Power of a mechanical crawler (track, chase ...) VS wheels?

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Christophe
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Power of a mechanical crawler (track, chase ...) VS wheels?




by Christophe » 15/11/19, 11:42

I am looking for power (or rather losses) a rubber crawler traction system to compare it to traditional tires (20% losses).

The parameters are (at least) total weight to move, vehicle speed, track surface in contact ... we will neglect the more complex phase of acceleration but I would like the start torque nonetheless!

Has anyone ever studied the question?

I imagine that the power depends, also (above all), the type of soil ... but we will retain a rather hard ground to simplify calculations (sand well packed for example?) ...
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Ahmed
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by Ahmed » 16/11/19, 10:31

What is the practical interest of such a question? When choosing a caterpillar propulsion is that we favor the lift and adhesion. Aside from tracked vehicles, usually military (and there, consumption is really not a criterion!), The others are not intended to make significant trips, just to move a tool to the best of the work to be done (backhoe , bulldozer, stump cutter, drill, etc ...). Often powerful machines, for which the resistance of the tracks to the advancement is negligible.
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by Christophe » 16/11/19, 13:25

Ahmed wrote:the others are not intended to make significant trips, just to move a tool to the best of the job (digger, bulldozer, stump cutter, drill, etc ...).


Your answer surprises me a little, my dear Ahmed ... : Shock: I think you have forgotten the movements on the snow! When was the snow bike invented? A few decades ago ...

In some regions of the North of the planet (to the south much less ...), we move caterpillars during (at least) 4 months of the year ...



Closer to home, these machines also work every day during 4 at 5 winter months:





Good bin, I will try to find some datasheet from these manufacturers as you do not want to help me calculate! : Cry: : Cry: : Cry: : Cheesy: : Cheesy: : Cheesy:

I have already found one and I find 40% of losses about (so double the tires ...) ... which is not so bad finally.

This estimate was made with some data manufacturers that I mixed ...
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by dede2002 » 16/11/19, 13:43

40% is a lot, almost half the power is used to melt the snow!

Already, 20% for the tire is huge, why are we still using tires ...?

This goes back to your question about shock absorbers, less energy would be "wasted" by not using shock absorbers or tires, but it would be less comfortable. :P
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by Christophe » 16/11/19, 14:09

dede2002 wrote:40% is a lot, almost half the power is used to melt the snow!


Not really melt but hang ... There is more rolling and internal friction on a track than a wheel ... so 40% it does not surprise me more than that when we know that a classic wheel is 20 % ...

dede2002 wrote:Already, 20% for the tire is huge, why are we still using tires ...?


What a question! And you have an alternative? The wheel does not work very long on asphalt at high speed! The wooden wheel a little longer (at a very moderate speed) ... 1000 km can be? : Cheesy:

For the 20% of power losses in tires, it is a data builder (I did not know until 2 or 3 years ago ...)

Attention it is for a tire on road in normal conditions of rolling ...

dede2002 wrote:This goes back to your question about shock absorbers, less energy would be "wasted" by not using shock absorbers or tires, but it would be less comfortable. :P


Yes that's it ... and a tire is an air shock!

To win 1 year or 2 technical control on the shock absorbers or kneecaps or suspension arm, just lower the pressure of its tires to 1.0-1,5 bars ... In Belgium the test of arms and kneecap is particularly destructive! It is a torture of the mechanics (they make lateral and longitudinal movements of the tire of about 10 cm), conditions that do not arrive on road in normal driving!

But it is true that there are armored potholes in Belgium! : Evil:
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by Ahmed » 16/11/19, 14:39

Yes, I zapped the snow ... : Oops:
I think that most of the friction of a track system is less the multiple support wheels that the contact between the axes of the pads and sprockets, to which we must add the deformation of the rubber band (it all depends on the configuration of traction chevrons) ... At high speed, as on your famous snowmobile, it should not be negligible.
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by Christophe » 16/11/19, 14:44

Yes that's it! Hence the 40% I found ... approximate approach but likely!

Is there no way to put all this in equation ??

The advantage of the crawler is to have a zero friction floor.
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by dede2002 » 16/11/19, 14:45

Christophe wrote:What a question! And you have an alternative? : Cheesy: ...


The alternative would be to drive slower ... : Mrgreen:
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by Ahmed » 16/11/19, 14:48

The friction on the ground is not zero, it is minimized because in a straight line skating is in principle quite weak. On the other hand, it increases considerably when the speeds of the two tracks vary, which is necessarily the case during a turn.
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Re: Power of a mechanical crawler (track, chase ...) VS wheels?




by Christophe » 16/11/19, 15:14

It's not fake Ahmed!

Well, she comes this equation? : Cheesy:

Already how do we normalize a caterpillar?
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