CBO's BMX Motel on wheels

[CBO]

I race BMX here in the states. To race the best competition you must travel all over the country for national races. These trips can wreak havoc on one's bank account. I drove down to Oklahoma in February and slept in my 99 Accord in 18 degree cold to save on hotel costs. I wasn't a fan of that!

So my goal here is to build a more comfortable place to sleep that will fit me, my wife, my almost 3yo son, and probably my 90lb black lab as well. Keep it light, goal weight around 700lb so a 4 cylinder car can pull it and still get good mpg. This will have no galley to save weight, build time, and material cost. Will have AC. No 12v system, but will have 110v for ac, outlets, lights. Also, I'm cheap. So I'm looking to spend as little as possible.

The rough plan.



Planning on using a 4x8 HF trailer if I can find one. Width is an issue though. Wife thinks 4ft wide isnt enough for us or my son in the top bunk. Todler beds are 52" long. We should at least give him that. Widening to 54 inches interior would give us a full size bed. Looking into building around the fenders like this:



Or building out the floor and widening the axle.

Trying to keep this as simple as possible so someone please tell me their kid sleeps great on a 4ft long bed in their camper. Please!

So to maximize width I'm considering walls of 3/4" or even open to 1/2" plywood. No wall framing. Will carpet glued on the walls be enough to avoid condensation? Will 1/2" be strong enough by itself? Will have roof spars of course.

The AC will stick through the wall up front and be visually contained outside by a utility box. During AC use I'll just prop up the box door.





Outer roof layer a 1/4 or 1/8" type of wood sheet. And to weather seal im planning to coat the roof/walls with HF truck bedliner, and then a white exterior paint over that. It should be cheap, water tight, and easy.

I kind of dont want to use a roof vent/fan so to minimize wind resistance. Probably going with one door and 2-3 windows. Currently still in the planning phase and hunting for a used trailer. Would like to hear what y'all think and hear your suggestions.

-CBO

[working on it]

...

So to maximize width I'm considering walls of 3/4" or even open to 1/2" plywood. No wall framing. Will carpet glued on the walls be enough to avoid condensation? Will 1/2" be strong enough by itself? Will have roof spars of course.

The AC will stick through the wall up front and be visually contained outside by a utility box. During AC use I'll just prop up the box door.





Outer roof layer a 1/4 or 1/8" type of wood sheet. And to weather seal im planning to coat the roof/walls with HF truck bedliner, and then a white exterior paint over that. It should be cheap, water tight, and easy.

I kind of dont want to use a roof vent/fan so to minimize wind resistance. Probably going with one door and 2-3 windows[/color][/i][*][/b]. Currently still in the planning phase and hunting for a used trailer. Would like to hear what y'all think and hear your suggestions.

-CBO

• I also have a 4'x 8', and sorta planned as you are planning, to keep it lightweight (under 1000 lbs) and with A.C inside. But, my squareback TTT grew far heavier (and complex, in cramming too much gear into it), and now exceeds 2000 lbs. I used 3/4" plywood for the entire structure, with no insulation except for a small amount of sidewall carpeting, and rubber/carpet matting on the floor. I also used 1/2" oak as interior window and A/C unit framing/trimwork, and some 1' oak for a shelf fence; with heavy steel hardware, 150 lbs of on-board generator/extended-run fuel tank (with slide-mount mechanisms for both; and two fire extinguishers on-board, JIC), and cooler and full Aquatainer added-in, there was no way it would stay under 1000lbs. Not to mention the 110vac and 12vdc systems: with multiple circuit breakers/GFCI's/surge protectors/fuse box enclosure/inverter/battery/two battery chargers/50-30-20 amp adapter set. and several heavy-duty extension cords for shore-power connections. And the list goes on, "Ad infinitum". It just kept growing heavier....
• *I'm considering walls of 3/4" or even open to 1/2" plywood. No wall framing. Will carpet glued on the walls be enough to avoid condensation? Will 1/2" be strong enough by itself? Will have roof spars of course
  **Outer roof layer a 1/4 or 1/8" type of wood sheet
• *,**Since I used 3/4" plywood, with steel bracing bolted and glued in place, I chose to just place the 3/4" plywood roof, by laying it directly on top of, but not over-lapping, the edges of the walls...instead of using spars. The strong, gusseted, angle braces and the inner rear bulkhead made spars superfluous, since it is only 48" wide x 48" long (unsupported by transverse spars) overhead. I think that if you were to place your (1/2" thick or less) roof directly on top of the walls (1/2" thick or more) as I did, minimal spars would be needed, or none, if bolting steel braces underneath. In retrospect, I should've used 1/2" plywood, losing little strength, but weighing much less, overall.
• ***I kind of dont want to use a roof vent/fan
  **** one door and 2-3 windows
• ***,****I used vents placed on the sidewalls, instead of on the roof, and used computer case fans to assist in airflow, but I usually prefer using my 11" fan, and two open awning-style windows for ventilation, during pleasant weather (the awning windows and the "waterproof" side vents don't allow any rain in). See: http://www.tnttt.com/viewtopic.php?f=21&t=70100&p=1225933#p1225827

