Starting draft

Thanks Tim, these numbers are great. I will post in the other thread too, but this is the “elasticity” that I was referring to when talking about the inner ability for animals to buffer the draft.

Because they are not geared machines that move at a given speed, or power setting, these animals can apply rapid and escalating, or de-escalating exertion. In this case the draft is in response to overcoming inertia, so there is a measurable point or exertion required to move the load, but the animals start at zero and increase their exertion until they reach that point. The elasticity is not so much in the tissue, but in the way it is applied by the brain.

But if we consider the accuracy of setting the point of draft in giving the animals an effective and consistent angle, so that they can apply not only their rear-end power, but also utilize the ballast from their body weight, then there is also another energy center where the requirements are not directly linear, as in a geared machine.

These numbers also point out how the measured draft increases precisely because the animals are pushing harder. There is a lot of elasticity in that. Animals are clutch, transmission, and throttle all in one, and when they are in good condition they can quickly modify the exertion that is required.

John, the angle of draft, and draft point on the shoulder are consistent from small to big, which is why most of the wagon-hitch horses have been traditionally “leggy”. If you consider some of Tim’s numbers from the other tread relating to wheel size then a tall horse can have reasonably good advantage over the high hitch point on a wagon that will have less draft resistance due to wheel size. This way these delivery wagons could be loaded pretty heavily. Not to mention how the larger wheels would help on the cobble-stone streets.

In terms of 16.2 hh being the best size. It may have more to do with manufacturers picking an average size to aim for, so that farmers could have a known entity.

Carl

John, we’re saying the same thing. I was thinking of “ideal” draft angle which is relative to the animal. The hitch point will change with the equipment, and yes then the animal can be compromised.

Carl

I think Mitch has pointed out an important issue here. That is exactly what I was meaning.. Somewhere I have a copy of an 1860 chart used by vehicle makers of the time regards traction line and splinter bar height, wheel height and wheel bases ect. As Carl says the draft or traction line is constant thru the different heights of horses. My point is that perhaps we need a new version of these old charts to suit the fact we pull modern tractor implements. I noticed yesterday when I was out with the slitter I made that the front of my hitch cart was light on the front wheel.. The eveners were already in the top hole so mabey I need to make a new mounting with higher holes ??..
John

Thought it’d be a good time to post this pic courtesy of Ray Steele. Looks like this single is making some adjustments to get/keep the load moving too!

hey geoff, i think i hear what you are saying. i totally understand the force created from a horses hind quarters in a pull like the one pictured above. but after you’ve been hit in the face with the dirt coming out from under their front feet, you start wondering how much is balancing and how much is digging? beautiful to watch, ain’t it.

hey tim, please excuse my remark. it wasn’t meant that way. actually i liked your description and have seen horses pinned, sometimes with such strain that there forelegs were momentarily free. i was trying to say like us all that a horse is a living breathing machine capable of many many shifts of force, balance, muscle or whatever. one hour after birth they are on their feet and a few hours later able to run, stronger and faster than we will ever be. they already have all the skills we want to “teach” them at their disposal. and they just wait there, ears trained on us, all they want to know is what we want. on a good day anyway. mitch