekipman yükler. Bu ekipmanlardan bir kısmı görsel bir kısmı fonksiyoneldir. Örneğin; çalışmayan şnorkel, aktif olmayan dummy telsiz anteni bunlardan bazılarıdır. Yükseltilmiş ve MT – XT lastik takılmış bir aracı zaten teorik olarak asfaltta bile yüksek hızda sürmeyeceğimiz kabulü ile hareket edersek, araç aerodinamiğini olumsuz etkilemekten başka bir işe yaramayan şnorkelin hayati olumsuz bir etkiye sahip olması söz konusu olmayacaktır.

Ancak; tavan seviyesine koyulan her ilave yük araç güvenliğini olumsuz etkilemektedir. Bu yüzden sadece olsun diye tavan seviyesine işinize gerçekten yaramayacak hiçbir ağır ekipman koymayınız.

Eğer fiili kullanım ihtiyacınız nedeniyle araç tavanında; sepet, stepne, çadır, port bagaj, tente vs gibi ekipmanlar var ise, bunların yaratacağı olumsuz etkilerin farkında olarak araç kullanmamız hayati derecede önemlidir.

Araç yükseldikçe ve/veya daraldıkça veya referans kabul ettiğimiz 100 kg sepet yükü arttıkça etkiler olumsuz yönde artacaktır.

Saygılar Sevgiler

22/05/2020

Süleyman ATILGAN

İletişim: Facebook & Instagram

Süleyman Atılgan tarafından profesyonel olarak hazırlanmış off road temel teknik ve off road sürüş tavsiyelerini içeren diğer makalelerini aşağıda görüntüleyebilirsiniz.

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Süleyman Atılgan Off-Road Teknik

Offroad ‘da Dik Tırmanış ve Karın Açısı

Off-road Temel Teknik Bilgiler Sevgili off-road ve doğa tutkunu arkadaşlar, Of

Bugünkü konumuz “Offroad ‘da dik tırmanış ve karın açısı”:

Evet, Sevgili Arkadaşlar, bu akşam hafta sonu gezilerimizin birinde yaptığımız dik bir çıkışın teknik analizi yapacağız.

Konu ile ilgili ilk videomuz aşağıdadır. Daha çok debelenme sürecine ait görüntülerdir.

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İkinci videomuz ise çıkışın başarılı bir şekilde gerçekleştiği sürece aittir.

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Ekli resimlerin üzerinde gerekli açıklamalar var.

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İlk videoda, aracın dik yokuşta ilerleme ile ilgili bir problem yaşamadığına, ancak, askıda kaldığı an, artık yol almasının mümkün olmadığına dikkat edin. En dik pozisyonda bile, kısa kısa geri-ileri hareket edebilmekte. Bu da yokuşta yol tutuş problemi olmadığını göstermektedir.

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Off-road Temel Teknik Bilgiler

Sevgili off-road ve doğa tutkunu arkadaşlar, Off-road Temel Teknik Bilgiler yazı dizimizin bir paylaşımı ile daha birlikteyiz. Vereceğim bilgiler; konsantre, teknik temele dayalı, yaşanmış tecrübeleri içeren ve bazıları off-road literatüründe ilk kez isim bulacak detayları içeren paylaşımlardır. Okuyuculara fayda sağlaması dileği ile.

Problem askıda kaldığında, tekerlekler traksiyon kaybedince ortaya çıkıyor. Tekerleklerde traksiyon yoksa, lastik ebadı, cinsi, hamuru, orta,arka,ön kilitler, pilotaj, vs hiçbir işe yaramaz. Şimdi,  iyi bir pilotajla buradan çıkılır diye düşünenler olabilir. Pilotaj lastik yol tutmuyorsa bir işe yaramaz. Pilotaj, o duruma düşmemek noktasında fark yaratır sadece. Bu da tecrübe ile gelişecek, ne zaman ne yapmam lazım öngörüsüdür. İkinci videoda ise çıkış, her iki yöntemin kombinasyonu olarak gerçekleşmekte. Hem üst köşe bir miktar törpülenmiş, hem de yol tutuşunun kaybolduğu anı geçmesini sağlayacak atalete ulaşabilmiş olarak yola devam etmektedir.

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Üst köşeye geldiğimizde karın açısı yeterli olmadığı için, şaşi oturuyor, lastik havada kalıyor veya havada kalmasa bile, araç şase üstünde iken, amortisör stroku uzun bile olsa, bir noktadan sonra, lastikte sadece dingil ağırlığı kalıyor. Bu diklikte bir yerde, ~2.5 ton aracı yürütmek için sadece dingil ağırlığı altında sağlanabilecek traksiyon yeterli olamıyor doğal olarak. Aracın kendi ağırlığı da tekerleklere olabildiğince intikal etmeli. Coilover amortisörler biraz fark yaratabilecektir.

Konuyu daha iyi anlayabilmek için artikülasyon yazımızı okumanızı tavsiye edeceğim.

