Mount whole fuselage or motor with pipe, cowling and RPM and thermometers to the right side of a car or on top of a truck.

This simple method was used before onboard dataloggers were available to get accurate RPM / speed mapping with different pipe lenghts, propellers, fuels, head caskets etc. I have not used but as Dick wrote when .61 two strokes were THE F3A engines in 80s some serious pilots did.

I have located the bearing point on "Pendel" elevator and did some experiments with rudder amplifier tab.