ORIGINAL: earlwb
The MVVS .15 is a huge engine. I doubt they would make a .11 or .12 out of it. It mnight be interesting though. But making a 11 or 12 out of that big MVVS .15 would put you at a weight disadvantage over the smaller other brand engines in that size range. Now MVVS used to make 2cc and some smaller engines but they quit doing that quite a while ago. I took a look at the Pe Reiver's MVVS site and I didn't see anything smaller than the .15 engines depicted there for sale.
I have the MVVS 1.5cc diesel engine and it has a one piece crankcase and cylinder so you cannot rotate the cylinder around.
That's not exactly a valid comparison Earl, the Fox is an old school plain bearing loop scavenged motor, while the MVVS is TBR schnuerle ported. Different as chalk & cheese for totally different applications.
Both very good at what they do.
As an aside it would be interesting to make a .12 out of a MVVS .15 just to see how fast you could get it to go. The larger gas passages could make a real screamer out of it.
Regards
Greg