Ron, On my thread, there was a story from what happened to Garfield in a corner with his trailer, so I do agree that the hitch won't save me from every law of physics or that of a ham fisted maneuver by the driver and that towing requires more attention - no matter what hitch.
I fully agree about the tongue issue, I just wanted to clarify the difference between a hard pull to the left with an electrical brake issue VS a very slight or negligible push from the hitch when the van does more braking than the TT with the controller set low on purpose.
I'll not disagree with Ron, but maybe I can seek to clarify for those that may not be entirely familiar with the Hensley operation...
Ron says: "Because of the way the HA's linkage works, it is especially important to ensure a HA-equipped TT is not allowed to push on the TV."
To which I would suggest we append: "....in a cornering situation where one link has had a chance to go past the center position." I'm guessing this would be almost a 30 degree turn.
While the brake controller should always be active so that the TV's brakes do not supply the primary force stopping the TT, in a primarily straight line or slight turning situation, less than say 15 or 20 degrees, there is no reason to anticipate the Hensley will enhance anything other than a straight and true, fully undramatic stop, absent the uneven trailer braking situation being discussed here.
We could look more closely at the geometry to determine exactly what angles have the potential to become un-nerving, but in a panic situation, we won't have the option of chosing the specific conditions anyway.
All you have to do is take your Hensley Arrow equipped rig out on a vacant stretch of road, and turn down the gain on the brake controller. Then brake while steering. Merely changing lanes while braking hard will do the trick.
The tongue will move either left or right as the linkage collapses, the trailer will stay directly behind the tow vehicle for the simple reason that it can't go anywhere else under those conditions.
And none ever have.
The RGIH might work differently, but then, he don't sell many hitches.
Maybe Milt's comment should be appended with the phrase: "...up to the limits of adhesion." Under normal circumstances, most of us are not skidding down the road, but when either the TT or the TV start to skid, unusual things happen.
Milt, that's the realm we're in here. This recent discussion is all and only about "slippery conditions." The Hensley can only "hit the stop" when either the TV or TT (or both) is skidding. And I know there is no "stop." People who use this phrase are talking about what happens when the links interfere at their limits of travel.
You may be old and wise, but I've still got about 5 years on you.
6MISFITZ wrote: Ron, On my thread, there was a story from what happened to Garfield in a corner with his trailer, so I do agree that the hitch won't save me from every law of physics or that of a ham fisted maneuver by the driver and that towing requires more attention - no matter what hitch.
Gee, I think I was just insulted!!! LOL! (Kidding Mike!)
Anyway, this thread extension appears to be focusing around an incident that I experienced last summer, so I thought I should clarify things, expecially because it underscores the need to ensure there's proper braking pressure to the trailer to control the Hensley even in situations where it may not be thought necessary.
I experienced a situation last summer where I was slowly coasting into an intersection to make a 90 degree left turn. I was in a small town and there was no traffic around and I had the whole intersection to myself. I rolled into the intersection doing 10-15 kph and quickly cranked on the wheel without applying the brakes. After pulling a long trailer for a while you get into the habit of pulling well into the intersection and turn sharply, and that's what I did.
What happend next I didn't foresee, although I should have. The short wheelbase Yukon turned very quickly as usual, but of course the trailer wanted to keep moving forward in a straight line, so it did. With no brakes to slow it down, it pushed against the Hensley which pivoted to the right and slammed against the stops with enough force to cause the rear wheels of my Yukon to lose traction and skid several feet towards the curb. As soon as I started sliding I instinctively hit the brakes which allowed the trailer to pull back on the Hensley and immediately halted the spin. If we were going much faster we easily could have jacknifed the whole rig.
As I see it there were three major factors that attibuted to this incident:
1. I didn't apply (even lightly) the brakes to help control the trailer in a decelerating change-in-direction manouver.
2. The intersection was wet as it had recently started to rain. It had also been very recently paved and was covered in a mixture of oily water.
3. The short wheelbase of my Yukon worked against me as it turns VERY quickly. A longer WB vehicle wouldn't have been able to turn as quickly and might have prevented this incident.
I consider myself a conservative driver (expecially when it comes to towing) but this incident really caught me by surprise because of the low speed involved. What I've learned from this is the need to apply the brakes in pretty well any decelerating speed manouver in order to ensure the Hensley is well behaved. It also convinced me that there is no way I will ever tow the trailer on snow or ice.
