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Building a 5th Wheel Air Ride Hitch


bmzero

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You have "mad skills". I so enjoy looking at your projects..... :)

Jack & Danielle Mayer #60376 Lifetime Member
Living on the road since 2000

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Looks like TIG work??

"JOE DIRT"--1994 Volvo WIA64TES VED12, 425HP, SUPER 10, SINGLED, 370 REARS, DOMETIC AUXILLARY A/C, ONAN QD10000 GENNY
2006 Fleetwood Wilderness Advantage AX6 40ft
"I'm not in right now.......I'm out finding myself. If I get back before I return, leave me a message and one of us will get back to you..??"

I'm right 97% of the time.........and nobody cares about the other 4%

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Man, BM, that's impressive. I am just wondering if there is sufficient resistance to twisting the hitch due to non-straght- line forces that would try to rotate the hitch around its vertical axis, ie, a sudden stop while turning, ect. The lateral bars at the rear of the hitch would keep the rear floating part of the hitch from going side to side but it seems that the front of the floating part could move right or left if excessive force was applied and twist the floating part [as viewed from above]. I'm not trying to be too critical but I am fascinated by your design and have spent a lot of time studying it and that is just a question that popped up. You have probably thought all of that through and I may be missing something. Thanks for all the pictures. I look forward to following your progress on what, to me, seems a very challenging project. Godspeed. Charlie

Don't ever tell a soldier that he doesn't understand the cost of war.

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Man, BM, that's impressive. I am just wondering if there is sufficient resistance to twisting the hitch due to non-straght- line forces that would try to rotate the hitch around its vertical axis, ie, a sudden stop while turning, ect. The lateral bars at the rear of the hitch would keep the rear floating part of the hitch from going side to side but it seems that the front of the floating part could move right or left if excessive force was applied and twist the floating part [as viewed from above]. I'm not trying to be too critical but I am fascinated by your design and have spent a lot of time studying it and that is just a question that popped up. You have probably thought all of that through and I may be missing something. Thanks for all the pictures. I look forward to following your progress on what, to me, seems a very challenging project. Godspeed. Charlie

 

Thanks for checking it out Charlie. That's what the remaining parts (in the previously attached eDrawings screenshots), being cut now, are for. They will connect the upper arms together, and the lower arms together. That will eliminate the twist. Once you see them added to the hitch, it will make more sense. You bring up a valid concern, though.

 

"Challenging" is exactly right. Henry told me this was going to be a big project. I believed him, but I still underestimated the amount of time it would take. I have greatly enjoyed it, though. It has forced me to learn Solidworks and the entire process of creating working, real world, assemblies, something a web designer like myself usually only dreams of. It has been a great learning experience.

"Willy Mammoth" - Volvo 730, Sold

Heartland Cyclone 4000 Toy Hauler
T-Minus 26 years and counting to being a full timer.

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HDT porn, love it...... Nice work

"It is better to have more truck than you need than to need more truck than you have"

2001 Volvo 660, Cummins 400 ISX, Eaton 3 Peddle Auto Shift    
2014 Fuzion 40' Toyhauler
2015 Smart Car                                                                                                                                                                          

                                                                                                            

 

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All right, I feel much better now. I figured you had those forces in mind but I didn't see any hardware resisting them......I jumped the gun.....Sorry. I still tend to try to pound square pegs into round holes. I look forward to all your updates. Studying the drawings is fascinating. I'm afraid my pea brain would pop from all the thinking required of this project. My hat is off to you and I will continue follow and marvel at it. I hope you don't mind some questions from an old guy with rusty gears clanking and grinding in his head [me]. Weld On !!! Charlie

Don't ever tell a soldier that he doesn't understand the cost of war.

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Thanks for checking it out Charlie. That's what the remaining parts (in the previously attached eDrawings screenshots), being cut now, are for. They will connect the upper arms together, and the lower arms together. That will eliminate the twist. Once you see them added to the hitch, it will make more sense. You bring up a valid concern, though.

 

"Challenging" is exactly right. Henry told me this was going to be a big project. I believed him, but I still underestimated the amount of time it would take. I have greatly enjoyed it, though. It has forced me to learn Solidworks and the entire process of creating working, real world, assemblies, something a web designer like myself usually only dreams of. It has been a great learning experience.

