The manual for the Haban sickle mower states the cutting speed should be 1050-1200 strokes per minute. I measured the crankshaft driving the sickle at about 850 RPM.  Are strokes per minute considered out and back, or just one direction? If just one direction the speed would be about 1700 strokes per minute. If out and back then 850. This was measured in the shop with full batteries and no load conditions using a digital tachometer.