Meanwhile, in the Netherlands:
Clubmate Rob and his dad inherited an old long time unused OS FS40 (one of OS' first fourstrokes smaller than .60, so really an oldie, according to OS' timeline introduced in '81).
They also picked up an old unused Robbe Charter for free, so basically for the cost of a set of bearings and the conversion (ignition, solenoid-stuff and telemetry stuff) they had this very nice summer-evening-flyer.
From first start on gas to adjusted curve took them about 20 minutes of runtime.
Prop is an APC 11 x 6, initially engine peaked at 8100 RPM and was tuned down rich by about 300~400 RPM, so 7700~7800 on the ground.
After about 30 minutes of flying and groundrunning and general messing about, the engine all by itself gained allready 200 RPM and was hitting 8K on the ground despite its rich pre-flight setting.
Absolutely not bad for this old girl, and plenty power for the 60" winspan, 4.6 lbs trainer.... Yup, that is right, This plane, despite the "complicated and heavy conversion" weighs exactly what my own Charter back in 1982 weighed with a .25 glow engine in the nose...