Windspoon-R aircraft propeller offering

The Windspoon-R is a reinforced three-blade ground-adjustable aircraft propeller made by DUC Helices of France for piston engines in light aircraft, ultralights and Light Sport Aircraft class airframes. It is the reinforced variant of the Windspoon propeller family, intended for engines with higher power, and it converts shaft power from a reduced-drive engine into thrust in tractor or pusher configurations.

The reinforced structure raises the engine power the propeller accepts. The three-blade Windspoon-R is rated for a maximum engine power of 140 hp and a maximum rotational speed of 2700 rpm, against 120 hp for the standard three-blade version and 100 hp for the two-blade version. The diameter is 1727 mm (68 inches), and other diameters are available on request. The three-blade Windspoon-R weighs 4.21 kg (9.39 lb), and its moment of inertia is 3911 kg.cm2, a figure that engine and gearbox designers need when checking torsional behavior of the drive line.

The hub is made of forged carbon, formed from layers of unidirectional carbon fiber epoxy prepreg, and is built as two half-hubs that clamp the blades. The maker's comparison tests give carbon half-hub weights of roughly half those of aluminum half-hubs, around 270 g each. The glass transition temperature of the hub material was measured at about 104 to 107 degrees C, which is relevant when the propeller sits close to a hot engine or exhaust.

For installation, the blades are set in the hub with six M8 screws and nuts, and the assembled propeller is bolted to the propeller shaft, or to an aluminum adaptor spacer, with six long M8 screws. The final tightening torque is 25 Nm, and the screws are tightened again after one hour of operation. The blade pitch is adjustable on the ground with the maker's adjusting tool, so the pitch is set for the engine and airframe. Spinners with 210 mm and 250 mm diameters are offered, including versions for added engine cooling, and the manual states that the aircraft must not fly without a spinner. Engines above 65 hp need three indexing pins of 10 mm on the shaft or adaptor.

The manual lists the three-blade Windspoon-R for the Rotax 912S at a blade angle of 12 degrees and for the Rotax 914 at 14 degrees, in 3-axis tractor and pusher layouts and in pendular pusher layouts, each with a time between overhaul of 800 hours. Right-hand and left-hand versions are sold, and other engine applications are studied by the maker on request.

Regarding standards, the maker declares conformity of the Windspoon propeller with ASTM F2506 for Light Sport Aircraft propellers, after strength testing of the blade root and retention at twice the centrifugal load, endurance testing and teardown inspection. DUC Helices operates an ISO 9001 certified quality system.