See Irwin.

This is a small size four cylinder X-engine.

“Meteormotor drawing”

From Appendix 6: We found a photo of the engine from the drawing, held by a nice young lady, which in turn shows the lightness of the engine. (Sixty-four pounds, complete with carburetor and magneto).

"Here you can see more details of this 2-stroke engine" (PiP = pm)