T-MOTOR MF3016 Polymer Folding Propeller

The T-MOTOR MF3016 is a folding two-blade propeller made of polymer with carbon fibre in the 30 in class for heavy-lift multicopters and agricultural drones from T-MOTOR (China). It measures 30.4 in in diameter with a 10.9 in pitch; 775.8 is given as the figure in millimetres for the diameter.

The 10.9 in pitch is a little over a third of the diameter: flat, laid out for hovering with a large load at low rotational speed. T-MOTOR states the weight per single blade, 184 g; to compare it with complete propellers it is multiplied by the number of blades and the hub added. The maximum thrust is 16 kg. The speed of 4,000 rpm is the recommended maximum speed at 16 kg of thrust. As a working range the manufacturer recommends 4 to 8 kg of thrust per rotor at 2,000 to 2,800 rpm. The blades fold for transport and are opened by centrifugal force in operation.

For agricultural drones, plant protection law applies alongside aviation law: spraying plant protection products from the air is in principle prohibited in the EU and possible only under an exemption from the authority. In aviation terms the open category ends at 25 kg take-off mass including payload; aircraft with propellers of this size often exceed it, and then the specific category applies, with a risk assessment of the operation.

On a folding propeller the hinge and blade seat are the wear points: they must be clean and free of play, and both blades must open evenly. On agricultural drones residues of spray agents and moisture add to that and attack hinges and surfaces; after use the propeller is inspected. Polymer with carbon fibre breaks forgivingly, but nicks at the tip and leading edge cause clear imbalance at 30 in; propellers are replaced in pairs.