Hensley Arrow: How does it REALLY work?

Stressor wrote:

Ron Gratz wrote:
The TT end of the linkage (the rear, upper, orange part of the HA) can move side to side and also can rotate (yaw). In fact, it only can move if it simultaneously translates and rotates. This is exactly what a pendulum does. As any given point on the pendulum rod moves to the side, the rod simultaneously changes its angle relative to vertical. If a lateral force is applied to the TT, the TT will swing to the side until the yaw angle is sufficient for the tires to develop an equal opposing force via their slip angles.

The orange head on my Hensley is fixed into position and never, ever moves. Two great big iron bars keep it from moving at all. There is no movement except through the linkage.

I don't think Ron was trying to imply that the orange head moved - only that the linkage on that side (the trailer side) of the Hensley could move side to side while rotating [added] (angulating) with respect to the TV. I don't believe he's saying the rear link ever rotates with respect to the TT.

Stressor wrote:
Tim,

tluxon wrote:

The VPP moves only as a result of a change in geometry. The lateral forces may or may not result in a change in geometry. With the Hensley, the vast majority of lateral force is reacted to by the tires of both vehicles due to the nature of the leverage of the linkage.

My point exactly. The leverage of the linkage prevents a change in geometry.

I hope what you mean by "prevents" is "greatly resists". The end result is that any change will be virtually imperceptible, but it is possible for a significant lateral force to create a slight change in the geometry of the linkage which indeed would result in a change in the angle between the TT and TV. The magnitude would have to be very large and it would still result in an extremely small angle change and leverage against the TV. It would be virtually impossible for the TV to react in a way that could cause oscillation, so the driver will never be able to detect any change.

[added] Now, if you take the tires out of the equation by hanging the vehicles into a position much like a clock pendulum, the motion - and resultant continual change in geometry - is quite free. It just simulates the motion of a much longer pendulum due to the linkage. Make sense?

Tim