RE: .049 VA split case
Yes that is the one the mark 1. it is a very small engine. it has a adjustable timing/compression piston. the connecting rod screws into the piston. once you get it to the setting you like you loctite it into place.
Anyway 25,000 on a 4.5x4 out of it. would be perfect on a 10 ounce 100Sq plane.