How Hensley Works - simplified

[2airishuman]

which brings this cartoonish thread back near the other 'yes BUTT head' threads on the topic.

we trace and retrace which only makes the rut deeper, but in my posts and for the purposes of debate this still applies...

the haha DOES eliminate sway completely...

IF sway is defined as lateral movement of the trailer on the ball (fishtailing)...

(angulated and alternating movement while moving forward)

properly setup the trailer move as if it were on rails, connected as ONE to the tv....

all potential lateral instability however, is NOT eliminated.

but the tv would need to lose traction and then the 2 would move together side to side.

i don't think that is how sway is traditionally defined.

that would be the 'sheet hittiin the fan' in scientific terms.....


the better term might be trailer induced yaw of the tv, but i'm not savy enough to be sure...

http://www.airforums.com/forums/f464...tml#post466512

Originally Posted by SteveH

the claims that it cannot sway seem to be a little far fetched to me...all that needs to happen....is for the rear wheels of the tow vehicle to go into a slide to the side...

so while we may all be typing 'sway' clearly the word is being used for ALL slip sliding away....

and again brakes need to function, brake controller needs to work, traction, gravity and a driver with a HEAD are required.

can you wreck any rig combo? sure just like wrecking a thread or a topic or relationships...

but it takes a lotta effort!

many of us have gone to extra and repeated efforts to also explain that...

if the trailer brakes FAIL (or the controller) and the driver BRAKES while turning and going down hill on black ice on a roadway banked away from the apex...

bad things will happen but it isn't termed sway.

also this hitch doesn't protect against atomic fallout, bullies, road collapse or networknitwits...

all clearly other forms of sway.

these guys did a great job of exchanging ideas on how the haha 'works' for a few pages...

and until the silliness hit.

looks like we can be proud of getting to that point MUCH quicker.

Woodalls Open Roads Forum: Travel Trailers: Hensley Arrow: How does it REALLY work?

the cad is cute and exactly on par with the video, GOOD JOB!

cheers
2air'

[HiHoAgRV]

My only reason, well the main reason, I did the cad files was to show that if someone understands from all of our verbage that a hitch can keep a trailer from ever possibly swinging side to side, they could be mistaken. A hitch that mimics a 5th wheel setup can have the same great result as a 5th wheel - a side force on the trailer has a much smaller tendency to rotate the TV and start uncontrolled oscillations. If that is the root defination of 'sway' then I'm on the same page as ya'll. It could be intrepreted incorrectly - "the 18 wheeler started to sway and then hit the ditch" - could never happen by the above definition of 'sway'. I guess it's all in the definitions.

All said, it's a great product and helps many folks enjoy the Airstream experience that otherwise might not

Oh yea, the other reason I did the images - it was fun!

[ScottW]

The bottom line is.......manure happens! slow down, keep off the interstates and enjoy life in the slow lane.
Just my humble opinion.

[Jaxon]

Originally Posted by 2airishuman

that would be the 'sheet hittiin the fan' in scientific terms.....
[/B][/I]

cheers
2air'

Hey 2air, Is that an axis III or axis V dx?

[SteveH]

Originally Posted by 2airishuman

which brings this cartoonish thread back near the other 'yes BUTT head' threads on the topic.

we trace and retrace which only makes the rut deeper, but in my posts and for the purposes of debate this still applies...

the haha DOES eliminate sway completely...

IF sway is defined as lateral movement of the trailer on the ball (fishtailing)...

(angulated and alternating movement while moving forward)

properly setup the trailer move as if it were on rails, connected as ONE to the tv....

all potential lateral instability however, is NOT eliminated.

but the tv would need to lose traction and then the 2 would move together side to side.

i don't think that is how sway is traditionally defined.

that would be the 'sheet hittiin the fan' in scientific terms.....


the better term might be trailer induced yaw of the tv, but i'm not savy enough to be sure...

http://www.airforums.com/forums/f464...tml#post466512



so while we may all be typing 'sway' clearly the word is being used for ALL slip sliding away....

and again brakes need to function, brake controller needs to work, traction, gravity and a driver with a HEAD are required.

can you wreck any rig combo? sure just like wrecking a thread or a topic or relationships...

but it takes a lotta effort!

many of us have gone to extra and repeated efforts to also explain that...

if the trailer brakes FAIL (or the controller) and the driver BRAKES while turning and going down hill on black ice on a roadway banked away from the apex...

bad things will happen but it isn't termed sway.

also this hitch doesn't protect against atomic fallout, bullies, road collapse or networknitwits...

all clearly other forms of sway.

these guys did a great job of exchanging ideas on how the haha 'works' for a few pages...

and until the silliness hit.

looks like we can be proud of getting to that point MUCH quicker.

