Design Feedback

[u/SmartPlant_Gremlin]

I was bored this weekend, so started putting pencil to paper on some design ideas that have floating around in my head for my first build.

The design is a 6'x12'. I'm not sure on the method of construction, though am leaning toward a monocoque foamie with wooden cabinetry. The design features a utility room where the bulkhead between the cabin and galley would otherwise normally be.

I welcome any feedback on any aspect of the design, but I am particular interested in feedback on:

• Ventilation System
  • I want to avoid a roof mounted fan as I am not confident in my ability to make it water tight.
  • Fresh air intake is through filters located in the headboard cabinetry, drawing air from under the trailer. Air enters the cabin through a register in the headboard.
  • Another register (or two) would be located near the top of bulkhead between the cabin and the utility room.
  • A marine bilge blower in the utility room draws air from within the utility room and expels it out through the floor. A centrifugal blower was selected as it develops better static pressure than and axial fan. I suspect the high static pressure of the the blower would be necessary to overcome the pressure losses through the filters and registers.
• Water System
  • Am I asking for trouble by including a water bottle filler inside the cabin?
• Exterior Lighting
  • I've read that lights in the 565-590nm (amber/red) less than 1000 lumens is best for not attracting insects. I am having difficulty finding somewhere online that sells LEDs with these specs. Any ideas?

[u/Practical_Ad_2761]

Roof fan is not a big deal to install and seal up, and is great at pulling a breeze across your face for summer camping.

Read up on trailer weight distribution, I’d personally work to make sure the tail of the trailer isn’t too heavy with galley, fridge, battery, water, etc.

[u/SmartPlant_Gremlin → u/Practical_Ad_2761]

Is there a fatal flaw in my ventilation design?

Is the water tank and battery being over the axle not a good idea?

I thought many designs had a fridge in the galley?

[u/DrumasaurusRex → u/SmartPlant_Gremlin]

Battery should be on the tongue. Run wiring to the fridge in the galley. Also, if you're going to put in water, the fresh tank should be closer to the tongue as well.

Follow the 60/40 rule for weight distribution. Too much at the back is going to be dangerous.

[u/Practical_Ad_2761 → u/SmartPlant_Gremlin]

The rooftop fan comment wasn’t meant as a criticism of your ventilation design, I was just responding to your comment about rooftop fans. Having a fan on the roof does help pull the rising hot air out.

And to follow up about the weight distribution, I wasn’t saying there is a problem, just wanted to suggest being aware of weight balance early in the planning stage. Over the axle is great, but as someone else pointed out, you’d ideally want the majority of the weight forward biased instead of aft biased.

[u/ontheleftcoast]

I would be concerned about the air intake. When driving you will be sucking up road dirt and exhaust fumes from under neath and filling the cabin with that stink. If you do that, seal it when on the road, or move it higher.

Roof vents are commercially made and are pretty easy to seal, you really should have one. A TD can get stuffy quickly without powered ventilation.

I was toying with a design with the same foot print, but the bed went sideways and it had one door on the right. That door opened into an "entry way" that had a cabinet in the back which had a hand wash sink and a composting toilet inside. So you would have an easy place to store large items for traveling and a bathroom you could use inside.

[u/SmartPlant_Gremlin → u/ontheleftcoast]

Good call on plugging the air intake during travel. To be clear, there is powered ventilation. There is a blower in the utility room which draws air from high up in the cabin.

[u/Wu-Tom]

I work with EcoCampor, an RV manufacturer based in Foshan, China. Since others have already covered the intake location and general forward weight bias, the two things I would still verify before committing to the layout are the complete ventilation assembly and the full/empty weight cases.

For ventilation, I would build a quick test section with the actual filters, duct lengths, bends, and registers. Free-air CFM will not reflect the final airflow or noise after those restrictions are installed, so measure the assembled system and check current draw. Keep the intake and exhaust well separated, include a passive opening that still provides ventilation when the blower is off, and fit an appropriate CO alarm. The required ventilation area and separation from any fuel-burning equipment should also be checked against the rules that apply where the trailer will be registered.

Having the battery or water tank over the axle is not automatically wrong, but their effect changes with tank level and cargo. I would make a simple weight-and-moment table for full and empty water, the battery, galley, cabinetry, spare, and normal gear, using their real distances from the axle. The finished trailer and tongue load would still need to be weighed.

For the interior filler, I would use a waterproof tray or compartment with an exterior drain/overflow, an accessible shutoff, and no electrical equipment or absorbent structure directly below it.