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
BurbMan wrote:
With the Hensley, the same lateral force is still present, and with the same magnitude, but the VPP created by the 4-bar linkage effectively moves the force forward in the TV, eliminating the leverage of the moment, and greatly increasing the TV's ability to resist the force.
How'd I do guys?
Don
Don,
I would give you a B+. The HA does not eliminate the moment arm unless you have a TV with an overhang of around 30". In general, the HA significantly reduces the moment arm by projecting the pivot point a fixed distance (lets assume 47" for the time being) forward from the ball connector.
For example, lets assume that, for your rig with a conventional hitch, the TV rear axle to ball distance is 65". Therefore, the conventional hitch would have a moment arm of 65". Lets also assume that installing a HA would add and extra length of 12". This means the axle to ball distance with the HA would be 65+12 = 77". Now if the HA projects the point of application of lateral force forward by 47", the moment arm would be 77-47 = 30". The moment arm has not been eliminated, but it has been reduced from 65" to 30" – more than 50%. Fill in the correct numbers for your rig and you can do the calculations.
But, as the telemarketers say, Wait! There’s more! At the risk of giving away some of the plot, you soon will read that the HA also reduces the magnitude of the lateral force relative to that which would be exerted by a TT coupled with a conventional hitch. So, the reduction in length of the moment arm combined with a reduction in magnitude of the effective lateral force produces a compound effect on the moment which is trying to steer the TV. Stay tuned.
Ron
