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what would be the best winch for a suuki vitara ie pounds pulling power
This is an excerpt from the very good book 'Off road recovery techniques' by Nick Cole.QuoteFriction is a force that offers resistance to motion between surfaces in contact. The coefficient of Friction is a measure of the amount of friction existing between those surfaces. When a load is to be moved horizontally, it is defined as a pull and at any angle away from horizontal is defined as lifting, when a vector addition of the relative forces has to be used.PullingE=uWLiftingE=W(u cos a + sin a)E is the effort to move the loadW is the weight of the casultyu is the coefficient of frictiona is the angle from horizontal Friction imposes an initial resistance to movement, and once moving it reduces slightly to the figures listed. These values can only be established by experiment and can change by a marked amount, particularly in the presence of lubricants and varying conditions of the two surfaces in contact. It is possible for a coefficient to have a value greater than 1, which is unlikely in practice unless the casualty is below the surface level and pulling builds up material in front as with a bulldozer.Coefficients of Friction.Asphalt / rubber 0.5 - 0.8Rubber / steel 0.6 - 0.9Rubber / asphalt (wet) 0.25 - 0.75Rubber / asphalt (dry) 0.5 - 0.8Rubber / concrete (wet) 0.45 - 0.75Rubber / concrete (dry) 0.6 - 0.85Dry masonry / brickwork 0.6 - 0.7Masonry / dry clay 0.5Masonry / wet clay 0.3Timber / stone 0.4Timber / timber 0.2 - 0.5Timber / metal 0.2 - 0.6Wheeled load on tarmac - 0.02 - 0.05Iron / Stone 0.3 - 0.7Lubricated metal surfaces 0.1 - 0.2Vehicle in wet and clinging clay 0.5Vehicle in hard wet sand 0.17Vehicle in soft wet sand 0.2Vehicle in soft dry sand 0.25Vehicle in shallow mud 0.33Vehicle in bog 0.5Vehicle in marsh 0.5Vehicle on gravel 0.2Vehicle on grass 0.14If the weight of the vehicle is 2000Kg's in the case of a LWB Frontera and it's stuck in a bog on a flat surface. The effort required to extract it will be E = 0.5x2000 which is 1000kg's or a 2000lb winch.QuoteFor pulling up a slope, the following table is usefulu / slope angle at which pulling effort is a maximum (degrees)0.02 / 88.90.05 / 87.10.1 / 84.30.2 / 78.70.3 / 73.30.4 / 68.20.5 / 63.40.6 / 59.00.7 / 55.00.8 / 51.30.9 / 48.01.0 / 451.1 / 42.31.2 / 39.8From the table above, if a LWB Frontera is stuck in a bog (u=0.5) then the largest value of E will be if the vehicle needs towing up a slope of 63.4 degrees (any more and a lifting effect takes place and aids the winch - at 90 degrees the vehicle is just being lifted directly up, so E=W after the initial suction is overcome)soE = W (u cos a + sin a)E = 2000 x((0.5 x cos 63.4) + (sin 63.4)E = 2000 x (0.2239+0.8942)E = 2000 x 1.1181E = 2236.2Kg's.or 5000lb's <>(if anyone is any good at maths, can you check mine - it's been a decade or so since I've done trig ;) )Just picture trying to tow a vehicle up a 63 degree slope in your head though ;) That is the power winch needed for towing a 2000Kg vehicle through a bog.
Friction is a force that offers resistance to motion between surfaces in contact. The coefficient of Friction is a measure of the amount of friction existing between those surfaces. When a load is to be moved horizontally, it is defined as a pull and at any angle away from horizontal is defined as lifting, when a vector addition of the relative forces has to be used.PullingE=uWLiftingE=W(u cos a + sin a)E is the effort to move the loadW is the weight of the casultyu is the coefficient of frictiona is the angle from horizontal Friction imposes an initial resistance to movement, and once moving it reduces slightly to the figures listed. These values can only be established by experiment and can change by a marked amount, particularly in the presence of lubricants and varying conditions of the two surfaces in contact. It is possible for a coefficient to have a value greater than 1, which is unlikely in practice unless the casualty is below the surface level and pulling builds up material in front as with a bulldozer.Coefficients of Friction.Asphalt / rubber 0.5 - 0.8Rubber / steel 0.6 - 0.9Rubber / asphalt (wet) 0.25 - 0.75Rubber / asphalt (dry) 0.5 - 0.8Rubber / concrete (wet) 0.45 - 0.75Rubber / concrete (dry) 0.6 - 0.85Dry masonry / brickwork 0.6 - 0.7Masonry / dry clay 0.5Masonry / wet clay 0.3Timber / stone 0.4Timber / timber 0.2 - 0.5Timber / metal 0.2 - 0.6Wheeled load on tarmac - 0.02 - 0.05Iron / Stone 0.3 - 0.7Lubricated metal surfaces 0.1 - 0.2Vehicle in wet and clinging clay 0.5Vehicle in hard wet sand 0.17Vehicle in soft wet sand 0.2Vehicle in soft dry sand 0.25Vehicle in shallow mud 0.33Vehicle in bog 0.5Vehicle in marsh 0.5Vehicle on gravel 0.2Vehicle on grass 0.14
For pulling up a slope, the following table is usefulu / slope angle at which pulling effort is a maximum (degrees)0.02 / 88.90.05 / 87.10.1 / 84.30.2 / 78.70.3 / 73.30.4 / 68.20.5 / 63.40.6 / 59.00.7 / 55.00.8 / 51.30.9 / 48.01.0 / 451.1 / 42.31.2 / 39.8
Here's a post I put up many moons ago on another forum about winching coefficents.
I made a basic calculator based on the same calculations simplied some years ago...http://www.stonefisk.com/winchcalc.htm