Folding propellers aircraft propeller offering

The Mejzlik folding propeller range is a set of two-bladed carbon fibre folding propellers for unmanned aircraft, made by Mejzlik Propellers in the Czech Republic. They are electric-propulsion propellers whose blades fold back when the motor is stopped, and they are listed as off-the-shelf parts in the maker's carbon fibre propeller price list.

Folding blades reduce drag on aircraft that glide with the motor off, such as fixed-wing UAVs, and on VTOL configurations where lift motors are idle in cruise. The blades also reduce the risk of damage on landing and make transport easier. Mejzlik describes a hub fastened to the motor on both sides, reinforced blade supports and high-safety-factor screws, with propellers delivered assembled and balanced.

The price list gives the range as diameter x pitch in inches. Sizes run from 14x4.5 and 16x5.5 through 18x6, 20x6.7 and 22x7.4 up to 28x9.4. Each size comes in counterclockwise (CCW) and clockwise (CW) rotation, and in puller and pusher variants, so an integrator can choose the correct type for front-mounted, rear-mounted or counter-rotating motors. A prepreg version of the 22x7.4 propeller is also listed. Availability is shown per part number as off-the-shelf (OTS) or on demand; the 18x6, 20x6.7, 22x7.4 and 28x9.4 sizes are marked OTS.

For integration, the propeller must be matched to the motor shaft or mount, the thrust level, and the rotation direction of each motor. Mejzlik also produces propellers in custom shapes and sizes, including folding designs, on request. Because the list gives each propeller by diameter and pitch, the integrator can compare sizes directly against the thrust and shaft speed of the chosen motor, and the same part families are offered in fixed-blade form for installations that do not need folding.

Typical applications are fixed-wing UAVs with a pusher or tractor electric motor, motor-gliders, and VTOL aircraft where cruise propellers or lift propellers must fold to cut drag in other flight phases.