Hensley Arrow: How does it REALLY work?

tluxon wrote:
I decided to put a little work into seeing what arc the coupler travels through as the trailer rotates in a "swing". It took a little time to construct the points so I stopped at 8 degrees in each direction.



What I learned from this is that in the first 8 degrees of swing, the coupler gets 2.15 inches closer to the tow vehicle. This simulates a pretty short pendulum which makes the lifting wedge angle fairly steep. It appears to me that a strong tension between the TV and TT would work quite effectively at keeping the angle within a few degrees of center. I'm curious to hear what Ron has to say about it.

Tim

Tim,

I agree with your numbers. I might also mention that, for the 8-degree swing, the VPP will be about 13" left and about 13" forward of the centered ball location.

Please keep in mind that this phase of the thread began with a discussion of how much wind force would be required on the side of a HA-equipped TT to make it swing against the "resistance of the hitch".

Lets assume that a "drag" force of 1000# acts through the ball at the 8 degree angle. This rearward force will act on a moment arm of about 1' relative to the location of the instantaneous center of rotation (a.k.a. VPP). It will produce a CW moment of about 1000 ft-lb.

Lets assume the TT body length is about 30' and the center of the right-directed wind force acts at about 20' rearward of the VPP. The required wind force is 50#.

Therefore, even at this rather large TT yaw angle, a wind gust could easily overcome the HA's "yaw resistance". It's good that the TT's tires are there to provide the swing resistance that the HA cannot.

Now, if you want to evaluate the dynamic force added by the "reel in" effect, you could use the method I presented in the link found in my previous response to Will.

Ron