HI Guys,
The OS 10 is probably *30* years old, but I haven't had a GH .09. I, too, just like those old engines. Especially in an OTS plane like the Wee Duper Zilch.
The little OS 10 looks just exactly like a early '70s OS 35S (that was put in the dryer on high heat! LOL!!) and runs just like it, but it isn't close to the power of the OS 10 FP, etc..
Bill <><