S> It may have perfect balance, but the con-rod angle means next to no
S> skirt on the piston, which would worry me a little. I suppose they are
S> short of space otherwise they could have gone for a rhombic drive - but
S> that appears to need more space under the crankshafts for the bottom
S> part of the rhombus when the piston is at TDC.
Only ahieves primary balance - piston motion is still non-sinusoidal so
there are higher order vibes to contend with. Also doesn't need much in the
way of piston skirt as the side thrust from the two con rods cancels out.
The type of rhombic drive illustrated in the link, with co-axial piston
rods, is pretty much specific to Stirling engines. The Lanchester engine
(ISTR 1903 or so) had a similar arrangement of four con rods but with
pairedcylinders in a horizontally opposed arrangement. I'm not sure, but I
think this may sort out some of the remaining, higher order, imbalance of
the single cylinder arrangement.
nickh=== Posted with Qusnetsoft NewsReader 220.127.116.11