Sorting out loose ends for a new foamie, all input welcome

[vigilant1]

About the raised center section of the roof: What is your reasoning for that (instead of making the whole cabin 75" high?). It will be more complicated to construct as shown (two extra corners per wall), and not as strong (no direct load path from wall to wall). Also, those top corners in a "regular" trailer are handy for cabinets/storage. I've considered a design like this, but I haven't actually stood in one. My concern would be that, with my head up in that box, it might feel a bit "tight" (there's nothing to see except stuff below eye level, possibly requiring stooping down). And, I might be smacking my noggin on those edges (esp when bumbling around at night) resulting in salty language.

Anyway, something to think about.
Mark

[peeler]

About the raised center section of the roof: What is your reasoning for that (instead of making the whole cabin 75" high?). It will be more complicated to construct as shown (two extra corners per wall), and not as strong (no direct load path from wall to wall). Also, those top corners in a "regular" trailer are handy for cabinets/storage. I've considered a design like this, but I haven't actually stood in one. My concern would be that, with my head up in that box, it might feel a bit "tight" (there's nothing to see except stuff below eye level, possibly requiring stooping down). And, I might be smacking my noggin on those edges (esp when bumbling around at night) resulting in salty language.

Anyway, something to think about.
Mark

It was for me, a way to give a small standing area inside the camper, while keeping most of the camper shorter than the wheelbase is wide. The trailer I am building on has a (roughly) 72" wide wheelbase, and a deck height somewhere around 20", and if I build the whole camper 75" high, that will give me a final height of roughly 8', on a 6' wide wheelbase. That to me, combined with building it light, seemed to be pushing beyond the limits of stability when traveling during windy weather, or even being passed by 2 large trucks timed just right, on either or both sides. I think if in the future I build a larger camper, on a 7' wide wheelbase, then I would certainly build taller all around.

As far as the trolley top, meh.. really I always thought they seemed neat. It was a way to reduce the wind drag a bit. I am also hoping to install my vents on the sides of that trolley top, instead of on the roof. Perhaps non-traditional, perhaps using 12 volt muffin fans with a hand crafted vent space, and some sort of cover over the outside to keep rainy weather out.

I still have not decided on windows. The door will be hand crafted. I think one window up toward the front may also be an emergency exit window.

Our tow vehicle for this camper is an old but trusty Dodge Grand Caravan, now approaching 300,000 miles. Probably broken in at this point LoL Anyways the camper as designed really tucks in well, right behind the van, with only the trolley top really protruding up a lot higher than the van's roof. The rest of the camper, both width and height, should allow air to flow pretty well aerodynamically from van on to around the camper. The nose cone side angles arent optimal , and may even add a bit of side turbulence. I'm not well versed on aerodynamics, I know the most of the drag will come from that flat back end. But still, the lines flow well with the van, the trailer tire's footprints follow right in the van's tire prints, the van is also 6' wide, and the roof of the van is 6' at its highest point, tapering back to around 5'6" height at the rear hatch.

[vigilant1]

That to me, combined with building it light, seemed to be pushing beyond the limits of stability when traveling during windy weather, or even being passed by 2 large trucks timed just right, on either or both sides. I think if in the future I build a larger camper, on a 7' wide wheelbase, then I would certainly build taller all around.

As far as aerodynamics, the vertical "sail" of vehicle (how it behaves in crosswinds, with passing trucks, etc) is largely a function of side area and height, it won't be appreciably affected by whether the central section is higher or the side is one slab. As far as aerodynamics, having an "inside corner" as you've got causes "interference drag" which goes down appreciably if you can make the corner less acute than 90 degrees. It's kinda academic at these speeds, but I'd guess it's about even between having more overall frontal area (i.e. with the roof higher all over) and having the interference drag from this raised 30" section.

Anyway, just some comments. I think it looks good as drawn, and the only thing that matters is that you like it.

[Talia62]

It was for me, a way to give a small standing area inside the camper, while keeping most of the camper shorter than the wheelbase is wide.

Easier to do that with a dropped floor.

[peeler]

It was for me, a way to give a small standing area inside the camper, while keeping most of the camper shorter than the wheelbase is wide.

Easier to do that with a dropped floor.

I considered that too I don't have the tools to weld with currently; I'm pretty sure the trailer frame would need to be modified to accomodate a dropped floor.

*edit* my original idea was to do both the trolley top and a section of dropped floor, but I couldn't really seem to pull it together without having to modify the trailer frame. There's the foot of overhang at the back, and then that first beam of metal. I was thinking that first beam is fairly important, so I never tried sketching it with that beam removed. With that back one gone, I could do a 3' long section of drop floor, or even a bit longer if I relocate that second beam forward a few more inches. I haven't explored that line of thought yet, and I am not sure if that would negatively affect the trailer's structural integrity.

[peeler]

I'm totally open to the idea of a section of dropped floor at the rear if I can pull it off without welding.

I'm even open to the idea of losing the trolley top from the design, we're just wanting to have a small standing area, preferably near the door.

