Small RMH for workshop

Morning/Afternoon/Evening all (depends where you are in the work)

I been looking at this forum for the last few months and have a head full of ideas on building various RMH and Stoves.
My first plan is to make a Rocket mass heater for my small workshop. Its just over 2m x 2m, and about 2m tall. its not a huge space but i plan on using it to work in during the winter months, and also as a drying room for laundry. Living in one of the wettest countries in the world (England), drying laundry can be a pain.
I've been collecting wood from trees i've been cutting down for a while now (still seasoning), and i've been accumilating parts to make the heater.
so far i have a small oil barrel, and a 13kg gas cylinder. The barrel will fit inside the cylinder.

so the plan is the barrel will hold the insulation for the flue/combustion chamber, and the cylinder will be upside down and used as the heat exchange.
only problems i'm having at the moment is the size of the combustion chamber/fuel feed/air feed/flue.
If i make the system from 3" box/tube section, does the air feed need to be included in this 3" or can i have an additional feed? i'm thinking more (controllable) air is better?
Also, does the exhaust need to be the same size as the rocket system? or can it be X% smaller?

Thanks for any replies

Mike

Mike Rigby : Welcome to Permies.com And Our sister Site, richsoil.com, your thinking is a little outside the box, and fails due to the inability to scale your heating
unit down small enough, unfortunately Laminar flow prevents working at the Reduced size you need to have for your small workspace/laudry !

Your room is way undersized for any Rocket Stove on the market or of a size liable to perform, 4'' is problematical but it is the smallest system that might work
as a separate Heater/Bell with a small secondary Bell located in your Tiny work shop Laundry drying area !

Right now you are saying 'Right,MATE ! and whose yer Father' i.e.' wheres your proof', This is where I send you to rocketstoves.com for your PDF Copy$15.oo
of Evans' and Jackson's Great book, ''Rocket Mass Heaters" there is STILL no other Book in any language with as much Rocket Stove, Pocket Rocket,
Rocket Mass Heater Family information ! ( and I Don't make a 1/2 Farthing ! )

This is literally the only way you are going to understand the Constant Cross-Sectional Area(s) of the rocket stove, and the ratio of height of the Heat Riser to the
Feed Tube, and to the Burn Tunnel.

Your fellow members will almost to a man strongly recommend that the 1st Rocket Mass Heater R.M.H., that you build follow the simple set of plans found in '' The Book''
before you go on to try more experimental builds as success is a better teacher than failure until you have enough information to easily determine where your Problem
area within your build can be found !For the Good of the Craft !
Big AL !

Thanks for the honest feedback.
Yeah the book is on the reading list.

Interesting idea of a double bell jar. Is this stacked or stood parallel? I have some ideas to change the design of number 2 however number 1 (the test) needs to be build first. Ideas like a heated air intake (similar to a few threads down), plenum chamber leading to multiple exhausts, etc. just see where the wind takes me.

Yeah I agree it's a small area but its what I have to work with. I don't think I'll be using any heat battery, just fins on the heat exchanger to save space.

I stumbled on this website whilst researching hobo stoves made from beer kegs but I loved the idea of controlling the exhaust fumes and more efficient burning of the rocket mass heater.

Mike Rigby : You caught me in a 'think-outside-the-box' + ' Building Air Castles for others to live in ! 'Moment . Sorry!

What I was thinking about was that with a D.I.Y. system that uses parts From the only Current Commercial Cast Core 4"
Rocket you could have your heater located near-by as primary heat for that area and run piping to an adjacent secondary
location - your work area, create a "Bell'' there, and then use the residual heat to warm your 'workshop' - you're not in the
porn business, are you? You need to share a little more information- none of the Rockets work well in a space that is to
be heated only part time !

Assuming that not all 4 walls of your house are outside walls, here is an idea that might work for you until you outgrow
your current space !

Drop in at our sister site and check out richsoil.com/electric-heat.jsp, for as small a space as you have, my
only other choice is a ceiling mounted , propane fired , radiant heat unit ! Perhaps this might provoke an idea of your own
that will work in such a small place For the good of the Craft !

As always comments and questions are Welcome Big AL

the only Current Commercial Cast Core 4" Rocket

That would be Dragon Heaters at Dragonheaters.com

Porn? Lol I wish. Wife would kill me!

It's an external building away from my house.
I'll post more info after I read the book