Mini Fithwheel Foamie for S10 pickup

[KCStudly]

The eagle embellishments are nice.

Should a mini 5th wheel be done? That's a whole 'nuther question. Second kind of cool makes people do strange things.

I see it being harder to back up due to the short distance between TV rear axle and 5W (fifth wheel) rear axle.

The height in the bunk was just a guess, a compromise between being able to sit up and being higher than the TV roof.

Agreed that the layout has negatives, but other than needing a step up I don't see much more trouble or lost space than any other rear entry front bed where you sleep along main axis having to climb out over your pillow.

Sleeping crosswise with one person trapped in doesn't appeal to me personally, either.

[ebutler]

quote For 1 inch sq tube construction I would not be comfortable without some form of truss. The weight penalty for taking this out to the profile and having it perform double duty is minimal.

Being a hybrid foamie builder I guess I am not a full convert; I would want a "rigid" structure between the axle and hitch. Since the lines of force are broken severely by the coupler post to under loft joint (...which is also a concentrated load point on the center line, not out at the walls), and again by the notch in the underside of the loft to main body, the best way that I can see to handle the leverage and load concentrations involves steel. Rather than bigger sticks, I chose to spread the structure out, in theory saving weight.

I had the same thought about curving the front (or faceting with mitered straight sections) to gain turning and pitch clearance with the TV cab, the whole front could be stealth bomber/geodesic dome like in construction for a really geometric look. quote

Thinking about this pinbox. http://www.reeseprod.com/content/produc ... 360&part=0 or this one http://www.reeseprod.com/content/produc ... 360&part=0 There is a video on the second link that shows how it works. Looks ideal for short box trucks. The truss frame is what I am looking at, strong and light weight.
A tear is out of the question for my wife. I am thinking that I could use some of the ideas from big rigs for aerodymanics. They seem to have a good handle on this.
Elmo

[atahoekid]

ive been contemplating a foamie fifth wheel for a while. Scamp makes a 19 ft fifth wheel that seems about the right size to me. In my ideal world, i could find a frame from that size 5'er to scavenge. Otherwise you're looking at having to fabricate one. i think KC is on the right track with his drawing and definitely the stress area is correct and triangulating the frame will make it strong.

To my way of thinking, the issues to consider are the need for a sliding hitch and the headroom in the bed area vs. the aerodynamic issues. The body needs to be constructed using the same principles we use for building any other foamie.

I'd like to see this happen.

[ebutler]

The triangulation is a must for the type frame I am thinking of. Having built a tube fuselage for an airplane I am a believer in the strength to weight ratio. I have the tools and will soon complete a 24' X40' shop so will have the space to build it. Too bad that I am totally cad challenged( don't know squat about it).
Elmo

[GPW]

... let me guess .... you have a powered recumbent too .... ???

[ebutler]

... let me guess .... you have a powered recumbent too .... ???

yes I do. 2 1/2 hp Harbor Freight engine gets 150 mpg. I built the bike frame from 4130 chrome moly tubing it is a modified Easy Racer type. I run the engine through the bikes gearing so it will pull any hill I can get traction on and still have a good cruise speed too. One day I want to build a bike tear to pull behind it
elmo

[atahoekid]

Holy crap!! I'm guessing with your set of fabricating skills, that frame will be no problem. I'm jealous of your shop. i built my Road Foamie in 1/2 of my garage. That was no fun... A 5'er Foamie will need more room than that. You should have plenty. I know what you mean by CAD skills. I learned the old fashioned way. Still do drawings that way. I guess I should learn one of these days.

[KCStudly]

When we moved into our current home 15 years ago, I set up a drafting table in the basement office because I couldn't afford to buy the CAD software that was available back then. I went to the local drafting supply place to pick up a few things (I forget what, maybe pencil lead or vellum) and they had a nice chuckle at my expense saying, "does anyone still use this stuff anymore?"... and they were in the business!

Anyway, if you have any design and/or drafting experience at all, once you go 3D CAD, you will never go back.

