Hensley Arrow: How does it REALLY work?

Ron Gratz wrote:
Virtual Pivot Point versus Apparent Pivot Point

It appears that the virtual pivot point and the apparent pivot point converge to the same location when the angle between TV and TT is zero.

Define:
Virtual Pivot Point (VPP) is the location at which straight lines projected through the centers of the side links will converge.
VPPmax is the location of the VPP when the angle between TV and TT is zero.
Apparent Pivot Point (APP) is the location at which the longitudinal centerline of the TT intersects the longitudinal centerline of the TV.
APPmax is the location of the APP when the angle between TV and TT is zero.

My AutoCAD models indicate that VPP and APP converge to the same point, VPPmax = APPmax, when the angle between TV and TT is zero. Also, for non-zero angles, APP never lies forward of VPPmax. Please disregard my earlier incorrect statement about the APP being at infinity in front of the TV when the angle is zero.

I hope that Tim can use his modeling software to confirm these findings when he returns. If they are correct, our task of answering how the HA really works should be simplified.

Ron

My SolidWorks model shows me that everything you say here is 100% correct except for the statement, "APP never lies forward of VPPmax". According to the model, APP and VPPmax do in fact converge to where they are equal when angle TV-TT is zero. However, at all other angles, APP is actually further forward than VPPmax. This surprised me, so as an example, I've attached an image depicting the relationship when angle TV-TT is 5 degrees.



I guess it doesn't matter too much when it comes to sway since most dangerous sway events seem to be triggered when the angle between the TV and the TT is quite small. For me, using either the APP or the VPP for figuring the pivot point when it comes to sway prevention would both be practical.

Tim