pivoting frames and mounting campers

[dwh]

Hrmm...just had another thought.

All of this is all about isolating the camper box from chassis twist. The theory being that if twisting motion is transferred to the camper, it will torque the camper out of shape.

But what if that basic premise doesn't always apply? Maybe Carl Hunter's design was successful because his setup incorporated the chassis of his Bigfoot trailer as part of the structure. I.e., his FG frame couldn't twist excessively, because the Bigfoot trailer frame on top stiffened it up.

Sure, he used a pivot, but it's a rather stiff sort of pivot. It looks to be right at the natural pivot point for the higher (front) section of the frame, so he had to space the rear of the trailer up off the rear frame up to line it up.

Seems like the triangle might help to stiffen the FG frame rather than freeing it up for maximum flex.


Here's a detail of Bigfoot's front pivot. Also, he used an FG639, not an FG140.

 

[lehel1]

so far so good

hello all

interesting reading.

as many of you already know we mounted our camper on a flatbed, as we also use our truck for hauling so that decision was made easier for us after looking into a 3 or 4 point frame setup as our unimog camper had. we decided do it this way might be enough to meet our needs and help keep it simple.

we're happy to report that our visit to the holister overland ralley in october was a great experience for us. we ran our truck thru all the obsticle courses and the final day expo challenge. yes, we ran our truck extremely slow but the truck preformed flawless. this is something we probably would never have done on our own but the rally sure gives a save enviorment to test our rig. not to be missed if you have a chance to make one.

a key phrase mentioned by one of the instructers that we really appreciated and really brings overland exploring to a point for us is always "protect the asset". we're not just recreationally fourwheeling but moving from point a to b and for many of us taking our home with us.

anyhow, lots of great pics of the event posted under "finished events, big thank you to holister overland rally team"

hope your all enjoying. we are signed up and going to the overland expo next april, hope some of you will be able to make it.

cheers lehel and laura

 

[westyss]

just thought I would fuel the fire with my take on cabin mounting, I have my cabin mounted on an aluminum deck, and that deck is sitting on the frame with a UHMW / rubber sandwich, and its held on with a series of springs, solid mount and a thing I call "side load prevent er" alot like a dump body would be mounted, as in sitting on the frame and held in place with a few items. I have some pics in my build thread on page four near the bottom.
http://www.expeditionportal.com/forum/showthread.php?t=48351&page=4

 

[westyss]

oh, and yeah it seems to work great, I have around 20,000km on the rig about 6000km of that on dirt trails, and there are no signs of any wear or structure failure, it all seems to be working well together. I felt that if I went with a pivot system it would just sit too high and not be worthwhile to me to have a rising top, as it is , when the top is down the height inside is 5' and outside it sits around 5" above cab height. I really wanted to keep it low profile as much as the fuso can be low profile.

top down, 5" over height of cab , 5' of interior headroom.

top up, 6'6" headroom, 18" of lift.

I last had a westy so really like the low profile for driving but need solid side walls.I like simplicity too and I dont think I could have made the frame mounting system any simpler.

 

[dhackney]

Some shots of another solidly mounted deck with a camper. We met this couple at OvEx 2010. They lost their LR/LC (can't remember which) in a shipping accident (dropped container). They built this on a Japanese market (RHD), narrow cab, short wheelbase FG they got in Canada. I can't recall where they got the camper. IIRC the cable stowed in the frame was for emergency towing purposes.

 

[dhackney]

a key phrase mentioned by one of the instructors that we really appreciated and really brings overland exploring to a point for us is always "protect the asset" . we're not just recreationally fourwheeling but moving from point a to b and for many of us taking our home with us.

(emphasis added)

Lehel,

You bring up a key point, and one that is critically important in real-world utilization of an overlanding rig of this type.

While a Taco/LC/LR may be a 2nd, 3rd or 4th vehicle in a household and, in the end, not the end of the world if it rolls down a cliff (unoccupied), an overlanding rig of this scale, especially overseas, is your entire world. In many cases, including ours and many of the overlanders you meet out there, it is their only home.

