Hensley Arrow: How does it REALLY work?

Stressor wrote:
Tim,

If it can be demonstrated empirically, the theory needs to accomodate what is actually happening to be a valid theory. That is what theories do.

You've got the right idea here, but it's the other way around. The scientific approach is to generate a theory to describe a phenomenon and then design experiments and collect relevant empirical data to prove the theory works. The theory need not 'accomodate' whatever empirical data you select, the experiment has to be designed to produce data such that the theory is proven valid or disproven.

Stressor wrote:
The point of fixity when towing is point C, representing your tow vehicle with all of its mass and resistance to changing direction. Holding DE and AB to a fixed length makes them rockers in 4-bar parlance, and while C does not exist physically, except as the entire mass of the TV as it is attached at the hitch receiver, the linkage acts as if it is a rigid connection. That the legs are fixed, rigid entities to a pulling force was demonstrated by a come-a-long and a willow tree.

Point C is imaginary. It's a conceptual or virtual point that describes the actions of the linkage. It represents only the theroretical ellipse traced by the locii of intersections of the links, and gives us some understanding of the directions in which the force vectors are acting.

Stressor wrote:
In operation, if a force is applied to the travel trailer sufficient to move C, the entire rig moves to the side. This is something no Hensley owner will argue.

Since 'C' is imaginary, the only force that can be applied to it is an imaginary force. Forces act on bodies.

Stressor wrote:
That the links pivot as demonstrated if point C is moved, by turning a steering wheel for example, is what you are all calling translation. The links move to the side.

That's certainly not what I'm calling translation. From a straight ahead position of the TV/TT combination, the initial movement of the black part relative to the orange part has can only be in translation, i.e. sideways. As the links move, the rotationsl effects become apparent.

Stressor wrote:
At approximately 30 degrees angular difference between the TV and the TT, the links are fully extended, translated if you will, and continued turning beyond that causes the links to rotate until they run into themselves at about 75 degrees TV/TV angular difference in the real world.

There ain't no magic.

The only 'magic' I was referring to (and why I put it in quotes) is that coming from Adam Smith's invisible hand. We buy things of perceived value when the price is acceptable to us. If the price is 'too high' we don't buy. That Hensley stays in business is proof that 'enough' people perceive adequate value in the hitch at its current price.

Ed B