Mini Fithwheel Foamie for S10 pickup

[ebutler]

What are the pitfalls to building a mini Fithwheel Foamie camper trailer to use behind a S10 chevy pickup? I think that you could have a large bed in the balcony and have a fairly roomy area in the rest. Since the foam is very light the frame for the trailer could be built out of light gauge metal and have a single axel (torsion). Make the frame like a space frame? If the front is shaped properly the aerodymanics would be good and would solve the problem of dead airspace between the tow vehicle and the trailer. Should tow very well also. What am I missing here?
Elmo

[GPW]

Plausible !!

[pchast]

I'd love to see a design for that. With a Side Wall Truss
and torsion box floor it could be really light. The Biggest
problem would be support for the hitch pin?

[ebutler]

It is in the idea stage now. I think that a steel frame will be necessary as a foundation.
There will be a torsion box floor for sure.
Elmo

[GPW]

The question is, what would be the advantage in going away from the more traditional Foamie trailer setup ? ... Thinking you’d not only need a steel frame , but one specifically designed for that application ... a very Sturdy steel frame ...

[KCStudly]

Actually, I can see a couple of advantages.

1. You can get more interior space in a relatively shorter tow package.
2. The towing and turning characteristics would, in theory be improved (though the aerodynamics might suffer from that of a trad TD that rides wholly in the TV slipstream).
3. The 2nd kind of cool factor (a Nutnfancy term meaning personal drool factor).

I think this could be done with a single axle and a light weight steel sq tube frame. The key is to bring the loads from the hitch "goose neck" back into the main frame in such a way that you do not create any stress risers at the bottom rear edge of the loft. I'm thinking triangulated truss, not a single big box stick frame member.

Let me see if I can whip up a conceptual sketch.

[KCStudly]

Spit ball sketch for discussion purposes... TLAR.

Red is critical structure, blue is basic outline. The dashed line represents the rear edge of the rear of the bed with the potential for storage in the triangular bay that would otherwise just be there for aesthetics.


Here's another image with the sketch dimensions turned on, tho they tend to garble the image. The dims are very arbitrary at this point and could vary greatly depending on real world dims from the TV.



78 inches from under side to top in the drop down area at back with 10 inches of ground clearance would give a little over 6 ft inside using 2 inch foam, or could be reduced a lot for a slouchy or 1-1/2 thk foam.

Again, this is just thrown out there with no real engineering having been done on it, so...

[ebutler]

I think that I would need a sliding receiver for the short bed. The hitch needs to be on or very near to the leading edge of the trailer.
Elmo

[KCStudly]

[ebutler]

KC thanks for the drawing. I am thinking of using 1" square tubing.
Elmo

[loaderman]

Look at new fifth wheel trailers for design ideas. Fronts are rounded and then taper down to the back, the air you displaced with the front actually pushes you forward.

Thinking you do not need red lines above the bottom of the fifth wheel area. really all you need is the pico design turned into a 5th wheel idea.
Depends on what walls are skinned with maybe.

[KCStudly]

Thinking you do not need red lines above the bottom of the fifth wheel area.

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.

If we were to consider doing this in ultra light foam with minimum frame, I would think that the side foam profile would need to be arched or curved at the transitions, and that epoxy/glass would be needed; both adding complication to the build. Since the OP said he was thinking small tube frame work, I leaned in this direction.

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.

Again, all just back of the napkin thinking.

[GPW]

What about taking advantage of the “curve” .... Stress would be more equally distributed huh ? No stress risers...... 1” tubing is fairly easy to bend ... if you have the equipment ...

[citylights]

Head space in the bed would be a premium. Entry and exit for the bed for two people would be a problem. Commercial 5th wheels are much higher than the cab for this reason, but the obvious down side is the air drag. Also commercial 5th wheels are based on a full size truck and wide. I have reservations about the functionality of this layout. Much of the space in the back is lost by the need for a walkway from entry to the bed.

[GPW]

Sorry , couldn’t help doing a little artistic embellishing ... Looks like an Eagle .... That would be Cool eh ??