[atahoekid]

When we moved into our current home 15 years ago, I set up a drafting table in the basement office because I couldn't afford to buy the CAD software that was available back then. I went to the local drafting supply place to pick up a few things (I forget what, maybe pencil lead or vellum) and they had a nice chuckle at my expense saying, "does anyone still use this stuff anymore?"... and they were in the business!

Anyway, if you have any design and/or drafting experience at all, once you go 3D CAD, you will never go back.

I know you're right but I can draw (yup, I still have the tools) faster than I can try to figure out CAD. I'm still old school...

[RandyG]

The support angles can be built under the cab and dont have to be so big. A trailer is just a bridge from the hitch to the axle, well pretty much. There are many bridges designed with a flat upper with the support under it. Some are done with cables, hmmm . I'm not sure about the stresses you get with a fifth wheel, I havent put much thought into it. But if you were to build the frame throughout the cab, would it be a foamy - steel hybrid? Kc has a good design, not arguing that, there are alot of ways to go about it.

[wagondude]

The Scamp might be just the ticket. Here is a strange duck: viewtopic.php?f=52&t=57718 . The Scamp has a platform where the pin should mount terminating in a tongue that converts it to a bumper pull. It is right down the road from me. I need to stop by and get pics of the setup from better angles. Never seen one set up like that before. The Scamp could be pulled by an S10, though.

[atahoekid]

Ive been giving this some thought today since I had a lot of windshield time. I took into consideration the fifth wheels and the framework they are built on and I'm thinking that there should be a way to build it without the massive frame that KC drew up. I do believe triangulating it is the way to go but i'm not sure it needs to be that hefty.

Since I'm working on an IPAD and I don't know how to sketch anything with it, I'll try to explain in words. We can call the frame where the bed is the upper frame, where the living area is can be called the main frame and the upright section joining those two halves can be called the vertical frame. The biggest concerns I have are where the upper frame joins the vertical frame and where the main frame joins the vertical frame. My TLAR engineering eye says if you create a ladder style frame for the upper frame and a similar one for the main frame and triangulate the areas immediately adjacent to the attachment point with the vertical members you can resist the forces that want to pull it horizontally apart. Resisting the vertical forces that would like to shear the main and upper frames from the vertical frame would take triangular gusset plates in the corners. Boxing in and Cross bracing the vertical frame should make it strong enough to resist the forces that want to bend and torque it.
flaws in my thinking?

I'll sketch something up once I get home this weekend and post it. Should be easier than trying to visualize if from words

[RandyG]

Thats what I was thinking Mel. If you look at big fifth wheel flat beds, that hold bulldozers and such, they are build the same way you mention but with heavy I-beams and channels and triangle supports in the corners. Sub those beams for some smaller square tubing and it will work for alight foamie.

[ebutler]

Ive been giving this some thought today since I had a lot of windshield time. I took into consideration the fifth wheels and the framework they are built on and I'm thinking that there should be a way to build it without the massive frame that KC drew up. I do believe triangulating it is the way to go but i'm not sure it needs to be that hefty.

Since I'm working on an IPAD and I don't know how to sketch anything with it, I'll try to explain in words. We can call the frame where the bed is the upper frame, where the living area is can be called the main frame and the upright section joining those two halves can be called the vertical frame. The biggest concerns I have are where the upper frame joins the vertical frame and where the main frame joins the vertical frame. My TLAR engineering eye says if you create a ladder style frame for the upper frame and a similar one for the main frame and triangulate the areas immediately adjacent to the attachment point with the vertical members you can resist the forces that want to pull it horizontally apart. Resisting the vertical forces that would like to shear the main and upper frames from the vertical frame would take triangular gusset plates in the corners. Boxing in and Cross bracing the vertical frame should make it strong enough to resist the forces that want to bend and torque it.
flaws in my thinking?

I'll sketch something up once I get home this weekend and post it. Should be easier than trying to visualize if from words

I have plans from GlenL and the frame is similar to what you described with the addition of X braces in the upper frame and the "vertical" frame.
The main problem is to scale the members down and keep the strength needed.
Elmo

[ebutler]

I plan to make the trailer no wider than the tow vehicle. Trying to cut down drag.
Elmo