Woodalls Open Roads Forum: Travel Trailers: Hensley Arrow: How does it REALLY work?

the cad is cute and exactly on par with the video, GOOD JOB!

cheers
2air'

2air,

If you would quote my entire post, and not just a section of it that you want to use as fodder for ridicule, I think it would be more fair. The section you left out, "Granted, this senario would also be a major problem for any other type of tow vehicle/trailer combo...even a fifth wheel", pretty much says what you have said. Or, does the fact that you have a ton of posts on this forum, and I have few, give you that right?

Have a nice day, I am finished with this thread.

[2airishuman]

Originally Posted by SteveH

...If you would quote my entire post...

hello steveH...

only quoted the piece that the comment was directed toward.

intent was just to focus on the terms sway and all

no malice was intended.

had the full quote been included, my reply would have also addressed the other issues contained...

such as...

...After studying how the thing works in this thread...

since studying THIS thread isn't a useful way to appreciate HOW it works...

the 5th wheel analogy is incomplete, the video is misleading, the sway word is used vaguely and so on....

Originally Posted by SteveH

...Have a nice day...

back at ya dude! no foolin...

and post count here has almost nothing to do with nothing.

Originally Posted by Jaxon

... Is that an axis III or axis V dx?

i'm looking for the right differential now but my book stops at the 5th dimension, or is it the 6th?

YouTube - The 5th Dimension - Feelin' Alright

now THAT'S sway baby!

cheers
2air'

[wheel interested]

Hey this thread has a little of everything I like, information, drama, humor. I think both the lego video and 2Air's explanation has given me a much better idea of how the HA works. Never underestimate the value of teaching with toys and laughter. Also good advice Paula.

[HiHoAgRV]

Originally Posted by 2airishuman

...these guys did a great job of exchanging ideas on how the haha 'works' for a few pages...

Woodalls Open Roads Forum: Travel Trailers: Hensley Arrow: How does it REALLY work?

cheers
2air'

Great link, I agree it should be recommended reading since it was kept purely analytical, no cap letters, and they quickly agreed on what certain words mean. It does give several issues to be aware of such as several cases of where the system did jack knife and how the TT is not actually 'locked' to the TV and how the "bump" has a bite. The marketing guys muddy the water is by implying the trailer has no chance of movement unless initiated by the TV and how the system acts like the two are a single unit. If they said 'Makes your bumper pull tow like a 5th wheel', buddy I'm with ya!!!

[2airishuman]

Originally Posted by HiHoAgRV

Great link, I agree it should be recommended reading ...

IT IS recommended reading over here, POST 5...

http://www.airforums.com/forums/f464...ide-26279.html

where the wild claims and counter claims don't litter the learning...

the problem with most of these other threads is jumping around, endless debates and silly silly 'don't waste yer money' comments...

the haha thread isn't about me, it's about the product and powered by experienced users or the sincerely curious, and the soon 2b users...

we're past the dollar debate and all about helping each other with the contraption....

we don't need drawings or video just to argue, cuze we are all (mostly) about keeping it "straight as an arrow" in haha land.

so i hope to keep it that way, and don't expect the best little bits to always be reposted elsewhere....

btw there is NO CHANCE of trailer movement unless initiated by the tv driver and it really DOES allow the 2 pieces to act as ONE...

as long as we define sway and craphittingthefan events clearly.

cheers
2air'

[HiHoAgRV]

Originally Posted by 2airishuman

...so i hope to keep it that way, and don't expect the best little bits to always be reposted elsewhere....
2air'

So tell us the truth and don't hold back,
Do you like the thing?

Numbers say this and that, snake oil and B.S., opinions vary of how the magic is bottled but it seems everyone is happy with the product and the companys service It's kinda fun debating the inconsequental details because-
For all the moaning, I have not seen a single post that said 'I bought it and want my money back' - now that's as good as it gets.

Maybe the Trailer manufacturer's can say the same one day

[2airishuman]

Originally Posted by HiHoAgRV

So tell us the truth and don't hold back, Do you like the thing?...

i'll let ya know when and if i get one...

kinda pricey for what it does.

cheers
2air'

[ROBERTSUNRUS]

Hi, 2air. I had my $3,000.00 all laid out for a new Ha Ha, but that part about not protecting me from "Bullies" killed the deal. I would have quoted your whole post, but it would take up too much of my computer screen. Sorry!

