Thx for the analysis. In my conversation with Harry years ago, he struck me as a "basement bomber"; i.e., a guy who had a knack for mechanics but the advanced mathematical analysis (and material science) required for advanced engineering design always eluded him.
New Mystery, why the rotary valve? It's easy to see how Cyclone ended up with the valve debacle. Harry read Stumpf's book and like many "ingenious inventors" figured that he had a magic formula that few were clever enough to latch onto...just take a few basic rules and push them to the limits and you will beat everyone else. Of course, experts in the field all know of these principles and take them for granted; they realize that the minutiae is more important than the big picture because the theory only tells you what is potentially possible while the nitpicking details define the limits of what is achievable.
If you look at the design of big steam turbines you realize they obey Stumpf's rules nicely and they do get fantastic results. However, they don't try to open and close a valve in a few ten thousandths of a second over and over for hours on end. They don't have recompression and clearance volume requirements. As we have seen, supercritical steam requires a fantastically short cutoff to achieve an efficient degree of expansion. This expansion reduces the mean effective pressure, reducing power density. The only way to improve power density for the same steam conditions and cutoff is to boost rpm...exacerbating the valve problems....and so on.
The old saying about the spirit being willing but the flesh being weak can apply to machines as well; the theory might be willing but the machinery can be weak.
What I find so fantastic is that apparently having given up on the original mission of building a supercritical, highly superheated, short cutoff, high speed engine --- they are now embarking on almost exactly the opposite premise. The rotary valve is going to be low pressure and temperature and probably present even worse lubrication issues. I keep wondering if they are retaining the radial layout because they think it is somehow better, or more aesthetic or simply don't want to send an even bigger message to the faithful that the whole thing failed.
As near as I can determine, the "new and improved" Cyclone Mark 5 is about equivalent to a Semple engine used by classic steam boating enthusiasts from the 50s to the 70s.
There are, however, any number of engines that are more realistic than the original Cyclone fantasy OR the rotary valve dud they are now pushing. Not a lot of real original thought is even necessary, you could look at any of these and come up with something better than the two current alternatives although you might want to pick and choose features.....or look at other engines as these were just sort of selected at random:
A person might want to look at ways reducing clearance volume a tad, more robust cam design and so on but I'd guess any of these old designs would out-perform anything they have managed so far.
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