I was wondering....did you have a plan to load-test the hitch before placing it into towing service?

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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I was wondering....did you have a plan to load-test the hitch before placing it into towing service?

 

I have thought about that a lot, but haven't come up with a good way to do it other than a big empty parking lot and leave the jacks pretty low on the trailer. I'm also going to put some streaming cameras pointing at it so I could hopefully see any flex that might not be handled properly. Slowly, I would increase the various forces (twist, turn, start stop, etc.).

"Willy Mammoth" - Volvo 730, Sold

Heartland Cyclone 4000 Toy Hauler
T-Minus 26 years and counting to being a full timer.

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I have been watching you hitch build waiting for the completed product. I like your design and use of the B&W head for ease of hookup and no slop.

 

I'm wondering how long you heims will last in this application..... I know there are some high and low quality stuff out there, but I have not had that great of luck with some of the claimed higher quality stuff in a daily driver chassis application.

 

What did you use for this project? I'll be interested in how they hold up for you.

1999 Peterbilt 385 C12 430/1650 13spd

2006 Dodge 3500 DRW 4x4

2010 Hitchhiker Champagne 36 LKRSB

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All right, I feel much better now. I figured you had those forces in mind but I didn't see any hardware resisting them......I jumped the gun.....Sorry. I still tend to try to pound square pegs into round holes. I look forward to all your updates. Studying the drawings is fascinating. I'm afraid my pea brain would pop from all the thinking required of this project. My hat is off to you and I will continue follow and marvel at it. I hope you don't mind some questions from an old guy with rusty gears clanking and grinding in his head [me]. Weld On !!! Charlie

 

Charlie, here's a spy photo from the laser cutter of the swingarm plates.

 

f963c06c-77d5-49b5-b2a3-0c0a02383d18-o.j

"Willy Mammoth" - Volvo 730, Sold

Heartland Cyclone 4000 Toy Hauler
T-Minus 26 years and counting to being a full timer.

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Trust in the SolidWorks. Use the built in stress analysis, it works very well.

 

I'm still a SolidWorks newbie, but I was under the impression that you had to know a lot more about your assembly than I do get accurate FEA data. Garbage in, garbage out.

"Willy Mammoth" - Volvo 730, Sold

Heartland Cyclone 4000 Toy Hauler
T-Minus 26 years and counting to being a full timer.

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I have been watching you hitch build waiting for the completed product. I like your design and use of the B&W head for ease of hookup and no slop.

 

I'm wondering how long you heims will last in this application..... I know there are some high and low quality stuff out there, but I have not had that great of luck with some of the claimed higher quality stuff in a daily driver chassis application.

 

What did you use for this project? I'll be interested in how they hold up for you.

 

I have used about ever brand of heim out there in racing applications. I chose FK's RSMX series for this. We have settled on FK for the heims in our racing applications and have been very happy with them. They're not cheap, but in the long run, we're not replacing them nearly as often and haven't had a parts failure yet.

 

http://www.fkrodends.com/RSMXRSMXT18.html

"Willy Mammoth" - Volvo 730, Sold

Heartland Cyclone 4000 Toy Hauler
T-Minus 26 years and counting to being a full timer.

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The price on those isn't all that bad....I have paid about the same for a QA1 in the .750" size for the Jeep trackbar. May have to try one of these if the QA wears out.

 

I'm running an FK (unknown series) on my Dodge track bar and it has yet to show any play after 10,000 miles, so may be on to something there!

 

Thanks for sharing you build and pics with us!

1999 Peterbilt 385 C12 430/1650 13spd

2006 Dodge 3500 DRW 4x4

2010 Hitchhiker Champagne 36 LKRSB

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The price on those isn't all that bad....I have paid about the same for a QA1 in the .750" size for the Jeep trackbar. May have to try one of these if the QA wears out.

 

I'm running an FK (unknown series) on my Dodge track bar and it has yet to show any play after 10,000 miles, so may be on to something there!

 

Thanks for sharing you build and pics with us!

