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Old 01-04-2011, 02:46 AM   #127
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Moderator - Please close this thread

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This thread seems to have deteriorated into a violation of the spirit of the forums; that is, helpful discussion without vitriolic hateful comments.

Andy deserves better than this. So do interested forum members.
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Old 01-04-2011, 10:31 AM   #128
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As a relatively new Airstream Owner, that has not had years of experience in these areas, I have found the information posted on this forum invaluable. I am in the middle of doing a major remodel and without the guidance and many years of experience provided I would never have been able to attempt this project. Andy has provided all of us with years of valuable experience as well as provided me with many of the parts necessary to complete my project. I think that it would be wise for us to remember the reason we all got excited about owning Airstreams and realize that we are all one family with many personalities. Let's have a great year and be greatful for what we have and for the knowledge, that those who are willing to provide, are constantly providing us to make our journey safer and more enjoyable.
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Old 01-11-2011, 10:28 PM   #129
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Torsion bars.

Here is the test results, of some load equalizing hitch torsion bars, as we promised.

The Hitch Torsion Bar Story

Andy
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Old 01-11-2011, 10:50 PM   #130
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The Hitch Torsion Bar Story

Many thanks Andy
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Old 01-11-2011, 11:41 PM   #131
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Originally Posted by Inland RV Center, In View Post
Here is the test results, of some load equalizing hitch torsion bars, as we promised.

The Hitch Torsion Bar Story

Andy
Hi, Thank You for posting this on the forum and it looked to be a good, fair test. I would like to ask you one question. I noticed that three of the bars were not graphed at the 1800 lb range, did they fail or break at, or before, that point?
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Old 01-12-2011, 01:51 AM   #132
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There is one conclusion which is only partially supported by the data. The statement, "Round bars DO NOT offer any significant difference in stiffness or softness from the tapered bars." In the test, Reese 800 lb round and tapered bars gave identical deflections in the 200 to 600 lb range, but diverged in the 800 to 1600 lb range to a great degree - in fact, the tapered bar deflected about 19.66% less than the round bar, which is statistically significant given the mean deflection was 2.36 (22%) at 1600 lbs. That means the tapered bar deflected 45.33% away across the result range of 1.5 - 3.0 @ 1600 lbs.

The actual conclusion shown by the data is: "Round bars DO NOT offer any significant difference in stiffness or softness from the tapered bars at tensions of 600# or below. At tensions of 800# and above, round bars are progressively less stiff than tapered bars."

There were a few ambiguities and omissions:

When both bars were deflected, which was measured, or were both measured and an average calculated?

How were they levered/balanced onto the scale? How much did the lever deflect in each case? Or were the bars laid parallel onto the scale, not at the spread angle they were designed for?

What was the arbitrary distance? What proportion of the working length of the bar was this?

As an arbitrary distance was used to measure deflection, were all the bars the same length. If not, what length of bar in each case was "overhang?" Using varying proportions of the bar length alters the capacity of the bar by moving the specified leverage point. If one bar design had longer or shorter bars, this would benefit or detract from that bar's apparent performance.

How was this arbitrary distance measured? Different WD hitches have different angles representing two sides of a triangle. The jack and scale, balanced across both bars, represents the third side of a triangle. Did you measure along the adjacent/opposite, or to the center of the hypotenuse - in the event the bars were stressed at their design angles and not in parallel.

Where the measurements taken at the point of leverage, or at their tips?

Additionally, after releasing the load, were measurements taken to see if any of the bars took a set after being so overloaded?

What was the temperature when each test was conducted? Temperature differences affect tensile strength in a statistically significant way. This can affect the behavior of the bars and mechanical scales.

Some or all data was supplied by "sources deemed reliable." Was the same scale and immovable receiver used by all parties? If not, how were the scales calibrated?

