Sled Dogs and Components of Force

In summary, the conversation discusses two different configurations for a team of sled dogs pulling a weighted sled. Configuration 1 involves the dogs pulling at an angle of 30 degrees off of the gangline, while Configuration 2 involves the dogs pulling in a
  • #1
AK Husky
1
0

Homework Statement


This is a real world problem, which I have been thinking about for some time now.
The problem is this: I have a weighted sled which requires a pulling force to move it, and I have a team of dogs generating that pulling force. I am trying to figure out the differences between two different ways of configuring the team.
Terms being used are
"gangline" -central rope, all the dogs and the sled are attached to this
"tugline" -two to three foot line coming off of the gangline in pairs, and attached to the harness of each dog

Configuration 1: Each pair of dogs is pulling on either side of the gangline, with the pulling force being applied via the tugline at an angle of about 30 degrees off of the gangline. Essentially, each dog is running forward, but also pulling outward at a bit of an angle to the direction of travel, in order to run alongside the gangline.

Configuration 2: Each pair of dogs is pulling on either side of the gangline, with the pulling force being applied via the tugline, with a spacer bar perpendicular to the gangline which allows the tugline to be parallel to the gangline. Each dog is basically running straight forward all the time.

Homework Equations


Components of force. Fx = F sin(30), Fy = F cos(30)

The Attempt at a Solution


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My intuition says that configuration 2 is the more efficient setup, if all the force being applied by the dogs can be applied in the direction of travel, the Y axis (think, traveling up the trail), there are no X components of force on either side of the line cancelling each other out.

I am trying to figure out if the X component of force each dog applies in configuration 1 is entirely wasted effort and does in fact cancel itself out. I do not think it does, thinking: if you hold up both ends of string with a weight in the middle, and move your hands apart along the X axis, the weight still progresses along the Y axis.

I have used configuration 1 for many years and it definitely works, but I would like to know if I am limiting my efficiency by a significant amount.

I haven't used many specific values in this question because in a real world setting the entire system is pretty dynamic; sled weight, pulling force required, and amount that each dog is pulling can vary quite a bit, but if you guys need more info or any clarification let me know.

TL;DR
Is having sled dogs pull at an angle significantly less efficient than having them pull in a straight line?

Thanks
Hopefully I posted this in the right section.
 
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  • #2
The dogs are definitely wasting effort in configuration 1 for the reasons you outline and configuration 2 should definitely be more efficient, as all the force is directed in the required direction.

In general, the forward force will reduce with the cosine of the angle. At 30° you have an 87% forward pull. At 60°, however, it would only be 50%. A rough estimate, therefore, is that you are losing about 13% of your dogs' effort.

Regarding your question about lifting a weight. It would be much harder to lift a weight with two people pulling out at an angle. As the weight rises and the angle becomes greater, it will become harder to generate any upward motion. Eventually, almost all the force from each side is simply pulling against the other..
 
  • #3
AK Husky said:
Is having sled dogs pull at an angle significantly less efficient than having them pull in a straight line?

i feel that the sled dogs pulling at small angles so that the y-component is more will be more efficient than the other way which you are proposing-
the arguments are that its not a theoretical framework which actually works -as mostly it is an idealization- in practical terms the two parallel pullings may not impart the twice-pullforce as the moment of the forces about the centre will act and a part will get lost in producing the torqoe to the contraption attached to the central rope. and this is vital as live pullers or dogs may not be adjusting their pulls exactly equal in magnitude and direction.
there are some practical advantages of the earlier ways of pulling at an angle- the freedom to puller dogs generate more force and as the terrain is not ideally flat the trained dogs could manuver to totake slightly new paths if it is desirable.
on the whole i think the configuration one will be found more efficient if suitable experiments be done to test the methodology.
 
  • #4
drvrm said:
the moment of the forces about the centre will act and a part will get lost in producing the torqoe to the contraption attached to the central rope.
I don't understand the point you are making here. Perhaps you are thinking of the transverse bars somehow being fixed at right angles to the path of travel, but in practice it would be able to rotate somewhat, so the pair of dogs would not need to stay exactly level. The force exerted by each dog would still be straight ahead.
 
  • #5
AK Husky said:
Each pair of dogs is pulling on either side of the gangline, with the pulling force being applied via the tugline, with a spacer bar perpendicular to the gangline which allows the tugline to be parallel to the gangline. Each dog is basically running straight forward all the time.

haruspex said:
Perhaps you are thinking of the transverse bars somehow being fixed at right angles to the path of travel, but in practice it would be able to rotate somewhat, so the pair of dogs would not need to stay exactly level. The force exerted by each dog would still be straight ahead.

yes i was thinking of the actual working of 'spacer bar' which is perpendicular to gangline and the tugline having parallel arrangement -if pulled by an exactly equal force- i was worried about this ideal condition
being achieved in practice.
 
  • #6
drvrm said:
yes i was thinking of the actual working of 'spacer bar' which is perpendicular to gangline and the tugline having parallel arrangement -if pulled by an exactly equal force- i was worried about this ideal condition
being achieved in practice.
My point is that even if you try to fix it right angles the gangline can twist, so it won't remain at right angles to the direction of travel.
 
  • #7
haruspex said:
My point is that even if you try to fix it right angles the gangline can twist, so it won't remain at right angles to the direction of travel.

yes i agree with you , that's why i raised the 'practicability' of the contraption being used and pull by the pair not being added straight along tugline.
moreover i have a hunch that local tryout might have been made with efficiency in view-we need those info-as its an age old practice.
 

What are sled dogs and what are their roles in a sled team?

Sled dogs are a type of working dog that have been bred and trained to pull sleds across snowy terrain. They are typically used in regions with harsh winter conditions, such as Alaska and Canada. In a sled team, each dog has a specific role, with the lead dog setting the pace and direction, swing dogs helping to navigate turns, and wheel dogs providing the most power to pull the sled.

What are the components of force in a sled dog team?

The four main components of force in a sled dog team are tension, friction, gravity, and air resistance. Tension is the force exerted by the dogs as they pull the sled, while friction is the resistance caused by the sled's runners against the snow. Gravity plays a role in maintaining the sled's weight and keeping it on the ground, while air resistance can impact the team's speed and efficiency.

How do sled dogs generate force to pull a sled?

Sled dogs generate force through a combination of their physical strength and their natural instincts and behaviors. They are bred for endurance and have strong muscles, particularly in their legs and shoulders, which allow them to pull heavy loads. They also work together as a team, utilizing their natural instincts to follow the lead dog and maintain a steady pace.

How do sled dogs communicate with each other while pulling a sled?

Sled dogs communicate with each other through a variety of vocalizations and body language. They may bark, howl, or whine to indicate their excitement or alert the team to potential hazards. They also use their body positions and movements to convey messages, such as when a lead dog turns to signal a change in direction. Communication is crucial for the team's success and is developed through training and experience together.

What are some safety considerations when working with sled dogs?

Safety is a top priority when working with sled dogs. Some important considerations include ensuring that the dogs are properly trained and conditioned for the task at hand, providing adequate nutrition and hydration, and monitoring the weather and trail conditions. It is also important to have a knowledgeable guide or musher leading the team and to have proper equipment, such as harnesses and sleds. In case of emergency, it is important to have a plan in place for caring for the dogs and seeking medical attention if needed.

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