 

QA1 is a good quality product as well. I have nothing bad to say about their products, whatsoever. For whatever reason, the FK's have just been head and shoulders above any competition for our racing applications. We run the FK's on our rear suspension radius rods on the Polaris RZR XP 1000. The amount of lateral force generated by one of these things in the corners is amazing. The FK's are the only ones that have held up so far. I have about 20+ race hours on the set that's in there now. Some of the others wouldn't last a single 4 hour race before showing large signs of wear.

 

 

3A260BB0-1CD3-4419-B447-4BDCD2D5B7BC-w.j

"Willy Mammoth" - Volvo 730, Sold

Heartland Cyclone 4000 Toy Hauler
T-Minus 26 years and counting to being a full timer.

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I'm still a SolidWorks newbie, but I was under the impression that you had to know a lot more about your assembly than I do get accurate FEA data. Garbage in, garbage out.

 

Not too many moons ago I was taking up space in a fairly intense aerospace landing gear project and we had hot-shot FEA geeks running out of our ears.........NASTRAN , Pro-E, Solidworks and some super-not-named-FEA software/hardware combos as well........This thing as dripping with money (our money.....)

 

Anyhow we had not one.......not two......oh no, we had THREE gear legs that had to be tested-to-failure in a HUGELY instrumented test fixture.

 

I shared a office with a VERY talented stress-geek that was a Aggie-Texan and he was very slow-talking but seldom said very much so many people assumed he was not very sharp......(bad bet)........He was by FAR the best FEA geek I had ever known......his name was Gary.

 

One day landing gear legs arrived and I ask Gary if he had run his FEA numbers yet like the rest of the geeks.........Gary said....."well I thought I would just go out and run a tape measure over the legs before I crunch the numbers"......... I said "well the rest of the geeks have crunched the numbers and the numbers look good so they say the test fixture should be sold for scrap after the first leg is tweeked"

 

Gary smiled maybe the "Rock-Star-Numbers are good........I'll just take a few measurements and crunch my numbers and see how far off I am".....

 

Gary took all three legs into inspection and ran them thru the CMM to confirm dimensions and then checked material specs and heat-treat and stress relief.........

 

Gary took his data into his half of our "cave" and crunched the numbers and his numbers were a TON different that the "Rock-Stars" numbers...... Garys numbers were a fair amount lower that all the other Geeks numbers

 

When the "Rock-Stars" reviewed Garys numbers........ they laughed and many made fun of the .....Aggie.......

 

Guess what......test day came and .......... Leg # 1 was tested......Garys numbers were dead-on........

 

Leg#2 was tested.........Garys numbers were dead-on.......

 

Rock-Stars Yelled....."Time Out"..........Recalibrate the test fixture.......

 

Lab geeks arrive the next morning and confirm and re-cert the test fixture......

 

Next day Leg #3 was tested.........Garys numbers were dead-on.......

 

Numbers were marginal and CONFIRMED......

 

Re-design the gear leg.........this time Gary was the LEAD FEA GEEK..........

 

Leg passed.........

 

Like you said......Garbage in, garbage out.........

 

In the real world the ACTUAL ENTIRE "machine" deals with the stress(s) and often subtle manfg-details are hard for FEA to account for.......

 

In aerospace FEA is huge........but we still trash a lot of parts in testing..........

 

Drive on.....(be careful.....)

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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FEA is definitely the way to go and if, for some reason, a product like this needed to be put into production, I would definitely invest the time into gathering the appropriate data to ensure FEA was accurate. Unfortunately, at this point, I do not have the time to devote to proper analysis of the raw materials, welds, affects of heat from welds, etc. to ensure accurate data goes into FEA, which is why I have probably over-engineered some of the parts.

 

I like your story, Dollytrolley. Thanks for sharing.

"Willy Mammoth" - Volvo 730, Sold

Heartland Cyclone 4000 Toy Hauler
T-Minus 26 years and counting to being a full timer.

