KDE Direct CF185-DP Dual-Edition Propeller Blades 18.5x6.3

The KDE-CF185-DP Dual-Edition propeller blades from KDE Direct (USA) are two-blade propeller blades made of 3K carbon fibre, 18.5 in in diameter and 6.3 in in pitch, dynamically balanced and built for the two-blade adapter system of KDE Direct on professional multicopters of the mid-sized class. 3K denotes a weave with 3,000 filaments per fibre tow.

The blades are supplied singly and sit in the KDE adapter KDE-DPA-ML-M4, two blades per direction-of-rotation set. The weight is given per blade at 18.8 g; to compare it with a complete propeller it is multiplied by the number of blades, with hub and adapter added. The installed diameter with adapter is 469.9 mm according to the dimensional drawing, and the blade bore is 5.5 mm with a continuous sleeve. Older production uses M3 screws, the current one M4. The performance curve has a thrust coefficient Ct of 0.0705 and a power coefficient Cp of 0.02028, measured at 3,500 ft altitude. Both are dimensionless; with air density, rotational speed and diameter they can be used to calculate thrust and power for other conditions.

In the KDE motor datasheets the highest measured thrust with this propeller is 8,079 g, measured on the KDE5215XF-330 motor at 33.6 V with two blades. That is the measured value of this one combination, not a limit of the propeller. Legally everything depends on the aircraft: up to 25 kg take-off mass operation stays in the open category, commercial use included, with class C3 marking and direct remote ID; above that the specific category begins.

On selection: the propeller fits only the KDE adapter system, and the screw size M3 or M4 must match the adapter. With carbon, edge damage, frayed trailing edges and dull-sounding areas point to delamination and are a reason to replace. Because the blades are balanced at the factory as a set, they are replaced together and not mixed singly from different sets.