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Heinrici 65mm date

Dave Allen

Last Subscription Date
I've recently come across this 65mm bore Heinrici hot air engine,it is rather rusty but does run.There is a patent No on top of the cylinder which I can just make out.
Is there a list somewhere that list's the patent numbers and the dates that they were introduced.
Thanks Dave


Brian Triebner

Last Subscription Date
Hi Dave: I have a 54 mm Heinrici. It has a number on the flat but I assumed a serial number. Can't help with the dating but Stirlingmaier is a member here from Germany and pretty much an expert on hot air engines. I'm sure he can help you.


Hi, Dave,
regarding German hot-air engines, it is important to differentiate between true patents (Deutsches Reichs-Patent, abbreviated DRP) and registered patterns (Deutsches Reichs-Gebrauchs-Muster, abbreviated DRGM or Gebrauchs-Muster-Schutz, abbreviated GMS).
You find the abbreviation and the number either stamped on the
engine desk or table (for instance DRGM 288423 which relates to Louis Heinrici's reg.pattern dated July 5, 1905) or embossed on the side of the cooling-water jacket (for instance DRP 109983 which relates to Louis Heinrici's patent dated August 4, 1899.
But don't mix it up with the engine's serial number.

If you send me the number of your engine I will tell you more. Please contact me via my homepage www.stirlingmaier.com.