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FEA is a great tool as is destructive testing. Before you get to that there is an engineer who has to design the thing to FEA and to destroy. I spent decades in the R & D industry from military, to commercial, to medical etc. in the northeast (Massachusetts 128 corridor, southern New Hampshire, CT) there were tens of thousand engineers and professionals in that region. Funny how after bunch of years you knew from your colleagues who the top dogs were and where they were at any particular time. Word used to spread, "Oh, he's with this company now, when did he changed the job"? The joke in those R & D circles was that in this entire region "there were only seventy or a hundred real engineers and the thousands of other were just support staff".

 

I don't dismiss modern tool, in the hands of a talented designer they are an incredible intellect multiplier, SolidWorks is one example, FEA is another and there are many others, but garbage in garbage out still applies. When I worked at Lockheed my job was to come up with designs and then hand them over to the draftsman with CAD to document it and make it pretty. The "real fun" was the design review when half a dozen of my colleagues would review it and decide whether my now "pretty thing" was a piece of brilliance or garbage in. After few of these sessions I was "invited" to be part of the design review "team", I guess I was OK.

But it also exposed me to how much "garbage" could be generated in a technology company (that division had 7,000 people and hundreds of designers), some of the stuff we looked at were "where was this guys head when he dreamed it up".

Millions of things, ships, airplanes, locomotives, jet engines, ship engines, bulldozers, etc were built before CAD and FEA.

Pyramids are still standing and Columbus made the voyage in a wooden ship. I'm sure there were designers involved in both of these.

You can pull more than 10 G's in one of these and they were designed way before CAD and FEA.

2920314390096176628SMRfIf_ph.jpg

 

Engineering is a combination of several things, certainly the theoretical knowledge and instruction is an important basis, but beyond that is the oodles of experience, advance instruction and a chance to practice it all. But underneath it all is still that "feel". When you look at at that drawing, or you look at that screen, does it feel right? Is it buildable? Does it do the job you want it to do? CAD or FEA will not do any of these for you.

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One of the best things about this forum is the shear ( :lol: PI ) amount of knowledge in really interesting areas. Dolley..that story was AWESOME. And the SR71 spyplane was designed with a slide rule! A while back I read an interesting article about how they were tearing down an old Atlas rocket engine...because the new generation of engineers simply couldn't understand that type of design. Too immersed in computer CAD!

 

One of my biggest beefs with CAD is the designers seem to disregard reality half the time. To make it "pretty" or whatever, they completely don't think about manufacturing ease or simplicity. Its too easy to just draw it up with all those swoopy curves etc (it all works!) and send it on. I think every CAD designer should have to run thru a reality course on manufacture and repair/maintenance.

 

I've been really enjoying following this build--and had to laugh about how you feel you are a "newbie" at CAD...but can produce that kind of complex 3D part. Hmmm..I think Henry maybe needs to watch his tail feathers....

 

I gotta admit I still like farmer engineering: build it out of the biggest piece of steel you can find in the scrap heap! At least it doesn't break (usually).

No camper at present.

Way too many farm machines to maintain.

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FEA is a great tool as is destructive testing. Before you get to that there is an engineer who has to design the thing to FEA and to destroy. I spent decades in the R & D industry from military, to commercial, to medical etc. in the northeast (Massachusetts 128 corridor, southern New Hampshire, CT) there were tens of thousand engineers and professionals in that region. Funny how after bunch of years you knew from your colleagues who the top dogs were and where they were at any particular time. Word used to spread, "Oh, he's with this company now, when did he changed the job"? The joke in those R & D circles was that in this entire region "there were only seventy or a hundred real engineers and the thousands of other were just support staff".

 

I don't dismiss modern tool, in the hands of a talented designer they are an incredible intellect multiplier, SolidWorks is one example, FEA is another and there are many others, but garbage in garbage out still applies. When I worked at Lockheed my job was to come up with designs and then hand them over to the draftsman with CAD to document it and make it pretty. The "real fun" was the design review when half a dozen of my colleagues would review it and decide whether my now "pretty thing" was a piece of brilliance or garbage in. After few of these sessions I was "invited" to be part of the design review "team", I guess I was OK.

But it also exposed me to how much "garbage" could be generated in a technology company (that division had 7,000 people and hundreds of designers), some of the stuff we looked at were "where was this guys head when he dreamed it up".

