6" flue dimensions

[roy]

I'm in the planning stages of my rocket stove and I'm a bit confused about dimensions for a 6" flue system. the rocket mass heater book clearly lists the layout for an 8" flue.

so can anybody help with the dimension for the
feed tube ( the books says 30 square inches)
burn tunnel ( just a bit smaller than the 6" flue in area?)
heat riser height and diameter
size of oil drum

i plan to use around 20' of flue and it is only to heat two rooms. we cook on another stove which gives us hot water. so is it best to cover the top of the drum with cob? and leave a larger area on the side uncovered?

also the ash pit clean out. are there any good you tube videos of this being built.

thanks for all the replies from my other posts.

looking forward to a warm cosy winter here in wales.

cheers

[Donkey]

A six inch flue... The formula for finding the area of a circle.. Pi times radius squared.

So 3 times 3 times 3.14 = 28.26 square inches.
The rule is to make no place less (or tighter) than your flue size.
The drum is the same, but the insulation jacket inside it can be a little larger..
Oddly enough, the gap above the heat riser needs to be a bit taller. Two inches is safe.
Etc. etc.

I wouldn't cover the barrel with cob.. It's a good radiator, top sides and all.

Can't help with the youtube thing..

[roy]

cheers donkey. that makes it a little clearer.

cant wait to get started.