Rumi Caravan Tiny Travel Trailer

The trailer provides a comfortable bed (double) in a wind-tight and insulated shell; plentiful and convenient storage, a toilet, a desk/table, a mini kitchen with single burner propane stove, sink, insulated water jug, electric heater, and an alcohol heater. It works well in conjunction with a portable gazebo and regular camping equipment.

It weighs only 415 pounds (189 kg) so it can be towed by a small car. If you build it yourself it will probably cost less than $1500 USD. 

It also doubles as a utility trailer; wide enough to transport 4x8 sheets or items too large or awkward for the car. (The entire rear panel is removable.)

Like my old truck camper, the trailer is very convenient for traveling–there is nothing to setup and it's completely self-contained so no campground is required. On a long trip just park overnight on a quiet street, on vacant land, or at a rest stop.

This website describes the construction of the outer shell.

Specifications

Construction Details

Drawings (click on links)

Walls

The walls are bolted directly to the sides of the trailer frame and are hollow construction throughout.

A simple method to build the wall frame is by using a construction panel. This allows you to work vertically and eliminates tricky clamping.

To build the construction panel join sheets of OSB or plywood together with metal roof truss plates and cut it to the outer shape of the trailer. Paint both sides white (optional). Support the panel vertically. Draw your plans directly on the construction panel. The panel in the photo was the plywood wall from a prototype trailer.

Framing members are either 1½”, 2½”, or 3½” wide, all ¾" thick--installed on the flat. Standard lumber sizes (1x2, 1x3, 1x4) could be used but it's better to buy the best quality stock, regardless of width and/or length, and rip the required sizes with a table saw. Use pieces that are as clear as possible (knot-free).

Frame in the door, windows, and fender supports. Add lots of structural strength where the walls bolt to the trailer frame. The bottom of the frame is level with the top of the axle so a cutout will eventually be required to allow for axle movement.

Screw the framing members to the construction panel with small screws. Don't be too concerned if your joints are not tight--the glue will bridge small gaps. When you have finalized the structure place some wax paper between each joint and the construction panel, then glue and gusset each piece in place.

A very good glue for this application is a Polyurethane Construction Adhesive such as LePages PL Premium or equivalent. This glue bonds to wood, metal, plastic and is perfect for this application–having excellent adhesion and remaining flexible.

Use gussets on each joint for added strength. These are small strips of thin metal roof flashing stapled or nailed over each freshly glued joint–let the glue squeeze out from under the gusset. (To ensure glue will stick to metal clean it with thinner and roughen with emery cloth or sand paper before cutting into strips.) Wipe off excess glue with a rag and paint thinner. 

After the glue dries trim frame to the curve with a jigsaw (or, before gluing, trace the curve onto each segment piece, remove from panel, cut with bandsaw). 

When glue has cured sufficiently remove frame from the construction panel and install the backside gussets with glue and staples or brads.  

The final result is amazingly strong. Framing members can also be easily added or removed.

Using a 1x6 board along the bottom instead of a 1x3 simplifies construction but adds unnecessary weight.

Reverse the construction panel to build the other wall.

Trailer Notes:

1. The trailer in the photo above is a Snowbear 480K. It's a standard 4 foot by 8 foot utility trailer (bolt-together kit) with a lightweight (200 lb) tubular frame. The supplied 8 inch wheels were replaced with 12 inch ones. The drawbar was relocated 12 inches forward for better weight distribution.
2. Some wood crosspieces and extensions were added for extra floor support and to accommodate the rear panel.
3. Trailers that have the axle located 60/40 (40% from the rear) are just about right. Hitch weight should be 10%-15% of gross trailer weight for proper towing. And backing up is easier when the axle is located towards the rear.
4. Almost any lightweight trailer will serve. Check out canoe trailers or other boat trailers. 
5. For a low deck get a trailer with the springs slung under the axle.
6. Shock absorbers would be beneficial.

Roof Spars

The roof spars are fabricated from clear spruce lumber 2½” wide by ¾” thick by approximately 50” long (measure to get the exact length). At each end a right-angle furniture bracket (Stanley 08-8894) was attached with machine screws. Put some carpenters glue on the threads at final installation.

Install the first and last spars at the ends. Then locate the remainder approximately 16” center to center. Consider where the crown roof skin will be located before finalizing the location of the spars. Locate another spar over rear panel framing. Refer to the drawing. Photo is of a plywood prototype, this trailer uses the same technique for the spars.

Install triangular blocks at the rear in the corners of roof spar and side frame to support the tail lights and to add stiffening (or use a metal right-angle bracket if lights are going to be mounted outboard).

