Hensley Arrow: How does it REALLY work?
There have been several discussions on this hitch that have become somewhat 'controversial'. I am NOT trying to stir this controversy/bashing back up. Instead, I'd like to see a good, intelligent di...
Forum Discussion
Milt (a.k.a. stressor) has posted results from a "demonstration" which is intended to prove that an unrestrained rear unit (orange portion) of a HA will not move when subjected to a lateral force. The demonstration proves nothing of the sort, and it is misleading.
The demonstration is misleading because it ignores the fact that force is a vector. Force has both a MAGNITUDE and a DIRECTION. In this demonstration, the magnitude of the force is irrelevant, although it is presented as being of utmost importance. The direction of the force is of utmost importance, but it has been ignored.
Given that the objective of the demonstration was to show that the rear unit would not move when subjected to a force, it was very fortunate that the black willow tree was located where it was. This fortunate location meant that the POW-R-PULL force would be applied almost exactly in line with the right side link when the hitch was aligned straight ahead.
As Milt stated, "...the hitch will attempt to line up the linkage with the direction of the pull." However, there was no need for the rear unit to move appreciably because the right link already was lined up before the force was applied. If the tree had been a couple feet to the right or a couple feet to the left, the right link and the rear unit would have moved accordingly.
The demonstration also is misleading because the force is applied at the right strut pin location rather than at the ball or at the left strut pin location. Attaching the cable to either of these locations would have caused the rear unit to move to the right.
The post states, "This is intended to simulate a side load on the travel trailer end ..." If so, it is an extremely poor simulation. The images clearly show the cable to be nearly parallel to the longitudinal axis of the hitch and, therefore, the cable force would produce little or no side component. If Milt really had wanted to simulate a side load, he should have attached the cable to either the ball or the left strut pin.
There was no need to go to the trouble of rigging up the POW-R-PULL. It would only be necessary to push laterally by hand on the unrestrained rear unit to see how easily it moves side to side.
Although Milt's incomplete "demonstration" did not test the effect of the angle of the imposed force, it is easy to predict what would have happened:
1. If you pull on the rear unit with a force angled to the LEFT, the rear unit will move to the LEFT.
2. If you pull on the rear unit with a force angled to the RIGHT, the rear unit will move to the RIGHT.
3. And, if you are so lucky as to pull with a force at just the correct angle, the rear unit will not move at all. I guess Milt was just lucky.
Milt achieved nothing more than a result that a fortuitous (for him) and misleading (for the rest of us).
Ron
The demonstration is misleading because it ignores the fact that force is a vector. Force has both a MAGNITUDE and a DIRECTION. In this demonstration, the magnitude of the force is irrelevant, although it is presented as being of utmost importance. The direction of the force is of utmost importance, but it has been ignored.
Given that the objective of the demonstration was to show that the rear unit would not move when subjected to a force, it was very fortunate that the black willow tree was located where it was. This fortunate location meant that the POW-R-PULL force would be applied almost exactly in line with the right side link when the hitch was aligned straight ahead.
As Milt stated, "...the hitch will attempt to line up the linkage with the direction of the pull." However, there was no need for the rear unit to move appreciably because the right link already was lined up before the force was applied. If the tree had been a couple feet to the right or a couple feet to the left, the right link and the rear unit would have moved accordingly.
The demonstration also is misleading because the force is applied at the right strut pin location rather than at the ball or at the left strut pin location. Attaching the cable to either of these locations would have caused the rear unit to move to the right.
The post states, "This is intended to simulate a side load on the travel trailer end ..." If so, it is an extremely poor simulation. The images clearly show the cable to be nearly parallel to the longitudinal axis of the hitch and, therefore, the cable force would produce little or no side component. If Milt really had wanted to simulate a side load, he should have attached the cable to either the ball or the left strut pin.
There was no need to go to the trouble of rigging up the POW-R-PULL. It would only be necessary to push laterally by hand on the unrestrained rear unit to see how easily it moves side to side.
Although Milt's incomplete "demonstration" did not test the effect of the angle of the imposed force, it is easy to predict what would have happened:
1. If you pull on the rear unit with a force angled to the LEFT, the rear unit will move to the LEFT.
2. If you pull on the rear unit with a force angled to the RIGHT, the rear unit will move to the RIGHT.
3. And, if you are so lucky as to pull with a force at just the correct angle, the rear unit will not move at all. I guess Milt was just lucky.
Milt achieved nothing more than a result that a fortuitous (for him) and misleading (for the rest of us).
Ron
