Abstract: A percussion drilling assembly includes a housing and a drill bit within a lower end of the housing. At least one of a piston or an anvil is within the housing above the drill bit. The drilling assembly also includes at least one sensor in at least one of the housing, the piston, or the anvil. A method of drilling includes drilling a formation with a percussion drilling assembly, the percussion drilling assembly having at least one sensor located in a component thereof. The at least one sensor may measure at least one property of the percussion drilling assembly while drilling. The measurements taken by the at least one sensor may be analyzed and a new percussion drilling assembly designed based on the analysis.

Abstract: A roller cone drill bit having a bit body. The bit body has a journal bearing coupled to an end portion thereof. A roller cone is coupled to the journal bearing. A first cutting element is coupled to the roller cone. A ratio of a radius of curvature of a crest portion of the first cutting element to a diameter of the first cutting element is between about 0.3:1 and about 0.8:1. A second cutting element is coupled to the roller cone. A ratio of a radius of curvature of a crest portion of the second cutting element to a diameter of the second cutting element is between about 0.05:1 and about 0.3:1. A height of the second cutting element is greater than the height of the first cutting element h between about 0.1 mm and about 6 mm.