[Jaxon]

Originally Posted by 2airishuman

i'm looking for the right differential now but my book stops at the 5th dimension, or is it the 6th?

now THAT'S sway baby!
cheers
2air'

Yeah, I hear ya'... myself, I'm Innagadavida... but I think I need to tweak my meds a bit...

http://www.youtube.com/watch?v=Jyf25Sb7wLs

[Ron Gratz]

I just ran across this thread and was surprised by the unresolved differences of opinion about how a trailer can or cannot move when attached to a Hensley Arrow. I really didn’t want to join another RV forum; and this one might seem like a strange choice since I’ve never owned an Airstream product. However, another opportunity to expound on how the Hensley Arrow works was too much to resist.

First, the disclaimers. I’ve never owned an Airstream product; although we did seriously consider buying an Airstream trailer in 1994. I’ve never towed with a Hensley Arrow; although I have been close enough to a couple to touch them. The only thing I’m currently towing is a Ford Explorer.

The question, “How does the Hensley Arrow work”, will receive different answers. Most owners will say, “Very well.” or “Just as advertised”. IMO, a good technical answer is, “The Hensley Arrow works by enabling a yaw-axis torque to be transmitted between TV and TT.” But, then, all friction-based sway controls also work by enabling a yaw-axis torque to be transmitted between TV and TT. So, the real answer to the HA question lies in the method by which it enables torque transfer.

The HA uses a “linkage” system to connect the TT to the TV. A rendering of the HA’s linkage is shown below on the left. The rendering is a bit misleading because the center-center spacing of the front pins is too small relative to the rear. The proper scale is shown in the plot on the right. The plot units are inches.

The location of the Virtual Pivot Point (VPP) is at the intersection of lines projected through the centers of the two side links. For the orientation shown on the right, the VPP would lie about 52” forward of the ball. The blue dots define the path followed by the ball as the TT swings relative to the TV. IMO, it is essential to understand how the VPP works in order to understand how the HA works.

The legend items are:
Lower (front) Unit, Left Side Link, Right Side Link, Rear (upper) Unit, Ball, Ball Path

More to come. I plan to make separate postings to keep individual posts from being too long.

Ron

[Sean Woodruff]

Ron, I know you'll keep everyone busy. Have fun!

[Ron Gratz]

The lateral force which can be exerted on the tow vehicle by the trailer is a primary cause of TV/TT yaw instability. This force is transmitted from TT to TV via the ball coupler.

If no sway control is used, no torque can be transmitted between TT and TV and the ball becomes the effective point of application of the lateral force. The longitudinal distance from the ball to the TV's rear axle is a lever arm over which the lateral force acts to produce a "steering" torque on the TV.

The primary function of the 4-bar linkage is to transmit yaw-axis torque between the TT and TV. The result is an effective forward moving of the point of application of lateral force. The effective point of application, which has been called the Virtual Pivot Point (VPP), is located at the intersection of lines projected through the centers of the side links. The plot below shows the approximate location of the HA's VPP when the angle between TV and TT is zero.

[JimGolden]

Hey Gang,

Check this out. Looks like a new and improved Hensley design in town, and at 2/3 the price.

The Jim Hensley Hitch Story | ProPride, Incorporated

[CanoeStream]

Originally Posted by JimGolden

Looks like a new and improved Hensley design in town, and at 2/3 the price.

That has received some discussion here for several weeks now. The thread was last posted to about 3 hours ago.

[Ron Gratz]

As the angle between TV and TT increases to 1 degree, 2 degrees, 3 degrees, and 4 degrees, the VPP moves to locations indicated by the 2nd, 3rd, 4th, and 5th x's respectively, as shown below.

When the angle reaches slightly more than 4 degrees, the VPP is at its maximum lateral excursion. It also in important to note that, at this relatively small articulation, the VPP has moved rearward about 24" from the 0 degree position. This means the reduction in steering torque is considerably less than when the linkage is in the centered orientation.

At each angle, the trailer swings as though its tongue were extended to the location of the VPP and the TT is pivoting about the VPP. At 4 degrees, the linkage has rotated so that the ball coupler now is offset about 3" from its centered position. And, the ball has moved forward about 1" relative to its centered position.

[Ron Gratz]

When the articulation reaches 10 degrees, the VPP has moved almost all the way back to the hitch. The VPP is about 9" forward and 9" to the side of the centered position of the ball. In 10 degrees of rotation of the linkage, the forward projection of the ball has decreased from about 52" to about 9". The TT continues to swing as though it were pivoting about the VPP.

When the articulation reaches about 15.5 degrees, the right link will be co-linear with the front link; and the VPP location will coincide with the center of the left front pin. The ball will have reached its maximum excursion of about 5". The forward projection of the VPP will be about 5".

Beyond the 15.5 degree angle, the linkage begins to "collapse" quite rapidly and the ball moves back toward the centerline. The maximum forward excursion of the ball is about 6.4" at an angle of about 62 degrees.