Thanks for that SA, I have already made a portable rocket inside a 5 gallon tin but the tube is only 4" dia, it works ok but could be improved, I am experimenting with the air intake plate and have found that an upright angle allows more air into the system and a slight self feed mode, it certainly burns the
wood quicker but I have no way of telling if that equates to more heat output as weather conditions play a part in any tests done, cheers Dave