Month in the Patent Office

Means for reducing the head resistance of air‐cooled engines and like obstructions on aircraft comprise moving, approximately peripherally of the radial airflow,one or more elemental aerofoils or riders, each of which is of aerofoil shape in longitudinal cross‐section and is preferably of arcuate or approximately arcuate shape in end view. As shown, two or more riders 5 are mounted on rotatable arms 6. The riders are caused to autorotate by off‐setting a portion 7 as shown, or they may be positively driven by the airscrew. Riders may be arranged to sweep out radially displaced surfaces and they may be connected together by rings. In a modification, a cowl is provided with louvres to cause it to auto‐rotate and with other louvres to give an inward blower effect. According to the Provisional Specification, the arms carrying the riders may be hinged and the propeller may be provided with bearings on its blades to carry the riders. Specifications 331,283, [Class 4], and 377,178 are referred to.