[Pmullen503]

A pop top is an option too for standing room. Whatever you do it either makes the tear bigger or more complex.

Back to the floor, 1/4" or 3/8" ply over foam will be adequate. I would suggest you think about any hard points you may want for mounting things. It's easy to cut out a rectangle in the foam and drop a section of 2x4 into the hole to spread out the load before you glue the skins on. That way you can use screws or lag bolt from one side to secure things you may want to bolt to the floor (or bolt the floor to.) I have hold downs lagged to the floor for transporting a motorcycle inside the tear.

[GPW]

Peeler , you’ve drawn a Good plan and you should stick with it .... Keep it Simple and it will be Fun ... !!!

[peeler]

A pop top is an option too for standing room. Whatever you do it either makes the tear bigger or more complex.

Back to the floor, 1/4" or 3/8" ply over foam will be adequate. I would suggest you think about any hard points you may want for mounting things. It's easy to cut out a rectangle in the foam and drop a section of 2x4 into the hole to spread out the load before you glue the skins on. That way you can use screws or lag bolt from one side to secure things you may want to bolt to the floor (or bolt the floor to.) I have hold downs lagged to the floor for transporting a motorcycle inside the tear.

The pop tops are super cool! I think because this is my first camper build, I am going to steer clear of it. But maybe on another build

Thanks for the floor information. I have sketched out the floor framing, and made it a point to run 2x2 or 2x3 under the lines where the cabinets, benches, bed supports, etc, will bolt down, and also points where the floor will bolt to the trailer. I added in some extra support in the walking areas (and porta-potty corner) by adding in some 1x2s, and I added the hold downs to my big list of things that could be used.

[ghcoe]

I have always liked pop up and pop out designs in theory. When I break it down it though it just adds so much more complexity to the design. To me, once you go that route it adds extra weight, adds more places for dust/dirt/water to infiltrate, heating and cooling becomes more of a issue, weakens the entire structure. In the end I think a simple strong structure is going to be so much more enjoyable because you will not have any of the above mentioned issues to deal with. Sure extra interior space is cool, but if you need it, just build a bigger trailer/camper.

[KCStudly]

I'm not sure that I agree on the strength issue. If you look at how Sharon did her 'MyAway" build with the cofferdam style raised rim around the roof opening I think that may be just as strong or maybe even stronger than a flat roof.

Tho all of your other stated concerns seem valid to me.

Then again, isn't it all just a design compromise? I mean, if we are just trying to keep thinks simple wouldn't we be better off stringing a line between two tress and a backpacking tube tent, and crawling in for the night? (Just throwing out a little perspective for the sake of healthy discussion.)

[ghcoe]

Anytime you have a opening in a wall or roof it creates a weak point. That is why houses as well as other structures. have extra support in those areas. Extra support adds extra weight. So I suppose it may not weaken the structure, but you will be adding extra weight to compensate for the weakened structure. Which adds to the complexity of build....

[GPW]

You can add a lot of strength when cutting out doors and windows by merely (and generously) Rounding off all the corners ... A squared corner is what the plane guys call a
“stress riser” ... and likely the first place to break under material stress... Think Hatch and not Door ... You don’t see square doors on boats and planes ... so why on trailers ... A little more trouble to make and hang , but worth it .... JMHO
On a Foamie , every little thing adds up to enhance the integrity of the finished product ...

[peeler]

You can add a lot of strength when cutting out doors and windows by merely (and generously) Rounding off all the corners ... A squared corner is what the plane guys call a
“stress riser” ... and likely the first place to break under material stress... Think Hatch and not Door ... You don’t see square doors on boats and planes ... so why on trailers ... A little more trouble to make and hang , but worth it .... JMHO
On a Foamie , every little thing adds up to enhance the integrity of the finished product ...

Check this out - I sketched up something a little different, but same basic dimensions as before:



still 6' wide x 10' long, i didn't add in all the measurements on it yet as its just a different idea for now. But... I kinda like it. It'd make for a better view of the counters in the back when standing. also a bit easier to construct. possibly a bit stronger (I was going to add support beams at both ends of the trolley top so it may not be much different strength wise. If standing in the back end, with say, a cooler on a counter, a coffee maker on another.. this I think would work better. The outside shell is certainly different looking. But I am OK with different

thanks for the input on rounded corners, I am going to try and round off the corners on doors, windows, vents, and floor hatches. and round the corners of the trailer body itself a bit.

Anyway there's that.

[GPW]

That looks Really Good and best thing , it’s a practical shape for the intended purpose ... All cuts are predictable angles ... no bending worries ...

Just thinking ,when cutting angles in sheets the width of the foam cut edge increases with the angle , so when joining a sheet with a lesser angle there will be some overlap of one of the edges , and that can be used for rounding over (reducing hard edges on the outside which cause vortices to form thus increasing drag ) , while slightly increasing the aerodynamics of all the rounded edges...
Hint: we try to line up the inside (interior) edges ... looks better inside ...