ORIGINAL: Kometfreak
As I am planning the purchase of my second turbine in the future, perhaps a year or so from now. Currently I have a RAM 750+ that somehow missed the iconol CC upgrade and melted the CC.
Perhaps the question that I have not seen answered is did Wren or any other manufacturer patent their products? I ask this because my father and I developed the variable needle valve for RC boat use 30 some years ago. The design then became the one built by Don Pinkert, whom we used to be semi-sponsored by. The valve later became with a few changes the one BVM sold and later patented.
Without the issuance of a patent somewhere, who is really the owner of the design?
Do you think JJ is interested in patents? Do you think that patents can be enforced on Chinese companies? By small manufacturers with limited resources?
I have seen more than one JJ engine. Since I actually built a MW54 MkI from plans I believe I know the engine quite well. I've also seen the insides of Jetcats, Model Mechanics and Simjet. The JJ is a carbon copy of the MW54. The other designs are quite different.
There is no question the JJ copied the designs. I think that's usually called STEALING. I definitely consider him a THIEF! Unfortunately there is very little that can be done about that.
What should be said is that JJ engines are built to very low standards. The metallurgy is wrong. The turbines are probably not real Inconel and are probably not x-rayed. When I say bad TOLERANCES I mean bad TOLERANCES and not clearances. This is the reason some JJs work ok and some don't. Some have way too much CLEARANCE between the turbine and shroud. Some have shafts and tunnels that are not truly concentric making the engine noisy, hot and weak.
While some of the issues (like poorly built and aligned fuel rings) can be solved by a competent modeler. Other issues like turning a good shaft and constructing a good c.c. are much more difficult to do and require tools that most modelers do not have.
Some of the things I've seen on JJ's are absolutely criminal! The way they hog out material out of the hub of the turbine is downright dangerous! And here again, the average, competent, smart modeler does not know how to deal with these issues. Not because he's unintelligent but because he doesn't have the knowledge needed.
The fact that JJ stole designs might make me not like him but the real reason I recommend that people stay away from these engines is the quality and safety issues involved.