I hope this helps to clarify things.
* This post was
edited 02/04/06 12:02pm by Garfie|d *
2001 Airstream Safari 25SS tugged by 2001 GMC Yukon 5.3L 3.73
Hensley Arrow • Jordan Ultima • Barker 3000 • Mckesh
bettered wrote: Ron says: "Because of the way the HA's linkage works, it is especially important to ensure a HA-equipped TT is not allowed to push on the TV."
To which I would suggest we append: "....in a cornering situation where one link has had a chance to go past the center position." I'm guessing this would be almost a 30 degree turn.
Ed,
I have stated previously (and Tim Luxon has confirmed with his diagrams -- somewhere back around Page 6) that, due to the HA's linkage geometry, the VPP moves about 20" to the side of the TV's longitudinal centerline when the angle between the TV and TT is about 4 degrees.
This means that, even with a relatively small angle between TT and TV, any forward thrust from the TT will be acting over a "steering lever arm" of more that 1.5 feet. In other words, any forward thrust from the TT would have a tendency to steer the TV. This is why it is important not to allow a HA-equipped TT to push against the TV no matter what the angle -- especially if the HA is being used to compensate for a short wheelbase.
bettered wrote: ---This recent discussion is all and only about "slippery conditions." The Hensley can only "hit the stop" when either the TV or TT (or both) is skidding.
Ed,
With this, I must respectfully disagree. The discussion, which includes several accounts other than Garfie|d's, is not all and only about "slippery conditions". In fact, even in Garfie|d's incident,
"With no brakes to slow it down, it pushed against the Hensley which pivoted to the right and slammed against the stops with enough force to cause the rear wheels of my Yukon to lose traction and skid several feet towards the curb.",
there is no indication that either the TV or the TT was skidding until after the Hensley "slammed against the stops".
Ron
* This post was
edited 02/04/06 09:26pm by Ron Gratz *
Quote: All you have to do is take your Hensley Arrow equipped rig out on a vacant stretch of road, and turn down the gain on the brake controller. Then brake while steering. Merely changing lanes while braking hard will do the trick.
The tongue will move either left or right as the linkage collapses, the trailer will stay directly behind the tow vehicle for the simple reason that it can't go anywhere else under those conditions.
And none ever have.
I'm guessing that the person who posted, Hensley jackknife, would disagree with these assertions.
I have stated previously (and Tim Luxon has confirmed with his diagrams -- somewhere back around Page 6) that, due to the HA's linkage geometry, the VPP moves about 20" to the side of the TV's longitudinal centerline when the angle between the TV and TT is about 4 degrees.
Ron
Wow! Thanks for the clarification Ron. At risk of re-opening the thread on a technical level, I'm wondering if the geometry/resultant force issue becomes critical as a result of the VPP's lateral travel reaching its extreme OR if it becomes significant when "hitting the stop" (collapse of one of the two links) occurs, causing a "jerk" load on the TV's rear wheels as was Garfield's experience. My expectation (not my experience) would be that the latter would be a more likely LOC event.
6MISFITZ wrote: Ron, On my thread, there was a story from what happened to Garfield in a corner with his trailer, so I do agree that the hitch won't save me from every law of physics or that of a ham fisted maneuver by the driver and that towing requires more attention - no matter what hitch.
Gee, I think I was just insulted!!! LOL! (Kidding Mike!)
........
I consider myself a conservative driver (expecially when it comes to towing) but this incident really caught me by surprise because of the low speed involved. What I've learned from this is the need to apply the brakes in pretty well any decelerating speed manouver in order to ensure the Hensley is well behaved. It also convinced me that there is no way I will ever tow the trailer on snow or ice.
I hope this helps to clarify things.
Sorry Garfield, I assure you that comment was not directed at you and in retrospect, I should have written that sentence more carefully .
We were not towing at the time but behind a trailer going through the narrow concrete gates (bollards) at the Peace Bridge 2 years back and that driver very unfortunately turned the tow vehicle too early causing the back of the trailer to swing wide into the concrete bollard and do some very significant damage to the side and back wall of the TT. In defense of that driver, it is a sharp right turn to make the 190 highway ramp once past the Peace Bridge bollard I was talking about.
So far it has not happened to me but I am very conscious of it every time I have to do a sharp turn and if in doubt, I use a spotter!
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