I think i have someone to take on the heater design project who is well credentialed for the project. Stay tuned. (please do not p-mail arnie directly or we will become a burden on him) It might make the most sense to submit three design proposals. One protable set up and two permanent, or maybe one for the pop top, too.

Here's my criteria for a portable:

My proposal is to design a heater specifically for the way i have been using my Plat Cat. Here's a photo, along with an explanation of the set up: http://www.concentric.net/~Sxs/PlatCat.html

The design would include:

- 4000-4,200 BTU (my guess based on the 3000 btu 3P12)

- not too tall (3p12 height, not much more), low center of gravity,

- designed as a "portable" with a stable base/stand so it can be set down anywhere, and enclosed back. tilted the appropriate angle 10 degrees, easy to carry (a handle), easy to store (protective cover for front?) and sturdy and light.

- quality quick release gas fittings for fast, safe hook-up to a "T" in the vehicle gas line under the sink. (I use high pressure gas hose, which may or may not be "legal." It almost has to be able to use hose since it is a portable or semi-portable set up.)

- a window insert made of rubberish-like material to be inserted in the car-door window, which is then closed on the insert. The flue would be inserted through a hole in the insert, snug fit, and the heater vent hose would slide over the flue pipe for venting.

If there are no legal/safety hurtles for a semi-portable design, building the heater iteslf will not be too much different than the 3p12.

BENEFITS: can be placed anywhere...for most effeicent heat delivery...or for the most convenient location at the moment, even outside to heat a side tent or free standing tent (they are that safe, BTW, no CO, temp is below point of combustion of paper, safety shutoffs if tipps over or malfunction). In addition, you only take it when you need it. Does not require cutting the van to instal, only tap into gas line, attach the thermostat to the wall and wire it to power and the harness w/plug for the heater. Then, just plug it in, quick connect the gas line, and the flue to the insert in the window, and fire it up.

Disadvantages: No instant flick of the switch heat.