Roof Skins

Roof skins are ⅛” marine plywood. Skins overlap each other and overhang the outside walls approximately ¼ inch. Double up the thickness at the rear of trailer by adding an 8” strip of thin plywood. Apply a bead of caulking along the roof spars, roof edges, and on overlaps. Use ratcheting tie downs lengthwise over the roof to hold the curved skins in place while fastening. If necessary dampen skins with water before bending. (Laying skins on wet lawn works well.)

Fasten with #9 roof screws (every 8 inches). Be sure to install screws at right-angles to the surface or the rubber gaskets will not seat properly.

Insulate the inside of the roof and curve with single-sided foil radiant barrier insulation. The foil faces the empty cavity between the spars (foil needs a minimum 5/8" air-tight space to be effective). This will provide R-5 insulating value as well as providing a good radiant barrier (i.e. acts like a heat reflector). Support the wrap on the spars with strips of ⅛” plywood or double-sided tape and caulk or tape along the edges to make it air-tight.

Door, Floor, Rear Panel, and Trim

Examine a standard house exterior door to get door frame and construction details (bear in mind that the trailer door opens outwards; plus, allow for a screen door mounted inside the trailer door). Install a door sill and slant it forward so that rain does not run inside. Use standard door weather stripping and lockset. Use a piano hinge if you can find one that’s made for exterior use (from an old camper for example).

Install ⅜” OSB floor and baseboards as required. Seal any gaps with expanding foam or Gorilla® tape. Most campsites have power outlets on the road side of trailer sites so install a power bar or power cord through the floor at the front on the road side. 

Here's an alternate light-weight floor idea: Stretch and fasten light steel mesh across the frame of the trailer. (Some stores refer to this mesh as Hardware Cloth.) Cover with 2' squares of interlocking garage floor pads. These pads are made of light but tough foam. I've seen them at Walmart in the automotive department. Unfortuately I haven't had a chance to try this out yet...so you're on your own here. This would probably save 10 to 15 pounds over an OSB floor.

Install exterior panels (⅛”, or ¼” plywood) with #5 or #6 roundhead screws (spray painted white) every 16 inches and around the door frame. Fill cracks or gaps with white paintable caulking. Install the windows.

Build the rear panel. Panel is bolted to the back with four #10 or ¼ inch bolts and shakeproof hardware. Install a gasket or weather stripping to seal it.

Tail lights are attached to blocks screwed into the corners of the wall and roof structure members. This allows the trailer to be used as a utility trailer without the rear panel in place. Or, mount the lights on the outside of the walls with brackets. Don't forget to run a ground wire to each light.

Install ¾”x¼” spruce trim along bottom edge of exterior panels to protect fragile edges. Install similar trim at rear to hide details. Install sheet metal strips on bottom of framing where rear of trailer could drag on steep driveways. 

Fenders

Fenders are fabricated from two layers of ⅛” skins. Pop-rivet one layer to four equally spaced metal strips (e.g. brick ties) that have been bent into an ‘L’ shape and drilled. Bend the fender into the shape you want and fasten to a piece of scrap plywood to hold that shape. Then glue and clamp the second layer on top of the first layer–hiding the pop-rivet heads. Coat the inside with black roofing compound to waterproof it. Mount fenders offset from the trailer wall with thin wood or plastic spacers and #10 machine screws.

Finishing

Paint it; add colorful trim or decals; install lights and you’re done!

Misc Notes

• To make it possible for this trailer to be towed by a low powered car the design was inspired by typical sailboat shapes...these are generally long and narrow. Increasing the width or height might  adversely affect the roadworthiness to the point where it's no fun towing it...especially into a head wind. If you have any doubts regarding the ability of your towing vehicle it might be advantageous to build a simple plywood prototype. This could be as simple as a 'post and beam' style of construction (simply bolt some 2x4's to the trailer frame and cover with plywood), then take it for a ride under windy conditions.
• Towing was very easy with my small car (2007 Suzuki SX4, 2L, 143hp, 5-speed manual transmission) with more than enough power. The narrow shape is great--no extra mirrors required. Fuel-efficiency was reduced by about 26% (from 34 mpg to 25 mpg, US gallons). Little side movement in cross-winds. More about aerodynamics here.
• If you don't have much experience with woodworking, don't have a shop, or are pressed for time try using the Alternate Construction Method (see the next section).
• If you don't own a table saw it might be worthwhile to purchase one. The one used in this project was a hardware store "house brand" costing less than $100. A mitre saw is also very useful--again, under $100. If you are going to borrow a friends table or mitre saw, offer to buy and use your own blades.
• Metal skins would be more durable; have trailer painted at an autobody shop or leave it natural.
• Why the name Rumi Caravan? Well, I love the poetry of sufi Mevlana Jalaluddin Rumi, especially this one:

