Mejzlik Propellers s.r.o. 16x5.5 3B MC

The Mejzlik 16x5.5 3B MC is a three-blade composite propeller from Mejzlik Propellers s.r.o. (Czech Republic) for compact multicopters with high thrust. The designation gives diameter and pitch, 16 in and 5.5 in, and the blade count as 3B. It is made by wet layup.

The 5.5 in pitch is a little over a third of the diameter: flat, laid out for hovering and static thrust. Three blades raise thrust at 16 in, where space on the frame is limited, and cost efficiency. The weight is 29 g with a tolerance of 10 per cent, and the propeller does not fold. The maximum speed of 11,200 rpm is, according to the datasheet, the hover limit (Limit hover RPM) and is bounded by blade-tip speed; in forward flight this limit drops. The maximum thrust of 11.4 kgf comes from a simulation by the manufacturer, not from a test-stand measurement.

Both values hold only together with a given motor, voltage and operating state and are comparable only within one manufacturer. Legally the aircraft counts: compact multicopters with 16 in propellers fall, depending on take-off mass, into class C2 (under 4 kg) or C3 (under 25 kg). Classes C1 to C3 require direct remote ID, and from 250 g the operator must register.

On selection: the composite is stiff and light but less forgiving in a crash than plastic; edges, blade root and hub are checked for delamination, visible as frayed edges and dull-sounding areas. Clockwise and counter-clockwise versions must sit in pairs on the motors. The speed limit is an upper bound, not an operating point.