HQProp Ltd D2x1.9x4 Cinewhoop Propeller

The HQProp D2x1.9x4 is a four-blade polycarbonate propeller for ducted cinewhoop micro drones with 1.5 mm motor shafts. The designation gives diameter, pitch and blade count: 2 in, 1.9 in, four blades. Cinewhoops are small camera drones with guard rings around the propellers, meant to fly close to obstacles and people.

The diameter is given as 51 mm. The 1.9 in pitch is flat and delivers thrust at low current draw; four blades supply at 2 in the thrust that the small diameter alone does not give, and cost efficiency. The weight is 0.6 g and the bore 1.5 mm; the hub measures 5.5 mm across and 5 mm in thickness. The propeller does not fold.

A guard ring does not make an aircraft a class: take-off mass and the manufacturer's marking remain decisive. In subcategory A1 only an aircraft of class C0 or C1 may fly over uninvolved people, and never over crowds. If the aircraft carries a camera and is not a toy, the operator must register even below 250 g.

On selection: the propeller fits only motors with a 1.5 mm shaft. Inside the guard ring the clearance between blade tips and inner wall is small; bent blades rub on the wall and brake the motor. At 0.6 g the smallest deformation is enough to cause vibration. A build needs four propellers, two per direction of rotation, and they are replaced as a set before they are visibly damaged.