King-sized camper for 3

[ai4kk]

We needed a camper for 3 adults that all 3 can fit in easily without having to climb over each other getting in and out of bed. I started with a standard teardrop with an added space in front of the bed, then realized that if I turned it around backwards, you could have inside or outside access to the galley.
How do I go about estimating weight? I want to keep it under 1,000 lbs so our 2 smaller vehicles (Kia Soul and Subaru Impreza) can tow it easily. I was thinking thin-wall square chromoly tubing trailer frame, with the main body composed of a 2"x2" wood frame covered with 1/4" oak plywood, 2" of foam, edges rounded/smoothed, then all fiber-glassed. The AC is a standard window mount in a housing on the roof and some kind of protection from low-hanging branches etc
Thoughts? Improvements? How do I make the Sketchup file small enough to upload here?

[KCStudly]

2 inch foam is overkill, IMO. I'm using 1-1/2 inch foam on a 64inch x 9'-8" Benroy-esque TD; with proper skins inside and out (in my case 5mm ply in and 2 plies of 6 oz FG/epoxy out) the box is rigid as all get out. No steel frame needed, just some select light weight cedar in key locations and enough blocking to catch screws here and there... and over there, and there too. Still, for

I'm not that familiar with Sketch-up, but there should be an "Export" option that lets you select a file format and size, if you dig deep enough into the "File" menu.

[ai4kk]

The chromoly steel frame only refers to the trailer frame itself. The structure would be framed with 2"x2" pine or a similar light but strong wood. What kind of foam and fiberglass do you use?

[KCStudly]

Ah, gotcha. Have you seen the ultralight chassis in the Design Resources/Design Library (pull down menu in header above)?

[yrock87]

2 inch foam is overkill unless you are doing a true foamie, then 2x2 frame is overkill. You will need to keep weight savings a priority to stay under 1000 at the campsite with that size trailer.

I have 3mm ply walls inside and out adhered to1 inch foam. I also used ripped down 1x1s for framing everywhere but the curves. I don't have the roof top ply on or a galley hatch yet but the strength of the foam ply composition has really impressed me. At least as sturdy as the 5/8s ply I have on hand or more. Just plan where you will be screwing in to place blocking in the walls...

[ai4kk]

That makes sense. Go with 1X1 and 1" foam. It needs to be sturdy enough to handle offroad use with a bit of suspension lift and bigger tires but not going to be doing the Baja 1000 while towing it. How well does the 1" insulate?
As far as the frame, that's probably not bug enough for a trailer of this size. Looking at the NT Aluminum 5x8 as well

[KCStudly]

As far as the frame, that's probably not bug enough for a trailer of this size.

The cabin box stiffens the trailer frame, not the other way around. The trailer can be light, too, so long as the tongue is built strong enough.

You will not reach your goal of 1k lbs in a camper that size if you over build.

Have you seen Sharon's trailer weight thread. I suggest you look it up, look at the graph and typical weights of trailers in that size, then go look at the lighter weight builds that managed to come in at of under 1k lbs (still being a little leery because not everyone who posted their weights stated explicitly that it was an actual over the scale weight, and not just an estimate). Check out their methods and materials and then decide if you are on the right track. Just saying... and trying to help.

[tac422]

You might look at The big Pink foamie construction method.
It weighs 1000 lbs fully loaded with all the stuff required for our camping trips.

Threads here :
http://tnttt.com/viewtopic.php?f=55&t=44091
viewtopic.php?f=55&t=56441&start=285

[TheOtherSean]

Sketchup only includes a real export option in the Pro (or for 30 days, the eval) version. The free Make version only allows export in its native .skp format and (IIRC) the Google Earth .kmz format. But there is a "purge" option that will delete unused content from your model file. Check out the purge section at https://help.sketchup.com/en/article/3000142.

[ai4kk]

thanks, I'll look for that when I get back from Seattle

[ai4kk]

Been playing with these ideas some more, looking at 1" X 1" wood frame covered with thin ply skin, 1" foam bonded to that and perforated both sides for better glue penetration, and painted canvas over that. The body itself is just a shell with the king-sized mattress and kitchen box sliding in from the back so I can use it as an enclosed utility trailer if I want.
The chassis is still looking like square tubing, but I will probably go with mild steel so I can stick-weld it myself; the weight difference on such a small project is fairly low, as in about 20 lbs different and the cost of buying and paying someone to TIG-weld thinwall Chromoly is pretty steep. Going with basic leaf springs for now as I can modify/widen the axle and use the springs from a small HF unit I have laying around but eventually would like to go to an aftermarket VW bus torsion suspension made for dune buggies and may then reinforce the body for offroad use with fiberglass over the painted canvas since the outer layer is going to be epoxy paint anyway.
Right now, just waiting for my hitch to come in for my 2016 Impreza as that made sense as the logical first step, if for no other reason than it will be easier picking up stuff with the aforementioned utility trailer than with the car alone.

[tony.latham]

I'll argue that 3/4" of foam insulation in the walls (and at least an inch in the ceiling) is plenty. It's not real easy to find 1" lumber four your internal walls.

Make sure that oak plywood has waterproof glue. I'd stay away from the box store junk. Take a look in your lumberyards for 1/4" plywood subfloor plywood. The stuff I buy in this one-lumberyard town is great and cheaper (and much better) than 1/4" AC fir plywood. I think it's top surface is birch and it'd make a great-looking woody.





And by the way, that reach-through galley is an idea... but you'll lose storage space inside your cabin and in the galley. Lots of it.



Here's our galley in action. The empty spot on the left holds the coffee pot and our French-press coffee mugs.



Tony

[ai4kk]

I love when folk point out stuff like that..and then enjoy finding ways around it if possible.
For 1X1s, was just going to rip them from bigger boards, the smaller the better. I like the idea of the nice birch plywood as that will be visible from the inside so will be a nice interior finish...highlighted by the exposed internal framework.
Will have to think about the galley design..we've always planned a removable kitchen box so that we can slide a real mattress in and out without having to fold and shove it through a door plus that allows us to use the kitchen box in a shelter, cabin, or even just out on a picnic table and use the trailer as a cargo trailer; this also saves us from having to title it as a camper trailer (required in FL for trailers with living quarters) as we can just register it as a homemade utility trailer.
Maybe detachable overhead cabinets that perform the same function and with the space between them and the kitchen box open or perhaps with swinging doors? The doors could normally be closed and form the backsplash plus provide hanging space for like in your pictures paper towel rolls etc but could be opened back against the main cabin doors if you wanted to reach inside the kitchen at night without getting out of the camper etc. Some of the bottom slideouts could go either way, either back or forward so we can access the important stuff like the cooler by sliding it forward instead of back. I'm not thinking so much of cooking from the inside (although the microwave might be mounted sideways and made reachable) as grabbing leftovers or making a sandwich for a midnight snack or a rainy-day meal.

[ai4kk]

I was going to build a frame, but ran across a converted popup on CL for $300. I get to use it for a couple of upcoming moves for myself and others then taking the box off to become a hen house or tool shed and will use the frame for the camper as it's the right size

https://www.facebook.com/floridacyclist/posts/10207407089395218

[markmitch]

Thats the same idea I am working with.