Artikülasyon ‘un yol tutuşa etkisi nedir? Faydalı artikülasyon nedir ?
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İkinci videoda yaptığım hamleyi parkura girdiğim ilk anda yapıp yürüyüp gidebilmem de mümkündü. Ancak bu durumda şu an yapmakta olduğumuz analizi yapmak için çok bir gerekçe kalmayacak ve burası da normal yürüyüp gittiğimiz yerlerden biri olacaktı. Bu yüzden risksiz bir şekilde parkurda biraz oynaşın. Bu hem işin tadını arttırıyor hem de tecrübeyi geliştiriyor. Burada amaç sadece çıkmak değil. Şartları enine boyuna analiz edip, hem tecrübe yükseltmek hem de gözden kaçan noktaları yakalayıp, gezide olan olmayan bütün arkadaşlarımızla paylaşmak.

Parkur çok kısa bir parkur değil, en azından araç boyundan daha uzun bir parkur. Bu da her noktada çok dikkatli olmamızı gerektiriyor. Dik çıkışların risklerinin değerlendirildiği dik iniş ve dik çıkış üzerine arşiv yazımızı okumanızda büyük fayda olacaktır.

Araçla dik çıkış mı daha tehlikeli, yoksa dik iniş mi daha tehlikeli ?
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Burada değerlendireceğim durum, bizim üzerinde tartıştığımız parkur içindir. Kumsal benzeri düz sürüş parkurunda durum daha başkadır.
Araç çok zıplatmaktan kaçının. Özellikle, sert zeminde kilitler devrede değilken ve yüksek devirde.
Aracın ön lastikleri havalandığı anda, orta kilit devrede değil ise veya orta kilit devrede olsa bile arka tekerleklerden biri traksiyon kaybederse ön tekerleklerin ikisi birden, veya, yerden ayrılma anı farklı olduğu için ön tekerleklerden biri, motorun tüm gücünü emebilecektir. Araç 4L değil de 4H da ise bu defa, ön tekerleklerin hızı iyice artacaktır. Araç havanlınca fren yapmak gibi bir alışkanlığımız yok, gaza basmaya devam ediyoruz. Bu da aracın hızını değil, lastiğin dönme hızını daha da arttıracak bir etken oluyor. Bir de zıpladıktan sonra ön tekerler yol tutuşun iyi olduğu bir zemine düşüyorsa, aks kesebilirsiniz veya diferansiyel içinde(aks dişlileri veya örümcek dişlilerin sıyrılması veya kırılması, avare dişlilerin eksen milinin kırılması, dişli muhafazasının kırılması vs gibi) hasara neden olabilirsiniz. (Örneğin yol kenarındaki dik toprak çıkıştan asfalta zıplıyorsanız ve bu çıkışı aracın hızını arttıramadan gaza yüklenip sadece ön tekerleklerin hızını çok arttırmışsanız.)

Aracın arka lastiklerinin dönme hızı ve aracın kendi hızı ne kadar düşük, ön tekerlerin dönme hızı ne kadar yüksek olur ise ve ön tekerler bu yüksek hıza ulaştıktan sonra, gerek aracın hızının düşük olmasından, gerekse zeminin lastiğin dönmesine müsaade etmemesinden, akslar üzerinde ortaya çıkan burulma etkisini karşılayamayacak ve kesecektir. Aksın diferansiyel tarafı dönmeye çalışacak, lastik tarafı ise zemine temas edince aniden durmaya çalışacaktır.
4L de ise durum biraz daha farklı. Genelde 4L ‘de araçlarda orta kilit de devrede oluyor. Bu da ön şaft ve arka şaft arasındaki hız farkını ortadan kaldıracaktır. Ancak ön tekerlekler havaya kalkınca, gerek aracın genel zıplama eğiliminden gerekse kaygan zemin şartları nedeniyle, arka tekerlekler de patinaja düşerek hızını fazlaca arttırırsa, bu defa ön tekerlekler yere temas ettiğinde, hız çok yüksek olmasa bile 4L aktarma gücünün daha yüksek olması nedeniyle aks yine kesebilir.

Ayrıca her geçişten sonra parkurun yapısı da değişebiliyor bazen önden giden araç yolu yapıyor bazen bozuyor. Videoda bir iz yapmaya çalışırken oluşan kanalı doluyor ve köşe biraz törpülenerek yok oluyor ve aracın karnının oturma riski azalıyor.

Sonuç ve Öneriler :

Arazide her zaman dikkatli olun, laubali araç sürmeyin. Parkurun ne derece tehlikeli olduğunu başlangıçta fark etmemiş olabilirsiniz, her an tetikte olun, mümkünse size yön veren bir yardımcınız mutlaka olsun.

Aks üzerindeki yükteki ani değişim aksın kapasitesinin üzerinde bir etki yaratır ise aks keser. Bu etkinin nasıl ortaya çıktığını anlamak ve o hareketlerden kaçınmak lazım.

Aracı zıplatmayın. Zıplamak keyifli gibi görünse de muhtemelen aracın aktarma organlarına en çok hasar veren kullanım biçimidir. Bizlerin kullandıkları özellikle daha güçlü parçalar ile modifiye edilmemiş araçlarda bu konuda daha da dikkatli olun.

Saygılar Sevgiler

13/05/2020

Süleyman ATILGAN

İletişim: Facebook & Instagram