• 

  vent 9139 used for three purposes.JPG (244.86 KiB) Viewed 819 times

• *****AC will stick through the wall up front and be visually contained outside by a utility box. During AC use I'll just prop up the box door.
• *****The A/C unit in my TTT is rear-mounted, high up on the bulkhead between cabin and galley. I used a a LG model LW5012J, with manual controls, and it's small and lightweight, and doesn't drip any water (so far...I have another LG, and it doesn't either...I still have a drip pan system in my TTT, though). My 90 degree internal (confined to the upper galley) ductwork, is rather complicated, and I had to modify several things to make it work correctly. Your approach, would encounter the same thermal shut-off problems mine did, at first, because an A/C inside a box wouldn't have direct exhaust route, and would not be able to vent it fast enough to avoid that problem. And the hot air still retained in the box would also overheat the chassis components, which need cooler ambient air. I suggest getting an aluminum tonguebox, that is front-opening, to let the exhaust exit, unimpaired.

• 

  aluminum tonguebox, ideal for a front-mount A-C unit.jpg (257.35 KiB) Viewed 819 times

• By attaching the rear wall of the box to the front wall of your trailer, you can cut a hole simultaneously thru both. Then, you can mount it with the front side sticking into the cabin, and the back half inside the tonguebox. After sealing the surrounding area (I used many layers of foil duct tape), you can isolate the two halves. And, with the exhaust flowing unhampered out the open front of the box, the air surrounding the chassis-cooling louvers will be much cooler than otherwise (you can even use a fan to \take in fresh air, from either side of the box). Another plus to using this type of box is that any water that might be produced in operation, can be directly routed out thru a simple hole thru the aluminum box bottom (any water left inside will not rust the aluminum). After years of thought perusing this subject, if I were to build another trailer, this is how I would build it, and dispense with my ducting entirely.
• finished galley as-is today, crowded with ductwork & generator system
• close-up of foil & fiberglass-insulated A/C exhaust duct
• front part of A/C sticks about halfway into the cabin; deflector on top
• Speedi-Boot turns exhaust flow 90 degrees to the right (also impedes flow, retains heat until helped to exit with a duct fan)
• thick layers of foil duct tape seals the A/C on the bulkhead

[CBO]

Holy cow. That was a very large in depth response! I'll just ask you, do the carpet walls condensate at all??

[working on it]

Holy cow. That was a very large in depth response! I'll just ask you, do the carpet walls condensate at all??

• The small floor mats I used (on only two walls), are just there to prevent skin-to-damp wall contact. They probably have little overall insulation value, since 90% of the walls/ceiling remain uncovered, but they do what I installed them for. I toss & turn a lot at night, due to bad back and knees, so I occasionally roll over enough to contact the wall. I did so, once, on a night where interior walls were cold and damp (but never to the point of water beading or dripping). I instantly awoke, and dried off that wall with a towel, and went back o sleep. Next trip, where conditions were much the same (cold/wet outside, humid inside), with the wall mats in place, there was no damp to the touch feeling there, though the other surfaces were getting moist/cold. So, I figure that the mats on the wall were at least absorbing and dissipating the moisture in their locations.

• 

  floor mat used on my walls.JPG (92.23 KiB) Viewed 683 times

• On that same trip, I started to use a combination of A/C, open vents/windows, my large(r) main cabin fan, and small space heater(s) to prevent interior moisture build-up, due to the water vapor given off in my exhaled breath. If I heat the exhaled air/cold ambient air mix, to a temperature at, or above, the outside air temperature, then no condensation occurs inside, and use the fan to circulate it out my near-to-the-ceiling sidewall vents, then it doesn't cause the walls to get moist; or, using another approach, I cool the interior to a temperature similar to the outside air temperature, then no condensation occurs inside, before the moisture is rapidly expelled from the vents, due to higher air pressure inside the cabin from using both the main fan, and A/C blower fan, at the same time (and the A/C also dehumidifies the air, somewhat) . This second approach is my favored one: I just bundle up, breathe cool air all night, and wake with my sinuses clear in the morning (I still bundle-up, maybe less so, with the heated air approach, but the warmer air affects my sinuses negatively). Maybe that's only my way, not applicable for others?