• To honor Rumi and experience maximum creativity and enjoyment from each step of the project, build it practicing inner stillness.
• Don't get caught up in making it very fancy, after all, it's a camping trailer. Fancy woodwork and paint jobs are great but soon get scratched and damaged. It won't be professional looking, but then again, you probably don't have access to the shop and tools that professionals use. Make it your work of art--where "imperfections" are part of the appeal (like the difference between a painting and a photograph). 
• What makes this trailer better than a store-bought unit are all the little goodies you add later--the hooks in just the right places, the LED lights, the shelves and drawers custom made for your stuff, the cute icons and decals that make it quintessentially you.
• The reason for the copyright is to prevent anyone from falsely claiming ownership of the design or website. You are free to use this information, but I'd appreciate credit if you refer to this material (or just provide a link to this site).
• If you plan to finish the inside, it will probably be easiest to build from the inside out (i.e. install interior panelling and insulation before installing the exterior skins).

Alternate Construction Method

• Use standard exterior G1S solid plywood walls and doors.
• Use strap hinges on the doors--with foam weatherstripping to seal it.
• Bed, table, seat, etc. are built-in and attached to the walls for simplicity (optional).

• Much faster to build, approximately half the time.
• Possible to build without a shop, just space to store tools and materials, and a rain/sun shade. Must be warm enough though--above 50 deg F overnight for proper drying and curing. (One of my favorites: setup in a corner of the parking lot at Home Depot or Lowe's, run in to buy material or rent tools as you need them; even better if there is a Burger King or Wendy's close at hand, and a movie theater too for afternoon breaks.)
• Use acrylic paintable caulk instead of glue for fast assembly.
• Windows or access doors/compartments can be installed at any time--even after unit is built.
• No construction panel required.
• Plywood doors tend to warp, use a stiffener or fabricate a standard thick door with frame.
• Much heavier, approximately 100 pounds more (for ½" plywood).
• Plywood tends to crumble and/or separate with moisture and vibration--marine plywood would be a better choice.
• Walls may need to be built up where spars, windows, fenders, and other structural items are fastened.
• Walls are not insulated and will sweat in cool weather or on cool nights--keep bedding away from walls. Ceiling and curve can still be insulated. Floor could be insulated. Fall/Winter/Spring camping will be limited.
• Walls are heavy and difficult to maneuver.
• Screws from the outside may protrude into the interior. Ouch!
• Fastening to the edge of plywood is usually weak.
• Finishing the interior is simple--just paint!
• Built-in bed, desk, etc. detracts from usefulness as utility trailer.
• More interior space (approx. 1" wider).
• Simpler tool requirements. Jig saw, drill, clamps, hand tools.
• More difficult to make wind-tight unless a standard door and frame is fabricated.
• When you're ready for The full Monty you can use the walls as contruction panels for the hollow wall version. 

More tiny travel trailer sites

• http://www.mikenchell.com/forums/halloffame.php
• http://www.tinytears.cc/scans.html
• http://www.tent-trailer.com/
• http://www.suite101.com/content/popular-brands-of-teardrop-travel-trailers-a102613
• http://timeouttrailers.org (USA)
• http://www.timeouttrailer.com (CANADA)
• http://www.roulottesprolite.com

Improvements

• For more storage space consider adding long side boxes to replace the fenders. For the Snowbear trailer they could be 16"H x 72"L x 7.5"D. These could be accessed from the interior or exterior (or both) as desired. To improve aerodynamics consider 'skirting in' the wheel wells. The 'skirts' could be hinged at the top to double as small roadside tables.
• To strengthen and waterproof roof and curve consider a penetrating epoxy such as Rot Doctor.
• A wheeled swivel hitch jack is well worth the extra 15 pounds.
• A curbside fold-down table or shelf is very handy.
• A sliding rain/sun-shade mounted on the roof that pulls out over the curb-side of the trailer. Could be as large as 54" x 80" to create a sheltered space for sitting, cooking, etc.
• A fold-away awning/shade for the roadside window. It could be a framed solar panel.
• Small light-weight 12 volt power pack. Charged from solar panel, car, or house. For powering small appliances, music players, LED lights, etc. Lithium-ion batteries are the lightest--get them from old laptop computers--usually only one cell goes bad and the whole battery pack is thrown away. I've cut open the battery packs and mixed and matched individual cells to get 12v and this works fine.
• A road-side slide-out to accommodate a side-ways bed. Also doubles as fold-up sofa. Dramatically increases 'living space'.

More Pictures

Free Camping Sites: