I was totally mystified, so let "Cortana" find their website for me. The "Big Mig" 1/2a engines seem to have a following, so maybe some of those folks will pitch in with some opinions. I suspect they're pretty typical R/C engines, with high output at higher rpm than we'd like, even for sport-stunt. Here's the website: http://www.nvengines.com/ Steve
Russia. The case is stamped on all of them, made in Russia. But I agree. It's got that type of design work. Look at the size of that intake and exhaust! It's made to flow some air in a hurry!
And yet, the NV website claims that per displacement, their engines are far more fuel efficient due to the cylinder technology they use.
This may be true in full 2 cycle mode, but I have always wondered how their slippery liners would fair in a 4-2-4 type run, if you put on a smaller venturi.
I doubt that they would be too much better on fuel, but you never know.
I know my OS.46LA becomes a miser when the needle is screwed in enough to give me 2-2-2 runs. 4-2-4, not so much!
They also have a gas version of the .40, that uses a glow plug vice ignition. Even though the website doesn't list a C/L model, in asking them they said they can put one together and it would be the same price. I ALMOST was tempted to try that, but chickened out. It's all too easy to just spend money on something that I know will work.