Millions of things, ships, airplanes, locomotives, jet engines, ship engines, bulldozers, etc were built before CAD and FEA.

Pyramids are still standing and Columbus made the voyage in a wooden ship. I'm sure there were designers involved in both of these.

You can pull more than 10 G's in one of these and they were designed way before CAD and FEA.

2920314390096176628SMRfIf_ph.jpg

 

Engineering is a combination of several things, certainly the theoretical knowledge and instruction is an important basis, but beyond that is the oodles of experience, advance instruction and a chance to practice it all. But underneath it all is still that "feel". When you look at at that drawing, or you look at that screen, does it feel right? Is it buildable? Does it do the job you want it to do? CAD or FEA will not do any of these for you.

X 10 .....Henry......my point exactly....

 

Once in a while a pretty-good looking airplane would be a dud...........and once in a while a UGLY airplane had some USEFUL features.....but for the most of "history" the best aircraft had a "artful" designer that injected that extra........."art"...... that was likely missing from the "initial concept".......

 

Drive on......(here is to the .....ART......of design)

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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I've been really enjoying following this build--and had to laugh about how you feel you are a "newbie" at CAD...but can produce that kind of complex 3D part. Hmmm..I think Henry maybe needs to watch his tail feathers....

 

So have I, I've been around engineering too long to think that I own the design world, met too many designers with as good and better skills. Brit and I have been keeping "in touch" outside the pages of this forum exchanging "thoughts". We were supposed to caucus at the East Coast Rally but I missed him due to my tardiness arriving. We were both looking towards an opportunity of communing together but maybe in the near future.

Younger engineers coming along are the future and it's the responsibility of old farts like me not to criticize but to share our experience to make things go smoothly.

A point about the experience is the discussion above about the links. They all were probably described by their manufacturers as the best ready to climb Himalayans. But in practice some are better than others so there is truth on one side and BS on the other.

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I have thought about that a lot, but haven't come up with a good way to do it other than a big empty parking lot and leave the jacks pretty low on the trailer. I'm also going to put some streaming cameras pointing at it so I could hopefully see any flex that might not be handled properly. Slowly, I would increase the various forces (twist, turn, start stop, etc.).

Bmzero,

 

Some moons ago "We" would be "infected" with a "project" that was "funding-deprived" ( usually the "original players" had blew-thru a few tons of $$$$) AND we.......the "clean-up-crew" were supposed to pull a few rabbits out of our ..........anyhow........Often we would need to do some "Quick-n-Dirty" static testing but was vastly short of $$$ for cobbling-up any kind of test fixtures so.........We often would beg, borrow, or steal a body shop frame machine.........

 

You would be amazed how quickly a Frame-Machine can be configured to give a hefty tug or two or three directions at the same time......

 

We knew the loads we needed to impart and we would plumb a few hyd-gages in the cyl-lines and then with a little math (slide-rule) we would calk the loads on the test article........ we deflected some parts and bent a few and as I recall we popped a few rivets as well.....some of the items were shaved pretty close for weight savings so getting close to yield was often the name of the game......

 

Now was it Rocket-Grade ...........well maybe not ......BUT we did find a few less than ideal stress modes that were quickly........."up-graded"......

 

It sure beat having the old machine scraping it's belly down the runway ...........

 

The frame machine loads are simple ultimate loads so you will still likely need to keep a sharp eye peeled for short-to-long term cycle-loads that often produce stress-induced-cracking........

 

A HDT rear frame section is a ideal test-article for interfacing with a Frame machine and I would guess that you could rig & test in fairly short order.......

 

Just something to ponder......

 

Drive on.............(stress-less......)

97 Freightshaker Century Cummins M11-370 / 1350 /10 spd / 3:08 /tandem/ 20ft Garage/ 30 ft Curtis Dune toybox with a removable horse-haul-module to transport Dolly-The-Painthorse to horse camps and trail heads all over the Western U S

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Watched few episodes of the new series "American Genius" on National Geographic channel featuring the beginnings of the airplane industry, television, computers. etc. Very inspiring about ordinary people pursuing their dreams and making them happen. One thing does come through though, they were not quitters, complainer or couch potatoes.

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