Due to Oxidation and ''High Temperature Hydrogen Attack'', also called ''Hydrogen Embrittlement'' ALL
metal is doomed within the combustion zone !
So why is 6" pipe stated as an alternative in the 6" design? I will look into though, thanks.
Friction pressure loss http://www.engineeringtoolbox.com/duct-friction-pressure-loss-d_444.html
also has a part to play in time in the pipes? very minor in larger pipes so it won't have been a factor in the standard designs. I found this after posting. As per my theory I think.
It will have a ~7' vertical flue creating draw. Draw gain No. 2 in the short riser model is the flue doesn't need a section going down, a major function of the barrel, getting the hot air down, to be used in the mass. No.3 It doesn't have a feed tube to service, the riser pipes sitting directly above a firebox.
I can't really compare a RMH to a stove for a truck, just nick the idea of the riser pipe in a closed stove. Yes I'm gna lose heat
up the chimney, but hopefully a lot less energy
as all the gases will be burned off, it should also be a lot cleaner for the environment. There is also the firebox which can be closed down overnight, so I get a box of hot embers for prolonged heat. I also need to say that in the UK a "truck" is generally a vehicle with max gross weight of 7.5T or more, I have a 14' x 7' insulated
living space so I don't get instantly cold again, the difficulty is control so I don't get too hot!