How was the immovable receiver designed? How did you ensure it did not flex under 1800 lbs of load? How much did the hitch body deflect? i.e. What was the unloaded/loaded deflection at the hitch end of the bar?
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Old 01-12-2011, 05:36 AM   #133
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Geeee Dave, did you question your mother how she cooked your meals?
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Old 01-12-2011, 06:14 AM   #134
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Quote:
Originally Posted by Dave Park View Post
There is one conclusion which is only partially supported by the data. The statement, "Round bars DO NOT offer any significant difference in stiffness or softness from the tapered bars." In the test, Reese 800 lb round and tapered bars gave identical deflections in the 200 to 600 lb range, but diverged in the 800 to 1600 lb range to a great degree - in fact, the tapered bar deflected about 19.66% less than the round bar, which is statistically significant given the mean deflection was 2.36 (22%) at 1600 lbs. That means the tapered bar deflected 45.33% away across the result range of 1.5 - 3.0 @ 1600 lbs.

The actual conclusion shown by the data is: "Round bars DO NOT offer any significant difference in stiffness or softness from the tapered bars at tensions of 600# or below. At tensions of 800# and above, round bars are progressively less stiff than tapered bars."

There were a few ambiguities and omissions:

When both bars were deflected, which was measured, or were both measured and an average calculated?

How were they levered/balanced onto the scale? How much did the lever deflect in each case? Or were the bars laid parallel onto the scale, not at the spread angle they were designed for?

What was the arbitrary distance? What proportion of the working length of the bar was this?

As an arbitrary distance was used to measure deflection, were all the bars the same length. If not, what length of bar in each case was "overhang?" Using varying proportions of the bar length alters the capacity of the bar by moving the specified leverage point. If one bar design had longer or shorter bars, this would benefit or detract from that bar's apparent performance.

How was this arbitrary distance measured? Different WD hitches have different angles representing two sides of a triangle. The jack and scale, balanced across both bars, represents the third side of a triangle. Did you measure along the adjacent/opposite, or to the center of the hypotenuse - in the event the bars were stressed at their design angles and not in parallel.

Where the measurements taken at the point of leverage, or at their tips?

Additionally, after releasing the load, were measurements taken to see if any of the bars took a set after being so overloaded?

What was the temperature when each test was conducted? Temperature differences affect tensile strength in a statistically significant way. This can affect the behavior of the bars and mechanical scales.

Some or all data was supplied by "sources deemed reliable." Was the same scale and immovable receiver used by all parties? If not, how were the scales calibrated?

How was the immovable receiver designed? How did you ensure it did not flex under 1800 lbs of load? How much did the hitch body deflect? i.e. What was the unloaded/loaded deflection at the hitch end of the bar?

It seem obvious that Andy has slanted his data and conclusions to support his past statments.

So, why does this not surprise me?

His own data contradicts his statements, and he omits data.
From his own chart, even if you go to the 800# column of the 800# bars, it clearly shows the round bars deflected more than the tapered, or trunion Reese bars. This clearly contradicts his statement of, "Round bars DO NOT offer any significant difference in stiffness or softness from the tapered bars."

I guess it's sort of like polititians of the past, "it depends on your definition of the word 'is", with Andy, it depends on your definition of the word "significant".
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Old 01-12-2011, 07:36 AM   #135
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Andy -- on the chart, the label of the horizontal axis reads "Force Exerted Hundred Pounds". Did you mean "Force Exerted Pounds", instead of hundred pounds?
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Old 01-12-2011, 07:45 AM   #136
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Thanks Andy for running and publishing the results.
Were the loads applied at the design stress point that is used when using the product? I ask this because the effective length of the Equalizer design is longer than Reese and varies as the rig goes from running straight to when it is going around a corner.

For the same rated poundage, the Equalizer bars are considerably heavier, an obviously, quite a bit stiffer that the equivalent Reese bars. The frictional dampening of the Equalizer hitch is adjustable but might vary as more hitch weight increased.

It is interesting to note that Norm Bue, who uses an Equalizer hitch, had frame separation on his relatively new 34 footer and had to have the elephant ears installed by a Texas dealer. The same thing happened with another past International president, who also uses a Equalizer on his 34 footer. I do believe that Andy has it right in his conclusion that lighter weight rated bars will result in a softer ride for the Airstream and better weight distribution of the axles of the trailer when rough roads are encountered.
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Old 01-12-2011, 08:27 AM   #137
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Test Results Good To See

Andy - Thanks for taking the time to run the tests and posting your article on this forum. Your results pretty much confirmed info that I had been given by a couple of manufactures.

