Of course, I suppose it never occurred to you that perhaps I'm making no money from it, because I give away my drawings and any help needed free of charge? It was never intended to be a money making proposition. But seeing so many people have asked about it, I am quite willing to help them. I estimate that about one heater is actually built for every ten enquiries. Or that is about the number from which I receive continuing contact and often photos and/or movies.
Oh how comforting it must be to revel in your own ignorance. I have had two approaches from companies to manufacture this heater in various configurations. One is in England and is a company who normally manufactures 10 - 50 HP Diesel boat engines, the other is an offshoot of a German company in Brazil that normally manufactures components for the die casting industry.
I'm sure that the first is worried because I can not guarantee them sole manufacturing rights for UK (that was a point of contention). They may be trying to register the design themselves, as I have told them I was not interested. The South Americans are hastening slowly. At the moment, the principal of the company is in USA negotiating with a well known small engine manufacturer on his core business.
Attached below you will see a "proof of concept" heater thrown together by the British company about ten months ago. Seen her undergoing its first test burn in the doorway of their workshop. Yes, that's snow on the ground. This test unit was used in that machine shop all last northern winter, (other photos are available of it in use)
You see, the world is a very big place and there are many places outside of the USA where people have a little more freedom, flair and imagination.