This means that the actual, real-world utilization of these vehicles is very, very different than a vehicle that is used on weekends or for vacation, especially domestically and in groups, where you can rely on your buddies to help you out (or AAA for that matter).

When you are solo--and in your home--even if your vehicle is capable of a lot (as you demonstrated at Hollister), you are VERY unlikely to ask the vehicle to demonstrate that prowess except in an emergency.

This real-world reality may help people considering a build and a payload design to understand how some examples of rigid mounted payloads have done so well and why long travel payload suspension systems may be overkill in real-world use.

When you are considering what type of payload suspension is right for your chassis and payload, don't forget to include the likely utilization of your vehicle as a primary evaluation factor:

If you are building a vehicle that you can't afford to toss away, then you will be very likely to "protect the asset." In that case, you will probably need a lot less ultimate vehicle capability than you may think.

Doug

 

[jesusgatos]

Great point. I'm not building a rock crawler or a desert race truck, but my past experiences with those type of vehicles has certainly influenced the way I'm building my motorhome (deuce and a half). Even if you're not going to use a vehicle to the full extent of its capabilities, I want to be able to get pretty far off the beaten path, without worrying too much about my rig, because I still won't be using it to anywhere near its full potential.

 

[Witchdoctor Oz]

Found this rural fire truck with a good view of the pivot mount at the front, could not get any closer, it looks very similar to others I’ve seen on this site.
The truck is an Isuzu 550 I think as it was de-badged. The image is well croped in but i also have the full size showing all the truck
It had some very cool roll down heat shields for all the windows.

Cheers
David

 

[Witchdoctor Oz]

This is the full shot.

 

[kerry]

In the first picture, it's hard for me to tell whether the two flat surfaces of the mount are an inch or so apart or whether there's some kind of bushing for the bolt and the two surfaces actually abut each other via the bushing. If there is a space, what's the purpose of it?

 

[dzzz]

that's the mount I used. With oak between frame and subframe:

 

[DontPanic42]

While going through some old pictures, I ran across these. They show the basis for the method I used to mount my RV to the FUSO. Yes, it is a garbage truck but their container is a hollow tube and my fiberglass RV is also basically a hollow tube. It is mounted ridgedly at the rear and has flexible mounts in the front much like the previous postings.

,

My version is a ridged mount in the rear also similar to Carl Hunters with a flexible mount up front but replacing the springs with airbags. The reason I used the airbags was because we had them from the rebuild of a wrecked Freightliner. The pump and tank also give me onboard air. The other change is that I have a subframe between the RV and the FUSO frame to accommodate the drop in the frame and there is a linseed soaked oak strip between the subframe and the FUSO frame.

,

Shocks were added to control roll and pitch. So far the only problem was a slow leak in a fitting, replaced all the plastic with brass, and I messed up a shock in Colorado several years ago. Thanks to the ever present "unforeseen circumstances" I do not have the miles on my rig by this time that I had planned on but so far so good.

 

[jesusgatos]

Yeah, I can take some pictures for you.


That's almost exactly right. On the military trucks, they don't use U-bolts though. They use standard hardware (nuts & bolts) on the outside of the framerails. I'll post some pictures.

Sorry, totally forgot about this. Here are the pics I promised to post a while ago. This is how the military mounted the boxes on the back of deuce and a halfs. They're all spring-mounted except for at the last pair at the back of the frame, those are just bolted together.

 

[westyss]

Those are some interesting pics, some comments about them; first pics show very little vertical movement available on the nearest springs, hard to say but I guesstimate not more than half an inch if that.
The last pic, I would say is showing the end with the most vertical movement available, probably the front mount, furthest from the solidly mounted one you mention, would that be right? And the piece of metal dropping down from the box would be the item that prevents sideways movement, I have been calling that one "The Side Load Preventor" Thats what it looks like to me, I dont see any bolts holding that metal piece onto the frame, just looks like it rides the side of the frame rail?? Thanks for the images.

 

[jesusgatos]

Took another pic that shows everything a little better. Those springs in the foreground are about 6" long, to give you a sense of scale.