Dave - Maybe you could take some time to run some controlled tests and then publish your results. I'd like to see what you conclude.
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Old 01-12-2011, 09:26 AM   #138
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Quote:
Originally Posted by Dave Park View Post
There is one conclusion which is only partially supported by the data. The statement, "Round bars DO NOT offer any significant difference in stiffness or softness from the tapered bars." In the test, Reese 800 lb round and tapered bars gave identical deflections in the 200 to 600 lb range, but diverged in the 800 to 1600 lb range to a great degree - in fact, the tapered bar deflected about 19.66% less than the round bar, which is statistically significant given the mean deflection was 2.36 (22%) at 1600 lbs. That means the tapered bar deflected 45.33% away across the result range of 1.5 - 3.0 @ 1600 lbs.

The actual conclusion shown by the data is: "Round bars DO NOT offer any significant difference in stiffness or softness from the tapered bars at tensions of 600# or below. At tensions of 800# and above, round bars are progressively less stiff than tapered bars."

There were a few ambiguities and omissions:

When both bars were deflected, which was measured, or were both measured and an average calculated?

How were they levered/balanced onto the scale? How much did the lever deflect in each case? Or were the bars laid parallel onto the scale, not at the spread angle they were designed for?

What was the arbitrary distance? What proportion of the working length of the bar was this?

As an arbitrary distance was used to measure deflection, were all the bars the same length. If not, what length of bar in each case was "overhang?" Using varying proportions of the bar length alters the capacity of the bar by moving the specified leverage point. If one bar design had longer or shorter bars, this would benefit or detract from that bar's apparent performance.

How was this arbitrary distance measured? Different WD hitches have different angles representing two sides of a triangle. The jack and scale, balanced across both bars, represents the third side of a triangle. Did you measure along the adjacent/opposite, or to the center of the hypotenuse - in the event the bars were stressed at their design angles and not in parallel.

Where the measurements taken at the point of leverage, or at their tips?

Additionally, after releasing the load, were measurements taken to see if any of the bars took a set after being so overloaded?

What was the temperature when each test was conducted? Temperature differences affect tensile strength in a statistically significant way. This can affect the behavior of the bars and mechanical scales.

Some or all data was supplied by "sources deemed reliable." Was the same scale and immovable receiver used by all parties? If not, how were the scales calibrated?

How was the immovable receiver designed? How did you ensure it did not flex under 1800 lbs of load? How much did the hitch body deflect? i.e. What was the unloaded/loaded deflection at the hitch end of the bar?
We will gladly wait for the results of your tests, for comparison purposes.

When might you consider starting them?

Andy
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Old 01-12-2011, 09:27 AM   #139
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Andy -- on the chart, the label of the horizontal axis reads "Force Exerted Hundred Pounds". Did you mean "Force Exerted Pounds", instead of hundred pounds?
That bottom line is pounds.

I will have that corrected this AM.

Thanks for bringing it to my attention.

Andy
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Old 01-12-2011, 09:31 AM   #140
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Quote:
Originally Posted by dwightdi View Post
Thanks Andy for running and publishing the results.
Were the loads applied at the design stress point that is used when using the product? I ask this because the effective length of the Equalizer design is longer than Reese and varies as the rig goes from running straight to when it is going around a corner.

For the same rated poundage, the Equalizer bars are considerably heavier, an obviously, quite a bit stiffer that the equivalent Reese bars. The frictional dampening of the Equalizer hitch is adjustable but might vary as more hitch weight increased.

It is interesting to note that Norm Bue, who uses an Equalizer hitch, had frame separation on his relatively new 34 footer and had to have the elephant ears installed by a Texas dealer. The same thing happened with another past International president, who also uses a Equalizer on his 34 footer. I do believe that Andy has it right in his conclusion that lighter weight rated bars will result in a softer ride for the Airstream and better weight distribution of the axles of the trailer when rough roads are encountered.
The loads were applied to each bar, exactly the same distance from the ball mount, and not the full length of the bar, as in the case of the Equalizer bars.

The bending was measured at that same place.

In that way, a direct comparison can be made.

Andy
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